Rendering backend using tiny-skia-cpp. More...

#include "donner/svg/renderer/RendererTinySkia.h"

Inheritance diagram for donner::svg::RendererTinySkia:

Public Member Functions
	RendererTinySkia (bool verbose=false)
	Creates the tiny-skia renderer.
	~RendererTinySkia ()
	Destructor.
	RendererTinySkia (RendererTinySkia &&) noexcept
	Move constructor.
RendererTinySkia &	operator= (RendererTinySkia &&) noexcept
	Move assignment operator.
	RendererTinySkia (const RendererTinySkia &)=delete
RendererTinySkia &	operator= (const RendererTinySkia &)=delete
void	draw (SVGDocument &document) override
	Draws the SVG document using the renderer.
void	beginFrameResourceScope () override
	Begins one aggregate resource-budget scope around a controller-managed frame.
void	endFrameResourceScope () override
	Completes a scope opened by beginFrameResourceScope.
void	beginFrame (const RenderViewport &viewport) override
	Begins a render pass for the given viewport.
void	endFrame () override
	Completes the current render pass.
void	setTransform (const Transform2d &transform) override
	Sets the absolute transform, replacing the current matrix.
void	pushTransform (const Transform2d &transform) override
	Pushes a relative transform.
void	popTransform () override
	Pops the most recent transform.
void	pushClip (const ResolvedClip &clip) override
	Pushes a clip rect or clip path.
void	popClip () override
	Pops the most recent clip.
void	pushIsolatedLayer (double opacity, MixBlendMode blendMode) override
	Pushes an isolated compositing layer.
void	popIsolatedLayer () override
	Pops the most recent isolated layer.
void	pushFilterLayer (const components::FilterGraph &filterGraph, const std::optional< Box2d > &filterRegion) override
	Pushes a filter layer.
void	popFilterLayer () override
	Pops the most recent filter layer.
void	pushMask (const std::optional< Box2d > &maskBounds) override
	Begins mask rendering.
void	pushMask (const std::optional< Box2d > &maskBounds, MaskType maskType) override
	Begins mask rendering with an explicit coverage mode.
void	transitionMaskToContent () override
	Switches from mask rendering to masked content rendering.
void	popMask () override
	Pops the current mask and composites the masked content.
bool	beginPatternTile (const Box2d &tileRect, const Transform2d &targetFromPattern) override
	Begins pattern tile recording.
void	endPatternTile (bool forStroke) override
	Ends pattern recording and stores the resulting pattern paint.
void	setPaint (const PaintParams &paint) override
	Sets the active paint parameters for subsequent draw calls.
void	drawPath (const PathShape &path, const StrokeParams &stroke) override
	Draws an arbitrary path.
void	drawRect (const Box2d &rect, const StrokeParams &stroke) override
	Draws an axis-aligned rectangle.
void	drawEllipse (const Box2d &bounds, const StrokeParams &stroke) override
	Draws an ellipse.
void	drawImage (const ImageResource &image, const ImageParams &params) override
	Draws an image resource.
void	drawBitmap (const RendererBitmap &bitmap, const ImageParams &params) override
	Zero-copy compose blit for premultiplied CPU bitmaps.
void	drawText (Registry &registry, const components::ComputedTextComponent &text, const TextParams &params) override
	Draws shaped text.
RendererBitmap	takeSnapshot () const override
	Captures a CPU-readable snapshot of the current frame.
std::unique_ptr< RendererInterface >	createOffscreenInstance () const override
	Creates an independent offscreen renderer instance of the same type as this one.
RendererResourceStats	resourceStats () const override
	Return resource-admission diagnostics for the current frame.
RendererFilterPreparationBudget *	filterPreparationBudget () override
	Shared driver-side filter preparation budget for this renderer family, when supported.
void	setDashWorkBudgetForTesting (std::size_t maximumWorkUnits)
	Reduce generated-dash work for a boundary test.
void	setGradientStopBudgetForTesting (std::size_t maximumStops)
	Reduce materialized gradient stops for a boundary test.
void	setTextGlyphBudgetForTesting (std::size_t maximumGlyphs)
	Reduce admitted text glyphs for a boundary test.
void	setTextMaterializationBudgetForTesting (RendererTextMaterializationBudget::Cost limits)
	Reduce decoded-outline and path-copy ceilings for a boundary test.
bool	save (const char *filename)
	Saves the last rendered frame to a PNG file.
void	setAntialias (bool antialias)
	Enables or disables anti-aliasing.
bool	antialias () const
	Returns whether anti-aliasing is enabled.
void	setRetainedSpansEnabled (bool enabled)
	Enables or disables retained rasterization.
bool	retainedSpansEnabled () const
	Returns whether retained rasterization is enabled.
void	setRetainedSpanBudgetBytes (std::size_t bytes)
	Sets the per-document ceiling on retained coverage.
const RetainedSpanStats &	retainedSpanStats () const
	Returns what retained rasterization did during the most recent frame.
int	width () const override
	Returns the rendered width in pixels.
int	height () const override
	Returns the rendered height in pixels.
const RendererTinySkiaFrameCounters &	frameCounters () const
	Conversions performed during the most recent frame.
Public Member Functions inherited from donner::svg::RendererInterface
virtual void	setPreserveTargetOnBeginFrame (bool preserve)
	Preserve the current render target when the next frame begins.
virtual bool	drawTextureSnapshot (const RendererTextureSnapshot &texture, const Box2d &targetRect, double opacity=1.0, bool pixelated=false)
	Draws a backend-owned texture snapshot into the given target rectangle.
virtual RendererBitmap	takeSnapshotInterruptibly (const std::function< bool()> &shouldCancel) const
	Captures a CPU-readable snapshot while allowing a low-priority caller to abort the readback.
virtual RendererReadbackStats	consumeReadbackStats ()
	Consume readback diagnostics accumulated by this renderer backend.
virtual void	injectFilterLocalRasterAllocationFailureForTesting ()
	Cause the next local filter raster allocation to fail in a boundary test.
virtual std::shared_ptr< const RendererTextureSnapshot >	takeTextureSnapshot ()
	Captures the current frame buffer as a backend-owned GPU texture.
virtual const RendererTextureSnapshot *	borrowTextureSnapshot () UTILS_LIFETIME_BOUND
	Borrows the current backend-owned GPU texture for a synchronous presentation operation.
virtual bool	requiresTextureSnapshotPresentation () const
	Returns true when presentation callers must use takeTextureSnapshot and must not fall back to CPU bitmap readback for normal frame handoff.
virtual void	setOffscreenCreationHookForTesting (std::function< void()>)
	Install a zero-default hook entered from inside offscreen backend construction.
virtual std::uint64_t	filterBudgetChunksForTesting () const
	Number of filter-budget command-buffer chunks submitted by this renderer family.
virtual void	setDebugGeometryOverlay (bool)
	Enable or disable the backend's geometry debug overlay.
virtual bool	debugGeometryOverlay () const
	Whether the backend's geometry debug overlay is enabled. Backends without an overlay always report false.

Detailed Description

Rendering backend using tiny-skia-cpp.

This backend provides a lightweight software rasterizer implementation of RendererInterface. It currently targets shape, image, gradient, clip, mask, pattern, and opacity-layer rendering. Text rendering is not yet implemented.

Constructor & Destructor Documentation

◆ RendererTinySkia()

donner::svg::RendererTinySkia::RendererTinySkia ( bool verbose = false )

explicit

Creates the tiny-skia renderer.

Parameters

verbose If true, emit diagnostic logging for unsupported features.

Member Function Documentation

◆ beginFrame()

void donner::svg::RendererTinySkia::beginFrame ( const RenderViewport & viewport )

overridevirtual

Begins a render pass for the given viewport.

Parameters

viewport The viewport dimensions for the render pass.

Implements donner::svg::RendererInterface.

◆ beginFrameResourceScope()

void donner::svg::RendererTinySkia::beginFrameResourceScope ( )

overridevirtual

Begins one aggregate resource-budget scope around a controller-managed frame.

A controller may render several offscreen passes before the root render pass. Backends that share frame budgets with their offscreen instances override this pair so every pass consumes one budget epoch instead of resetting independently. Ordinary single-pass callers may omit the scope and continue to rely on beginFrame.

Reimplemented from donner::svg::RendererInterface.

◆ beginPatternTile()

bool donner::svg::RendererTinySkia::beginPatternTile	(	const Box2d &	tileRect,
		const Transform2d &	targetFromPattern )

nodiscardoverridevirtual

Begins pattern tile recording.

Parameters

tileRect	Tile bounds in pattern space.
targetFromPattern	Transform from pattern tile space to target space.

Returns: True when recording started. False rejects an unsafe tile before allocation.

Implements donner::svg::RendererInterface.

◆ createOffscreenInstance()

std::unique_ptr< RendererInterface > donner::svg::RendererTinySkia::createOffscreenInstance ( ) const

nodiscardoverridevirtual

Creates an independent offscreen renderer instance of the same type as this one.

Used for rendering sub-documents into intermediate pixmaps when a backend needs an isolated offscreen pass (e.g., for feImage with SVG content). Returns nullptr if offscreen rendering is not supported.

Reimplemented from donner::svg::RendererInterface.

◆ draw()

void donner::svg::RendererTinySkia::draw ( SVGDocument & document )

overridevirtual

Draws the SVG document using the renderer.

Parameters

document The SVG document to render.

Implements donner::svg::RendererInterface.

◆ drawBitmap()

void donner::svg::RendererTinySkia::drawBitmap	(	const RendererBitmap &	bitmap,
		const ImageParams &	params )

overridevirtual

Zero-copy compose blit for premultiplied CPU bitmaps.

tiny-skia consumes premultiplied RGBA natively, so a tightly-packed premultiplied RendererBitmap is drawn through a borrowed PixmapView with no pixel-buffer conversion or copy. Padded and non-premultiplied bitmaps are packed into draw scratch before creating the view.

Parameters

bitmap	The bitmap to draw.
params	Image placement parameters.

Reimplemented from donner::svg::RendererInterface.

◆ drawEllipse()

void donner::svg::RendererTinySkia::drawEllipse	(	const Box2d &	bounds,
		const StrokeParams &	stroke )

overridevirtual

Draws an ellipse.

Parameters

bounds	The ellipse bounds.
stroke	Stroke configuration for the ellipse.

Implements donner::svg::RendererInterface.

◆ drawImage()

void donner::svg::RendererTinySkia::drawImage	(	const ImageResource &	image,
		const ImageParams &	params )

overridevirtual

Draws an image resource.

Parameters

image	The image resource to draw.
params	Image placement parameters.

Implements donner::svg::RendererInterface.

◆ drawPath()

void donner::svg::RendererTinySkia::drawPath	(	const PathShape &	path,
		const StrokeParams &	stroke )

overridevirtual

Draws an arbitrary path.

Parameters

path	The path to draw.
stroke	Stroke configuration for the path.

Implements donner::svg::RendererInterface.

◆ drawRect()

void donner::svg::RendererTinySkia::drawRect	(	const Box2d &	rect,
		const StrokeParams &	stroke )

overridevirtual

Draws an axis-aligned rectangle.

Parameters

rect	The rectangle bounds.
stroke	Stroke configuration for the rectangle.

Implements donner::svg::RendererInterface.

◆ drawText()

void donner::svg::RendererTinySkia::drawText	(	Registry &	registry,
		const components::ComputedTextComponent &	text,
		const TextParams &	params )

overridevirtual

Draws shaped text.

Parameters

registry	ECS registry used for resolving paint references.
text	The shaped text runs.
params	Text styling parameters.

Implements donner::svg::RendererInterface.

◆ endFrame()

void donner::svg::RendererTinySkia::endFrame ( )

overridevirtual

Completes the current render pass.

Implements donner::svg::RendererInterface.

◆ endFrameResourceScope()

void donner::svg::RendererTinySkia::endFrameResourceScope ( )

overridevirtual

Completes a scope opened by beginFrameResourceScope.

Reimplemented from donner::svg::RendererInterface.

◆ endPatternTile()

void donner::svg::RendererTinySkia::endPatternTile ( bool forStroke )

overridevirtual

Ends pattern recording and stores the resulting pattern paint.

Parameters

forStroke If true, store as stroke paint, otherwise fill paint.

Implements donner::svg::RendererInterface.

◆ filterPreparationBudget()

RendererFilterPreparationBudget * donner::svg::RendererTinySkia::filterPreparationBudget ( )

nodiscardoverridevirtual

Shared driver-side filter preparation budget for this renderer family, when supported.

Reimplemented from donner::svg::RendererInterface.

◆ frameCounters()

const RendererTinySkiaFrameCounters & donner::svg::RendererTinySkia::frameCounters ( ) const

inlinenodiscard

Conversions performed during the most recent frame.

See also: RendererTinySkiaFrameCounters

◆ height()

int donner::svg::RendererTinySkia::height ( ) const

overridevirtual

Returns the rendered height in pixels.

Implements donner::svg::RendererInterface.

◆ popClip()

void donner::svg::RendererTinySkia::popClip ( )

overridevirtual

Pops the most recent clip.

Implements donner::svg::RendererInterface.

◆ popFilterLayer()

void donner::svg::RendererTinySkia::popFilterLayer ( )

overridevirtual

Pops the most recent filter layer.

Implements donner::svg::RendererInterface.

◆ popIsolatedLayer()

void donner::svg::RendererTinySkia::popIsolatedLayer ( )

overridevirtual

Pops the most recent isolated layer.

Implements donner::svg::RendererInterface.

◆ popMask()

void donner::svg::RendererTinySkia::popMask ( )

overridevirtual

Pops the current mask and composites the masked content.

Implements donner::svg::RendererInterface.

◆ popTransform()

void donner::svg::RendererTinySkia::popTransform ( )

overridevirtual

Pops the most recent transform.

Implements donner::svg::RendererInterface.

◆ pushClip()

void donner::svg::RendererTinySkia::pushClip ( const ResolvedClip & clip )

overridevirtual

Pushes a clip rect or clip path.

Parameters

clip	The resolved clip to apply.

Implements donner::svg::RendererInterface.

◆ pushFilterLayer()

void donner::svg::RendererTinySkia::pushFilterLayer	(	const components::FilterGraph &	filterGraph,
		const std::optional< Box2d > &	filterRegion )

overridevirtual

Pushes a filter layer.

Parameters

filterGraph	The filter graph to apply when the layer is popped.
filterRegion	Optional filter region bounds in user space.

Implements donner::svg::RendererInterface.

◆ pushIsolatedLayer()

void donner::svg::RendererTinySkia::pushIsolatedLayer	(	double	opacity,
		MixBlendMode	blendMode )

overridevirtual

Pushes an isolated compositing layer.

Parameters

opacity	Group opacity applied when the layer is composited back.
blendMode	Mix-blend-mode applied when the layer is composited back.

Implements donner::svg::RendererInterface.

◆ pushMask() [1/2]

void donner::svg::RendererTinySkia::pushMask ( const std::optional< Box2d > & maskBounds )

inlineoverridevirtual

Begins mask rendering.

Parameters

maskBounds	Optional mask bounds clip.
maskType	Whether mask coverage comes from luminance or alpha.

Implements donner::svg::RendererInterface.

◆ pushMask() [2/2]

void donner::svg::RendererTinySkia::pushMask	(	const std::optional< Box2d > &	maskBounds,
		MaskType	maskType )

overridevirtual

Begins mask rendering with an explicit coverage mode.

Appended after the legacy virtual surface to preserve existing vtable slot order. The default compatibility implementation delegates to the one-argument luminance entry point. Backends that support MaskType::Alpha override this overload.

Parameters

maskBounds	Optional clip rect for the mask region.
maskType	Whether mask coverage comes from luminance or alpha.

Reimplemented from donner::svg::RendererInterface.

◆ pushTransform()

void donner::svg::RendererTinySkia::pushTransform ( const Transform2d & transform )

overridevirtual

Pushes a relative transform.

Parameters

transform The transform to compose with the current matrix.

Implements donner::svg::RendererInterface.

◆ resourceStats()

RendererResourceStats donner::svg::RendererTinySkia::resourceStats ( ) const

nodiscardoverridevirtual

Return resource-admission diagnostics for the current frame.

Reimplemented from donner::svg::RendererInterface.

◆ save()

bool donner::svg::RendererTinySkia::save ( const char * filename )

Saves the last rendered frame to a PNG file.

Parameters

filename The output PNG filename.

Returns: True if the file was written.

◆ setPaint()

void donner::svg::RendererTinySkia::setPaint ( const PaintParams & paint )

overridevirtual

Sets the active paint parameters for subsequent draw calls.

Parameters

paint The resolved paint state.

Implements donner::svg::RendererInterface.

◆ setRetainedSpanBudgetBytes()

void donner::svg::RendererTinySkia::setRetainedSpanBudgetBytes ( std::size_t bytes )

inline

Sets the per-document ceiling on retained coverage.

Exceeding it evicts the coldest shapes; a working set that does not fit at all turns retention off for that document.

See also: RetainedSpanDocumentState.

Parameters

bytes Ceiling in bytes.

◆ setRetainedSpansEnabled()

void donner::svg::RendererTinySkia::setRetainedSpansEnabled ( bool enabled )

inline

Enables or disables retained rasterization.

When enabled, each shape's coverage is recorded the first time it is rasterized and replayed on later frames for as long as every input that coverage depended on is unchanged, which turns a redraw of an unchanged document into blits. Output is byte-identical either way; the cost is the memory the recordings occupy, bounded by setRetainedSpanBudgetBytes.

Off by default, because a renderer that draws each document once pays the recording cost with nothing to replay it onto.

Parameters

enabled Whether to retain and replay per-shape coverage.

◆ setTransform()

void donner::svg::RendererTinySkia::setTransform ( const Transform2d & transform )

overridevirtual

Sets the absolute transform, replacing the current matrix.

Parameters

transform The transform to apply.

Implements donner::svg::RendererInterface.

◆ takeSnapshot()

RendererBitmap donner::svg::RendererTinySkia::takeSnapshot ( ) const

nodiscardoverridevirtual

Captures a CPU-readable snapshot of the current frame.

Returns: A snapshot of the rendered frame.

Implements donner::svg::RendererInterface.

◆ transitionMaskToContent()

void donner::svg::RendererTinySkia::transitionMaskToContent ( )

overridevirtual

Switches from mask rendering to masked content rendering.

Implements donner::svg::RendererInterface.

◆ width()

int donner::svg::RendererTinySkia::width ( ) const

overridevirtual

Returns the rendered width in pixels.

Implements donner::svg::RendererInterface.

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

donner/svg/renderer/RendererTinySkia.h

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ RendererTinySkia()

Member Function Documentation

◆ beginFrame()

◆ beginFrameResourceScope()

◆ beginPatternTile()

◆ createOffscreenInstance()

◆ draw()

◆ drawBitmap()

◆ drawEllipse()

◆ drawImage()

◆ drawPath()

◆ drawRect()

◆ drawText()

◆ endFrame()

◆ endFrameResourceScope()

◆ endPatternTile()

◆ filterPreparationBudget()

◆ frameCounters()

◆ height()

◆ popClip()

◆ popFilterLayer()

◆ popIsolatedLayer()

◆ popMask()

◆ popTransform()

◆ pushClip()

◆ pushFilterLayer()

◆ pushIsolatedLayer()

◆ pushMask() [1/2]

◆ pushMask() [2/2]

◆ pushTransform()

◆ resourceStats()

◆ save()

◆ setPaint()

◆ setRetainedSpanBudgetBytes()

◆ setRetainedSpansEnabled()

◆ setTransform()

◆ takeSnapshot()

◆ transitionMaskToContent()

◆ width()