2023-03-01 11:07:08 -07:00
4 changed files with 128 additions and 142 deletions
--- a/artist/shapes/doc.go
+++ b/artist/shapes/doc.go
@ -1,6 +1,6 @@
 // Package shapes provides some basic shape drawing routines.
 //
-// A word about patterns:
+// A word about using patterns with shape routines:
 //
 // Most drawing routines have a version that samples from other canvases, and a
 // version that samples from a solid color. None of these routines can use
--- a/artist/shapes/ellipse.go
+++ b/artist/shapes/ellipse.go
@ -3,19 +3,25 @@ package shapes
 import "math"
 import "image"
 import "image/color"
-import "git.tebibyte.media/sashakoshka/tomo/artist"
+// import "git.tebibyte.media/sashakoshka/tomo/artist"
 import "git.tebibyte.media/sashakoshka/tomo/canvas"

-// FillEllipse draws a filled ellipse with the specified pattern.
+// FillEllipse draws the content of one canvas onto another, clipped by an
+// ellipse stretched to the bounds of the source canvas. The offset point
+// defines where the origin point of the source canvas is positioned in relation
+// to the origin point of the destination canvas. To prevent the entire source
+// canvas's bounds from being used, it must be cut with canvas.Cut().
 func FillEllipse (
 	destination canvas.Canvas,
-	source artist.Pattern,
-	bounds image.Rectangle,
+	source      canvas.Canvas,
+	offset      image.Point,
 ) (
 	updatedRegion image.Rectangle,
 ) {
-	bounds = bounds.Canon()
-	data, stride := destination.Buffer()
+	dstData, dstStride := destination.Buffer()
+	srcData, srcStride := source.Buffer()
+	
+	bounds := source.Bounds()
 	realWidth, realHeight := bounds.Dx(), bounds.Dy()
 	bounds = bounds.Intersect(destination.Bounds()).Canon()
 	if bounds.Empty() { return }
@ -27,35 +33,38 @@ func FillEllipse (
 		xf := (float64(x) + 0.5) / float64(realWidth)  - 0.5
 		yf := (float64(y) + 0.5) / float64(realHeight) - 0.5
 		if math.Sqrt(xf * xf + yf * yf) <= 0.5 {
-			data[x + bounds.Min.X + (y + bounds.Min.Y) * stride] =
-				source.AtWhen(x, y, realWidth, realHeight)
+			dstData[x + offset.X + (y + offset.Y) * dstStride] =
+				srcData[x + y * srcStride]
 		}
 	}}
 	return
 }

-// StrokeEllipse draws the outline of an ellipse with the specified line weight
-// and pattern.
+// StrokeRectangle is similar to FillEllipse, but it draws an elliptical inset
+// outline of the source canvas onto the destination canvas. To prevent the
+// entire source canvas's bounds from being used, it must be cut with
+// canvas.Cut().
 func StrokeEllipse (
 	destination canvas.Canvas,
-	source artist.Pattern,
-	weight int,
-	bounds image.Rectangle,
+	source      canvas.Canvas,
+	offset      image.Point,
+	weight      int,
 ) {
 	if weight < 1 { return }

-	data, stride := destination.Buffer()
-	bounds = bounds.Canon().Inset(weight - 1)
-	width, height := bounds.Dx(), bounds.Dy()
+	dstData, dstStride := destination.Buffer()
+	srcData, srcStride := source.Buffer()
+	
+	bounds := source.Bounds().Inset(weight - 1)

 	context := ellipsePlottingContext {
-		data: data,
-		stride: stride,
-		source: source,
-		width: width,
-		height: height,
-		weight: weight,
-		bounds: bounds,
+		dstData:   dstData,
+		dstStride: dstStride,
+		srcData:   srcData,
+		srcStride: srcStride,
+		weight:    weight,
+		offset:    offset,
+		bounds:    bounds.Intersect(destination.Bounds()),
 	}
 	
 	bounds.Max.X -= 1
@ -129,18 +138,26 @@ func StrokeEllipse (
 }

 type ellipsePlottingContext struct {
-	data []color.RGBA
-	stride int
-	source artist.Pattern
-	width, height int
-	weight int
-	bounds image.Rectangle
+	dstData   []color.RGBA
+	dstStride int
+	srcData   []color.RGBA
+	srcStride int
+	weight    int
+	offset    image.Point
+	bounds    image.Rectangle
 }

 func (context ellipsePlottingContext) plot (x, y int) {
-	if (image.Point { x, y }).In(context.bounds) {
-		squareAround (
-			context.data, context.stride, context.source, x, y,
-			context.width, context.height, context.weight)
-	}
+	square :=
+		image.Rect(0, 0, context.weight, context.weight).
+		Sub(image.Pt(context.weight / 2, context.weight / 2)).
+		Add(image.Pt(x, y)).
+		Intersect(context.bounds)
+	
+	for y := square.Min.Y; y < square.Min.Y; y ++ {
+	for x := square.Min.X; x < square.Min.X; x ++ {
+		context.dstData[x + y * context.dstStride] =
+			context.srcData [
+				x + y * context.dstStride]
+	}}
 }
--- a/artist/shapes/line.go
+++ b/artist/shapes/line.go
@ -6,14 +6,14 @@ import "git.tebibyte.media/sashakoshka/tomo/canvas"

 // TODO: draw thick lines more efficiently

-// Line draws a line from one point to another with the specified weight and
-// pattern.
-func Line (
+// ColorLine draws a line from one point to another with the specified weight
+// and color.
+func ColorLine (
 	destination canvas.Canvas,
-	source      canvas.Canvas,
-	weight int,
-	min image.Point,
-	max image.Point,
+	color       color.RGBA,
+	weight      int,
+	min         image.Point,
+	max         image.Point,
 ) (
 	updatedRegion image.Rectangle,
 ) {
@ -21,43 +21,49 @@ func Line (
 	updatedRegion = image.Rectangle { Min: min, Max: max }.Canon()
 	updatedRegion.Max.X ++
 	updatedRegion.Max.Y ++
-	width  := updatedRegion.Dx()
-	height := updatedRegion.Dy()
 	
-	if abs(max.Y - min.Y) <
-		abs(max.X - min.X) {
+	data, stride := destination.Buffer()
+	bounds := destination.Bounds()
+	context := linePlottingContext {
+		dstData:   data,
+		dstStride: stride,
+		color:     color,
+		weight:    weight,
+		bounds:    bounds,
+		min:       min,
+		max:       max,
+	}
+	
+	if abs(max.Y - min.Y) < abs(max.X - min.X) {
+		if max.X < min.X { context.swap() }
+		context.lineLow()
 		
-		if max.X < min.X {
-			temp := min
-			min = max
-			max = temp
-		}
-		lineLow(destination, source, weight, min, max, width, height)
 	} else {
-	
-		if max.Y < min.Y {
-			temp := min
-			min = max
-			max = temp
-		}
-		lineHigh(destination, source, weight, min, max, width, height)
+		if max.Y < min.Y { context.swap() }
+		context.lineHigh()
 	}
 	return
 }

-func lineLow (
-	destination canvas.Canvas,
-	source Pattern,
-	weight int,
-	min image.Point,
-	max image.Point,
-	width, height int,
-) {
-	data, stride := destination.Buffer()
-	bounds := destination.Bounds()
+type linePlottingContext struct {
+	dstData   []color.RGBA
+	dstStride int
+	color     color.RGBA
+	weight    int
+	bounds    image.Rectangle
+	min       image.Point
+	max       image.Point
+}

-	deltaX := max.X - min.X
-	deltaY := max.Y - min.Y
+func (context *linePlottingContext) swap () {
+	temp := context.max
+	context.max = context.min
+	context.min = temp
+}
+
+func (context linePlottingContext) lineLow () {
+	deltaX := context.max.X - context.min.X
+	deltaY := context.max.Y - context.min.Y
 	yi     := 1

 	if deltaY < 0 {
@ -66,34 +72,23 @@ func lineLow (
 	}

 	D := (2 * deltaY) - deltaX
-	y := min.Y
+	point := context.min

-	for x := min.X; x < max.X; x ++ {
-		if !(image.Point { x, y }).In(bounds) { break }
-		squareAround(data, stride, source, x, y, width, height, weight)
-		// data[x + y * stride] = source.AtWhen(x, y, width, height)
+	for ; point.X < context.max.X; point.X ++ {
+		if !point.In(context.bounds) { break }
+		context.plot(point)
 		if D > 0 {
-			y += yi
 			D += 2 * (deltaY - deltaX)
+			point.Y += yi
 		} else {
 			D += 2 * deltaY
 		}
 	}
 }

-func lineHigh (
-	destination canvas.Canvas,
-	source Pattern,
-	weight int,
-	min image.Point,
-	max image.Point,
-	width, height int,
-) {
-	data, stride := destination.Buffer()
-	bounds := destination.Bounds()
-
-	deltaX := max.X - min.X
-	deltaY := max.Y - min.Y
+func (context linePlottingContext) lineHigh () {
+	deltaX := context.max.X - context.min.X
+	deltaY := context.max.Y - context.min.Y
 	xi     := 1

 	if deltaX < 0 {
@ -102,14 +97,13 @@ func lineHigh (
 	}

 	D := (2 * deltaX) - deltaY
-	x := min.X
+	point := context.min

-	for y := min.Y; y < max.Y; y ++ {
-		if !(image.Point { x, y }).In(bounds) { break }
-		squareAround(data, stride, source, x, y, width, height, weight)
-		// data[x + y * stride] = source.AtWhen(x, y, width, height)
+	for ; point.Y < context.max.Y; point.Y ++ {
+		if !point.In(context.bounds) { break }
+		context.plot(point)
 		if D > 0 {
-			x += xi
+			point.X += xi
 			D += 2 * (deltaX - deltaY)
 		} else {
 			D += 2 * deltaX
@ -117,27 +111,20 @@ func lineHigh (
 	}
 }

-func abs (in int) (out int) {
-	if in < 0 { in *= -1}
-	out = in
-	return
+func abs (n int) int {
+	if n < 0 { n *= -1}
+	return n
 }

-// TODO: this method of doing things sucks and can cause a segfault. we should
-// not be doing it this way
-func squareAround (
-	data   []color.RGBA,
-	stride int,
-	source Pattern,
-	x, y, patternWidth, patternHeight, diameter int,
-) {
-	minY := y - diameter + 1
-	minX := x - diameter + 1
-	maxY := y + diameter
-	maxX := x + diameter
-	for y = minY; y < maxY; y ++ {
-	for x = minX; x < maxX; x ++ {
-		data[x + y * stride] =
-			source.AtWhen(x, y, patternWidth, patternHeight)
+func (context linePlottingContext) plot (center image.Point) {
+	square :=
+		image.Rect(0, 0, context.weight, context.weight).
+		Sub(image.Pt(context.weight / 2, context.weight / 2)).
+		Add(center).
+		Intersect(context.bounds)
+
+	for y := square.Min.Y; y < square.Min.Y; y ++ {
+	for x := square.Min.X; x < square.Min.X; x ++ {
+		context.dstData[x + y * context.dstStride] = context.color
 	}}
 }
--- a/artist/shapes/rectangle.go
+++ b/artist/shapes/rectangle.go
@ -4,11 +4,10 @@ import "image"
 import "git.tebibyte.media/sashakoshka/tomo/canvas"
 import "git.tebibyte.media/sashakoshka/tomo/shatter"

-// FillRectangle draws a rectangular subset of one canvas onto the other. The
-// offset point defines where the origin point of the source canvas is
-// positioned in relation to the origin point of the destination canvas. To
-// prevent the entire source canvas from being drawn, it must be cut with
-// canvas.Cut().
+// FillRectangle draws the content of one canvas onto another. The offset point
+// defines where the origin point of the source canvas is positioned in relation
+// to the origin point of the destination canvas. To prevent the entire source
+// canvas from being drawn, it must be cut with canvas.Cut().
 func FillRectangle (
 	destination canvas.Canvas,
 	source      canvas.Canvas,
@ -49,24 +48,7 @@ func StrokeRectangle (
 		FillRectangle(destination, source, offset)
 		return
 	}
-
-	top :=  image.Rect (
-		bounds.Min.X, bounds.Min.Y,
-		bounds.Max.X, insetBounds.Min.Y)
-	bottom := image.Rect (
-		bounds.Min.X, insetBounds.Max.Y,
-		bounds.Max.X, bounds.Max.Y)
-	left := image.Rect (
-		bounds.Min.X, insetBounds.Min.Y,
-		insetBounds.Min.X, insetBounds.Max.Y)
-	right := image.Rect (
-		insetBounds.Max.X, insetBounds.Min.Y,
-		bounds.Max.X, insetBounds.Max.Y)
-	
-	FillRectangle (destination, canvas.Cut(source, top),    offset)
-	FillRectangle (destination, canvas.Cut(source, bottom), offset)
-	FillRectangle (destination, canvas.Cut(source, left),   offset)
-	FillRectangle (destination, canvas.Cut(source, right),  offset)
+	FillRectangleShatter(destination, source, offset, insetBounds)
 }

 // FillRectangleShatter is like FillRectangle, but it does not draw in areas
@ -75,10 +57,10 @@ func FillRectangleShatter (
 	destination canvas.Canvas,
 	source      canvas.Canvas,
 	offset      image.Point,
-	rocks       []image.Rectangle,
+	rocks       ...image.Rectangle,
 ) {
-	tiles := shatter.Shatter(source.Bounds())
+	tiles := shatter.Shatter(source.Bounds(), rocks...)
 	for _, tile := range tiles {
-		tile
+		FillRectangle(destination, canvas.Cut(source, tile), offset)
 	}
 }