func DisplaySubImageShifted(
itlx, itly int, w, h int,
image *opencv.IplImage,
otlx, otly int) {
channels := image.Channels()
in := toByteSlice(image.ImageData(),
image.Width()*image.Height()*channels)
for iy, oy := itly, otly; iy < itly+h; iy, oy = iy+1, oy+1 {
for ix, ox := itlx, otlx; ix < itlx+w; ix, ox = ix+1, ox+1 {
// image origin is top-left
imagep := (ix + (iHeight-1-iy)*iWidth) * channels
// openVG origin is bottom-left
outp := (ox + oy*iWidth) * VG_CHANS
out[outp+0] = C.VGubyte(in[imagep+2]) // red
out[outp+1] = C.VGubyte(in[imagep+1]) // green
out[outp+2] = C.VGubyte(in[imagep+0]) // blue
out[outp+3] = 255 // alpha
}
}
}
func DisplayImage(image *opencv.IplImage) {
DisplaySubImage(0, 0, image.Width(), image.Height(), image)
}