Use Scanx rasterizer, fixes #334

Author: tdewolff

path.go

@@ -2341,10 +2341,8 @@ func (p *Path) ToPDF() string {
 	return sb.String()[1:] // remove the first space
 }
 
-// ToRasterizer rasterizes the path using the given rasterizer and resolution.
-func (p *Path) ToRasterizer(ras *vector.Rasterizer, resolution Resolution) {
-	// TODO: smoothen path using Ramer-...
-
+// ToVectorRasterizer rasterizes the path to *vector.Rasterizer using the given rasterizer and resolution.
+func (p *Path) ToVectorRasterizer(ras *vector.Rasterizer, resolution Resolution) {
 	dpmm := resolution.DPMM()
 	tolerance := PixelTolerance / dpmm // tolerance of 1/10 of a pixel
 	dy := float64(ras.Bounds().Size().Y)
@@ -2401,7 +2399,8 @@ func fixedPoint26_6(x, y float64) fixed.Point26_6 {
 	}
 }
 
-func (p *Path) ToScanx(ras *scanx.Scanner, dy float64, resolution Resolution) {
+// ToScanxScanner rasterizes the path to *scanx.Scanner using the given rasterizer, height, and resolution.
+func (p *Path) ToScanxScanner(ras *scanx.Scanner, dy float64, resolution Resolution) {
 	dpmm := resolution.DPMM()
 	tolerance := PixelTolerance / dpmm // tolerance of 1/10 of a pixel
 	for i := 0; i < len(p.d); {

path_test.go

@@ -950,7 +950,7 @@ func TestPathLengthParametrization(t *testing.T) {
 }
 
 func BenchmarkToRasterizer(b *testing.B) {
-	res := DPMM(0.5)
+	res := DPMM(10.0)
 	data, err := os.ReadFile("resources/netherlands.path")
 	if err != nil {
 		panic(err)
@@ -969,7 +969,7 @@ func BenchmarkToRasterizer(b *testing.B) {
 	ras.Reset(int(w), int(h))
 
 	src := image.NewUniform(image.Black)
-	p.ToRasterizer(ras, res)
+	p.ToVectorRasterizer(ras, res)
 	ras.Draw(img, rect, src, image.Point{0, 0})
 
 	f, _ := os.Create("ToRasterizer.png")
@@ -979,13 +979,13 @@ func BenchmarkToRasterizer(b *testing.B) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		ras.Reset(int(w), int(h))
-		p.ToRasterizer(ras, res)
+		p.ToVectorRasterizer(ras, res)
 		ras.Draw(img, rect, src, image.Point{0, 0})
 	}
 }
 
 func BenchmarkToScanx(b *testing.B) {
-	res := DPMM(0.5)
+	res := DPMM(10.0)
 	data, err := os.ReadFile("resources/netherlands.path")
 	if err != nil {
 		panic(err)
@@ -1003,7 +1003,7 @@ func BenchmarkToScanx(b *testing.B) {
 	scanner := scanx.NewScanner(spanner, int(w), int(h))
 
 	scanner.SetColor(image.Black)
-	p.ToScanx(scanner, h, res)
+	p.ToScanxScanner(scanner, h, res)
 	scanner.Draw()
 
 	f, _ := os.Create("ToScanx.png")
@@ -1013,7 +1013,7 @@ func BenchmarkToScanx(b *testing.B) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		scanner.Clear()
-		p.ToScanx(scanner, h, res)
+		p.ToScanxScanner(scanner, h, res)
 		scanner.Draw()
 	}
 }

patterns.go

@@ -8,7 +8,7 @@ import (
 type Pattern interface {
 	SetView(Matrix) Pattern
 	SetColorSpace(ColorSpace) Pattern
-	ClipTo(Renderer, *Path)
+	RenderTo(Renderer, *Path)
 }
 
 //type CanvasPattern struct {
@@ -126,8 +126,8 @@ func (p *HatchPattern) Tile(clip *Path) *Path {
 	return hatch
 }
 
-// ClipTo tiles the hatch pattern to the clipping path and renders it to the renderer.
-func (p *HatchPattern) ClipTo(r Renderer, clip *Path) {
+// RenderTo tiles the hatch pattern to the clipping path and renders it to the renderer.
+func (p *HatchPattern) RenderTo(r Renderer, clip *Path) {
 	hatch := p.Tile(clip)
 	r.RenderPath(hatch, Style{Fill: p.Fill}, Identity)
 }

renderers/rasterizer/rasterizer.go

@@ -2,12 +2,14 @@ package rasterizer
 
 import (
 	"image"
+	"image/color"
 	"math"
 
+	"github.com/srwiley/rasterx"
+	"github.com/srwiley/scanx"
 	"github.com/tdewolff/canvas"
 	"golang.org/x/image/draw"
 	"golang.org/x/image/math/f64"
-	"golang.org/x/image/vector"
 )
 
 // TODO: add ASM optimized version for NRGBA images, since those are much faster to write as PNG
@@ -27,7 +29,8 @@ type Rasterizer struct {
 	resolution canvas.Resolution
 	colorSpace canvas.ColorSpace
 
-	ras *vector.Rasterizer // reuse
+	spanner *scanx.ImgSpanner
+	scanner *scanx.Scanner
 }
 
 // New returns a renderer that draws to a rasterized image. The final width and height of the image is the width and height (mm) multiplied by the resolution (px/mm), thus a higher resolution results in larger images. By default the linear color space is used, which assumes input and output colors are in linearRGB. If the sRGB color space is used for drawing with an average of gamma=2.2, the input and output colors are assumed to be in sRGB (a common assumption) and blending happens in linearRGB. Be aware that for text this results in thin stems for black-on-white (but wide stems for white-on-black).
@@ -48,12 +51,14 @@ func FromImage(img draw.Image, resolution canvas.Resolution, colorSpace canvas.C
 	if colorSpace == nil {
 		colorSpace = canvas.DefaultColorSpace
 	}
+	spanner := scanx.NewImgSpanner(img)
 	return &Rasterizer{
 		Image:      img,
 		resolution: resolution,
 		colorSpace: colorSpace,
 
-		ras: &vector.Rasterizer{},
+		spanner: spanner,
+		scanner: scanx.NewScanner(spanner, bounds.Dx(), bounds.Dy()),
 	}
 }
 
@@ -95,90 +100,59 @@ func (r *Rasterizer) RenderPath(path *canvas.Path, style canvas.Style, m canvas.
 		}
 	}
 
-	padding := 2
-	dx, dy := 0, 0
-	origin := r.Bounds().Min
 	size := r.Bounds().Size()
-	dpmm := r.resolution.DPMM()
-	x := int(bounds.X0*dpmm) - padding
-	y := size.Y - int((bounds.Y1)*dpmm) - padding
-	w := int(bounds.W()*dpmm) + 2*padding
-	h := int(bounds.H()*dpmm) + 2*padding
-	if (x+w <= origin.X || origin.X+size.X <= x) && (y+h <= origin.Y || origin.Y+size.Y <= y) {
-		return // outside canvas
-	}
-
-	zp := image.Point{x, y}
-	if x < origin.X {
-		dx = -x
-		x = origin.X
-	}
-	if y < origin.Y {
-		dy = -y
-		y = origin.Y
-	}
-	if origin.X+size.X <= x+w {
-		w = origin.X + size.X - x
-	}
-	if origin.Y+size.Y <= y+h {
-		h = origin.Y + size.Y - y
-	}
-	if w <= 0 || h <= 0 {
-		return // has no size
-	}
-
 	if style.HasFill() {
 		if style.Fill.IsPattern() {
 			if hatch, ok := style.Fill.Pattern.(*canvas.HatchPattern); ok {
 				style.Fill = hatch.Fill
 				fill = hatch.Tile(fill)
+			} else {
+				pattern := style.Fill.Pattern.SetColorSpace(r.colorSpace)
+				pattern.RenderTo(r, fill)
 			}
 		}
-
-		var src image.Image
-		if style.Fill.IsColor() {
-			c := r.colorSpace.ToLinear(style.Fill.Color)
-			src = image.NewUniform(r.Image.ColorModel().Convert(c))
-		} else if style.Fill.IsGradient() {
+		if style.Fill.IsGradient() {
 			gradient := style.Fill.Gradient.SetColorSpace(r.colorSpace)
-			src = NewGradientImage(gradient, zp, size, r.resolution)
-			// TODO: convert to dst color model
-		} else if style.Fill.IsPattern() {
-			pattern := style.Fill.Pattern.SetColorSpace(r.colorSpace)
-			pattern.ClipTo(r, fill)
-		}
-		if src != nil {
-			r.ras.Reset(w, h)
-			fill = fill.Translate(-float64(x)/dpmm, -float64(size.Y-y-h)/dpmm)
-			fill.ToRasterizer(r.ras, r.resolution)
-			r.ras.Draw(r.Image, image.Rect(x, y, x+w, y+h), src, image.Point{dx, dy})
+			r.scanner.Clear()
+			r.scanner.SetColor(rasterx.ColorFunc(func(x, y int) color.Color {
+				// TODO: convert to dst color model
+				return gradient.At(float64(x), float64(y))
+			}))
+			fill.ToScanxScanner(r.scanner, float64(size.Y), r.resolution)
+			r.scanner.Draw()
+		} else if style.Fill.IsColor() {
+			c := r.colorSpace.ToLinear(style.Fill.Color)
+			r.scanner.Clear()
+			r.scanner.SetColor(color.Color(r.Image.ColorModel().Convert(c)))
+			fill.ToScanxScanner(r.scanner, float64(size.Y), r.resolution)
+			r.scanner.Draw()
 		}
 	}
 	if style.HasStroke() {
 		if style.Stroke.IsPattern() {
 			if hatch, ok := style.Stroke.Pattern.(*canvas.HatchPattern); ok {
 				style.Stroke = hatch.Fill
 				stroke = hatch.Tile(stroke)
+			} else {
+				pattern := style.Stroke.Pattern.SetColorSpace(r.colorSpace)
+				pattern.RenderTo(r, stroke)
 			}
 		}
-
-		var src image.Image
-		if style.Stroke.IsColor() {
-			c := r.colorSpace.ToLinear(style.Stroke.Color)
-			src = image.NewUniform(r.Image.ColorModel().Convert(c))
-		} else if style.Stroke.IsGradient() {
+		if style.Stroke.IsGradient() {
 			gradient := style.Stroke.Gradient.SetColorSpace(r.colorSpace)
-			src = NewGradientImage(gradient, zp, size, r.resolution)
-			// TODO: convert to dst color model
-		} else if style.Stroke.IsPattern() {
-			pattern := style.Stroke.Pattern.SetColorSpace(r.colorSpace)
-			pattern.ClipTo(r, stroke)
-		}
-		if src != nil {
-			r.ras.Reset(w, h)
-			stroke = stroke.Translate(-float64(x)/dpmm, -float64(size.Y-y-h)/dpmm)
-			stroke.ToRasterizer(r.ras, r.resolution)
-			r.ras.Draw(r.Image, image.Rect(x, y, x+w, y+h), src, image.Point{dx, dy})
+			r.scanner.Clear()
+			r.scanner.SetColor(rasterx.ColorFunc(func(x, y int) color.Color {
+				// TODO: convert to dst color model
+				return gradient.At(float64(x), float64(y))
+			}))
+			stroke.ToScanxScanner(r.scanner, float64(size.Y), r.resolution)
+			r.scanner.Draw()
+		} else if style.Stroke.IsColor() {
+			c := r.colorSpace.ToLinear(style.Stroke.Color)
+			r.scanner.Clear()
+			r.scanner.SetColor(color.Color(r.Image.ColorModel().Convert(c)))
+			stroke.ToScanxScanner(r.scanner, float64(size.Y), r.resolution)
+			r.scanner.Draw()
 		}
 	}
 }