layout

type Command struct {
	Op      string
	ID      string
	Rect    Rect
	Color   css.Color
	Opacity float64
	Widths  Edges
	Colors  css.ColorSides
	Radii   [4]float64
	Shadow  *css.Shadow `json:",omitempty"`
	Text    string      `json:",omitempty"`
	Runs    []Run       `json:",omitempty"`
	Image   image.Image `json:"-"`
}

type Edges struct{ Top, Right, Bottom, Left float64 }

type Glyph struct {
	ID            uint32
	X, Y, Advance float64
	Cluster       int
}

type Kind string

type Measure func(width float64) (Size, []text.Line, error)

type Node struct {
	ID               string
	Kind             Kind
	Style            *css.Style
	Children         []*Node
	Content          string
	ImageSize        Size
	Image            image.Image `json:"-"`
	Measure          Measure     `json:"-"`
	ScrollX, ScrollY float64
	NoWrap           bool // measure text at unbounded width; useful for single-line editors
	EditorScroll     bool // clip and clamp own text on both axes, without child scrolling
	// Rect, when HasRect is set on a direct child of a Stack, is the child's
	// border-box geometry relative to the Stack's content box. It replaces the
	// child's authored width, height and margin; it is ignored elsewhere.
	// A flex-styled Stack with a visible Rect child is rejected.
	Rect    Rect
	HasRect bool
}

type Options struct {
	Width, Height float64
	TextEngine    *text.Engine
}

type Output struct {
	Tree    *Result
	Display []Command
}

type Rect struct{ X, Y, W, H float64 }

type Result struct {
	ID                            string
	Kind                          Kind
	Border, Content, Clip         Rect
	Margin, Padding, BorderWidths Edges
	ContentSize                   Size
	ScrollX, ScrollY              float64
	Lines                         []text.Line `json:"-"`
	Children                      []*Result
	Clipped                       bool
}

type Run struct {
	Start, End    int
	X, Y, Advance float64
	// Face is borrowed for in-process rasterization. FaceID and Size preserve
	// the shaping identity and logical pixel size in serialized display lists.
	Face   *text.Face `json:"-"`
	FaceID string
	Size   float64
	Glyphs []Glyph
}

type Size struct{ W, H float64 }