232 lines
6.5 KiB
Go
232 lines
6.5 KiB
Go
package shapes
|
|
|
|
import "math"
|
|
import "image"
|
|
import "image/color"
|
|
import "git.tebibyte.media/sashakoshka/tomo/artist"
|
|
|
|
// TODO: redo fill ellipse, stroke ellipse, etc. so that it only takes in
|
|
// destination and source, using the bounds of destination as the bounds of the
|
|
// ellipse and the bounds of source as the "clipping rectangle". Line up the Min
|
|
// of both canvases.
|
|
|
|
func FillEllipse (
|
|
destination artist.Canvas,
|
|
source artist.Canvas,
|
|
bounds image.Rectangle,
|
|
) (
|
|
updatedRegion image.Rectangle,
|
|
) {
|
|
dstData, dstStride := destination.Buffer()
|
|
srcData, srcStride := source.Buffer()
|
|
|
|
offset := source.Bounds().Min.Sub(destination.Bounds().Min)
|
|
drawBounds :=
|
|
source.Bounds().Sub(offset).
|
|
Intersect(destination.Bounds()).
|
|
Intersect(bounds)
|
|
if bounds.Empty() { return }
|
|
updatedRegion = bounds
|
|
|
|
point := image.Point { }
|
|
for point.Y = drawBounds.Min.Y; point.Y < drawBounds.Max.Y; point.Y ++ {
|
|
for point.X = drawBounds.Min.X; point.X < drawBounds.Max.X; point.X ++ {
|
|
if inEllipse(point, bounds) {
|
|
offsetPoint := point.Add(offset)
|
|
dstIndex := point.X + point.Y * dstStride
|
|
srcIndex := offsetPoint.X + offsetPoint.Y * srcStride
|
|
dstData[dstIndex] = srcData[srcIndex]
|
|
}
|
|
}}
|
|
return
|
|
}
|
|
|
|
func StrokeEllipse (
|
|
destination artist.Canvas,
|
|
source artist.Canvas,
|
|
bounds image.Rectangle,
|
|
weight int,
|
|
) {
|
|
if weight < 1 { return }
|
|
|
|
dstData, dstStride := destination.Buffer()
|
|
srcData, srcStride := source.Buffer()
|
|
|
|
drawBounds := destination.Bounds().Inset(weight - 1)
|
|
offset := source.Bounds().Min.Sub(destination.Bounds().Min)
|
|
if drawBounds.Empty() { return }
|
|
|
|
context := ellipsePlottingContext {
|
|
plottingContext: plottingContext {
|
|
dstData: dstData,
|
|
dstStride: dstStride,
|
|
srcData: srcData,
|
|
srcStride: srcStride,
|
|
weight: weight,
|
|
offset: offset,
|
|
bounds: bounds,
|
|
},
|
|
radii: image.Pt(drawBounds.Dx() / 2, drawBounds.Dy() / 2),
|
|
}
|
|
context.center = drawBounds.Min.Add(context.radii)
|
|
context.plotEllipse()
|
|
}
|
|
|
|
type ellipsePlottingContext struct {
|
|
plottingContext
|
|
radii image.Point
|
|
center image.Point
|
|
}
|
|
|
|
func (context ellipsePlottingContext) plotEllipse () {
|
|
x := float64(0)
|
|
y := float64(context.radii.Y)
|
|
|
|
// region 1 decision parameter
|
|
decision1 :=
|
|
float64(context.radii.Y * context.radii.Y) -
|
|
float64(context.radii.X * context.radii.X * context.radii.Y) +
|
|
(0.25 * float64(context.radii.X) * float64(context.radii.X))
|
|
decisionX := float64(2 * context.radii.Y * context.radii.Y * int(x))
|
|
decisionY := float64(2 * context.radii.X * context.radii.X * int(y))
|
|
|
|
// draw region 1
|
|
for decisionX < decisionY {
|
|
points := []image.Point {
|
|
image.Pt(-int(x) + context.center.X, -int(y) + context.center.Y),
|
|
image.Pt( int(x) + context.center.X, -int(y) + context.center.Y),
|
|
image.Pt(-int(x) + context.center.X, int(y) + context.center.Y),
|
|
image.Pt( int(x) + context.center.X, int(y) + context.center.Y),
|
|
}
|
|
if context.srcData == nil {
|
|
context.plotColor(points[0])
|
|
context.plotColor(points[1])
|
|
context.plotColor(points[2])
|
|
context.plotColor(points[3])
|
|
} else {
|
|
context.plotSource(points[0])
|
|
context.plotSource(points[1])
|
|
context.plotSource(points[2])
|
|
context.plotSource(points[3])
|
|
}
|
|
|
|
if (decision1 < 0) {
|
|
x ++
|
|
decisionX += float64(2 * context.radii.Y * context.radii.Y)
|
|
decision1 += decisionX + float64(context.radii.Y * context.radii.Y)
|
|
} else {
|
|
x ++
|
|
y --
|
|
decisionX += float64(2 * context.radii.Y * context.radii.Y)
|
|
decisionY -= float64(2 * context.radii.X * context.radii.X)
|
|
decision1 +=
|
|
decisionX - decisionY +
|
|
float64(context.radii.Y * context.radii.Y)
|
|
}
|
|
}
|
|
|
|
// region 2 decision parameter
|
|
decision2 :=
|
|
float64(context.radii.Y * context.radii.Y) * (x + 0.5) * (x + 0.5) +
|
|
float64(context.radii.X * context.radii.X) * (y - 1) * (y - 1) -
|
|
float64(context.radii.X * context.radii.X * context.radii.Y * context.radii.Y)
|
|
|
|
// draw region 2
|
|
for y >= 0 {
|
|
points := []image.Point {
|
|
image.Pt( int(x) + context.center.X, int(y) + context.center.Y),
|
|
image.Pt(-int(x) + context.center.X, int(y) + context.center.Y),
|
|
image.Pt( int(x) + context.center.X, -int(y) + context.center.Y),
|
|
image.Pt(-int(x) + context.center.X, -int(y) + context.center.Y),
|
|
}
|
|
if context.srcData == nil {
|
|
context.plotColor(points[0])
|
|
context.plotColor(points[1])
|
|
context.plotColor(points[2])
|
|
context.plotColor(points[3])
|
|
} else {
|
|
context.plotSource(points[0])
|
|
context.plotSource(points[1])
|
|
context.plotSource(points[2])
|
|
context.plotSource(points[3])
|
|
}
|
|
|
|
if decision2 > 0 {
|
|
y --
|
|
decisionY -= float64(2 * context.radii.X * context.radii.X)
|
|
decision2 += float64(context.radii.X * context.radii.X) - decisionY
|
|
} else {
|
|
y --
|
|
x ++
|
|
decisionX += float64(2 * context.radii.Y * context.radii.Y)
|
|
decisionY -= float64(2 * context.radii.X * context.radii.X)
|
|
decision2 +=
|
|
decisionX - decisionY +
|
|
float64(context.radii.X * context.radii.X)
|
|
}
|
|
}
|
|
}
|
|
|
|
// FillColorEllipse fills an ellipse within the destination canvas with a solid
|
|
// color.
|
|
func FillColorEllipse (
|
|
destination artist.Canvas,
|
|
color color.RGBA,
|
|
bounds image.Rectangle,
|
|
) (
|
|
updatedRegion image.Rectangle,
|
|
) {
|
|
dstData, dstStride := destination.Buffer()
|
|
|
|
realBounds := bounds
|
|
bounds = bounds.Intersect(destination.Bounds()).Canon()
|
|
if bounds.Empty() { return }
|
|
updatedRegion = bounds
|
|
|
|
point := image.Point { }
|
|
for point.Y = bounds.Min.Y; point.Y < bounds.Max.Y; point.Y ++ {
|
|
for point.X = bounds.Min.X; point.X < bounds.Max.X; point.X ++ {
|
|
if inEllipse(point, realBounds) {
|
|
dstData[point.X + point.Y * dstStride] = color
|
|
}
|
|
}}
|
|
return
|
|
}
|
|
|
|
// StrokeColorEllipse is similar to FillColorEllipse, but it draws an inset
|
|
// outline of an ellipse instead.
|
|
func StrokeColorEllipse (
|
|
destination artist.Canvas,
|
|
color color.RGBA,
|
|
bounds image.Rectangle,
|
|
weight int,
|
|
) (
|
|
updatedRegion image.Rectangle,
|
|
) {
|
|
if weight < 1 { return }
|
|
|
|
dstData, dstStride := destination.Buffer()
|
|
insetBounds := bounds.Inset(weight - 1)
|
|
|
|
context := ellipsePlottingContext {
|
|
plottingContext: plottingContext {
|
|
dstData: dstData,
|
|
dstStride: dstStride,
|
|
color: color,
|
|
weight: weight,
|
|
bounds: bounds.Intersect(destination.Bounds()),
|
|
},
|
|
radii: image.Pt(insetBounds.Dx() / 2, insetBounds.Dy() / 2),
|
|
}
|
|
context.center = insetBounds.Min.Add(context.radii)
|
|
context.plotEllipse()
|
|
return
|
|
}
|
|
|
|
func inEllipse (point image.Point, bounds image.Rectangle) bool {
|
|
point = point.Sub(bounds.Min)
|
|
x := (float64(point.X) + 0.5) / float64(bounds.Dx()) - 0.5
|
|
y := (float64(point.Y) + 0.5) / float64(bounds.Dy()) - 0.5
|
|
return math.Hypot(x, y) <= 0.5
|
|
}
|