donner::svg::components Namespace Reference

Contains the implementation of the Donner ECS,. More...

Classes
struct	AttributesComponent
	Stores XML attribute values. More...
struct	CircleComponent
	Parameters for a "<circle>" element. More...
struct	CircleProperties
	Properties for a "<circle>" element. More...
struct	ClassComponent
	Holds the value of the class attribute of an element. More...
struct	ClipPathComponent
	Parameters for the "<clipPath>" element. More...
struct	ComputedAbsoluteTransformComponent
	Stores the computed transform value for an entity, relative to the world. More...
struct	ComputedCircleComponent
	Computed properties for a "<circle>" element, which applies values from the CSS cascade. More...
struct	ComputedEllipseComponent
	Computed properties for a "<ellipse>" element, which applies values from the CSS cascade. More...
struct	ComputedFilterComponent
	Computed filter parameters parsed by FilterSystem, represents the resolved DOM hierarchy of a "<filter>" element. More...
struct	ComputedGradientComponent
	Created by PaintSystem during render tree instantiation. More...
struct	ComputedLinearGradientComponent
	Computed properties for a "<linearGradient>" element. More...
struct	ComputedLocalTransformComponent
	Stores the computed transform value for an entity, relative to the parent. More...
struct	ComputedPathComponent
	Stores a PathSpline used for rendering a shape, which may be generated from the parameters of shapes such as circle, rect, line, poly, and path. More...
struct	ComputedPatternComponent
	Computed properties for "<pattern>" elements, after resolving and inheriting values from referenced patterns. More...
struct	ComputedRadialGradientComponent
	Computed properties for a "<radialGradient>" element. More...
struct	ComputedRectComponent
	Computed properties for a "<rect>" element, which applies values from the CSS cascade. More...
struct	ComputedShadowTreeComponent
	An instantiated ShadowTreeComponent, which points to the roots of parallel entity trees. More...
struct	ComputedSizedElementComponent
	Stores the computed bounds of a sized element, resolving units and percentages. More...
struct	ComputedStopComponent
	Stores the computed properties of a "<stop>" element. More...
struct	ComputedStyleComponent
	Contains the computed style properties for an element, which is a combination of the style="" attribute, the CSS stylesheet, and the CSS cascade where properties are inherited from the parent. More...
struct	ComputedViewboxComponent
	Computed value of a viewbox for the current element. More...
class	DocumentContext
	Holds global state of an SVG document, such as the root element, id-to-element mapping, and the document size. More...
struct	DoNotInheritFillOrStrokeTag
	This component is added to entities to indicate that 'fill' and 'stroke' attributes should not be inherited, which is used for "<pattern>" because it establishes a shadow tree, and we do not want to recursively inherit 'fill' or 'stroke' values into the children. More...
struct	EllipseComponent
	Parameters for a "<ellipse>" element. More...
struct	EllipseProperties
	Parameters for a "<ellipse>" element. More...
struct	EvaluatedReferenceComponent
	Represents a reference to another entity which has been evaluated from a Reference string. More...
struct	FEGaussianBlurComponent
	Parameters for SVGFEGaussianBlurElement. More...
struct	FilterComponent
	Parameters for a "<filter>" element. More...
struct	FilterPrimitiveComponent
	Parameters for SVGFilterPrimitiveStandardAttributes. More...
class	FilterSystem
	Handles parsing and instantiating SVG filter effects from the SVG DOM. More...
struct	GradientComponent
	Common parameters for gradient elements, "<linearGradient>" and "<radialGradient>". More...
struct	IdComponent
	Holds the value of the id attribute of an element. More...
struct	ImageComponent
	Parameters for the "<image>" element. More...
class	LayoutSystem
	Handles layout and bounds calculations for SVG elements. More...
struct	LinearGradientComponent
	Parameters for a "<linearGradient>" element. More...
struct	LineComponent
	Parameters for a "<line>" element. More...
struct	LoadedImageComponent
	Loaded image resource, created from a ImageComponent. More...
struct	MaskComponent
	Parameters for the "<mask>" element. More...
class	OffscreenShadowTreeComponent
	Defines an offscreen shadow tree attached to the current entity (the shadow host). More...
struct	PaintResolvedReference
	Contains rendering information for a paint server, such as the subtree needed if it establishes an isolated layer, and where the paint server is located. More...
class	PaintSystem
	Manages Paint Servers for gradients and patterns, handling style and structural inheritance and creating "computed" state and shadow trees for these elements. More...
struct	PathComponent
	Parameters for a "<path>" element. More...
struct	PathLengthComponent
	Stores a user-overridden path length on an element. More...
struct	PatternComponent
	Parameters for "<pattern>" elements which are not captured by ViewboxComponent and SizedElementComponent. More...
struct	PolyComponent
	Parameters for a "<polygon>" or "<polyline>" element. More...
struct	PreserveAspectRatioComponent
	Stores the preserveAspectRatio attribute of "<svg>" and "<pattern>". More...
struct	RadialGradientComponent
	Parameters for a "<radialGradient>" element. More...
struct	RectComponent
	Parameters for a "<rect>" element. More...
struct	RectProperties
	Parameters for a "<rect>" element. More...
struct	RenderingBehaviorComponent
	Component that controls how the attached element is rendered, determines how different element types are rendered. More...
class	RenderingContext
	Rendering controller, which instantiates and and manages the rendering tree. More...
struct	RenderingInstanceComponent
	An instance of the entity in the rendering tree. More...
struct	ResolvedClipPath
	Contains resolved information about the clip-path property, such as which element it is pointing to. More...
struct	ResolvedMask
	Contains resolved information about the mask property, such as which element it is pointing to. More...
class	ResourceManagerContext
	Resource manager, which handles loading resources from URLs and caching results. More...
struct	ShadowEntityComponent
	A component attached to entities in the shadow tree, indicating which light entity they are mirroring. More...
class	ShadowTreeComponent
	Indicates the entry point to a shadow tree, which instantiates a virtual tree of entities mirroring another entity's tree. More...
class	ShadowTreeSystem
	Instantiates shadow trees for elements that are not part of the main render graph, such as "<use>" and "<pattern>" elements. More...
class	ShapeSystem
	Creates computed path for shapes such as "<circle>", "<line>", and "<path>". More...
struct	SizedElementComponent
	Stores the properties of a sized element, x, y, width, height. More...
struct	SizedElementProperties
	Stores an offset/size for elements that are positioned with x/y/width/height attributes with respect to their parent. More...
struct	StopComponent
	Stores the properties of a "<stop>" element. More...
struct	StopProperties
	Parameters for a "<stop>" element. More...
struct	StyleComponent
	Contains properties the style="" attribute for an element, local to the element. More...
struct	StylesheetComponent
	Data for a "<style>" element. More...
class	StyleSystem
	Computes stylesheet information for elements, applying the CSS cascade and inheritance rules. More...
struct	SubtreeInfo
	Created on the start of a subtree, to inform the renderer about which element ends the current subtree, plus how many isolated layers need to be popped when the subtree is complete. More...
struct	TransformComponent
	Stores the raw transform value set on an entity, for the transform presentation attribute. More...
class	TreeComponent
	Stores the tree structure for an SVG element, such as the parent, children, and siblings. More...
struct	ViewboxComponent
	A component attached to entities that have a viewbox attribute, such as "<svg>" and "<pattern>". More...

Typedefs
using	ResolvedPaintServer
	The resolved paint server for a fill or stroke.
using	ResolvedFilterEffect = std::variant<std::vector<FilterEffect>, ResolvedReference>
	The resolved filter effect for a filter.

Enumerations
enum class	RenderingBehavior {   Default ,   Nonrenderable ,   NoTraverseChildren ,   ShadowOnlyChildren }
	Controls how the attached element is rendered, determines how different element types are rendered. More...
enum class	ShadowBranchType {   Main ,   OffscreenFill ,   OffscreenStroke ,   OffscreenMask }
	There are two types of shadow trees: More...

Functions
bool	HasPaint (const ResolvedPaintServer &paint)
	Returns true if the paint server is not a PaintServer::None.
template<typename Func >
void	ForAllChildren (EntityHandle handle, const Func &func)
	Iterate over all children of the given entity and call the given functor for each child.

Detailed Description

Contains the implementation of the Donner ECS,.

See also

Entity Component System (ECS).

Classes are named as follows:

• *System - Stateless object that accesses and manipulates components.
• *Component - Data storage struct with minimal logic, which may be attached to an Entity.
• Computed*Component - Created when processing the tree and preparing it for rendering, stores intermediate object state derived from regular components. Is used to apply the CSS cascade and to cache shape path data.
• *Context - Contains global state of an SVG document, which are stored in the Registry::ctx().
• *Tag - Used to tag an entity with a specific purpose, like to disable rendering behavior (like inheritance with DoNotInheritFillOrStrokeTag).

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Class Documentation

donner::svg::components::CircleComponent

struct donner::svg::components::CircleComponent

Parameters for a "<circle>" element.

Collaboration diagram for donner::svg::components::CircleComponent:

Class Members
CircleProperties	properties	The properties for the circle.

donner::svg::components::ClassComponent

struct donner::svg::components::ClassComponent

Holds the value of the class attribute of an element.

Collaboration diagram for donner::svg::components::ClassComponent:

Class Members
RcString	className	The value of the class attribute.

donner::svg::components::ClipPathComponent

struct donner::svg::components::ClipPathComponent

Parameters for the "<clipPath>" element.

Class Members
optional< ClipPathUnits >	clipPathUnits	The parsed value of the "clipPathUnits" attribute, which defines the coordinate system for the contents of the clip path.

donner::svg::components::ComputedAbsoluteTransformComponent

struct donner::svg::components::ComputedAbsoluteTransformComponent

Stores the computed transform value for an entity, relative to the world.

This applies the transform from the from all parent entities, and represents the transform of the entity from the root.

Collaboration diagram for donner::svg::components::ComputedAbsoluteTransformComponent:

Class Members
Transformd	entityFromWorld	Transform from the entity from the world.

donner::svg::components::ComputedFilterComponent

struct donner::svg::components::ComputedFilterComponent

Computed filter parameters parsed by FilterSystem, represents the resolved DOM hierarchy of a "<filter>" element.

Collaboration diagram for donner::svg::components::ComputedFilterComponent:

Class Members
vector< FilterEffect >	effectChain	Parsed list of effects, which can be chained together to create complex effects. These are evaluated in order.
FilterUnits	filterUnits = FilterUnits::Default	The computed filter units.
Lengthd	height = Lengthd(120.0, Lengthd::Unit::Percent)	The computed height of the filter.
PrimitiveUnits	primitiveUnits = PrimitiveUnits::Default	The computed primitive units.
Lengthd	width = Lengthd(120.0, Lengthd::Unit::Percent)	The computed width of the filter.
Lengthd	x = Lengthd(-10.0, Lengthd::Unit::Percent)	The computed x-coordinate of the filter.
Lengthd	y = Lengthd(-10.0, Lengthd::Unit::Percent)	The computed y-coordinate of the filter.

donner::svg::components::ComputedLocalTransformComponent

struct donner::svg::components::ComputedLocalTransformComponent

Stores the computed transform value for an entity, relative to the parent.

This resolves presentation attributes and the CSS cascade and stores the resulting value for the current entity.

Collaboration diagram for donner::svg::components::ComputedLocalTransformComponent:

Class Members
Transformd	entityFromParent	Transform from the entity from its parent.
CssTransform	rawCssTransform	Raw CSS transform value, before resolving percentages relative to the viewport.

donner::svg::components::ComputedSizedElementComponent

struct donner::svg::components::ComputedSizedElementComponent

Stores the computed bounds of a sized element, resolving units and percentages.

Contains the computed rect and inherited viewbox of the parent element.

Collaboration diagram for donner::svg::components::ComputedSizedElementComponent:

Class Members
Boxd	bounds	The computed rect of this sized element.
Boxd	inheritedViewbox	The viewbox of the parent element, used for preserveAspectRatio transformations.

donner::svg::components::ComputedStyleComponent

struct donner::svg::components::ComputedStyleComponent

Contains the computed style properties for an element, which is a combination of the style="" attribute, the CSS stylesheet, and the CSS cascade where properties are inherited from the parent.

Class Members
optional< PropertyRegistry >	properties	The computed style properties. std::nullopt may be present mid-computation before all properties have been cascaded.

donner::svg::components::ComputedViewboxComponent

struct donner::svg::components::ComputedViewboxComponent

Computed value of a viewbox for the current element.

If this element does not define a viewbox, this is the viewbox of the nearest ancestor or the document itself.

Collaboration diagram for donner::svg::components::ComputedViewboxComponent:

Class Members
Boxd	viewbox	The viewbox of the element, or the viewbox of the nearest ancestor.

donner::svg::components::DoNotInheritFillOrStrokeTag

struct donner::svg::components::DoNotInheritFillOrStrokeTag

This component is added to entities to indicate that 'fill' and 'stroke' attributes should not be inherited, which is used for "<pattern>" because it establishes a shadow tree, and we do not want to recursively inherit 'fill' or 'stroke' values into the children.

donner::svg::components::EllipseComponent

struct donner::svg::components::EllipseComponent

Parameters for a "<ellipse>" element.

Collaboration diagram for donner::svg::components::EllipseComponent:

Class Members
EllipseProperties	properties	The properties of the ellipse.

donner::svg::components::EvaluatedReferenceComponent

struct donner::svg::components::EvaluatedReferenceComponent

template<typename ReferenceType>
struct donner::svg::components::EvaluatedReferenceComponent< ReferenceType >

Represents a reference to another entity which has been evaluated from a Reference string.

This is used by PaintSystem for gradients and patterns which have an href attribute for inheritance.

Template Parameters

ReferenceType

tag which determines which subsystem the reference is for, used to avoid collisions.

Class Members
typedef ReferenceType	Type ReferenceType	Tag type of this reference.

Class Members
EntityHandle	target	The resolved target entity of the reference.

donner::svg::components::FEGaussianBlurComponent

struct donner::svg::components::FEGaussianBlurComponent

Parameters for SVGFEGaussianBlurElement.

Class Members
double	stdDeviationX = 0.0	The standard deviation of the Gaussian blur in the x direction.
double	stdDeviationY = 0.0	The standard deviation of the Gaussian blur in the y direction.

donner::svg::components::FilterComponent

struct donner::svg::components::FilterComponent

Parameters for a "<filter>" element.

Contains the filter bounds, which determines how large the canvas needs to be when applying the filter, and filter configuration such as units for its parameters.

Class Members
FilterUnits	filterUnits = FilterUnits::Default	The parsed value of the "filterUnits" attribute, which defines the coordinate system for the x, y, width, and height attributes of the mask.
optional< Lengthd >	height	Height of the filter, defaults to 120% (outside of the element itself).
PrimitiveUnits	primitiveUnits = PrimitiveUnits::Default	The parsed value of the "primitiveUnits" attribute, which defines the coordinate system for the various attributes of the filter effects.
optional< Lengthd >	width	Width of the filter, defaults to 120% (outside of the element itself).
optional< Lengthd >	x	The x-coordinate of the filter, defaults to -10% (outside the element itself).
optional< Lengthd >	y	The y-coordinate of the filter, defaults to -10% (outside the element itself).

donner::svg::components::FilterPrimitiveComponent

struct donner::svg::components::FilterPrimitiveComponent

Parameters for SVGFilterPrimitiveStandardAttributes.

Class Members
optional< Lengthd >	height	The height of the filter region.
optional< RcString >	result	Name of the filter primitive, which enables it to be used as a reference for subsequent filter primitives under the same "<filter>" element.
optional< Lengthd >	width	The width of the filter region.
optional< Lengthd >	x	The x-coordinate of the filter region.
optional< Lengthd >	y	The y-coordinate of the filter region.

donner::svg::components::GradientComponent

struct donner::svg::components::GradientComponent

Common parameters for gradient elements, "<linearGradient>" and "<radialGradient>".

When this component is present, either LinearGradientComponent or RadialGradientComponent must be present.

Class Members
optional< GradientUnits >	gradientUnits	The parsed value of the "gradientUnits" attribute, which specifies how the coordinate system for linear/radial gradient positional attributes (such as x1, y1, cx, cy). Empty if no attribute was specified.
optional< Reference >	href	The parsed value of the "href" attribute, which specifies a reference to a gradient element to inherit from.
optional< GradientSpreadMethod >	spreadMethod	The parsed value of the "spreadMethod" attribute, which specifies how the gradient is repeated on its edges (such as spread, reflect, or repeat). Empty if no attribute was specified.

donner::svg::components::IdComponent

struct donner::svg::components::IdComponent

Holds the value of the id attribute of an element.

Collaboration diagram for donner::svg::components::IdComponent:

Class Members
RcString	id	The value of the id attribute, the element ID.

donner::svg::components::ImageComponent

struct donner::svg::components::ImageComponent

Parameters for the "<image>" element.

Collaboration diagram for donner::svg::components::ImageComponent:

Class Members
RcString	href	URI to the image resource, which can either be a file path, URL, or data URL (e.g. "data:image/png;base64,...").

donner::svg::components::LineComponent

struct donner::svg::components::LineComponent

Parameters for a "<line>" element.

Note that unlike other elements, the x1, y1, x2, and y2 properties are not presentation attributes, so they must be specified on the element and not through CSS. This means that we don't need a ComputedLineComponent counterpart of this struct.

From https://www.w3.org/TR/SVG2/shapes.html#LineElement

‍A future specification may convert the ‘x1’, ‘y1’, ‘x2’, and ‘y2’ attributes to geometric properties. Currently, they can only be specified via element attributes, and not CSS.

Collaboration diagram for donner::svg::components::LineComponent:

Class Members
Lengthd	x1	The x-coordinate of the start of the line.
Lengthd	x2	The x-coordinate of the end of the line.
Lengthd	y1	The y-coordinate of the start of the line.
Lengthd	y2	The y-coordinate of the end of the line.

donner::svg::components::LoadedImageComponent

struct donner::svg::components::LoadedImageComponent

Loaded image resource, created from a ImageComponent.

Class Members
optional< ImageResource >	image	Loaded image resource.

donner::svg::components::PaintResolvedReference

struct donner::svg::components::PaintResolvedReference

Contains rendering information for a paint server, such as the subtree needed if it establishes an isolated layer, and where the paint server is located.

Collaboration diagram for donner::svg::components::PaintResolvedReference:

Class Members
optional< Color >	fallback	Fallback color to use if this paint fails to instantiate. This can happen for various reasons, such as if a gradient has no stops (making it invalid).
ResolvedReference	reference	Reference to the paint server element.
optional< SubtreeInfo >	subtreeInfo	If this paint server creates a subtree, such as for patterns, contains subtree info to inform the renderer how to render it.

donner::svg::components::PathLengthComponent

struct donner::svg::components::PathLengthComponent

Stores a user-overridden path length on an element.

If the user has not overridden the path length, this component will not be attached.

Class Members
double	value	The user-overridden path length, in user units.

donner::svg::components::PatternComponent

struct donner::svg::components::PatternComponent

Parameters for "<pattern>" elements which are not captured by ViewboxComponent and SizedElementComponent.

Collaboration diagram for donner::svg::components::PatternComponent:

Class Members
optional< Reference >	href	An optional href to another pattern, which is used to inherit properties from if not by this entity.
optional< PatternContentUnits >	patternContentUnits	The pattern content units of the pattern, if std::nullopt, the pattern content units are inherited from the parent or defaulted to PatternContentUnits::Default.
optional< PatternUnits >	patternUnits	The pattern units of the pattern, if std::nullopt, the pattern units are inherited from the parent or defaulted to PatternUnits::Default.
SizedElementProperties	sizeProperties	Contains the x, y, width, and height properties of the pattern tile rectangle.

donner::svg::components::PreserveAspectRatioComponent

struct donner::svg::components::PreserveAspectRatioComponent

Stores the preserveAspectRatio attribute of "<svg>" and "<pattern>".

Collaboration diagram for donner::svg::components::PreserveAspectRatioComponent:

Class Members
PreserveAspectRatio	preserveAspectRatio	The preserveAspectRatio of the element, defaults to PreserveAspectRatio::None().

donner::svg::components::RectComponent

struct donner::svg::components::RectComponent

Parameters for a "<rect>" element.

Collaboration diagram for donner::svg::components::RectComponent:

Class Members
RectProperties	properties	The properties of the rectangle.

donner::svg::components::ShadowEntityComponent

struct donner::svg::components::ShadowEntityComponent

A component attached to entities in the shadow tree, indicating which light entity they are mirroring.

This component exists on every shadow entity, forming a one-to-one mapping between shadow entities and light entities.

Class Members
Entity	lightEntity	The entity that this shadow entity is mirroring.

donner::svg::components::SizedElementComponent

struct donner::svg::components::SizedElementComponent

Stores the properties of a sized element, x, y, width, height.

Used for "<svg>", "<image>" and xml_foreignObject by the standard, and also internally with "<use>" for Donner.

Collaboration diagram for donner::svg::components::SizedElementComponent:

Class Members
SizedElementProperties	properties	The properties of the sized element, x, y, width, height.

donner::svg::components::StopComponent

struct donner::svg::components::StopComponent

Stores the properties of a "<stop>" element.

Collaboration diagram for donner::svg::components::StopComponent:

Class Members
StopProperties	properties	The properties of the "<stop>" element.

donner::svg::components::SubtreeInfo

struct donner::svg::components::SubtreeInfo

Created on the start of a subtree, to inform the renderer about which element ends the current subtree, plus how many isolated layers need to be popped when the subtree is complete.

Class Members
Entity	lastRenderedEntity	Indicates the last entity within the current subtree. The renderer will continue rendering entities until it reaches this one, then it will pop restorePopDepth isolated layers from the render state.
int	restorePopDepth = 0	How many isolated layers to pop after rendering this entity.

donner::svg::components::TransformComponent

struct donner::svg::components::TransformComponent

Stores the raw transform value set on an entity, for the transform presentation attribute.

This can be sourced from the transform="..." XML attribute, or from the transform CSS property.

Collaboration diagram for donner::svg::components::TransformComponent:

Class Members
Property< CssTransform >	transform	Value of the transform, if it is set. Defaults to std::nullopt. Represents the entity-from-parent transform.

donner::svg::components::ViewboxComponent

struct donner::svg::components::ViewboxComponent

A component attached to entities that have a viewbox attribute, such as "<svg>" and "<pattern>".

Class Members
optional< Boxd >	viewbox	Stored viewbox, if any.

Typedef Documentation

ResolvedPaintServer

using donner::svg::components::ResolvedPaintServer

Initial value:

 
    std::variant<PaintServer::None, PaintServer::Solid, PaintResolvedReference>

The resolved paint server for a fill or stroke.

Enumeration Type Documentation

RenderingBehavior

enum class donner::svg::components::RenderingBehavior

strong

Controls how the attached element is rendered, determines how different element types are rendered.

Enumerator
Default	The default rendering behavior, which renders and traverses children.
Nonrenderable	The element and its children are not rendered.
NoTraverseChildren	The element is rendered, but its children are not traversed.
ShadowOnlyChildren	Only traverse this element's children within a shadow tree instantiation.

ShadowBranchType

enum class donner::svg::components::ShadowBranchType

strong

There are two types of shadow trees:

• Main: One for elements in the main render graph, such as "<use>" elements, where each "<use>" element holds one instantiation, which behaves as if the referenced element was copy-pasted within the tree.
• Offscreen: Shadow trees for paint servers and offscreen purposes, which are not enumerated as part of the render graph. For example, a 'fill' attribute may reference a "<pattern>" paint server, which needs to be rendered into a buffer before being tiled into the main render graph.

Shadow trees always belong to specific branches, and there are no multiples; there are a finite number of branches. To enable this, list each branch individually, with everything except Main being an offscreen branch.

Enumerator
Main	For entities enumerated in the main render graph.
OffscreenFill	For 'fill' attributes.
OffscreenStroke	For 'stroke' attributes.
OffscreenMask	For mask contents, used for the 'mask' attribute.

Function Documentation

ForAllChildren()

template<typename Func >

void donner::svg::components::ForAllChildren	(	EntityHandle	handle,
		const Func &	func )

Iterate over all children of the given entity and call the given functor for each child.

Iterates in pre-order traversal order.

Parameters

handle	Entity handle to iterate over.
func	Functor to call for each child.

HasPaint()

bool donner::svg::components::HasPaint ( const ResolvedPaintServer & paint )

inline

Returns true if the paint server is not a PaintServer::None.

Parameters

paint

The paint server to check.

Returns

True if the paint server is not a PaintServer::None.