image collector.

_examples/image_writer/main.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/wcharczuk/go-chart"
+)
+
+func main() {
+	graph := chart.Chart{
+		Series: []chart.Series{
+			chart.ContinuousSeries{
+				XValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
+				YValues: []float64{1.0, 2.0, 3.0, 4.0, 5.0},
+			},
+		},
+	}
+	collector := &chart.ImageWriter{}
+	graph.Render(chart.PNG, collector)
+
+	image, err := collector.Image()
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Printf("Final Image: %dx%d\n", image.Bounds().Size().X, image.Bounds().Size().Y)
+}

raster_renderer.go

@@ -210,5 +210,9 @@ func (rr *rasterRenderer) ClearTextRotation() {
 
 // Save implements the interface method.
 func (rr *rasterRenderer) Save(w io.Writer) error {
+	if typed, isTyped := w.(RGBACollector); isTyped {
+		typed.SetRGBA(rr.i)
+		return nil
+	}
 	return png.Encode(w, rr.i)
 }