97 lines
2.5 KiB
Go
97 lines
2.5 KiB
Go
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package xcanvas
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import "image"
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import "image/color"
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import "github.com/jezek/xgbutil"
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import "git.tebibyte.media/tomo/ggfx"
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import "github.com/jezek/xgbutil/xgraphics"
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import "git.tebibyte.media/tomo/tomo/canvas"
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// Canvas satisfies the canvas.Canvas interface. It draws to an xgraphics.Image.
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type Canvas struct {
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*xgraphics.Image
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}
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// New creates a new canvas from a bounding rectangle.
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func New (x *xgbutil.XUtil, bounds image.Rectangle) Canvas {
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return Canvas { xgraphics.New(x, bounds) }
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}
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// NewFrom creates a new canvas from an existing xgraphics.Image.
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func NewFrom (image *xgraphics.Image) Canvas {
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return Canvas { image }
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}
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// Pen returns a new drawing context.
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func (this Canvas) Pen () canvas.Pen {
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return pen {
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image: this.Image,
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gfx: ggfx.Image[uint8] {
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Pix: this.Image.Pix,
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Stride: this.Image.Stride,
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Bounds: this.Image.Rect,
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Width: 4,
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},
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}
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}
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// Clip returns a sub-canvas of this canvas.
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func (this Canvas) Clip (bounds image.Rectangle) Canvas {
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return Canvas { this.Image.SubImage(bounds).(*xgraphics.Image) }
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}
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// TODO: we need to implement:
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// - cap
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// - joint
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// - align
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type pen struct {
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image *xgraphics.Image
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gfx ggfx.Image[uint8]
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closed bool
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endCap canvas.Cap
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joint canvas.Joint
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weight int
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align canvas.StrokeAlign
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stroke [4]uint8
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fill [4]uint8
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}
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func (this pen) Rectangle (bounds image.Rectangle) {
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if this.weight == 0 {
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this.gfx.FillRectangle(this.fill[:], bounds)
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} else {
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this.gfx.StrokeRectangle(this.stroke[:], this.weight, bounds)
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}
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}
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func (this pen) Path (points ...image.Point) {
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if this.weight == 0 {
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this.gfx.FillPolygon(this.fill[:], points...)
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} else if this.closed {
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this.gfx.StrokePolygon(this.stroke[:], this.weight, points...)
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} else {
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this.gfx.PolyLine(this.stroke[:], this.weight, points...)
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}
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}
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func (this pen) Closed (closed bool) { this.closed = closed }
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func (this pen) Cap (endCap canvas.Cap) { this.endCap = endCap }
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func (this pen) Joint (joint canvas.Joint) { this.joint = joint }
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func (this pen) StrokeWeight (weight int) { this.weight = weight }
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func (this pen) StrokeAlign (align canvas.StrokeAlign) { this.align = align }
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func (this pen) Stroke (stroke color.Color) { this.stroke = convertColor(stroke) }
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func (this pen) Fill (fill color.Color) { this.fill = convertColor(fill) }
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func convertColor (c color.Color) [4]uint8 {
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r, g, b, a := c.RGBA()
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return [4]uint8 {
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uint8(b >> 8),
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uint8(g >> 8),
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uint8(a >> 8),
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uint8(r >> 8),
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}
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}
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