| Flutter Impeller |

Classes | Public Types | Public Member Functions | Static Public Attributes | List of all members
impeller::Canvas Class Reference

`#include <canvas.h>`

## Classes
struct | SaveLayerState

## Public Types
using | BackdropFilterProc = std::function< std::shared_ptr< FilterContents >(FilterInput::Ref, const Matrix &effect_transform, Entity::RenderingMode rendering_mode)>

## Public Member Functions
| Canvas (ContentContext &renderer, const RenderTarget &render_target, bool is_onscreen, bool requires_readback)
| Canvas (ContentContext &renderer, const RenderTarget &render_target, bool is_onscreen, bool requires_readback, Rect cull_rect)
| Canvas (ContentContext &renderer, const RenderTarget &render_target, bool is_onscreen, bool requires_readback, IRect cull_rect)
| ~Canvas ()=default
void | SetBackdropData (std::unordered_map< int64_t, BackdropData > backdrop_data, size_t backdrop_count)
| Update the backdrop data used to group together backdrop filters within the same layer. More...
std::optional< Rect > | GetLocalCoverageLimit () const
| Return the culling bounds of the current render target, or nullopt if there is no coverage. More...
void | Save (uint32_t total_content_depth=kMaxDepth)
void | SaveLayer (const Paint &paint, std::optional< Rect > bounds=std::nullopt, const flutter::DlImageFilter *backdrop_filter=nullptr, ContentBoundsPromise bounds_promise=ContentBoundsPromise::kUnknown, uint32_t total_content_depth=kMaxDepth, bool can_distribute_opacity=false, std::optional< int64_t > backdrop_id=std::nullopt)
bool | Restore ()
size_t | GetSaveCount () const
void | RestoreToCount (size_t count)
const Matrix & | GetCurrentTransform () const
void | ResetTransform ()
void | Transform (const Matrix &transform)
void | Concat (const Matrix &transform)
void | PreConcat (const Matrix &transform)
void | Translate (const Vector3 &offset)
void | Scale (const Vector2 &scale)
void | Scale (const Vector3 &scale)
void | Skew (Scalar sx, Scalar sy)
void | Rotate (Radians radians)
void | DrawPath (const flutter::DlPath &path, const Paint &paint)
void | DrawPaint (const Paint &paint)
void | DrawLine (const Point &p0, const Point &p1, const Paint &paint, bool reuse_depth=false)
void | DrawDashedLine (const Point &p0, const Point &p1, Scalar on_length, Scalar off_length, const Paint &paint)
void | DrawRect (const Rect &rect, const Paint &paint)
void | DrawOval (const Rect &rect, const Paint &paint)
void | DrawArc (const Arc &arc, const Paint &paint)
void | DrawRoundRect (const RoundRect &rect, const Paint &paint)
void | DrawDiffRoundRect (const RoundRect &outer, const RoundRect &inner, const Paint &paint)
void | DrawRoundSuperellipse (const RoundSuperellipse &rse, const Paint &paint)
void | DrawCircle (const Point &center, Scalar radius, const Paint &paint)
void | DrawPoints (const Point points[], uint32_t count, Scalar radius, const Paint &paint, PointStyle point_style)
void | DrawImage (const std::shared_ptr< Texture > &image, Point offset, const Paint &paint, const SamplerDescriptor &sampler={})
void | DrawImageRect (const std::shared_ptr< Texture > &image, Rect source, Rect dest, const Paint &paint, const SamplerDescriptor &sampler={}, SourceRectConstraint src_rect_constraint=SourceRectConstraint::kFast)
void | DrawTextFrame (const std::shared_ptr< TextFrame > &text_frame, Point position, const Paint &paint)
void | DrawVertices (const std::shared_ptr< VerticesGeometry > &vertices, BlendMode blend_mode, const Paint &paint)
void | DrawAtlas (const std::shared_ptr< AtlasContents > &atlas_contents, const Paint &paint)
void | ClipGeometry (const Geometry &geometry, Entity::ClipOperation clip_op, bool is_aa=true)
void | EndReplay ()
uint64_t | GetOpDepth () const
uint64_t | GetMaxOpDepth () const
bool | RequiresReadback () const
bool | SupportsBlitToOnscreen () const
bool | EnsureFinalMipmapGeneration () const

## Static Public Attributes
static constexpr uint32_t | kMaxDepth = 1 << 24

## Detailed Description

Definition at line 120 of file canvas.h.

## Member Typedef Documentation

## ◆ BackdropFilterProc

using impeller::Canvas::BackdropFilterProc = std::function<std::shared_ptr<FilterContents>( FilterInput::Ref, const Matrix& effect_transform, Entity::RenderingMode rendering_mode)>

Definition at line 124 of file canvas.h.

## Constructor & Destructor Documentation

## ◆ Canvas() [1/3]

impeller::Canvas::Canvas | ( | ContentContext & | renderer,
|  | const RenderTarget & | render_target,
|  | bool | is_onscreen,
|  | bool | requires_readback
| ) |  |

Definition at line 197 of file canvas.cc.

201 : renderer_(renderer),
202 render_target_(render_target),
203 is_onscreen_(is_onscreen),
204 requires_readback_(requires_readback),
205 clip_coverage_stack_(EntityPassClipStack(
206 Rect::MakeSize(render_target.GetRenderTargetSize()))) {
207 Initialize(std::nullopt);
208 SetupRenderPass();
209 }
impeller::TRect< Scalar >::MakeSize
constexpr static TRect MakeSize(const TSize< U > &size)
Definition: rect.h:150

## ◆ Canvas() [2/3]

impeller::Canvas::Canvas | ( | ContentContext & | renderer,
|  | const RenderTarget & | render_target,
|  | bool | is_onscreen,
|  | bool | requires_readback,
|  | Rect | cull_rect
| ) |  |
| explicit

Definition at line 211 of file canvas.cc.

216 : renderer_(renderer),
217 render_target_(render_target),
218 is_onscreen_(is_onscreen),
219 requires_readback_(requires_readback),
220 clip_coverage_stack_(EntityPassClipStack(
221 Rect::MakeSize(render_target.GetRenderTargetSize()))) {
222 Initialize(cull_rect);
223 SetupRenderPass();
224 }

## ◆ Canvas() [3/3]

impeller::Canvas::Canvas | ( | ContentContext & | renderer,
|  | const RenderTarget & | render_target,
|  | bool | is_onscreen,
|  | bool | requires_readback,
|  | IRect | cull_rect
| ) |  |
| explicit

Definition at line 226 of file canvas.cc.

231 : renderer_(renderer),
232 render_target_(render_target),
233 is_onscreen_(is_onscreen),
234 requires_readback_(requires_readback),
235 clip_coverage_stack_(EntityPassClipStack(
236 Rect::MakeSize(render_target.GetRenderTargetSize()))) {
237 Initialize(Rect::MakeLTRB(cull_rect.GetLeft(), cull_rect.GetTop(),
238 cull_rect.GetRight(), cull_rect.GetBottom()));
239 SetupRenderPass();
240 }
impeller::TRect< Scalar >::MakeLTRB
constexpr static TRect MakeLTRB(Type left, Type top, Type right, Type bottom)
Definition: rect.h:129

References impeller::TRect< T >::GetBottom(), impeller::TRect< T >::GetLeft(), impeller::TRect< T >::GetRight(), impeller::TRect< T >::GetTop(), and impeller::TRect< Scalar >::MakeLTRB().

## ◆ ~Canvas()

impeller::Canvas::~Canvas | ( |  | ) |
| default

## Member Function Documentation

## ◆ ClipGeometry()

void impeller::Canvas::ClipGeometry | ( | const Geometry & | geometry,
|  | Entity::ClipOperation | clip_op,
|  | bool | is_aa = `true`
| ) |  |

Definition at line 826 of file canvas.cc.

828 {
829 if (IsSkipping()) {
830 return;
831 }
832
833 // Ideally the clip depth would be greater than the current rendering
834 // depth because any rendering calls that follow this clip operation will
835 // pre-increment the depth and then be rendering above our clip depth,
836 // but that case will be caught by the CHECK in AddRenderEntity above.
837 // In practice we sometimes have a clip set with no rendering after it
838 // and in such cases the current depth will equal the clip depth.
839 // Eventually the DisplayList should optimize these out, but it is hard
840 // to know if a clip will actually be used in advance of storing it in
841 // the DisplayList buffer.
842 // See https://github.com/flutter/flutter/issues/147021
843 FML_DCHECK(current_depth_ <= transform_stack_.back().clip_depth)
844 << current_depth_ << " <=? " << transform_stack_.back().clip_depth;
845 uint32_t clip_depth = transform_stack_.back().clip_depth;
846
847 const Matrix clip_transform =
848 Matrix::MakeTranslation(Vector3(-GetGlobalPassPosition())) *
849 GetCurrentTransform();
850
851 std::optional<Rect> clip_coverage = geometry.GetCoverage(clip_transform);
852 if (!clip_coverage.has_value()) {
853 return;
854 }
855
856 ClipContents clip_contents(
857 clip_coverage.value(),
858 /*is_axis_aligned_rect=*/geometry.IsAxisAlignedRect() &&
859 GetCurrentTransform().IsTranslationScaleOnly());
860 clip_contents.SetClipOperation(clip_op);
861
862 EntityPassClipStack::ClipStateResult clip_state_result =
863 clip_coverage_stack_.RecordClip(
864 clip_contents, //
865 /*transform=*/clip_transform, //
866 /*global_pass_position=*/GetGlobalPassPosition(), //
867 /*clip_depth=*/clip_depth, //
868 /*clip_height_floor=*/GetClipHeightFloor(), //
869 /*is_aa=*/is_aa);
870
871 if (clip_state_result.clip_did_change) {
872 // We only need to update the pass scissor if the clip state has changed.
873 SetClipScissor(clip_coverage_stack_.CurrentClipCoverage(),
874 *render_passes_.back().inline_pass_context->GetRenderPass(),
875 GetGlobalPassPosition());
876 }
877
878 ++transform_stack_.back().clip_height;
879 ++transform_stack_.back().num_clips;
880
881 if (!clip_state_result.should_render) {
882 return;
883 }
884
885 // Note: this is a bit of a hack. Its not possible to construct a geometry
886 // result without begninning the render pass. We should refactor the geometry
887 // objects so that they only need a reference to the render pass size and/or
888 // orthographic transform.
889 Entity entity;
890 entity.SetTransform(clip_transform);
891 entity.SetClipDepth(clip_depth);
892
893 GeometryResult geometry_result = geometry.GetPositionBuffer(
894 renderer_, //
895 entity, //
896 *render_passes_.back().inline_pass_context->GetRenderPass() //
897 );
898 clip_contents.SetGeometry(geometry_result);
899 clip_coverage_stack_.GetLastReplayResult().clip_contents.SetGeometry(
900 geometry_result);
901
902 clip_contents.Render(
903 renderer_, *render_passes_.back().inline_pass_context->GetRenderPass(),
904 clip_depth);
905 }
impeller::Canvas::GetCurrentTransform
const Matrix & GetCurrentTransform() const
Definition: canvas.cc:271
impeller::ClipContents::SetGeometry
void SetGeometry(GeometryResult geometry)
Set the pre-tessellated clip geometry.
Definition: clip_contents.cc:37
impeller::EntityPassClipStack::CurrentClipCoverage
std::optional< Rect > CurrentClipCoverage() const
Definition: entity_pass_clip_stack.cc:24
impeller::EntityPassClipStack::GetLastReplayResult
ReplayResult & GetLastReplayResult()
Definition: entity_pass_clip_stack.h:61
impeller::EntityPassClipStack::RecordClip
ClipStateResult RecordClip(const ClipContents &clip_contents, Matrix transform, Point global_pass_position, uint32_t clip_depth, size_t clip_height_floor, bool is_aa)
Definition: entity_pass_clip_stack.cc:100
impeller::EntityPassClipStack::ReplayResult::clip_contents
ClipContents clip_contents
Definition: entity_pass_clip_stack.h:26
impeller::Matrix::MakeTranslation
static constexpr Matrix MakeTranslation(const Vector3 &t)
Definition: matrix.h:95

References impeller::EntityPassClipStack::ReplayResult::clip_contents, impeller::EntityPassClipStack::ClipStateResult::clip_did_change, impeller::EntityPassClipStack::CurrentClipCoverage(), impeller::Geometry::GetCoverage(), GetCurrentTransform(), impeller::EntityPassClipStack::GetLastReplayResult(), impeller::Geometry::GetPositionBuffer(), impeller::Geometry::IsAxisAlignedRect(), impeller::Matrix::MakeTranslation(), impeller::EntityPassClipStack::RecordClip(), impeller::ClipContents::Render(), impeller::Entity::SetClipDepth(), impeller::ClipContents::SetClipOperation(), impeller::ClipContents::SetGeometry(), impeller::Entity::SetTransform(), and impeller::EntityPassClipStack::ClipStateResult::should_render.

Referenced by impeller::DlDispatcherBase::clipOval(), impeller::DlDispatcherBase::clipPath(), impeller::DlDispatcherBase::clipRect(), impeller::DlDispatcherBase::clipRoundRect(), and impeller::DlDispatcherBase::clipRoundSuperellipse().

## ◆ Concat()

void impeller::Canvas::Concat | ( | const Matrix & | transform | ) |

Definition at line 255 of file canvas.cc.

255 {
256 transform_stack_.back().transform = GetCurrentTransform() * transform;
257 }
transform
Matrix transform
Definition: gaussian_blur_filter_contents.cc:214

References GetCurrentTransform(), and transform.

Referenced by DrawTextFrame(), Rotate(), Scale(), Skew(), Transform(), and Translate().

## ◆ DrawArc()

void impeller::Canvas::DrawArc | ( | const Arc & | arc,
|  | const Paint & | paint
| ) |  |

Definition at line 678 of file canvas.cc.

678 {
679 Entity entity;
680 entity.SetTransform(GetCurrentTransform());
681 entity.SetBlendMode(paint.blend_mode);
682
683 if (paint.style == Paint::Style::kFill) {
684 ArcGeometry geom(arc);
685 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
686 return;
687 }
688
689 const Rect& oval_bounds = arc.GetOvalBounds();
690 if (paint.stroke.width > oval_bounds.GetSize().MaxDimension()) {
691 // This is a special case for rendering arcs whose stroke width is so large
692 // you are effectively drawing a sector of a circle.
693 // https://github.com/flutter/flutter/issues/158567
694 Arc expanded_arc(oval_bounds.Expand(Size(paint.stroke.width * 0.5f)),
695 arc.GetStart(), arc.GetSweep(), true);
696
697 ArcGeometry geom(expanded_arc);
698 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
699 return;
700 }
701
702 // IncludeCenter incurs lots of extra work for stroking an arc, including:
703 // - It introduces segments to/from the center point (not too hard).
704 // - It introduces joins on those segments (a bit more complicated).
705 // - Even if the sweep is >=360 degrees, we still draw the segment to
706 // the center and it basically looks like a pie cut into the complete
707 // boundary circle, as if the slice were cut, but not extracted
708 // (hard to express as a continuous kTriangleStrip).
709 if (!arc.IncludeCenter()) {
710 if (arc.IsFullCircle()) {
711 return DrawOval(oval_bounds, paint);
712 }
713
714 // Our fast stroking code only works for circular bounds as it assumes
715 // that the inner and outer radii can be scaled along each angular step
716 // of the arc - which is not true for elliptical arcs where the inner
717 // and outer samples are perpendicular to the traveling direction of the
718 // elliptical curve which may not line up with the center of the bounds.
719 //
720 // TODO(flar): It also only supports Butt and Square caps for now.
721 // See https://github.com/flutter/flutter/issues/169400
722 if (oval_bounds.IsSquare() && paint.stroke.cap != Cap::kRound) {
723 ArcGeometry geom(arc, paint.stroke);
724 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
725 return;
726 }
727 }
728
729 ArcStrokeGeometry geom(arc, paint.stroke);
730 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
731 }
impeller::Canvas::DrawOval
void DrawOval(const Rect &rect, const Paint &paint)
Definition: canvas.cc:649
impeller::Rect
TRect< Scalar > Rect
Definition: rect.h:792
impeller::Cap::kRound
@ kRound
impeller::Size
TSize< Scalar > Size
Definition: size.h:159
impeller::Paint::Style::kFill
@ kFill

References impeller::Paint::blend_mode, impeller::StrokeParameters::cap, DrawOval(), impeller::TRect< T >::Expand(), GetCurrentTransform(), impeller::Arc::GetOvalBounds(), impeller::TRect< T >::GetSize(), impeller::Arc::GetStart(), impeller::Arc::GetSweep(), impeller::Arc::IncludeCenter(), impeller::Arc::IsFullCircle(), impeller::TRect< T >::IsSquare(), impeller::Paint::kFill, impeller::kRound, impeller::Entity::SetBlendMode(), impeller::Entity::SetTransform(), impeller::Paint::stroke, impeller::Paint::style, and impeller::StrokeParameters::width.

Referenced by impeller::DlDispatcherBase::drawArc().

## ◆ DrawAtlas()

void impeller::Canvas::DrawAtlas | ( | const std::shared_ptr< AtlasContents > & | atlas_contents,
|  | const Paint & | paint
| ) |  |

Definition at line 1117 of file canvas.cc.

1118 {
1119 atlas_contents->SetAlpha(paint.color.alpha);
1120
1121 Entity entity;
1122 entity.SetTransform(GetCurrentTransform());
1123 entity.SetBlendMode(paint.blend_mode);
1124 entity.SetContents(paint.WithFilters(atlas_contents));
1125
1126 AddRenderEntityToCurrentPass(entity);
1127 }

References impeller::Color::alpha, impeller::Paint::blend_mode, impeller::Paint::color, GetCurrentTransform(), impeller::Entity::SetBlendMode(), impeller::Entity::SetContents(), impeller::Entity::SetTransform(), and impeller::Paint::WithFilters().

Referenced by impeller::DlDispatcherBase::drawAtlas().

## ◆ DrawCircle()

void impeller::Canvas::DrawCircle | ( | const Point & | center,
|  | Scalar | radius,
|  | const Paint & | paint
| ) |  |

Definition at line 803 of file canvas.cc.

805 {
806 Size half_size(radius, radius);
807 if (AttemptDrawBlurredRRect(
808 Rect::MakeOriginSize(center - half_size, half_size * 2),
809 {radius, radius}, paint)) {
810 return;
811 }
812
813 Entity entity;
814 entity.SetTransform(GetCurrentTransform());
815 entity.SetBlendMode(paint.blend_mode);
816
817 if (paint.style == Paint::Style::kStroke) {
818 CircleGeometry geom(center, radius, paint.stroke.width);
819 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
820 } else {
821 CircleGeometry geom(center, radius);
822 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
823 }
824 }
impeller::Paint::Style::kStroke
@ kStroke
impeller::TRect< Scalar >::MakeOriginSize
constexpr static TRect MakeOriginSize(const TPoint< Type > &origin, const TSize< Type > &size)
Definition: rect.h:144

References impeller::Paint::blend_mode, GetCurrentTransform(), impeller::Paint::kStroke, impeller::TRect< Scalar >::MakeOriginSize(), impeller::Entity::SetBlendMode(), impeller::Entity::SetTransform(), impeller::Paint::stroke, impeller::Paint::style, and impeller::StrokeParameters::width.

Referenced by impeller::DlDispatcherBase::drawCircle(), and DrawOval().

## ◆ DrawDashedLine()

void impeller::Canvas::DrawDashedLine | ( | const Point & | p0,
|  | const Point & | p1,
|  | Scalar | on_length,
|  | Scalar | off_length,
|  | const Paint & | paint
| ) |  |

Definition at line 605 of file canvas.cc.

609 {
610 // Reasons to defer to regular DrawLine:
611 // - performance for degenerate and "regular line" cases
612 // - length is non-positive - DrawLine will draw appropriate "dot"
613 // - off_length is non-positive - no gaps, DrawLine will draw it solid
614 // - on_length is negative - invalid dashing
615 //
616 // Note that a 0 length "on" dash will draw "dot"s every "off" distance
617 // apart so we proceed with the dashing process in that case.
618 Scalar length = p0.GetDistance(p1);
619 if (length > 0.0f && on_length >= 0.0f && off_length > 0.0f) {
620 Entity entity;
621 entity.SetTransform(GetCurrentTransform());
622 entity.SetBlendMode(paint.blend_mode);
623
624 StrokeDashedLineGeometry geom(p0, p1, on_length, off_length, paint.stroke);
625 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
626 } else {
627 DrawLine(p0, p1, paint);
628 }
629 }
impeller::Canvas::DrawLine
void DrawLine(const Point &p0, const Point &p1, const Paint &paint, bool reuse_depth=false)
Definition: canvas.cc:583
impeller::Scalar
float Scalar
Definition: scalar.h:19

References impeller::Paint::blend_mode, DrawLine(), GetCurrentTransform(), impeller::TPoint< T >::GetDistance(), impeller::Entity::SetBlendMode(), impeller::Entity::SetTransform(), and impeller::Paint::stroke.

Referenced by impeller::DlDispatcherBase::drawDashedLine().

## ◆ DrawDiffRoundRect()

void impeller::Canvas::DrawDiffRoundRect | ( | const RoundRect & | outer,
|  | const RoundRect & | inner,
|  | const Paint & | paint
| ) |  |

Definition at line 765 of file canvas.cc.

767 {
768 Entity entity;
769 entity.SetTransform(GetCurrentTransform());
770 entity.SetBlendMode(paint.blend_mode);
771
772 if (paint.style == Paint::Style::kFill) {
773 FillDiffRoundRectGeometry geom(outer, inner);
774 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
775 } else {
776 StrokeDiffRoundRectGeometry geom(outer, inner, paint.stroke);
777 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
778 }
779 }

References impeller::Paint::blend_mode, GetCurrentTransform(), impeller::Paint::kFill, impeller::Entity::SetBlendMode(), impeller::Entity::SetTransform(), impeller::Paint::stroke, and impeller::Paint::style.

Referenced by impeller::DlDispatcherBase::drawDiffRoundRect().

## ◆ DrawImage()

void impeller::Canvas::DrawImage | ( | const std::shared_ptr< Texture > & | image,
|  | Point | offset,
|  | const Paint & | paint,
|  | const SamplerDescriptor & | sampler = `{}`
| ) |  |

Definition at line 925 of file canvas.cc.

928 {
929 if (!image) {
930 return;
931 }
932
933 const Rect source = Rect::MakeSize(image->GetSize());
934 const Rect dest = source.Shift(offset);
935
936 DrawImageRect(image, source, dest, paint, sampler);
937 }
impeller::Canvas::DrawImageRect
void DrawImageRect(const std::shared_ptr< Texture > &image, Rect source, Rect dest, const Paint &paint, const SamplerDescriptor &sampler={}, SourceRectConstraint src_rect_constraint=SourceRectConstraint::kFast)
Definition: canvas.cc:939
impeller::TRect::Shift
constexpr TRect< T > Shift(T dx, T dy) const
Returns a new rectangle translated by the given offset.
Definition: rect.h:606

References DrawImageRect(), impeller::TRect< Scalar >::MakeSize(), and impeller::TRect< T >::Shift().

## ◆ DrawImageRect()

void impeller::Canvas::DrawImageRect | ( | const std::shared_ptr< Texture > & | image,
|  | Rect | source,
|  | Rect | dest,
|  | const Paint & | paint,
|  | const SamplerDescriptor & | sampler = `{}`,
|  | SourceRectConstraint | src_rect_constraint = `SourceRectConstraint::kFast`
| ) |  |

Definition at line 939 of file canvas.cc.

944 {
945 if (!image || source.IsEmpty() || dest.IsEmpty()) {
946 return;
947 }
948
949 ISize size = image->GetSize();
950 if (size.IsEmpty()) {
951 return;
952 }
953
954 std::optional<Rect> clipped_source =
955 source.Intersection(Rect::MakeSize(size));
956 if (!clipped_source) {
957 return;
958 }
959
960 if (AttemptColorFilterOptimization(image, source, dest, paint, sampler,
961 src_rect_constraint)) {
962 return;
963 }
964
965 if (*clipped_source != source) {
966 Scalar sx = dest.GetWidth() / source.GetWidth();
967 Scalar sy = dest.GetHeight() / source.GetHeight();
968 Scalar tx = dest.GetLeft() - source.GetLeft() * sx;
969 Scalar ty = dest.GetTop() - source.GetTop() * sy;
970 Matrix src_to_dest = Matrix::MakeTranslateScale({sx, sy, 1}, {tx, ty, 0});
971 dest = clipped_source->TransformBounds(src_to_dest);
972 }
973
974 auto texture_contents = TextureContents::MakeRect(dest);
975 texture_contents->SetTexture(image);
976 texture_contents->SetSourceRect(*clipped_source);
977 texture_contents->SetStrictSourceRect(src_rect_constraint ==
978 SourceRectConstraint::kStrict);
979 texture_contents->SetSamplerDescriptor(sampler);
980 texture_contents->SetOpacity(paint.color.alpha);
981 texture_contents->SetDeferApplyingOpacity(paint.HasColorFilter());
982
983 Entity entity;
984 entity.SetBlendMode(paint.blend_mode);
985 entity.SetTransform(GetCurrentTransform());
986
987 if (!paint.mask_blur_descriptor.has_value()) {
988 entity.SetContents(paint.WithFilters(std::move(texture_contents)));
989 AddRenderEntityToCurrentPass(entity);
990 return;
991 }
992
993 FillRectGeometry out_rect(Rect{});
994
995 entity.SetContents(paint.WithFilters(
996 paint.mask_blur_descriptor->CreateMaskBlur(texture_contents, &out_rect)));
997 AddRenderEntityToCurrentPass(entity);
998 }
impeller::TextureContents::MakeRect
static std::shared_ptr< TextureContents > MakeRect(Rect destination)
Definition: texture_contents.cc:28
impeller::SourceRectConstraint::kStrict
@ kStrict
Sample only within the source rectangle. May be slower.
impeller::ISize
ISize64 ISize
Definition: size.h:162
impeller::Matrix::MakeTranslateScale
static constexpr Matrix MakeTranslateScale(const Vector3 &s, const Vector3 &t)
Definition: matrix.h:113

References impeller::Color::alpha, impeller::Paint::blend_mode, impeller::Paint::color, GetCurrentTransform(), impeller::TRect< T >::GetHeight(), impeller::TRect< T >::GetLeft(), impeller::TRect< T >::GetTop(), impeller::TRect< T >::GetWidth(), impeller::Paint::HasColorFilter(), impeller::TRect< T >::Intersection(), impeller::TRect< T >::IsEmpty(), impeller::TSize< T >::IsEmpty(), impeller::kStrict, impeller::TextureContents::MakeRect(), impeller::TRect< Scalar >::MakeSize(), impeller::Matrix::MakeTranslateScale(), impeller::Paint::mask_blur_descriptor, impeller::Entity::SetBlendMode(), impeller::Entity::SetContents(), impeller::Entity::SetTransform(), impeller::TRect< T >::TransformBounds(), and impeller::Paint::WithFilters().

Referenced by DrawImage(), impeller::DlDispatcherBase::drawImageRect(), and impeller::NinePatchConverter::DrawNinePatch().

## ◆ DrawLine()

void impeller::Canvas::DrawLine | ( | const Point & | p0,
|  | const Point & | p1,
|  | const Paint & | paint,
|  | bool | reuse_depth = `false`
| ) |  |

Definition at line 583 of file canvas.cc.

586 {
587 Entity entity;
588 entity.SetTransform(GetCurrentTransform());
589 entity.SetBlendMode(paint.blend_mode);
590
591 auto geometry = std::make_unique<LineGeometry>(p0, p1, paint.stroke);
592
593 if (renderer_.GetContext()->GetFlags().antialiased_lines &&
594 !paint.color_filter && !paint.invert_colors && !paint.image_filter &&
595 !paint.mask_blur_descriptor.has_value() && !paint.color_source) {
596 auto contents = LineContents::Make(std::move(geometry), paint.color);
597 entity.SetContents(std::move(contents));
598 AddRenderEntityToCurrentPass(entity, reuse_depth);
599 } else {
600 AddRenderEntityWithFiltersToCurrentPass(entity, geometry.get(), paint,
601 /*reuse_depth=*/reuse_depth);
602 }
603 }
impeller::ContentContext::GetContext
std::shared_ptr< Context > GetContext() const
Definition: content_context.cc:939
impeller::LineContents::Make
static std::unique_ptr< LineContents > Make(std::unique_ptr< LineGeometry > geometry, Color color)
Definition: line_contents.cc:137

References impeller::Paint::blend_mode, impeller::Paint::color, impeller::Paint::color_filter, impeller::Paint::color_source, impeller::ContentContext::GetContext(), GetCurrentTransform(), impeller::Paint::image_filter, impeller::Paint::invert_colors, impeller::LineContents::Make(), impeller::Paint::mask_blur_descriptor, impeller::Entity::SetBlendMode(), impeller::Entity::SetContents(), impeller::Entity::SetTransform(), and impeller::Paint::stroke.

Referenced by DrawDashedLine(), impeller::DlDispatcherBase::drawLine(), impeller::DlDispatcherBase::drawPoints(), and impeller::DlDispatcherBase::SimplifyOrDrawPath().

## ◆ DrawOval()

void impeller::Canvas::DrawOval | ( | const Rect & | rect,
|  | const Paint & | paint
| ) |  |

Definition at line 649 of file canvas.cc.

649 {
650 // TODO(jonahwilliams): This additional condition avoids an assert in the
651 // stroke circle geometry generator. I need to verify the condition that this
652 // assert prevents.
653 if (rect.IsSquare() && (paint.style == Paint::Style::kFill ||
654 (paint.style == Paint::Style::kStroke &&
655 paint.stroke.width < rect.GetWidth()))) {
656 // Circles have slightly less overhead and can do stroking
657 DrawCircle(rect.GetCenter(), rect.GetWidth() * 0.5f, paint);
658 return;
659 }
660
661 if (AttemptDrawBlurredRRect(rect, rect.GetSize() * 0.5f, paint)) {
662 return;
663 }
664
665 Entity entity;
666 entity.SetTransform(GetCurrentTransform());
667 entity.SetBlendMode(paint.blend_mode);
668
669 if (paint.style == Paint::Style::kStroke) {
670 StrokeEllipseGeometry geom(rect, paint.stroke);
671 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
672 } else {
673 EllipseGeometry geom(rect);
674 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
675 }
676 }
impeller::Canvas::DrawCircle
void DrawCircle(const Point &center, Scalar radius, const Paint &paint)
Definition: canvas.cc:803

References impeller::Paint::blend_mode, DrawCircle(), impeller::TRect< T >::GetCenter(), GetCurrentTransform(), impeller::TRect< T >::GetSize(), impeller::TRect< T >::GetWidth(), impeller::TRect< T >::IsSquare(), impeller::Paint::kFill, impeller::Paint::kStroke, impeller::Entity::SetBlendMode(), impeller::Entity::SetTransform(), impeller::Paint::stroke, impeller::Paint::style, and impeller::StrokeParameters::width.

Referenced by DrawArc(), impeller::DlDispatcherBase::drawOval(), and impeller::DlDispatcherBase::SimplifyOrDrawPath().

## ◆ DrawPaint()

void impeller::Canvas::DrawPaint | ( | const Paint & | paint | ) |

Definition at line 340 of file canvas.cc.

340 {
341 Entity entity;
342 entity.SetTransform(GetCurrentTransform());
343 entity.SetBlendMode(paint.blend_mode);
344
345 CoverGeometry geom;
346 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
347 }

References impeller::Paint::blend_mode, GetCurrentTransform(), impeller::Entity::SetBlendMode(), and impeller::Entity::SetTransform().

Referenced by impeller::DlDispatcherBase::drawColor(), and impeller::DlDispatcherBase::drawPaint().

## ◆ DrawPath()

void impeller::Canvas::DrawPath | ( | const flutter::DlPath & | path,
|  | const Paint & | paint
| ) |  |

Definition at line 326 of file canvas.cc.

326 {
327 Entity entity;
328 entity.SetTransform(GetCurrentTransform());
329 entity.SetBlendMode(paint.blend_mode);
330
331 if (paint.style == Paint::Style::kFill) {
332 FillPathGeometry geom(path);
333 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
334 } else {
335 StrokePathGeometry geom(path, paint.stroke);
336 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
337 }
338 }

References impeller::Paint::blend_mode, GetCurrentTransform(), impeller::Paint::kFill, impeller::Entity::SetBlendMode(), impeller::Entity::SetTransform(), impeller::Paint::stroke, and impeller::Paint::style.

Referenced by DrawTextFrame(), and impeller::DlDispatcherBase::SimplifyOrDrawPath().

## ◆ DrawPoints()

void impeller::Canvas::DrawPoints | ( | const Point | points[],
|  | uint32_t | count,
|  | Scalar | radius,
|  | const Paint & | paint,
|  | PointStyle | point_style
| ) |  |

Definition at line 907 of file canvas.cc.

911 {
912 if (radius <= 0) {
913 return;
914 }
915
916 Entity entity;
917 entity.SetTransform(GetCurrentTransform());
918 entity.SetBlendMode(paint.blend_mode);
919
920 PointFieldGeometry geom(points, count, radius,
921 /*round=*/point_style == PointStyle::kRound);
922 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
923 }
impeller::PointStyle::kRound
@ kRound
Points are drawn as squares.
points
std::vector< Point > points
Definition: tessellator_libtess.cc:76

References impeller::Paint::blend_mode, GetCurrentTransform(), impeller::kRound, points, impeller::Entity::SetBlendMode(), and impeller::Entity::SetTransform().

Referenced by impeller::DlDispatcherBase::drawPoints().

## ◆ DrawRect()

void impeller::Canvas::DrawRect | ( | const Rect & | rect,
|  | const Paint & | paint
| ) |  |

Definition at line 631 of file canvas.cc.

631 {
632 if (AttemptDrawBlurredRRect(rect, {}, paint)) {
633 return;
634 }
635
636 Entity entity;
637 entity.SetTransform(GetCurrentTransform());
638 entity.SetBlendMode(paint.blend_mode);
639
640 if (paint.style == Paint::Style::kStroke) {
641 StrokeRectGeometry geom(rect, paint.stroke);
642 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
643 } else {
644 FillRectGeometry geom(rect);
645 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
646 }
647 }

References impeller::Paint::blend_mode, GetCurrentTransform(), impeller::Paint::kStroke, impeller::Entity::SetBlendMode(), impeller::Entity::SetTransform(), impeller::Paint::stroke, and impeller::Paint::style.

Referenced by impeller::DlDispatcherBase::drawRect(), and impeller::DlDispatcherBase::SimplifyOrDrawPath().

## ◆ DrawRoundRect()

void impeller::Canvas::DrawRoundRect | ( | const RoundRect & | rect,
|  | const Paint & | paint
| ) |  |

Definition at line 733 of file canvas.cc.

733 {
734 auto& rect = round_rect.GetBounds();
735 auto& radii = round_rect.GetRadii();
736 if (radii.AreAllCornersSame()) {
737 if (AttemptDrawBlurredRRect(rect, radii.top_left, paint)) {
738 return;
739 }
740
741 if (paint.style == Paint::Style::kFill) {
742 Entity entity;
743 entity.SetTransform(GetCurrentTransform());
744 entity.SetBlendMode(paint.blend_mode);
745
746 RoundRectGeometry geom(rect, radii.top_left);
747 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
748 return;
749 }
750 }
751
752 Entity entity;
753 entity.SetTransform(GetCurrentTransform());
754 entity.SetBlendMode(paint.blend_mode);
755
756 if (paint.style == Paint::Style::kFill) {
757 FillRoundRectGeometry geom(round_rect);
758 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
759 } else {
760 StrokeRoundRectGeometry geom(round_rect, paint.stroke);
761 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
762 }
763 }

References impeller::Paint::blend_mode, impeller::RoundRect::GetBounds(), GetCurrentTransform(), impeller::RoundRect::GetRadii(), impeller::Paint::kFill, impeller::Entity::SetBlendMode(), impeller::Entity::SetTransform(), impeller::Paint::stroke, and impeller::Paint::style.

Referenced by impeller::DlDispatcherBase::drawRoundRect(), and impeller::DlDispatcherBase::SimplifyOrDrawPath().

## ◆ DrawRoundSuperellipse()

void impeller::Canvas::DrawRoundSuperellipse | ( | const RoundSuperellipse & | rse,
|  | const Paint & | paint
| ) |  |

Definition at line 781 of file canvas.cc.

782 {
783 auto& rect = round_superellipse.GetBounds();
784 auto& radii = round_superellipse.GetRadii();
785 if (radii.AreAllCornersSame() &&
786 AttemptDrawBlurredRSuperellipse(rect, radii.top_left, paint)) {
787 return;
788 }
789
790 Entity entity;
791 entity.SetTransform(GetCurrentTransform());
792 entity.SetBlendMode(paint.blend_mode);
793
794 if (paint.style == Paint::Style::kFill) {
795 RoundSuperellipseGeometry geom(rect, radii);
796 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
797 } else {
798 StrokeRoundSuperellipseGeometry geom(round_superellipse, paint.stroke);
799 AddRenderEntityWithFiltersToCurrentPass(entity, &geom, paint);
800 }
801 }

References impeller::Paint::blend_mode, impeller::RoundSuperellipse::GetBounds(), GetCurrentTransform(), impeller::RoundSuperellipse::GetRadii(), impeller::Paint::kFill, impeller::Entity::SetBlendMode(), impeller::Entity::SetTransform(), impeller::Paint::stroke, and impeller::Paint::style.

Referenced by impeller::DlDispatcherBase::drawRoundSuperellipse(), and impeller::testing::TEST_P().

## ◆ DrawTextFrame()

void impeller::Canvas::DrawTextFrame | ( | const std::shared_ptr< TextFrame > & | text_frame,
|  | Point | position,
|  | const Paint & | paint
| ) |  |

Definition at line 1660 of file canvas.cc.

1662 {
1663 Scalar max_scale = GetCurrentTransform().GetMaxBasisLengthXY();
1664 if (max_scale * text_frame->GetFont().GetMetrics().point_size >
1665 kMaxTextScale) {
1666 fml::StatusOr<flutter::DlPath> path = text_frame->GetPath();
1667 if (path.ok()) {
1668 Save(1);
1669 Concat(Matrix::MakeTranslation(position));
1670 DrawPath(path.value(), paint);
1671 Restore();
1672 return;
1673 }
1674 }
1675
1676 Entity entity;
1677 entity.SetClipDepth(GetClipHeight());
1678 entity.SetBlendMode(paint.blend_mode);
1679
1680 auto text_contents = std::make_shared<TextContents>();
1681 text_contents->SetTextFrame(text_frame);
1682 text_contents->SetForceTextColor(paint.mask_blur_descriptor.has_value());
1683 text_contents->SetScale(max_scale);
1684 text_contents->SetColor(paint.color);
1685 text_contents->SetOffset(position);
1686 text_contents->SetTextProperties(paint.color,
1687 paint.style == Paint::Style::kStroke
1688 ? std::optional(paint.stroke)
1689 : std::nullopt);
1690
1691 entity.SetTransform(GetCurrentTransform() *
1692 Matrix::MakeTranslation(position));
1693
1694 if (AttemptBlurredTextOptimization(text_frame, text_contents, entity,
1695 paint)) {
1696 return;
1697 }
1698
1699 entity.SetContents(paint.WithFilters(std::move(text_contents)));
1700 AddRenderEntityToCurrentPass(entity, false);
1701 }
impeller::Canvas::Restore
bool Restore()
Definition: canvas.cc:1469
impeller::Canvas::Concat
void Concat(const Matrix &transform)
Definition: canvas.cc:255
impeller::Canvas::DrawPath
void DrawPath(const flutter::DlPath &path, const Paint &paint)
Definition: canvas.cc:326
impeller::Canvas::Save
void Save(uint32_t total_content_depth=kMaxDepth)
Definition: canvas.cc:1183
impeller::kMaxTextScale
static constexpr Scalar kMaxTextScale
Definition: canvas.cc:1658
impeller::Matrix::GetMaxBasisLengthXY
Scalar GetMaxBasisLengthXY() const
Definition: matrix.h:323

References impeller::Paint::blend_mode, impeller::Paint::color, Concat(), DrawPath(), GetCurrentTransform(), impeller::Matrix::GetMaxBasisLengthXY(), impeller::kMaxTextScale, impeller::Paint::kStroke, impeller::Matrix::MakeTranslation(), impeller::Paint::mask_blur_descriptor, Restore(), Save(), impeller::Entity::SetBlendMode(), impeller::Entity::SetClipDepth(), impeller::Entity::SetContents(), impeller::Entity::SetTransform(), impeller::Paint::stroke, impeller::Paint::style, and impeller::Paint::WithFilters().

Referenced by impeller::DlDispatcherBase::drawTextFrame().

## ◆ DrawVertices()

void impeller::Canvas::DrawVertices | ( | const std::shared_ptr< VerticesGeometry > & | vertices,
|  | BlendMode | blend_mode,
|  | const Paint & | paint
| ) |  |

Definition at line 1004 of file canvas.cc.

1006 {
1007 // Override the blend mode with kDestination in order to match the behavior
1008 // of Skia's SK_LEGACY_IGNORE_DRAW_VERTICES_BLEND_WITH_NO_SHADER flag, which
1009 // is enabled when the Flutter engine builds Skia.
1010 if (!paint.color_source) {
1011 blend_mode = BlendMode::kDst;
1012 }
1013
1014 Entity entity;
1015 entity.SetTransform(GetCurrentTransform());
1016 entity.SetBlendMode(paint.blend_mode);
1017
1018 // If there are no vertex colors.
1019 if (UseColorSourceContents(vertices, paint)) {
1020 AddRenderEntityWithFiltersToCurrentPass(entity, vertices.get(), paint);
1021 return;
1022 }
1023
1024 // If the blend mode is destination don't bother to bind or create a texture.
1025 if (blend_mode == BlendMode::kDst) {
1026 auto contents = std::make_shared<VerticesSimpleBlendContents>();
1027 contents->SetBlendMode(blend_mode);
1028 contents->SetAlpha(paint.color.alpha);
1029 contents->SetGeometry(vertices);
1030 entity.SetContents(paint.WithFilters(std::move(contents)));
1031 AddRenderEntityToCurrentPass(entity);
1032 return;
1033 }
1034
1035 // If there is a texture, use this directly. Otherwise render the color
1036 // source to a texture.
1037 if (paint.color_source &&
1038 paint.color_source->type() == flutter::DlColorSourceType::kImage) {
1039 const flutter::DlImageColorSource* image_color_source =
1040 paint.color_source->asImage();
1041 FML_DCHECK(image_color_source &&
1042 image_color_source->image()->impeller_texture());
1043 auto texture = image_color_source->image()->impeller_texture();
1044 auto x_tile_mode = static_cast<Entity::TileMode>(
1045 image_color_source->horizontal_tile_mode());
1046 auto y_tile_mode =
1047 static_cast<Entity::TileMode>(image_color_source->vertical_tile_mode());
1048 auto sampler_descriptor =
1049 skia_conversions::ToSamplerDescriptor(image_color_source->sampling());
1050 auto effect_transform = image_color_source->matrix();
1051
1052 auto contents = std::make_shared<VerticesSimpleBlendContents>();
1053 contents->SetBlendMode(blend_mode);
1054 contents->SetAlpha(paint.color.alpha);
1055 contents->SetGeometry(vertices);
1056 contents->SetEffectTransform(effect_transform);
1057 contents->SetTexture(texture);
1058 contents->SetTileMode(x_tile_mode, y_tile_mode);
1059 contents->SetSamplerDescriptor(sampler_descriptor);
1060
1061 entity.SetContents(paint.WithFilters(std::move(contents)));
1062 AddRenderEntityToCurrentPass(entity);
1063 return;
1064 }
1065
1066 auto src_paint = paint;
1067 src_paint.color = paint.color.WithAlpha(1.0);
1068
1069 std::shared_ptr<ColorSourceContents> src_contents =
1070 src_paint.CreateContents();
1071 src_contents->SetGeometry(vertices.get());
1072
1073 // If the color source has an intrinsic size, then we use that to
1074 // create the src contents as a simplification. Otherwise we use
1075 // the extent of the texture coordinates to determine how large
1076 // the src contents should be. If neither has a value we fall back
1077 // to using the geometry coverage data.
1078 Rect src_coverage;
1079 auto size = src_contents->GetColorSourceSize();
1080 if (size.has_value()) {
1081 src_coverage = Rect::MakeXYWH(0, 0, size->width, size->height);
1082 } else {
1083 auto cvg = vertices->GetCoverage(Matrix{});
1084 FML_CHECK(cvg.has_value());
1085 auto texture_coverage = vertices->GetTextureCoordinateCoverage();
1086 if (texture_coverage.has_value()) {
1087 src_coverage =
1088 Rect::MakeOriginSize(texture_coverage->GetOrigin(),
1089 texture_coverage->GetSize().Max({1, 1}));
1090 } else {
1091 src_coverage = cvg.value();
1092 }
1093 }
1094 src_contents = src_paint.CreateContents();
1095
1096 clip_geometry_.push_back(Geometry::MakeRect(Rect::Round(src_coverage)));
1097 src_contents->SetGeometry(clip_geometry_.back().get());
1098
1099 auto contents = std::make_shared<VerticesSimpleBlendContents>();
1100 contents->SetBlendMode(blend_mode);
1101 contents->SetAlpha(paint.color.alpha);
1102 contents->SetGeometry(vertices);
1103 contents->SetLazyTextureCoverage(src_coverage);
1104 contents->SetLazyTexture([src_contents,
1105 src_coverage](const ContentContext& renderer) {
1106 // Applying the src coverage as the coverage limit prevents the 1px
1107 // coverage pad from adding a border that is picked up by developer
1108 // specified UVs.
1109 auto snapshot =
1110 src_contents->RenderToSnapshot(renderer, {}, Rect::Round(src_coverage));
1111 return snapshot.has_value() ? snapshot->texture : nullptr;
1112 });
1113 entity.SetContents(paint.WithFilters(std::move(contents)));
1114 AddRenderEntityToCurrentPass(entity);
1115 }
impeller::Entity::TileMode
TileMode
Definition: entity.h:48
impeller::Geometry::MakeRect
static std::unique_ptr< Geometry > MakeRect(const Rect &rect)
Definition: geometry.cc:83
impeller::skia_conversions::ToSamplerDescriptor
impeller::SamplerDescriptor ToSamplerDescriptor(const flutter::DlImageSampling options)
Definition: skia_conversions.cc:24
impeller::BlendMode::kDst
@ kDst
impeller::TRect< Scalar >::Round
Round(const TRect< U > &r)
Definition: rect.h:699
impeller::TRect< Scalar >::MakeXYWH
constexpr static TRect MakeXYWH(Type x, Type y, Type width, Type height)
Definition: rect.h:136

References impeller::Color::alpha, impeller::Paint::blend_mode, impeller::Paint::color, impeller::Paint::color_source, GetCurrentTransform(), impeller::kDst, impeller::TRect< Scalar >::MakeOriginSize(), impeller::Geometry::MakeRect(), impeller::TRect< Scalar >::MakeXYWH(), impeller::TRect< Scalar >::Round(), impeller::Entity::SetBlendMode(), impeller::Entity::SetContents(), impeller::Entity::SetTransform(), impeller::skia_conversions::ToSamplerDescriptor(), impeller::Color::WithAlpha(), and impeller::Paint::WithFilters().

Referenced by impeller::CanvasDlDispatcher::drawVertices(), and impeller::testing::TEST_P().

## ◆ EndReplay()

void impeller::Canvas::EndReplay | ( |  | ) |

Definition at line 2086 of file canvas.cc.

2086 {
2087 FML_DCHECK(render_passes_.size() == 1u);
2088 render_passes_.back().inline_pass_context->GetRenderPass();
2089 render_passes_.back().inline_pass_context->EndPass(
2090 /*is_onscreen=*/!requires_readback_ && is_onscreen_);
2091 backdrop_data_.clear();
2092
2093 // If requires_readback_ was true, then we rendered to an offscreen texture
2094 // instead of to the onscreen provided in the render target. Now we need to
2095 // draw or blit the offscreen back to the onscreen.
2096 if (requires_readback_) {
2097 BlitToOnscreen(/*is_onscreen_=*/is_onscreen_);
2098 }
2099 if (!EnsureFinalMipmapGeneration()) {
2100 VALIDATION_LOG << "Failed to generate onscreen mipmaps.";
2101 }
2102 if (!renderer_.GetContext()->FlushCommandBuffers()) {
2103 // Not much we can do.
2104 VALIDATION_LOG << "Failed to submit command buffers";
2105 }
2106 render_passes_.clear();
2107 renderer_.GetRenderTargetCache()->End();
2108 clip_geometry_.clear();
2109
2110 Reset();
2111 Initialize(initial_cull_rect_);
2112 }
impeller::Canvas::EnsureFinalMipmapGeneration
bool EnsureFinalMipmapGeneration() const
Definition: canvas.cc:2068
impeller::ContentContext::GetRenderTargetCache
const std::shared_ptr< RenderTargetAllocator > & GetRenderTargetCache() const
Definition: content_context.h:269
VALIDATION_LOG
#define VALIDATION_LOG
Definition: validation.h:91

References VALIDATION_LOG.

Referenced by impeller::CanvasDlDispatcher::FinishRecording(), and impeller::testing::TEST_P().

## ◆ EnsureFinalMipmapGeneration()

bool impeller::Canvas::EnsureFinalMipmapGeneration | ( |  | ) | const

For picture snapshots we need addition steps to verify that final mipmaps are generated.

Definition at line 2068 of file canvas.cc.

2068 {
2069 if (!render_target_.GetRenderTargetTexture()->NeedsMipmapGeneration()) {
2070 return true;
2071 }
2072 std::shared_ptr<CommandBuffer> cmd_buffer =
2073 renderer_.GetContext()->CreateCommandBuffer();
2074 if (!cmd_buffer) {
2075 return false;
2076 }
2077 std::shared_ptr<BlitPass> blit_pass = cmd_buffer->CreateBlitPass();
2078 if (!blit_pass) {
2079 return false;
2080 }
2081 blit_pass->GenerateMipmap(render_target_.GetRenderTargetTexture());
2082 blit_pass->EncodeCommands();
2083 return renderer_.GetContext()->EnqueueCommandBuffer(std::move(cmd_buffer));
2084 }
impeller::RenderTarget::GetRenderTargetTexture
std::shared_ptr< Texture > GetRenderTargetTexture() const
Definition: render_target.cc:176

## ◆ GetCurrentTransform()

const Matrix & impeller::Canvas::GetCurrentTransform | ( |  | ) | const

Definition at line 271 of file canvas.cc.

271 {
272 return transform_stack_.back().transform;
273 }

Referenced by ClipGeometry(), Concat(), DrawArc(), DrawAtlas(), DrawCircle(), DrawDashedLine(), DrawDiffRoundRect(), impeller::DlDispatcherBase::drawDisplayList(), DrawImageRect(), DrawLine(), DrawOval(), DrawPaint(), DrawPath(), DrawPoints(), DrawRect(), DrawRoundRect(), DrawRoundSuperellipse(), impeller::DlDispatcherBase::drawShadow(), DrawTextFrame(), DrawVertices(), and PreConcat().

## ◆ GetLocalCoverageLimit()

std::optional< Rect > impeller::Canvas::GetLocalCoverageLimit | ( |  | ) | const

Return the culling bounds of the current render target, or nullopt if there is no coverage.

Definition at line 1200 of file canvas.cc.

1200 {
1201 if (!clip_coverage_stack_.HasCoverage()) {
1202 // The current clip is empty. This means the pass texture won't be
1203 // visible, so skip it.
1204 return std::nullopt;
1205 }
1206
1207 auto maybe_current_clip_coverage = clip_coverage_stack_.CurrentClipCoverage();
1208 if (!maybe_current_clip_coverage.has_value()) {
1209 return std::nullopt;
1210 }
1211
1212 auto current_clip_coverage = maybe_current_clip_coverage.value();
1213
1214 // The maximum coverage of the subpass. Subpasses textures should never
1215 // extend outside the parent pass texture or the current clip coverage.
1216 std::optional<Rect> maybe_coverage_limit =
1217 Rect::MakeOriginSize(GetGlobalPassPosition(),
1218 Size(render_passes_.back()
1219 .inline_pass_context->GetTexture()
1220 ->GetSize()))
1221 .Intersection(current_clip_coverage);
1222
1223 if (!maybe_coverage_limit.has_value() || maybe_coverage_limit->IsEmpty()) {
1224 return std::nullopt;
1225 }
1226
1227 return maybe_coverage_limit->Intersection(
1228 Rect::MakeSize(render_target_.GetRenderTargetSize()));
1229 }
impeller::EntityPassClipStack::HasCoverage
bool HasCoverage() const
Definition: entity_pass_clip_stack.cc:28
impeller::RenderTarget::GetRenderTargetSize
ISize GetRenderTargetSize() const
Definition: render_target.cc:171
impeller::TRect::Intersection
constexpr std::optional< TRect > Intersection(const TRect &o) const
Definition: rect.h:532

References impeller::EntityPassClipStack::CurrentClipCoverage(), impeller::RenderTarget::GetRenderTargetSize(), impeller::EntityPassClipStack::HasCoverage(), impeller::TRect< T >::Intersection(), impeller::TRect< Scalar >::MakeOriginSize(), and impeller::TRect< Scalar >::MakeSize().

Referenced by impeller::DlDispatcherBase::drawDisplayList(), and SaveLayer().

## ◆ GetMaxOpDepth()

uint64_t impeller::Canvas::GetMaxOpDepth | ( |  | ) | const
| inline

Definition at line 263 of file canvas.h.

263 { return transform_stack_.back().clip_depth; }

Referenced by impeller::CanvasDlDispatcher::saveLayer().

## ◆ GetOpDepth()

uint64_t impeller::Canvas::GetOpDepth | ( |  | ) | const
| inline

Definition at line 261 of file canvas.h.

261 { return current_depth_; }

Referenced by impeller::CanvasDlDispatcher::saveLayer().

## ◆ GetSaveCount()

size_t impeller::Canvas::GetSaveCount | ( |  | ) | const

Definition at line 310 of file canvas.cc.

310 {
311 return transform_stack_.size();
312 }

Referenced by impeller::DlDispatcherBase::drawDisplayList(), and RestoreToCount().

## ◆ PreConcat()

void impeller::Canvas::PreConcat | ( | const Matrix & | transform | ) |

Definition at line 259 of file canvas.cc.

259 {
260 transform_stack_.back().transform = transform * GetCurrentTransform();
261 }

References GetCurrentTransform(), and transform.

Referenced by impeller::DlDispatcherBase::drawShadow().

## ◆ RequiresReadback()

bool impeller::Canvas::RequiresReadback | ( |  | ) | const
| inline

Definition at line 271 of file canvas.h.

271 { return requires_readback_; }

## ◆ ResetTransform()

void impeller::Canvas::ResetTransform | ( |  | ) |

Definition at line 263 of file canvas.cc.

263 {
264 transform_stack_.back().transform = {};
265 }

Referenced by impeller::DlDispatcherBase::transformReset().

## ◆ Restore()

bool impeller::Canvas::Restore | ( |  | ) |

Definition at line 1469 of file canvas.cc.

1469 {
1470 FML_DCHECK(transform_stack_.size() > 0);
1471 if (transform_stack_.size() == 1) {
1472 return false;
1473 }
1474
1475 // This check is important to make sure we didn't exceed the depth
1476 // that the clips were rendered at while rendering any of the
1477 // rendering ops. It is OK for the current depth to equal the
1478 // outgoing clip depth because that means the clipping would have
1479 // been successful up through the last rendering op, but it cannot
1480 // be greater.
1481 // Also, we bump the current rendering depth to the outgoing clip
1482 // depth so that future rendering operations are not clipped by
1483 // any of the pixels set by the expiring clips. It is OK for the
1484 // estimates used to determine the clip depth in save/saveLayer
1485 // to be overly conservative, but we need to jump the depth to
1486 // the clip depth so that the next rendering op will get a
1487 // larger depth (it will pre-increment the current_depth_ value).
1488 FML_DCHECK(current_depth_ <= transform_stack_.back().clip_depth)
1489 << current_depth_ << " <=? " << transform_stack_.back().clip_depth;
1490 current_depth_ = transform_stack_.back().clip_depth;
1491
1492 if (IsSkipping()) {
1493 transform_stack_.pop_back();
1494 return true;
1495 }
1496
1497 if (transform_stack_.back().rendering_mode ==
1498 Entity::RenderingMode::kSubpassAppendSnapshotTransform ||
1499 transform_stack_.back().rendering_mode ==
1500 Entity::RenderingMode::kSubpassPrependSnapshotTransform) {
1501 auto lazy_render_pass = std::move(render_passes_.back());
1502 render_passes_.pop_back();
1503 // Force the render pass to be constructed if it never was.
1504 lazy_render_pass.inline_pass_context->GetRenderPass();
1505
1506 SaveLayerState save_layer_state = save_layer_state_.back();
1507 save_layer_state_.pop_back();
1508 auto global_pass_position = GetGlobalPassPosition();
1509
1510 std::shared_ptr<Contents> contents = CreateContentsForSubpassTarget(
1511 save_layer_state.paint, //
1512 lazy_render_pass.inline_pass_context->GetTexture(), //
1513 Matrix::MakeTranslation(Vector3{-global_pass_position}) * //
1514 transform_stack_.back().transform //
1515 );
1516
1517 lazy_render_pass.inline_pass_context->EndPass();
1518
1519 // Round the subpass texture position for pixel alignment with the parent
1520 // pass render target. By default, we draw subpass textures with nearest
1521 // sampling, so aligning here is important for avoiding visual nearest
1522 // sampling errors caused by limited floating point precision when
1523 // straddling a half pixel boundary.
1524 Point subpass_texture_position;
1525 if (transform_stack_.back().did_round_out) {
1526 // Subpass coverage was rounded out, origin potentially moved "down" by
1527 // as much as a pixel.
1528 subpass_texture_position =
1529 (save_layer_state.coverage.GetOrigin() - global_pass_position)
1530 .Floor();
1531 } else {
1532 // Subpass coverage was truncated. Pick the closest phyiscal pixel.
1533 subpass_texture_position =
1534 (save_layer_state.coverage.GetOrigin() - global_pass_position)
1535 .Round();
1536 }
1537
1538 Entity element_entity;
1539 element_entity.SetClipDepth(++current_depth_);
1540 element_entity.SetContents(std::move(contents));
1541 element_entity.SetBlendMode(save_layer_state.paint.blend_mode);
1542 element_entity.SetTransform(
1543 Matrix::MakeTranslation(Vector3(subpass_texture_position)));
1544
1545 if (element_entity.GetBlendMode() > Entity::kLastPipelineBlendMode) {
1546 if (renderer_.GetDeviceCapabilities().SupportsFramebufferFetch()) {
1547 ApplyFramebufferBlend(element_entity);
1548 } else {
1549 // End the active pass and flush the buffer before rendering "advanced"
1550 // blends. Advanced blends work by binding the current render target
1551 // texture as an input ("destination"), blending with a second texture
1552 // input ("source"), writing the result to an intermediate texture, and
1553 // finally copying the data from the intermediate texture back to the
1554 // render target texture. And so all of the commands that have written
1555 // to the render target texture so far need to execute before it's bound
1556 // for blending (otherwise the blend pass will end up executing before
1557 // all the previous commands in the active pass).
1558 auto input_texture = FlipBackdrop(GetGlobalPassPosition());
1559 if (!input_texture) {
1560 return false;
1561 }
1562
1563 FilterInput::Vector inputs = {
1564 FilterInput::Make(input_texture,
1565 element_entity.GetTransform().Invert()),
1566 FilterInput::Make(element_entity.GetContents())};
1567 auto contents = ColorFilterContents::MakeBlend(
1568 element_entity.GetBlendMode(), inputs);
1569 contents->SetCoverageHint(element_entity.GetCoverage());
1570 element_entity.SetContents(std::move(contents));
1571 element_entity.SetBlendMode(BlendMode::kSrc);
1572 }
1573 }
1574
1575 element_entity.Render(
1576 renderer_, //
1577 *render_passes_.back().inline_pass_context->GetRenderPass() //
1578 );
1579 clip_coverage_stack_.PopSubpass();
1580 transform_stack_.pop_back();
1581
1582 // We don't need to restore clips if a saveLayer was performed, as the clip
1583 // state is per render target, and no more rendering operations will be
1584 // performed as the render target workloaded is completed in the restore.
1585 return true;
1586 }
1587
1588 size_t num_clips = transform_stack_.back().num_clips;
1589 transform_stack_.pop_back();
1590
1591 if (num_clips > 0) {
1592 EntityPassClipStack::ClipStateResult clip_state_result =
1593 clip_coverage_stack_.RecordRestore(GetGlobalPassPosition(),
1594 GetClipHeight());
1595
1596 // Clip restores are never required with depth based clipping.
1597 FML_DCHECK(!clip_state_result.should_render);
1598 if (clip_state_result.clip_did_change) {
1599 // We only need to update the pass scissor if the clip state has changed.
1600 SetClipScissor(
1601 clip_coverage_stack_.CurrentClipCoverage(), //
1602 *render_passes_.back().inline_pass_context->GetRenderPass(), //
1603 GetGlobalPassPosition() //
1604 );
1605 }
1606 }
1607
1608 return true;
1609 }
impeller::Capabilities::SupportsFramebufferFetch
virtual bool SupportsFramebufferFetch() const =0
Whether the context backend is able to support pipelines with shaders that read from the framebuffer ...
impeller::ColorFilterContents::MakeBlend
static std::shared_ptr< ColorFilterContents > MakeBlend(BlendMode blend_mode, FilterInput::Vector inputs, std::optional< Color > foreground_color=std::nullopt)
the [inputs] are expected to be in the order of dst, src.
Definition: color_filter_contents.cc:17
impeller::ContentContext::GetDeviceCapabilities
const Capabilities & GetDeviceCapabilities() const
Definition: content_context.cc:943
impeller::Entity::RenderingMode::kSubpassPrependSnapshotTransform
@ kSubpassPrependSnapshotTransform
impeller::Entity::RenderingMode::kSubpassAppendSnapshotTransform
@ kSubpassAppendSnapshotTransform
impeller::Entity::kLastPipelineBlendMode
static constexpr BlendMode kLastPipelineBlendMode
Definition: entity.h:28
impeller::EntityPassClipStack::RecordRestore
ClipStateResult RecordRestore(Point global_pass_position, size_t restore_height)
Definition: entity_pass_clip_stack.cc:54
impeller::EntityPassClipStack::PopSubpass
void PopSubpass()
Definition: entity_pass_clip_stack.cc:44
impeller::FilterInput::Make
static FilterInput::Ref Make(Variant input, bool msaa_enabled=true)
Definition: filter_input.cc:19
impeller::FilterInput::Vector
std::vector< FilterInput::Ref > Vector
Definition: filter_input.h:33
impeller::Point
TPoint< Scalar > Point
Definition: point.h:327
impeller::BlendMode::kSrc
@ kSrc

References impeller::Paint::blend_mode, impeller::EntityPassClipStack::ClipStateResult::clip_did_change, impeller::Canvas::SaveLayerState::coverage, impeller::EntityPassClipStack::CurrentClipCoverage(), impeller::Entity::GetBlendMode(), impeller::Entity::GetContents(), impeller::Entity::GetCoverage(), impeller::ContentContext::GetDeviceCapabilities(), impeller::TRect< T >::GetOrigin(), impeller::Entity::GetTransform(), impeller::Matrix::Invert(), impeller::Entity::kLastPipelineBlendMode, impeller::kSrc, impeller::Entity::kSubpassAppendSnapshotTransform, impeller::Entity::kSubpassPrependSnapshotTransform, impeller::FilterInput::Make(), impeller::ColorFilterContents::MakeBlend(), impeller::Matrix::MakeTranslation(), impeller::Canvas::SaveLayerState::paint, impeller::EntityPassClipStack::PopSubpass(), impeller::EntityPassClipStack::RecordRestore(), impeller::Entity::Render(), impeller::Entity::SetBlendMode(), impeller::Entity::SetClipDepth(), impeller::Entity::SetContents(), impeller::Entity::SetTransform(), impeller::EntityPassClipStack::ClipStateResult::should_render, and impeller::Capabilities::SupportsFramebufferFetch().

Referenced by impeller::DlDispatcherBase::drawShadow(), DrawTextFrame(), impeller::DlDispatcherBase::restore(), and RestoreToCount().

## ◆ RestoreToCount()

void impeller::Canvas::RestoreToCount | ( | size_t | count | ) |

Definition at line 318 of file canvas.cc.

318 {
319 while (GetSaveCount() > count) {
320 if (!Restore()) {
321 return;
322 }
323 }
324 }
impeller::Canvas::GetSaveCount
size_t GetSaveCount() const
Definition: canvas.cc:310

References GetSaveCount(), and Restore().

Referenced by impeller::DlDispatcherBase::drawDisplayList().

## ◆ Rotate()

void impeller::Canvas::Rotate | ( | Radians | radians | ) |

Definition at line 291 of file canvas.cc.

291 {
292 Concat(Matrix::MakeRotationZ(radians));
293 }
impeller::Matrix::MakeRotationZ
static Matrix MakeRotationZ(Radians r)
Definition: matrix.h:223

References Concat(), and impeller::Matrix::MakeRotationZ().

Referenced by impeller::DlDispatcherBase::rotate().

## ◆ Save()

void impeller::Canvas::Save | ( | uint32_t | total_content_depth = `kMaxDepth` | ) |

Definition at line 1183 of file canvas.cc.

1183 {
1184 if (IsSkipping()) {
1185 return SkipUntilMatchingRestore(total_content_depth);
1186 }
1187
1188 auto entry = CanvasStackEntry{};
1189 entry.transform = transform_stack_.back().transform;
1190 entry.clip_depth = current_depth_ + total_content_depth;
1191 entry.distributed_opacity = transform_stack_.back().distributed_opacity;
1192 FML_DCHECK(entry.clip_depth <= transform_stack_.back().clip_depth)
1193 << entry.clip_depth << " <=? " << transform_stack_.back().clip_depth
1194 << " after allocating " << total_content_depth;
1195 entry.clip_height = transform_stack_.back().clip_height;
1196 entry.rendering_mode = Entity::RenderingMode::kDirect;
1197 transform_stack_.push_back(entry);
1198 }
impeller::Entity::RenderingMode::kDirect
@ kDirect

References impeller::Entity::kDirect, and impeller::CanvasStackEntry::transform.

Referenced by impeller::DlDispatcherBase::drawDisplayList(), impeller::DlDispatcherBase::drawShadow(), DrawTextFrame(), impeller::DlDispatcherBase::save(), and SaveLayer().

## ◆ SaveLayer()

void impeller::Canvas::SaveLayer | ( | const Paint & | paint,
|  | std::optional< Rect > | bounds = `std::nullopt`,
|  | const flutter::DlImageFilter * | backdrop_filter = `nullptr`,
|  | ContentBoundsPromise | bounds_promise = `ContentBoundsPromise::kUnknown`,
|  | uint32_t | total_content_depth = `kMaxDepth`,
|  | bool | can_distribute_opacity = `false`,
|  | std::optional< int64_t > | backdrop_id = `std::nullopt`
| ) |  |

Definition at line 1231 of file canvas.cc.

1237 {
1238 TRACE_EVENT0("flutter", "Canvas::saveLayer");
1239 if (IsSkipping()) {
1240 return SkipUntilMatchingRestore(total_content_depth);
1241 }
1242
1243 auto maybe_coverage_limit = GetLocalCoverageLimit();
1244 if (!maybe_coverage_limit.has_value()) {
1245 return SkipUntilMatchingRestore(total_content_depth);
1246 }
1247 auto coverage_limit = maybe_coverage_limit.value();
1248
1249 if (can_distribute_opacity && !backdrop_filter &&
1250 Paint::CanApplyOpacityPeephole(paint) &&
1251 bounds_promise != ContentBoundsPromise::kMayClipContents) {
1252 Save(total_content_depth);
1253 transform_stack_.back().distributed_opacity *= paint.color.alpha;
1254 return;
1255 }
1256
1257 std::shared_ptr<FilterContents> filter_contents = paint.WithImageFilter(
1258 Rect(), transform_stack_.back().transform,
1259 Entity::RenderingMode::kSubpassPrependSnapshotTransform);
1260
1261 std::optional<Rect> maybe_subpass_coverage = ComputeSaveLayerCoverage(
1262 bounds.value_or(Rect::MakeMaximum()),
1263 transform_stack_.back().transform, //
1264 coverage_limit, //
1265 filter_contents, //
1266 /*flood_output_coverage=*/
1267 Entity::IsBlendModeDestructive(paint.blend_mode), //
1268 /*flood_input_coverage=*/!!backdrop_filter ||
1269 (paint.color_filter &&
1270 paint.color_filter->modifies_transparent_black()) //
1271 );
1272
1273 if (!maybe_subpass_coverage.has_value()) {
1274 return SkipUntilMatchingRestore(total_content_depth);
1275 }
1276
1277 auto subpass_coverage = maybe_subpass_coverage.value();
1278
1279 // When an image filter is present, clamp to avoid flicking due to nearest
1280 // sampled image. For other cases, round out to ensure than any geometry is
1281 // not cut off.
1282 //
1283 // See also this bug: https://github.com/flutter/flutter/issues/144213
1284 //
1285 // TODO(jonahwilliams): this could still round out for filters that use decal
1286 // sampling mode.
1287 ISize subpass_size;
1288 bool did_round_out = false;
1289 Point coverage_origin_adjustment = Point{0, 0};
1290 if (paint.image_filter) {
1291 subpass_size = ISize(subpass_coverage.GetSize());
1292 } else {
1293 did_round_out = true;
1294 subpass_size =
1295 static_cast<ISize>(IRect::RoundOut(subpass_coverage).GetSize());
1296 // If rounding out, adjust the coverage to account for the subpixel shift.
1297 coverage_origin_adjustment =
1298 Point(subpass_coverage.GetLeftTop().x -
1299 std::floor(subpass_coverage.GetLeftTop().x),
1300 subpass_coverage.GetLeftTop().y -
1301 std::floor(subpass_coverage.GetLeftTop().y));
1302 }
1303 if (subpass_size.IsEmpty()) {
1304 return SkipUntilMatchingRestore(total_content_depth);
1305 }
1306
1307 // When there are scaling filters present, these contents may exceed the
1308 // maximum texture size. Perform a clamp here, which may cause rendering
1309 // artifacts.
1310 subpass_size = subpass_size.Min(renderer_.GetContext()
1311 ->GetCapabilities()
1312 ->GetMaximumRenderPassAttachmentSize());
1313
1314 // Backdrop filter state, ignored if there is no BDF.
1315 std::shared_ptr<FilterContents> backdrop_filter_contents;
1316 Point local_position = Point(0, 0);
1317 if (backdrop_filter) {
1318 local_position = subpass_coverage.GetOrigin() - GetGlobalPassPosition();
1319 Canvas::BackdropFilterProc backdrop_filter_proc =
1320 [backdrop_filter = backdrop_filter](
1321 const FilterInput::Ref& input, const Matrix& effect_transform,
1322 Entity::RenderingMode rendering_mode) {
1323 auto filter = WrapInput(backdrop_filter, input);
1324 filter->SetEffectTransform(effect_transform);
1325 filter->SetRenderingMode(rendering_mode);
1326 return filter;
1327 };
1328
1329 std::shared_ptr<Texture> input_texture;
1330
1331 // If the backdrop ID is not nullopt and there is more than one usage
1332 // of it in the current scene, cache the backdrop texture and remove it from
1333 // the current entity pass flip.
1334 bool will_cache_backdrop_texture = false;
1335 BackdropData* backdrop_data = nullptr;
1336 // If we've reached this point, there is at least one backdrop filter. But
1337 // potentially more if there is a backdrop id. We may conditionally set this
1338 // to a higher value in the if block below.
1339 size_t backdrop_count = 1;
1340 if (backdrop_id.has_value()) {
1341 std::unordered_map<int64_t, BackdropData>::iterator backdrop_data_it =
1342 backdrop_data_.find(backdrop_id.value());
1343 if (backdrop_data_it != backdrop_data_.end()) {
1344 backdrop_data = &backdrop_data_it->second;
1345 will_cache_backdrop_texture =
1346 backdrop_data_it->second.backdrop_count > 1;
1347 backdrop_count = backdrop_data_it->second.backdrop_count;
1348 }
1349 }
1350
1351 if (!will_cache_backdrop_texture || !backdrop_data->texture_slot) {
1352 backdrop_count_ -= backdrop_count;
1353
1354 // The onscreen texture can be flipped to if:
1355 // 1. The device supports framebuffer fetch
1356 // 2. There are no more backdrop filters
1357 // 3. The current render pass is for the onscreen pass.
1358 const bool should_use_onscreen =
1359 renderer_.GetDeviceCapabilities().SupportsFramebufferFetch() &&
1360 backdrop_count_ == 0 && render_passes_.size() == 1u;
1361 input_texture = FlipBackdrop(
1362 GetGlobalPassPosition(), //
1363 /*should_remove_texture=*/will_cache_backdrop_texture, //
1364 /*should_use_onscreen=*/should_use_onscreen //
1365 );
1366 if (!input_texture) {
1367 // Validation failures are logged in FlipBackdrop.
1368 return;
1369 }
1370
1371 if (will_cache_backdrop_texture) {
1372 backdrop_data->texture_slot = input_texture;
1373 }
1374 } else {
1375 input_texture = backdrop_data->texture_slot;
1376 }
1377
1378 backdrop_filter_contents = backdrop_filter_proc(
1379 FilterInput::Make(std::move(input_texture)),
1380 transform_stack_.back().transform.Basis(),
1381 // When the subpass has a translation that means the math with
1382 // the snapshot has to be different.
1383 transform_stack_.back().transform.HasTranslation()
1384 ? Entity::RenderingMode::kSubpassPrependSnapshotTransform
1385 : Entity::RenderingMode::kSubpassAppendSnapshotTransform);
1386
1387 if (will_cache_backdrop_texture) {
1388 FML_DCHECK(backdrop_data);
1389 // If all filters on the shared backdrop layer are equal, process the
1390 // layer once.
1391 if (backdrop_data->all_filters_equal &&
1392 !backdrop_data->shared_filter_snapshot.has_value()) {
1393 // TODO(157110): compute minimum input hint.
1394 backdrop_data->shared_filter_snapshot =
1395 backdrop_filter_contents->RenderToSnapshot(renderer_, {});
1396 }
1397
1398 std::optional<Snapshot> maybe_snapshot =
1399 backdrop_data->shared_filter_snapshot;
1400 if (maybe_snapshot.has_value()) {
1401 Snapshot snapshot = maybe_snapshot.value();
1402 std::shared_ptr<TextureContents> contents = TextureContents::MakeRect(
1403 subpass_coverage.Shift(-GetGlobalPassPosition()));
1404 auto scaled =
1405 subpass_coverage.TransformBounds(snapshot.transform.Invert());
1406 contents->SetTexture(snapshot.texture);
1407 contents->SetSourceRect(scaled);
1408 contents->SetSamplerDescriptor(snapshot.sampler_descriptor);
1409
1410 // This backdrop entity sets a depth value as it is written to the newly
1411 // flipped backdrop and not into a new saveLayer.
1412 Entity backdrop_entity;
1413 backdrop_entity.SetContents(std::move(contents));
1414 backdrop_entity.SetClipDepth(++current_depth_);
1415 backdrop_entity.SetBlendMode(paint.blend_mode);
1416
1417 backdrop_entity.Render(renderer_, GetCurrentRenderPass());
1418 Save(0);
1419 return;
1420 }
1421 }
1422 }
1423
1424 // When applying a save layer, absorb any pending distributed opacity.
1425 Paint paint_copy = paint;
1426 paint_copy.color.alpha *= transform_stack_.back().distributed_opacity;
1427 transform_stack_.back().distributed_opacity = 1.0;
1428
1429 render_passes_.push_back(
1430 LazyRenderingConfig(renderer_, //
1431 CreateRenderTarget(renderer_, //
1432 subpass_size, //
1433 Color::BlackTransparent() //
1434 )));
1435 save_layer_state_.push_back(SaveLayerState{
1436 paint_copy, subpass_coverage.Shift(-coverage_origin_adjustment)});
1437
1438 CanvasStackEntry entry;
1439 entry.transform = transform_stack_.back().transform;
1440 entry.clip_depth = current_depth_ + total_content_depth;
1441 FML_DCHECK(entry.clip_depth <= transform_stack_.back().clip_depth)
1442 << entry.clip_depth << " <=? " << transform_stack_.back().clip_depth
1443 << " after allocating " << total_content_depth;
1444 entry.clip_height = transform_stack_.back().clip_height;
1445 entry.rendering_mode = Entity::RenderingMode::kSubpassAppendSnapshotTransform;
1446 entry.did_round_out = did_round_out;
1447 transform_stack_.emplace_back(entry);
1448
1449 // Start non-collapsed subpasses with a fresh clip coverage stack limited by
1450 // the subpass coverage. This is important because image filters applied to
1451 // save layers may transform the subpass texture after it's rendered,
1452 // causing parent clip coverage to get misaligned with the actual area that
1453 // the subpass will affect in the parent pass.
1454 clip_coverage_stack_.PushSubpass(subpass_coverage, GetClipHeight());
1455
1456 if (!backdrop_filter_contents) {
1457 return;
1458 }
1459
1460 // Render the backdrop entity.
1461 Entity backdrop_entity;
1462 backdrop_entity.SetContents(std::move(backdrop_filter_contents));
1463 backdrop_entity.SetTransform(
1464 Matrix::MakeTranslation(Vector3(-local_position)));
1465 backdrop_entity.SetClipDepth(std::numeric_limits<uint32_t>::max());
1466 backdrop_entity.Render(renderer_, GetCurrentRenderPass());
1467 }
impeller::Canvas::GetLocalCoverageLimit
std::optional< Rect > GetLocalCoverageLimit() const
Return the culling bounds of the current render target, or nullopt if there is no coverage.
Definition: canvas.cc:1200
impeller::Canvas::BackdropFilterProc
std::function< std::shared_ptr< FilterContents >(FilterInput::Ref, const Matrix &effect_transform, Entity::RenderingMode rendering_mode)> BackdropFilterProc
Definition: canvas.h:127
impeller::Entity::RenderingMode
RenderingMode
Definition: entity.h:33
impeller::Entity::IsBlendModeDestructive
static bool IsBlendModeDestructive(BlendMode blend_mode)
Returns true if the blend mode is "destructive", meaning that even fully transparent source colors wo...
Definition: entity.cc:127
impeller::EntityPassClipStack::PushSubpass
void PushSubpass(std::optional< Rect > subpass_coverage, size_t clip_height)
Definition: entity_pass_clip_stack.cc:32
impeller::FilterInput::Ref
std::shared_ptr< FilterInput > Ref
Definition: filter_input.h:32
subpass_size
ISize subpass_size
The output size of the down-sampling pass.
Definition: gaussian_blur_filter_contents.cc:202
impeller::WrapInput
std::shared_ptr< FilterContents > WrapInput(const flutter::DlImageFilter *filter, const FilterInput::Ref &input)
Generate a new FilterContents using this filter's configuration.
Definition: image_filter.cc:18
impeller::ContentBoundsPromise::kMayClipContents
@ kMayClipContents
The caller claims the bounds are a subset of an estimate of the reasonably tight bounds but likely cl...
impeller::ComputeSaveLayerCoverage
std::optional< Rect > ComputeSaveLayerCoverage(const Rect &content_coverage, const Matrix &effect_transform, const Rect &coverage_limit, const std::shared_ptr< FilterContents > &image_filter, bool flood_output_coverage, bool flood_input_coverage)
Compute the coverage of a subpass in the global coordinate space.
Definition: save_layer_utils.cc:19
impeller::Color::BlackTransparent
static constexpr Color BlackTransparent()
Definition: color.h:270
impeller::Paint::CanApplyOpacityPeephole
static bool CanApplyOpacityPeephole(const Paint &paint)
Whether or not a save layer with the provided paint can perform the opacity peephole optimization.
Definition: paint.h:40
impeller::TRect::RoundOut
RoundOut(const TRect< U > &r)
Definition: rect.h:683
impeller::TRect< Scalar >::MakeMaximum
constexpr static TRect MakeMaximum()
Definition: rect.h:188

References impeller::BackdropData::all_filters_equal, impeller::Color::alpha, impeller::BackdropData::backdrop_count, impeller::Color::BlackTransparent(), impeller::Paint::blend_mode, impeller::Paint::CanApplyOpacityPeephole(), impeller::CanvasStackEntry::clip_depth, impeller::CanvasStackEntry::clip_height, impeller::Paint::color, impeller::Paint::color_filter, impeller::ComputeSaveLayerCoverage(), impeller::CanvasStackEntry::did_round_out, impeller::ContentContext::GetContext(), impeller::ContentContext::GetDeviceCapabilities(), GetLocalCoverageLimit(), impeller::Paint::image_filter, impeller::Matrix::Invert(), impeller::Entity::IsBlendModeDestructive(), impeller::kMayClipContents, impeller::Entity::kSubpassAppendSnapshotTransform, impeller::Entity::kSubpassPrependSnapshotTransform, impeller::FilterInput::Make(), impeller::TRect< Scalar >::MakeMaximum(), impeller::TextureContents::MakeRect(), impeller::Matrix::MakeTranslation(), impeller::EntityPassClipStack::PushSubpass(), impeller::Entity::Render(), impeller::CanvasStackEntry::rendering_mode, impeller::TRect< T >::RoundOut(), impeller::Snapshot::sampler_descriptor, Save(), impeller::Entity::SetBlendMode(), impeller::Entity::SetClipDepth(), impeller::Entity::SetContents(), impeller::Entity::SetTransform(), impeller::BackdropData::shared_filter_snapshot, subpass_size, impeller::Capabilities::SupportsFramebufferFetch(), impeller::Snapshot::texture, impeller::BackdropData::texture_slot, impeller::CanvasStackEntry::transform, impeller::Snapshot::transform, impeller::Paint::WithImageFilter(), and impeller::WrapInput().

Referenced by impeller::DlDispatcherBase::drawDisplayList(), and impeller::DlDispatcherBase::saveLayer().

## ◆ Scale() [1/2]

void impeller::Canvas::Scale | ( | const Vector2 & | scale | ) |

Definition at line 279 of file canvas.cc.

279 {
280 Concat(Matrix::MakeScale(scale));
281 }
impeller::Matrix::MakeScale
static constexpr Matrix MakeScale(const Vector3 &s)
Definition: matrix.h:104

References Concat(), and impeller::Matrix::MakeScale().

Referenced by impeller::DlDispatcherBase::scale().

## ◆ Scale() [2/2]

void impeller::Canvas::Scale | ( | const Vector3 & | scale | ) |

Definition at line 283 of file canvas.cc.

283 {
284 Concat(Matrix::MakeScale(scale));
285 }

References Concat(), and impeller::Matrix::MakeScale().

## ◆ SetBackdropData()

void impeller::Canvas::SetBackdropData | ( | std::unordered_map< int64_t, BackdropData > | backdrop_data,
|  | size_t | backdrop_count
| ) |  |

Update the backdrop data used to group together backdrop filters within the same layer.

Definition at line 1882 of file canvas.cc.

1884 {
1885 backdrop_data_ = std::move(backdrop_data);
1886 backdrop_count_ = backdrop_count;
1887 }

Referenced by impeller::CanvasDlDispatcher::SetBackdropData().

## ◆ Skew()

void impeller::Canvas::Skew | ( | Scalar | sx,
|  | Scalar | sy
| ) |  |

Definition at line 287 of file canvas.cc.

287 {
288 Concat(Matrix::MakeSkew(sx, sy));
289 }
impeller::Matrix::MakeSkew
static constexpr Matrix MakeSkew(Scalar sx, Scalar sy)
Definition: matrix.h:127

References Concat(), and impeller::Matrix::MakeSkew().

Referenced by impeller::DlDispatcherBase::skew().

## ◆ SupportsBlitToOnscreen()

bool impeller::Canvas::SupportsBlitToOnscreen | ( |  | ) | const

Definition at line 2011 of file canvas.cc.

2011 {
2012 return renderer_.GetContext()
2013 ->GetCapabilities()
2014 ->SupportsTextureToTextureBlits() &&
2015 renderer_.GetContext()->GetBackendType() ==
2016 Context::BackendType::kMetal;
2017 }
impeller::Context::BackendType::kMetal
@ kMetal

## ◆ Transform()

void impeller::Canvas::Transform | ( | const Matrix & | transform | ) |

Definition at line 267 of file canvas.cc.

267 {
268 Concat(transform);
269 }

References Concat(), and transform.

Referenced by impeller::DlDispatcherBase::transformFullPerspective(), and impeller::DlDispatcherBase::transformReset().

## ◆ Translate()

void impeller::Canvas::Translate | ( | const Vector3 & | offset | ) |

Definition at line 275 of file canvas.cc.

275 {
276 Concat(Matrix::MakeTranslation(offset));
277 }

References Concat(), and impeller::Matrix::MakeTranslation().

Referenced by impeller::DlDispatcherBase::translate().

## Member Data Documentation

## ◆ kMaxDepth

constexpr uint32_t impeller::Canvas::kMaxDepth = 1 << 24
| static constexpr

Definition at line 122 of file canvas.h.

The documentation for this class was generated from the following files:

- impeller/display_list/canvas.h
- impeller/display_list/canvas.cc