// create an Alpha Icon or Cursor from an Image
// http://support.microsoft.com/kb/318876
func createAlphaCursorOrIconFromImage(im image.Image, hotspot image.Point, fIcon bool) (win.HICON, error) {
hBitmap, err := hBitmapFromImage(im)
if err != nil {
return 0, err
}
defer win.DeleteObject(win.HGDIOBJ(hBitmap))
// Create an empty mask bitmap.
hMonoBitmap := win.CreateBitmap(int32(im.Bounds().Dx()), int32(im.Bounds().Dy()), 1, 1, nil)
if hMonoBitmap == 0 {
return 0, newError("CreateBitmap failed")
}
defer win.DeleteObject(win.HGDIOBJ(hMonoBitmap))
var ii win.ICONINFO
if fIcon {
ii.FIcon = win.TRUE
}
ii.XHotspot = uint32(hotspot.X)
ii.YHotspot = uint32(hotspot.Y)
ii.HbmMask = hMonoBitmap
ii.HbmColor = hBitmap
// Create the alpha cursor with the alpha DIB section.
hIconOrCursor := win.CreateIconIndirect(&ii)
return hIconOrCursor, nil
}
func (b *nullBrush) Dispose() {
if b.hBrush != 0 {
win.DeleteObject(win.HGDIOBJ(b.hBrush))
b.hBrush = 0
}
}
func (b *SolidColorBrush) Dispose() {
if b.hBrush != 0 {
win.DeleteObject(win.HGDIOBJ(b.hBrush))
b.hBrush = 0
}
}
func (p *nullPen) Dispose() {
if p.hPen != 0 {
win.DeleteObject(win.HGDIOBJ(p.hPen))
p.hPen = 0
}
}
func (p *GeometricPen) Dispose() {
if p.hPen != 0 {
win.DeleteObject(win.HGDIOBJ(p.hPen))
p.hPen = 0
}
}
// Dispose releases the os resources that were allocated for the Font.
//
// The Font can no longer be used for drawing operations or with GUI widgets
// after calling this method. It is safe to call Dispose multiple times.
func (f *Font) Dispose() {
for dpi, hFont := range f.dpi2hFont {
if dpi != 0 {
win.DeleteObject(win.HGDIOBJ(hFont))
}
delete(f.dpi2hFont, dpi)
}
}
func (bmp *Bitmap) Dispose() {
if bmp.hBmp != 0 {
win.DeleteObject(win.HGDIOBJ(bmp.hBmp))
win.GlobalUnlock(bmp.hPackedDIB)
win.GlobalFree(bmp.hPackedDIB)
bmp.hPackedDIB = 0
bmp.hBmp = 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
}