DrawImage, LoadPNG

context.go

@@ -84,7 +84,7 @@ func (dc *Context) Height() int {
 }
 
 func (dc *Context) WritePNG(path string) error {
-	return writePNG(path, dc.im)
+	return SavePNG(path, dc.im)
 }
 
 func (dc *Context) SetLineWidth(lineWidth float64) {
@@ -303,6 +303,12 @@ func (dc *Context) DrawCircle(x, y, r float64) {
 	dc.DrawEllipticalArc(x, y, r, r, 0, 2*math.Pi)
 }
 
+func (dc *Context) DrawImage(im image.Image, x, y int) {
+	p := image.Pt(x, y)
+	r := image.Rectangle{p, p.Add(im.Bounds().Size())}
+	draw.Draw(dc.im, r, im, image.ZP, draw.Src)
+}
+
 // Text Functions
 
 func (dc *Context) SetFontFace(fontFace font.Face) {

examples/tiling.go

@@ -0,0 +1,21 @@
+package main
+
+import "github.com/fogleman/gg"
+
+func main() {
+	const NX = 4
+	const NY = 3
+	im, err := gg.LoadPNG("examples/gopher.png")
+	if err != nil {
+		panic(err)
+	}
+	w := im.Bounds().Size().X
+	h := im.Bounds().Size().Y
+	dc := gg.NewContext(w*NX, h*NY)
+	for y := 0; y < NY; y++ {
+		for x := 0; x < NX; x++ {
+			dc.DrawImage(im, x*w, y*h)
+		}
+	}
+	dc.WritePNG("out.png")
+}

util.go

@@ -24,7 +24,16 @@ func Degrees(radians float64) float64 {
 	return radians * 180 / math.Pi
 }
 
-func writePNG(path string, im image.Image) error {
+func LoadPNG(path string) (image.Image, error) {
+	file, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+	return png.Decode(file)
+}
+
+func SavePNG(path string, im image.Image) error {
 	file, err := os.Create(path)
 	if err != nil {
 		return err