// WriterTo returns an io.WriterTo that will write the plot as
// the specified image format.
//
// Supported formats are:
//
// eps, jpg|jpeg, pdf, png, svg, and tif|tiff.
func (p *Plot) WriterTo(w, h vg.Length, format string) (io.WriterTo, error) {
var c interface {
vg.CanvasSizer
io.WriterTo
}
switch format {
case "eps":
c = vgeps.New(w, h)
case "jpg", "jpeg":
c = vgimg.JpegCanvas{Canvas: vgimg.New(w, h)}
case "pdf":
c = vgpdf.New(w, h)
case "png":
c = vgimg.PngCanvas{Canvas: vgimg.New(w, h)}
case "svg":
c = vgsvg.New(w, h)
case "tif", "tiff":
c = vgimg.TiffCanvas{Canvas: vgimg.New(w, h)}
default:
return nil, fmt.Errorf("unsupported format: %q", format)
}
p.Draw(draw.New(c))
return c, nil
}
func TestIssue179(t *testing.T) {
scatter, err := plotter.NewScatter(plotter.XYs{{1, 1}, {0, 1}, {0, 0}})
if err != nil {
log.Fatal(err)
}
p, err := plot.New()
if err != nil {
log.Fatal(err)
}
p.Add(scatter)
p.HideAxes()
c := vgimg.JpegCanvas{Canvas: vgimg.New(5.08*vg.Centimeter, 5.08*vg.Centimeter)}
p.Draw(draw.New(c))
b := bytes.NewBuffer([]byte{})
if _, err = c.WriteTo(b); err != nil {
t.Error(err)
}
f, err := os.Open(filepath.Join("testdata", "issue179.jpg"))
if err != nil {
t.Error(err)
}
defer f.Close()
want, err := ioutil.ReadAll(f)
if err != nil {
t.Error(err)
}
if !bytes.Equal(b.Bytes(), want) {
t.Error("Image mismatch")
}
}