render

type Bounds struct {
	// Rect is a rectangular bounding box.
	Rect math32.Box2

	// Radius is the border radius for rounded rectangles, can be per corner
	// or one value for all.
	Radius sides.Floats

	// Path is the computed clipping path for the Rect and Radius.
	Path ppath.Path
}

type Context struct {

	// Style has the accumulated style values.
	// Individual elements inherit from this style.
	Style styles.Paint

	// Transform is the transformation matrix for this stack level.
	Transform math32.Matrix2

	// Cumulative is the accumulated transformation matrix.
	Cumulative math32.Matrix2

	// Bounds is the rounded rectangle clip boundary.
	// This is applied to the effective Path prior to adding to Render.
	Bounds Bounds

	// ClipPath is the current shape-based clipping path,
	// in addition to the Bounds, which is applied to the effective Path
	// prior to adding to Render.
	ClipPath ppath.Path

	// Mask is the current masking element, as rendered to a separate image.
	// This is composited with the rendering output to produce the final result.
	Mask image.Image
}

type ContextPop struct {
}

type ContextPush struct {
	Context Context
}

type Item interface {
	fmt.Stringer

	IsRenderItem()
}

type Path struct {
	// Path specifies the shape(s) to be drawn, using commands:
	// MoveTo, LineTo, QuadTo, CubeTo, ArcTo, and Close.
	// Each command has the applicable coordinates appended after it,
	// like the SVG path element. The coordinates are in the original
	// units as specified in the Paint drawing commands, without any
	// transforms applied. See [Path.Transform].
	Path ppath.Path

	// Context has the full accumulated style, transform, etc parameters
	// for rendering the path, combining the current state context (e.g.,
	// from any higher-level groups) with the current element's style parameters.
	Context Context
}

type Render []Item

type Renderer interface {

	// Render renders the given Render data.
	Render(r Render) Renderer

	// Size returns the size of the render target, in its preferred units.
	// For [Image] types, it will be [units.UnitDot] to indicate the actual
	// raw pixel size.
	Size() (units.Units, math32.Vector2)

	// SetSize sets the render size in given units. [units.UnitDot] is
	// used for [Image] and [Draw] renderers. Direct configuration of
	// other Renderer properties happens outside of this interface.
	// This is used for resizing [Image] and [Draw] renderers when
	// the relevant Scene size changes.
	SetSize(un units.Units, size math32.Vector2)

	// Image returns the rendered image after rendering.
	// If nil, then images are not supported by this renderer.
	Image() image.Image

	// Source returns the document source code representation
	// of the rendering output. This is supported by e.g., SVG
	// and PDF renderers.
	Source() []byte
}

type Text struct {
	// Text contains shaped Lines of text to be rendered, as produced by a
	// [shaped.Shaper]. Typically this text is  configured so that the
	// Postion is at the upper left corner of the resulting text rendering.
	Text *shaped.Lines

	// Position to render, which typically specifies the upper left corner of
	// the Text. This is added directly to the offsets and is transformed by the
	// active transform matrix. See also PositionAbs
	Position math32.Vector2

	// Context has the full accumulated style, transform, etc parameters
	// for rendering, combining the current state context (e.g.,
	// from any higher-level groups) with the current element's style parameters.
	Context Context
}