Ellipse and rectangle have both color and source routines
This commit is contained in:
parent
211219eb01
commit
bf2fdb5eaa
@ -2,6 +2,7 @@ package shapes
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import "math"
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import "image"
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import "image/color"
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import "git.tebibyte.media/sashakoshka/tomo/canvas"
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// FillEllipse draws the content of one canvas onto another, clipped by an
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@ -19,26 +20,25 @@ func FillEllipse (
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dstData, dstStride := destination.Buffer()
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srcData, srcStride := source.Buffer()
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bounds := source.Bounds()
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realWidth, realHeight := bounds.Dx(), bounds.Dy()
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bounds = bounds.Intersect(destination.Bounds()).Canon()
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bounds := source.Bounds().Intersect(destination.Bounds()).Canon()
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realBounds := source.Bounds()
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if bounds.Empty() { return }
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updatedRegion = bounds
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width, height := bounds.Dx(), bounds.Dy()
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for y := 0; y < height; y ++ {
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for x := 0; x < width; x ++ {
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xf := (float64(x) + 0.5) / float64(realWidth) - 0.5
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yf := (float64(y) + 0.5) / float64(realHeight) - 0.5
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if math.Sqrt(xf * xf + yf * yf) <= 0.5 {
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dstData[x + offset.X + (y + offset.Y) * dstStride] =
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srcData[x + y * srcStride]
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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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offsetPoint := point.Add(offset)
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dstIndex := offsetPoint.X + (offsetPoint.Y) * dstStride
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srcIndex := point.X + point.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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// StrokeRectangle is similar to FillEllipse, but it draws an elliptical inset
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// StrokeEllipse is similar to FillEllipse, but it draws an elliptical inset
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// outline of the source canvas onto the destination canvas. To prevent the
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// entire source canvas's bounds from being used, it must be cut with
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// canvas.Cut().
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@ -55,82 +55,176 @@ func StrokeEllipse (
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bounds := source.Bounds().Inset(weight - 1)
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context := 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.Intersect(destination.Bounds()),
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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.Intersect(destination.Bounds()),
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},
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radii: image.Pt(bounds.Dx() / 2 - 1, bounds.Dy() / 2 - 1),
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}
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bounds.Max.X -= 1
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bounds.Max.Y -= 1
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context.center = bounds.Min.Add(context.radii)
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context.plotEllipse()
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}
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radii := image.Pt (
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bounds.Dx() / 2,
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bounds.Dy() / 2)
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center := bounds.Min.Add(radii)
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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(radii.Y)
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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(radii.Y * radii.Y) -
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float64(radii.X * radii.X * radii.Y) +
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(0.25 * float64(radii.X) * float64(radii.X))
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decisionX := float64(2 * radii.Y * radii.Y * int(x))
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decisionY := float64(2 * radii.X * radii.X * int(y))
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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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context.plotSource(image.Pt( int(x) + center.X, int(y) + center.Y))
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context.plotSource(image.Pt(-int(x) + center.X, int(y) + center.Y))
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context.plotSource(image.Pt( int(x) + center.X, -int(y) + center.Y))
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context.plotSource(image.Pt(-int(x) + center.X, -int(y) + center.Y))
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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 * radii.Y * radii.Y)
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decision1 += decisionX + float64(radii.Y * radii.Y)
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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 * radii.Y * radii.Y)
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decisionY -= float64(2 * radii.X * radii.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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decision1 +=
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decisionX - decisionY +
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float64(radii.Y * radii.Y)
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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(radii.Y * radii.Y) * (x + 0.5) * (x + 0.5) +
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float64(radii.X * radii.X) * (y - 1) * (y - 1) -
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float64(radii.X * radii.X * radii.Y * radii.Y)
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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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context.plotSource(image.Pt( int(x) + center.X, int(y) + center.Y))
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context.plotSource(image.Pt(-int(x) + center.X, int(y) + center.Y))
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context.plotSource(image.Pt( int(x) + center.X, -int(y) + center.Y))
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context.plotSource(image.Pt(-int(x) + center.X, -int(y) + center.Y))
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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 * radii.X * radii.X)
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decision2 += float64(radii.X * radii.X) - decisionY
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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 * radii.Y * radii.Y)
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decisionY -= float64(2 * radii.X * radii.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(radii.X * radii.X)
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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 canvas.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 canvas.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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bounds = 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(bounds.Dx() / 2 - 1, bounds.Dy() / 2 - 1),
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}
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context.center = bounds.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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@ -4,8 +4,6 @@ import "image"
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import "image/color"
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import "git.tebibyte.media/sashakoshka/tomo/canvas"
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// TODO: draw thick lines more efficiently
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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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@ -3,6 +3,8 @@ 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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@ -18,6 +20,7 @@ func (context plottingContext) square (center image.Point) 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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Add(context.offset).
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Intersect(context.bounds)
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}
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@ -33,8 +36,13 @@ 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.Min.Y; y ++ {
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for x := square.Min.X; x < square.Min.X; x ++ {
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context.dstData[x + y * context.dstStride] =
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context.srcData [
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x + y * context.dstStride]
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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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@ -1,9 +1,12 @@
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package shapes
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import "image"
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import "image/color"
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import "git.tebibyte.media/sashakoshka/tomo/canvas"
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import "git.tebibyte.media/sashakoshka/tomo/shatter"
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// TODO: return updatedRegion for all routines in this package
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// FillRectangle draws the content of one canvas onto another. The offset point
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// defines where the origin point of the source canvas is positioned in relation
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// to the origin point of the destination canvas. To prevent the entire source
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@ -59,8 +62,60 @@ func FillRectangleShatter (
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offset image.Point,
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rocks ...image.Rectangle,
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) {
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tiles := shatter.Shatter(source.Bounds(), rocks...)
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tiles := shatter.Shatter(source.Bounds().Sub(offset), rocks...)
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for _, tile := range tiles {
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FillRectangle(destination, canvas.Cut(source, tile), offset)
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}
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}
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// FillColorRectangle fills a rectangle within the destination canvas with a
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// solid color.
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func FillColorRectangle (
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destination canvas.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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bounds = bounds.Canon().Intersect(destination.Bounds())
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if bounds.Empty() { return }
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updatedRegion = bounds
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for y := bounds.Min.Y; y < bounds.Max.Y; y ++ {
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for x := bounds.Min.X; x < bounds.Max.X; x ++ {
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dstData[x + y * dstStride] = color
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}}
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return
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}
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// FillColorRectangleShatter is like FillColorRectangle, but it does not draw in
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// areas specified in "rocks".
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func FillColorRectangleShatter (
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destination canvas.Canvas,
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color color.RGBA,
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bounds image.Rectangle,
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rocks ...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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FillColorRectangle(destination, color, tile)
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}
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}
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// StrokeColorRectangle is similar to FillColorRectangle, but it draws an inset
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// outline of the given rectangle instead.
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func StrokeColorRectangle (
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destination canvas.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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insetBounds := bounds.Inset(weight)
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if insetBounds.Empty() {
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FillColorRectangle(destination, color, bounds)
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return
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}
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FillColorRectangleShatter(destination, color, bounds, insetBounds)
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}
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Reference in New Issue
Block a user