unfix, flattenPath

util.go

@@ -10,6 +10,7 @@ import (
 	"os"
 	"strings"
 
+	"github.com/golang/freetype/raster"
 	"github.com/golang/freetype/truetype"
 
 	"golang.org/x/image/font"
@@ -77,6 +78,18 @@ func fi(x float64) fixed.Int26_6 {
 	return fixed.Int26_6(x * 64)
 }
 
+func unfix(x fixed.Int26_6) float64 {
+	const shift, mask = 6, 1<<6 - 1
+	if x >= 0 {
+		return float64(x>>shift) + float64(x&mask)/64
+	}
+	x = -x
+	if x >= 0 {
+		return -(float64(x>>shift) + float64(x&mask)/64)
+	}
+	return 0
+}
+
 func loadFontFace(path string, points float64) font.Face {
 	fontBytes, err := ioutil.ReadFile(path)
 	if err != nil {
@@ -91,3 +104,55 @@ func loadFontFace(path string, points float64) font.Face {
 		// Hinting: font.HintingFull,
 	})
 }
+
+func flattenPath(p raster.Path) [][]Point {
+	var result [][]Point
+	path := make([]Point, 0, 16)
+	var cx, cy float64
+	for i := 0; i < len(p); {
+		switch p[i] {
+		case 0:
+			if len(path) > 0 {
+				result = append(result, path)
+				path = make([]Point, 0, 16)
+			}
+			x := unfix(p[i+1])
+			y := unfix(p[i+2])
+			path = append(path, Point{x, y})
+			cx, cy = x, y
+			i += 4
+		case 1:
+			x := unfix(p[i+1])
+			y := unfix(p[i+2])
+			path = append(path, Point{x, y})
+			cx, cy = x, y
+			i += 4
+		case 2:
+			x1 := unfix(p[i+1])
+			y1 := unfix(p[i+2])
+			x2 := unfix(p[i+3])
+			y2 := unfix(p[i+4])
+			points := QuadraticBezier(cx, cy, x1, y1, x2, y2)
+			path = append(path, points...)
+			cx, cy = x2, y2
+			i += 6
+		case 3:
+			x1 := unfix(p[i+1])
+			y1 := unfix(p[i+2])
+			x2 := unfix(p[i+3])
+			y2 := unfix(p[i+4])
+			x3 := unfix(p[i+5])
+			y3 := unfix(p[i+6])
+			points := CubicBezier(cx, cy, x1, y1, x2, y2, x3, y3)
+			path = append(path, points...)
+			cx, cy = x3, y3
+			i += 8
+		default:
+			panic("bad path")
+		}
+	}
+	if len(path) > 0 {
+		result = append(result, path)
+	}
+	return result
+}