Initial commit
This commit is contained in:
Sasha Koshka
11
shapes/doc.go
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11
shapes/doc.go
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@@ -0,0 +1,11 @@
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// Package shapes provides some basic shape drawing routines.
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//
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// A word about using patterns with shape routines:
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//
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// Most drawing routines have a version that samples from other canvases, and a
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// version that samples from a solid color. None of these routines can use
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// patterns directly, but it is entirely possible to have a pattern draw to an
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// off-screen canvas and then draw a shape based on that canvas. As a little
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// bonus, you can save the canvas for later so you don't have to render the
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// pattern again when you need to redraw the shape.
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package shapes
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231
shapes/ellipse.go
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231
shapes/ellipse.go
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@@ -0,0 +1,231 @@
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package shapes
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import "art"
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import "math"
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import "image"
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import "image/color"
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// TODO: redo fill ellipse, stroke ellipse, etc. so that it only takes in
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// destination and source, using the bounds of destination as the bounds of the
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// ellipse and the bounds of source as the "clipping rectangle". Line up the Min
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// of both canvases.
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func FillEllipse (
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destination art.Canvas,
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source art.Canvas,
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bounds image.Rectangle,
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) (
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updatedRegion image.Rectangle,
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) {
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dstData, dstStride := destination.Buffer()
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srcData, srcStride := source.Buffer()
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offset := source.Bounds().Min.Sub(destination.Bounds().Min)
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drawBounds :=
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source.Bounds().Sub(offset).
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Intersect(destination.Bounds()).
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Intersect(bounds)
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if bounds.Empty() { return }
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updatedRegion = bounds
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point := image.Point { }
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for point.Y = drawBounds.Min.Y; point.Y < drawBounds.Max.Y; point.Y ++ {
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for point.X = drawBounds.Min.X; point.X < drawBounds.Max.X; point.X ++ {
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if inEllipse(point, bounds) {
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offsetPoint := point.Add(offset)
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dstIndex := point.X + point.Y * dstStride
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srcIndex := offsetPoint.X + offsetPoint.Y * srcStride
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dstData[dstIndex] = srcData[srcIndex]
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}
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}}
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return
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}
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func StrokeEllipse (
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destination art.Canvas,
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source art.Canvas,
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bounds image.Rectangle,
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weight int,
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) {
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if weight < 1 { return }
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dstData, dstStride := destination.Buffer()
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srcData, srcStride := source.Buffer()
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drawBounds := destination.Bounds().Inset(weight - 1)
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offset := source.Bounds().Min.Sub(destination.Bounds().Min)
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if drawBounds.Empty() { return }
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context := ellipsePlottingContext {
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plottingContext: plottingContext {
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dstData: dstData,
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dstStride: dstStride,
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srcData: srcData,
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srcStride: srcStride,
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weight: weight,
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offset: offset,
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bounds: bounds,
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},
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radii: image.Pt(drawBounds.Dx() / 2, drawBounds.Dy() / 2),
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}
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context.center = drawBounds.Min.Add(context.radii)
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context.plotEllipse()
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}
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type ellipsePlottingContext struct {
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plottingContext
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radii image.Point
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center image.Point
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}
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func (context ellipsePlottingContext) plotEllipse () {
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x := float64(0)
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y := float64(context.radii.Y)
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// region 1 decision parameter
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decision1 :=
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float64(context.radii.Y * context.radii.Y) -
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float64(context.radii.X * context.radii.X * context.radii.Y) +
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(0.25 * float64(context.radii.X) * float64(context.radii.X))
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decisionX := float64(2 * context.radii.Y * context.radii.Y * int(x))
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decisionY := float64(2 * context.radii.X * context.radii.X * int(y))
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// draw region 1
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for decisionX < decisionY {
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points := []image.Point {
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image.Pt(-int(x) + context.center.X, -int(y) + context.center.Y),
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image.Pt( int(x) + context.center.X, -int(y) + context.center.Y),
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image.Pt(-int(x) + context.center.X, int(y) + context.center.Y),
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image.Pt( int(x) + context.center.X, int(y) + context.center.Y),
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}
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if context.srcData == nil {
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context.plotColor(points[0])
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context.plotColor(points[1])
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context.plotColor(points[2])
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context.plotColor(points[3])
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} else {
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context.plotSource(points[0])
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context.plotSource(points[1])
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context.plotSource(points[2])
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context.plotSource(points[3])
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}
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if (decision1 < 0) {
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x ++
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decisionX += float64(2 * context.radii.Y * context.radii.Y)
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decision1 += decisionX + float64(context.radii.Y * context.radii.Y)
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} else {
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x ++
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y --
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decisionX += float64(2 * context.radii.Y * context.radii.Y)
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decisionY -= float64(2 * context.radii.X * context.radii.X)
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decision1 +=
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decisionX - decisionY +
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float64(context.radii.Y * context.radii.Y)
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}
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}
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// region 2 decision parameter
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decision2 :=
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float64(context.radii.Y * context.radii.Y) * (x + 0.5) * (x + 0.5) +
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float64(context.radii.X * context.radii.X) * (y - 1) * (y - 1) -
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float64(context.radii.X * context.radii.X * context.radii.Y * context.radii.Y)
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// draw region 2
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for y >= 0 {
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points := []image.Point {
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image.Pt( int(x) + context.center.X, int(y) + context.center.Y),
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image.Pt(-int(x) + context.center.X, int(y) + context.center.Y),
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image.Pt( int(x) + context.center.X, -int(y) + context.center.Y),
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image.Pt(-int(x) + context.center.X, -int(y) + context.center.Y),
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}
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if context.srcData == nil {
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context.plotColor(points[0])
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context.plotColor(points[1])
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context.plotColor(points[2])
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context.plotColor(points[3])
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} else {
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context.plotSource(points[0])
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context.plotSource(points[1])
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context.plotSource(points[2])
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context.plotSource(points[3])
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}
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if decision2 > 0 {
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y --
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decisionY -= float64(2 * context.radii.X * context.radii.X)
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decision2 += float64(context.radii.X * context.radii.X) - decisionY
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} else {
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y --
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x ++
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decisionX += float64(2 * context.radii.Y * context.radii.Y)
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decisionY -= float64(2 * context.radii.X * context.radii.X)
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decision2 +=
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decisionX - decisionY +
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float64(context.radii.X * context.radii.X)
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}
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}
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}
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// FillColorEllipse fills an ellipse within the destination canvas with a solid
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// color.
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func FillColorEllipse (
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destination art.Canvas,
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color color.RGBA,
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bounds image.Rectangle,
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) (
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updatedRegion image.Rectangle,
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) {
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dstData, dstStride := destination.Buffer()
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realBounds := bounds
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bounds = bounds.Intersect(destination.Bounds()).Canon()
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if bounds.Empty() { return }
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updatedRegion = bounds
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point := image.Point { }
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for point.Y = bounds.Min.Y; point.Y < bounds.Max.Y; point.Y ++ {
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for point.X = bounds.Min.X; point.X < bounds.Max.X; point.X ++ {
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if inEllipse(point, realBounds) {
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dstData[point.X + point.Y * dstStride] = color
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}
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}}
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return
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}
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// StrokeColorEllipse is similar to FillColorEllipse, but it draws an inset
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// outline of an ellipse instead.
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func StrokeColorEllipse (
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destination art.Canvas,
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color color.RGBA,
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bounds image.Rectangle,
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weight int,
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) (
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updatedRegion image.Rectangle,
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) {
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if weight < 1 { return }
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dstData, dstStride := destination.Buffer()
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insetBounds := bounds.Inset(weight - 1)
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context := ellipsePlottingContext {
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plottingContext: plottingContext {
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dstData: dstData,
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dstStride: dstStride,
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color: color,
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weight: weight,
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bounds: bounds.Intersect(destination.Bounds()),
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},
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radii: image.Pt(insetBounds.Dx() / 2, insetBounds.Dy() / 2),
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}
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context.center = insetBounds.Min.Add(context.radii)
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context.plotEllipse()
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return
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}
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func inEllipse (point image.Point, bounds image.Rectangle) bool {
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point = point.Sub(bounds.Min)
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x := (float64(point.X) + 0.5) / float64(bounds.Dx()) - 0.5
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y := (float64(point.Y) + 0.5) / float64(bounds.Dy()) - 0.5
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return math.Hypot(x, y) <= 0.5
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}
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110
shapes/line.go
Normal file
110
shapes/line.go
Normal file
@@ -0,0 +1,110 @@
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package shapes
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import "art"
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import "image"
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import "image/color"
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// ColorLine draws a line from one point to another with the specified weight
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// and color.
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func ColorLine (
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destination art.Canvas,
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color color.RGBA,
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weight int,
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min image.Point,
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max image.Point,
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) (
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updatedRegion image.Rectangle,
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) {
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updatedRegion = image.Rectangle { Min: min, Max: max }.Canon()
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updatedRegion.Max.X ++
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updatedRegion.Max.Y ++
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data, stride := destination.Buffer()
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bounds := destination.Bounds()
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context := linePlottingContext {
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plottingContext: plottingContext {
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dstData: data,
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dstStride: stride,
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color: color,
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weight: weight,
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bounds: bounds,
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},
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min: min,
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max: max,
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}
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if abs(max.Y - min.Y) < abs(max.X - min.X) {
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if max.X < min.X { context.swap() }
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context.lineLow()
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} else {
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if max.Y < min.Y { context.swap() }
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context.lineHigh()
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}
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return
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}
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type linePlottingContext struct {
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plottingContext
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min image.Point
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max image.Point
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}
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func (context *linePlottingContext) swap () {
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temp := context.max
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context.max = context.min
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context.min = temp
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}
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func (context linePlottingContext) lineLow () {
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deltaX := context.max.X - context.min.X
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deltaY := context.max.Y - context.min.Y
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yi := 1
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if deltaY < 0 {
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yi = -1
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deltaY *= -1
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}
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D := (2 * deltaY) - deltaX
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point := context.min
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for ; point.X < context.max.X; point.X ++ {
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context.plotColor(point)
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if D > 0 {
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D += 2 * (deltaY - deltaX)
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point.Y += yi
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} else {
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D += 2 * deltaY
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}
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}
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}
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func (context linePlottingContext) lineHigh () {
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deltaX := context.max.X - context.min.X
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deltaY := context.max.Y - context.min.Y
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xi := 1
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if deltaX < 0 {
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xi = -1
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deltaX *= -1
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}
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D := (2 * deltaX) - deltaY
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point := context.min
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for ; point.Y < context.max.Y; point.Y ++ {
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context.plotColor(point)
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if D > 0 {
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point.X += xi
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D += 2 * (deltaX - deltaY)
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} else {
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D += 2 * deltaX
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}
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}
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}
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func abs (n int) int {
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if n < 0 { n *= -1}
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return n
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}
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47
shapes/plot.go
Normal file
47
shapes/plot.go
Normal file
@@ -0,0 +1,47 @@
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package shapes
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import "image"
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import "image/color"
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// FIXME? drawing a ton of overlapping squares might be a bit wasteful.
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type plottingContext struct {
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dstData []color.RGBA
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dstStride int
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srcData []color.RGBA
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srcStride int
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color color.RGBA
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weight int
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offset image.Point
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bounds image.Rectangle
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}
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func (context plottingContext) square (center image.Point) (square image.Rectangle) {
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return image.Rect(0, 0, context.weight, context.weight).
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Sub(image.Pt(context.weight / 2, context.weight / 2)).
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Add(center).
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Intersect(context.bounds)
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}
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func (context plottingContext) plotColor (center image.Point) {
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square := context.square(center)
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for y := square.Min.Y; y < square.Max.Y; y ++ {
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for x := square.Min.X; x < square.Max.X; x ++ {
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context.dstData[x + y * context.dstStride] = context.color
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}}
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}
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func (context plottingContext) plotSource (center image.Point) {
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square := context.square(center)
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for y := square.Min.Y; y < square.Max.Y; y ++ {
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for x := square.Min.X; x < square.Max.X; x ++ {
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// we offset srcIndex here because we have already applied the
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// offset to the square, and we need to reverse that to get the
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// proper source coordinates.
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srcIndex :=
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x + context.offset.X +
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(y + context.offset.Y) * context.dstStride
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dstIndex := x + y * context.dstStride
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context.dstData[dstIndex] = context.srcData [srcIndex]
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}}
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}
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130
shapes/rectangle.go
Normal file
130
shapes/rectangle.go
Normal file
@@ -0,0 +1,130 @@
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package shapes
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import "art"
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import "image"
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import "art/shatter"
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import "image/color"
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// TODO: return updatedRegion for all routines in this package
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func FillRectangle (
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destination art.Canvas,
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source art.Canvas,
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bounds image.Rectangle,
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) (
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updatedRegion image.Rectangle,
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) {
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dstData, dstStride := destination.Buffer()
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srcData, srcStride := source.Buffer()
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offset := source.Bounds().Min.Sub(destination.Bounds().Min)
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drawBounds :=
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source.Bounds().Sub(offset).
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Intersect(destination.Bounds()).
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Intersect(bounds)
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if drawBounds.Empty() { return }
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updatedRegion = drawBounds
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point := image.Point { }
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for point.Y = drawBounds.Min.Y; point.Y < drawBounds.Max.Y; point.Y ++ {
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for point.X = drawBounds.Min.X; point.X < drawBounds.Max.X; point.X ++ {
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offsetPoint := point.Add(offset)
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dstIndex := point.X + point.Y * dstStride
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srcIndex := offsetPoint.X + offsetPoint.Y * srcStride
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dstData[dstIndex] = srcData[srcIndex]
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}}
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|
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return
|
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}
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func StrokeRectangle (
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destination art.Canvas,
|
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source art.Canvas,
|
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bounds image.Rectangle,
|
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weight int,
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) (
|
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updatedRegion image.Rectangle,
|
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) {
|
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insetBounds := bounds.Inset(weight)
|
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if insetBounds.Empty() {
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return FillRectangle(destination, source, bounds)
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}
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return FillRectangleShatter(destination, source, bounds, insetBounds)
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}
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|
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// FillRectangleShatter is like FillRectangle, but it does not draw in areas
|
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// specified in "rocks".
|
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func FillRectangleShatter (
|
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destination art.Canvas,
|
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source art.Canvas,
|
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bounds image.Rectangle,
|
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rocks ...image.Rectangle,
|
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) (
|
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updatedRegion image.Rectangle,
|
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) {
|
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tiles := shatter.Shatter(bounds, rocks...)
|
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for _, tile := range tiles {
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FillRectangle (
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art.Cut(destination, tile),
|
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source, tile)
|
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updatedRegion = updatedRegion.Union(tile)
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
// FillColorRectangle fills a rectangle within the destination canvas with a
|
||||
// solid color.
|
||||
func FillColorRectangle (
|
||||
destination art.Canvas,
|
||||
color color.RGBA,
|
||||
bounds image.Rectangle,
|
||||
) (
|
||||
updatedRegion image.Rectangle,
|
||||
) {
|
||||
dstData, dstStride := destination.Buffer()
|
||||
bounds = bounds.Canon().Intersect(destination.Bounds())
|
||||
if bounds.Empty() { return }
|
||||
|
||||
updatedRegion = bounds
|
||||
for y := bounds.Min.Y; y < bounds.Max.Y; y ++ {
|
||||
for x := bounds.Min.X; x < bounds.Max.X; x ++ {
|
||||
dstData[x + y * dstStride] = color
|
||||
}}
|
||||
|
||||
return
|
||||
}
|
||||
|
||||
// FillColorRectangleShatter is like FillColorRectangle, but it does not draw in
|
||||
// areas specified in "rocks".
|
||||
func FillColorRectangleShatter (
|
||||
destination art.Canvas,
|
||||
color color.RGBA,
|
||||
bounds image.Rectangle,
|
||||
rocks ...image.Rectangle,
|
||||
) (
|
||||
updatedRegion image.Rectangle,
|
||||
) {
|
||||
tiles := shatter.Shatter(bounds, rocks...)
|
||||
for _, tile := range tiles {
|
||||
FillColorRectangle(destination, color, tile)
|
||||
updatedRegion = updatedRegion.Union(tile)
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
// StrokeColorRectangle is similar to FillColorRectangle, but it draws an inset
|
||||
// outline of the given rectangle instead.
|
||||
func StrokeColorRectangle (
|
||||
destination art.Canvas,
|
||||
color color.RGBA,
|
||||
bounds image.Rectangle,
|
||||
weight int,
|
||||
) (
|
||||
updatedRegion image.Rectangle,
|
||||
) {
|
||||
insetBounds := bounds.Inset(weight)
|
||||
if insetBounds.Empty() {
|
||||
return FillColorRectangle(destination, color, bounds)
|
||||
}
|
||||
return FillColorRectangleShatter(destination, color, bounds, insetBounds)
|
||||
}
|
||||
Reference in New Issue
Block a user