// pdf, ps, and svg surfaces use the current surface (page)
func (g *Graphic) Image() (image.Image, error) {
var surface *C.cairo_surface_t
switch g.format {
case "eps", "pdf", "ps", "svg":
// map vector surfaces to an image surface
surface = C.cairo_surface_map_to_image(g.surface, nil)
defer C.cairo_surface_unmap_image(g.surface, surface)
status := C.cairo_surface_status(surface)
err := statusToError(status)
if err != nil {
return nil, err
}
case "png", "jpeg":
// no conversion needed
surface = g.surface
}
width := int(C.cairo_image_surface_get_width(surface))
height := int(C.cairo_image_surface_get_height(surface))
stride := int(C.cairo_image_surface_get_stride(surface))
format := C.cairo_image_surface_get_format(surface)
dataPtr := C.cairo_image_surface_get_data(surface)
data := C.GoBytes(unsafe.Pointer(dataPtr), C.int(stride*height))
var img image.Image
switch format {
case C.CAIRO_FORMAT_ARGB32:
img = &extimage.ARGB{
Pix: data,
Stride: stride,
Rect: image.Rect(0, 0, width, height),
}
case C.CAIRO_FORMAT_RGB24:
img = &extimage.RGB{
Pix: data,
Stride: stride,
Rect: image.Rect(0, 0, width, height),
}
case C.CAIRO_FORMAT_A8:
img = &image.Alpha{
Pix: data,
Stride: stride,
Rect: image.Rect(0, 0, width, height),
}
default:
// known unsupported formats:
// CAIRO_FORMAT_INVALID = -1,
// CAIRO_FORMAT_A1 = 3,
// CAIRO_FORMAT_RGB16_565 = 4,
// CAIRO_FORMAT_RGB30 = 5
panic(fmt.Sprintf("unsupported cairo image surface format: %d", int(format)))
}
return img, nil
}
//MapImage returns an image surface that is the most efficient mechanism
//for modifying the backing store of this surface.
//
//If r is Empty, the entire surface is mapped, otherwise, just the region
//described by r is mapped.
//
//Note that r is an image.Rectangle and not a cairo.Rectangle.
//
//It is the callers responsibility to all Close on the returned surface
//in order to upload the content of the mapped image to this surface and
//destroys the image surface.
//
//The returned surface is an ImageSurface with a special Close method.
//
//Warning
//
//Using this surface as a target or source while mapped is undefined.
//
//The result of mapping a surface multiple times is undefined.
//
//Changing the device transform of either surface before the image surface
//is unmapped is undefined.
//
//Originally cairo_surface_map_to_image.
func (e *XtensionSurface) MapImage(r image.Rectangle) (MappedImageSurface, error) {
var rect C.cairo_rectangle_int_t
rect.x, rect.y = C.int(r.Min.X), C.int(r.Min.Y)
rect.width, rect.height = C.int(r.Dx()), C.int(r.Dy())
rp := &rect
if r.Empty() {
//use entire image
rp = nil
}
return newMappedImageSurface(C.cairo_surface_map_to_image(e.s, rp), e.s)
}