// 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")
}
}
func main() {
rand.Seed(int64(0))
p, err := plot.New()
if err != nil {
panic(err)
}
p.Title.Text = "Plotutil example"
p.X.Label.Text = "X"
p.Y.Label.Text = "Y"
err = plotutil.AddLinePoints(
p,
"First", randomPoints(15),
)
if err != nil {
panic(err)
}
cnvs, err := vgx11.New(4*96, 4*96, "Example")
if err != nil {
panic(err)
}
p.Draw(draw.New(cnvs))
cnvs.Paint()
time.Sleep(5 * time.Second)
err = plotutil.AddLinePoints(
p,
"Second", randomPoints(15),
"Third", randomPoints(15),
)
if err != nil {
panic(err)
}
p.Draw(draw.New(cnvs))
cnvs.Paint()
time.Sleep(10 * time.Second)
// Save the plot to a PNG file.
// if err := p.Save(4, 4, "points.png"); err != nil {
// panic(err)
// }
}
func TestIssue179(t *testing.T) {
if !hasX11() {
t.Skip("no X11 environment")
}
scatter, err := plotter.NewScatter(plotter.XYs{{1, 1}, {0, 1}, {0, 0}})
if err != nil {
t.Fatalf("error: %v\n", err)
}
p, err := plot.New()
if err != nil {
t.Fatalf("error: %v\n", err)
}
p.Add(scatter)
p.HideAxes()
c, err := New(5.08*vg.Centimeter, 5.08*vg.Centimeter, "test issue179")
if err != nil {
t.Fatalf("error: %v\n", err)
}
p.Draw(draw.New(c))
b := bytes.NewBuffer([]byte{})
err = jpeg.Encode(b, c.ximg, nil)
if err != nil {
t.Error(err)
}
f, err := os.Open(filepath.Join("..", "vgimg", "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")
}
}