// Change the window's icon
func (wi *windowInternal) setIcon(icon image.Image) error {
// First destroy the previous one
if wi.icon != nil {
C.DestroyIcon(wi.icon)
}
type BGRA [4]uint8
// Windows wants BGRA pixels: swap red and blue channels
Rect := icon.Bounds()
iconPixels := make([]BGRA, Rect.Dy()*Rect.Dx())
for i, y := 0, 0; y < Rect.Dy(); y++ {
for x := 0; x < Rect.Dx(); x++ {
r, g, b, a := icon.At(x, y).RGBA()
iconPixels[i][0] = uint8(b)
iconPixels[i][1] = uint8(g)
iconPixels[i][2] = uint8(r)
iconPixels[i][3] = uint8(a)
}
}
// Create the icon from the pixel array
width, height := C.int(Rect.Dx()), C.int(Rect.Dy())
wi.icon = C.CreateIcon(C.GetModuleHandle(nil), width, height, 1, 32, nil, (*C.BYTE)(&iconPixels[0][0]))
if wi.icon == nil {
return fmt.Errorf("could not create icon (%d)", C.GetLastError())
}
C.SendMessage(wi.window.Handle, C.WM_SETICON, C.ICON_BIG, C.LPARAM(uintptr(unsafe.Pointer(wi.icon))))
C.SendMessage(wi.window.Handle, C.WM_SETICON, C.ICON_SMALL, C.LPARAM(uintptr(unsafe.Pointer(wi.icon))))
return nil
}
func (wi *windowInternal) close() ThreadError {
// Destroy the custom icon, if any
if wi.icon != nil {
C.DestroyIcon(wi.icon)
}
if wi.callback == nil {
// Destroy the window
if wi.window.IsValid() {
C.DestroyWindow(wi.window.Handle)
}
} else {
// The window is external : remove the hook on its message callback
C.__SetWindowLongPtr(wi.window.Handle, C.GWLP_WNDPROC, wi.callback)
}
return nil
}