func drawImage(w, h int, data unsafe.Pointer) {
var stride C.VGint = C.VGint(w * 4)
var format C.VGImageFormat = C.VG_sABGR_8888
var quality C.VGbitfield = C.VG_IMAGE_QUALITY_BETTER
var img C.VGImage
img = C.vgCreateImage(format, C.VGint(w), C.VGint(h), quality)
C.vgImageSubData(img, data, stride, format,
0, 0, C.VGint(w), C.VGint(h))
// vgDrawImage() applies the scale transformation,
// vgSetPixels() does not
C.vgDrawImage(img)
C.vgDestroyImage(img)
}
// poly converts coordinate slices
func poly(x, y []float64) (*C.VGfloat, *C.VGfloat, C.VGint) {
size := len(x)
if size != len(y) {
return nil, nil, 0
}
px := make([]C.VGfloat, size)
py := make([]C.VGfloat, size)
for i := 0; i < size; i++ {
px[i] = C.VGfloat(x[i])
py[i] = C.VGfloat(y[i])
}
return &px[0], &py[0], C.VGint(size)
}
// ClipRect limits the drawing area to specified rectangle
func ClipRect(x, y, w, h int) {
C.ClipRect(C.VGint(x), C.VGint(y), C.VGint(w), C.VGint(h))
}