//URL creates a Pattern similar to New, except that, instead of
//storing the uncompressed image data, a url to the image is stored.
//
//This is only useful on an SVG surface.
//
//Originally cairo_surface_set_mime_data.
func URL(URL *url.URL, r io.Reader) (cairo.Pattern, error) {
img, _, err := image.Decode(r)
if err != nil {
return nil, err
}
is, err := cairo.FromImage(img)
if err != nil {
return nil, err
}
defer is.Close()
bs := []byte(URL.String())
if err = embed(is, uri, bs); err != nil {
return nil, err
}
return newPattern(is)
}
//New creates a pattern of the image data in r of type mime.
//
//The returned pattern is essentially a SurfacePattern but the underlying
//surface is irrecoverable as any modification will lead to corruption.
//
//New will fail if there is not an image decoder for the relevant mime type
//installed with the image package.
//See the image package documentation for more information.
//It is up to you to ensure that the image data in r is of the mime type
//specified by mime.
//
//Originally cairo_surface_set_mime_data.
func New(mime mime, r io.Reader) (cairo.Pattern, error) {
if !mime.valid() {
return nil, errors.New("invalid or unsupported mime type: " + mime.s())
}
buf := bytes.NewBuffer(make([]byte, 0, 4096))
img, _, err := image.Decode(io.TeeReader(r, buf))
if err != nil {
return nil, err
}
is, err := cairo.FromImage(img)
if err != nil {
return nil, err
}
defer is.Close()
if err = embed(is, mime, buf.Bytes()); err != nil {
return nil, err
}
return newPattern(is)
}
Rectangle(cairo.Rect(0, 0, 256, 256)).
Fill()
c.
SetSourceColor(cairo.Color{G: 1}).
MoveTo(cairo.ZP).
LineTo(pt(256, 256)).
MoveTo(pt(256, 0)).
LineTo(pt(0, 256)).
SetLineWidth(10).
Stroke()
return nil
}},
{"clip-image", func(c *cairo.Context) error {
i, err := cairo.FromImage(img) //img declared globally and set in main
if err != nil {
return err
}
defer i.Close()
c.
Circle(cairo.Circ(128, 128, 76.8)).
Clip().
NewPath()
sz := i.Size()
c.Scale(pt(256/sz.X, 256/sz.Y))
if err = c.SetSourceSurface(i, cairo.ZP); err != nil {
return err
}