我有两个位图,分别名为largeBmp和smallBmp。我想在largeBmp上绘制smallBmp,然后将结果绘制到屏幕上。SmallBmp的白色像素应该是透明的。下面是我使用的代码:
public Bitmap Superimpose(Bitmap largeBmp, Bitmap smallBmp) {
Graphics g = Graphics.FromImage(largeBmp);
g.CompositingMode = CompositingMode.SourceCopy;
smallBmp.MakeTransparent();
int margin = 5;
int x = largeBmp.Width - smallBmp.Width - margin;
int y = largeBmp.Height - smallBmp.Height - margin;
g.DrawImage(smallBmp, new Point(x, y));
return largeBmp;
}
问题是,无论smallBmp是透明的,结果都是透明的!我只想看透largeBmp,而不是它背后的东西。
发布于 2010-07-16 02:23:48
CompositingMode.SourceCopy
是这里的问题所在。您希望CompositingMode.SourceOver
获得alpha混合。
发布于 2010-07-16 02:21:48
指定小位图的透明度颜色。例如:
Bitmap largeImage = new Bitmap();
Bitmap smallImage = new Bitmap();
--> smallImage.MakeTransparent(Color.White);
Graphics g = Graphics.FromImage(largeImage);
g.DrawImage(smallImage, new Point(10,10);
发布于 2019-09-22 16:59:44
Winform copy image on top of another
private void timerFFTp_Tick(object sender, EventArgs e)
{
if (drawBitmap)
{
Bitmap bitmap = new Bitmap(_fftControl.Width, _fftControl.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
_fftControl.DrawToBitmap(bitmap, new Rectangle(0, 0, _fftControl.Width, _fftControl.Height));
if (!fDraw)
{
bitmap.MakeTransparent();
Bitmap fftFormBitmap = new Bitmap(_fftForm.BackgroundImage);
Graphics g = Graphics.FromImage(fftFormBitmap);
g.DrawImage(bitmap, 0, 0);
_fftForm.BackgroundImage = fftFormBitmap;
}
else
{
fDraw = false;
_fftForm.Width = bitmap.Width + 16;
_fftForm.Height = bitmap.Height + 48;
_fftForm.BackgroundImage = bitmap;
}
}
}
https://stackoverflow.com/questions/3258577
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