Example #1
0
func (cw *CustomWidget) bufferedPaint(canvas *Canvas, updateBounds Rectangle) error {
	hdc := win.CreateCompatibleDC(canvas.hdc)
	if hdc == 0 {
		return newError("CreateCompatibleDC failed")
	}
	defer win.DeleteDC(hdc)

	buffered := Canvas{hdc: hdc, doNotDispose: true}
	if _, err := buffered.init(); err != nil {
		return err
	}

	w, h := int32(updateBounds.Width), int32(updateBounds.Height)
	if w < 1 {
		w = 1
	}
	if h < 1 {
		h = 1
	}
	hbmp := win.CreateCompatibleBitmap(canvas.hdc, w, h)
	if hbmp == 0 {
		return lastError("CreateCompatibleBitmap failed")
	}
	defer win.DeleteObject(win.HGDIOBJ(hbmp))

	oldbmp := win.SelectObject(buffered.hdc, win.HGDIOBJ(hbmp))
	if oldbmp == 0 {
		return newError("SelectObject failed")
	}
	defer win.SelectObject(buffered.hdc, oldbmp)

	win.SetViewportOrgEx(buffered.hdc, -int32(updateBounds.X), -int32(updateBounds.Y), nil)
	win.SetBrushOrgEx(buffered.hdc, -int32(updateBounds.X), -int32(updateBounds.Y), nil)

	err := cw.paint(&buffered, updateBounds)

	if !win.BitBlt(canvas.hdc,
		int32(updateBounds.X), int32(updateBounds.Y), w, h,
		buffered.hdc,
		int32(updateBounds.X), int32(updateBounds.Y), win.SRCCOPY) {
		return lastError("buffered BitBlt failed")
	}

	return err
}
Example #2
0
func (bmp *Bitmap) draw(hdc win.HDC, location Point) error {
	return bmp.withSelectedIntoMemDC(func(hdcMem win.HDC) error {
		size := bmp.Size()

		if !win.BitBlt(
			hdc,
			int32(location.X),
			int32(location.Y),
			int32(size.Width),
			int32(size.Height),
			hdcMem,
			0,
			0,
			win.SRCCOPY) {

			return lastError("BitBlt")
		}

		return nil
	})
}