我需要基于纯色（背景）和半透明图像的合并生成新图像。所有图像都是半透明的，因此它们都会与纯色混合。
我试过了：
private Image BlendImageWithWindowBackgoundColor(Image pImage, float pColorOpacity)
{
Image mResult = null;
if (pImage != null)
{
ColorMatrix matrix = new ColorMatrix(new float[][]{
new float[] {1F, 0, 0, 0, 0},
new float[] {0, 1F, 0, 0, 0},
new float[] {0, 0, 1F, 0, 0},
new float[] {0, 0, 0, pColorOpacity, 0}, //opacity in rage [0 1]
new float[] {0, 0, 0, 0, 1F}});
ImageAttributes imageAttributes = new ImageAttributes();
imageAttributes.SetColorMatrix(matrix);
imageAttributes.SetWrapMode(WrapMode.TileFlipXY);
mResult = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, PixelFormat.Format32bppArgb);
Graphics g = Graphics.FromImage(mResult);
g.Clear(Color.Red); //<--This is the color i want merged as background!
g.CompositingMode = CompositingMode.SourceCopy;
g.CompositingQuality = CompositingQuality.HighQuality;
g.DrawImage(pImage, new Rectangle(0, 0, Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height), 0, 0, pImage.Width, pImage.Height, GraphicsUnit.Pixel, imageAttributes);
}
return mResult;
}
如果我尝试pOpacity 0.5看不到RED，当pOpacity为0时它返回黑色。
即使我尝试使用g.CompositingMode = CompositingMode.SourceOver，它也只生成半透明图像，忽略红色背景。
如果你想平铺图像，你需要使用TextureBrush和Graphics.FillRectangle而不是Drawimage。你的代码应该是：
private void BlendImageWithWindowBackgoundColor( Image pImage, float pColorOpacity ) {
Image mResult = null;
Image tempImage = null; //we will set the opacity of pImage to pColorOpacity and copy
//it to tempImage
if( pImage != null ) {
Graphics g;
ColorMatrix matrix = new ColorMatrix( new float[][]{
new float[] {1F, 0, 0, 0, 0},
new float[] {0, 1F, 0, 0, 0},
new float[] {0, 0, 1F, 0, 0},
new float[] {0, 0, 0, pColorOpacity, 0}, //opacity in rage [0 1]
new float[] {0, 0, 0, 0, 1F}} );
ImageAttributes imageAttributes = new ImageAttributes();
imageAttributes.SetColorMatrix( matrix );
tempImage = new Bitmap( pImage.Width, pImage.Height, PixelFormat.Format32bppArgb );
g = Graphics.FromImage( tempImage );
g.Clear( Color.Transparent );
//setting pColorOpacity to pImage and drawing to tempImage
g.DrawImage( pImage, new Rectangle( 0, 0, tempImage.Width, tempImage.Height ),
0, 0, pImage.Width, pImage.Height, GraphicsUnit.Pixel, imageAttributes );
g.Dispose();
g = null;
//now we will tile the tempImage
TextureBrush texture = new TextureBrush( tempImage );
texture.WrapMode = WrapMode.TileFlipXY;
mResult = new Bitmap( Screen.PrimaryScreen.Bounds.Width,
Screen.PrimaryScreen.Bounds.Height,
PixelFormat.Format32bppArgb );
g = Graphics.FromImage( mResult );
g.Clear( Color.Red ); //<--This is the color i want merged as background!
g.FillRectangle( texture, new Rectangle( 0, 0, mResult.Width, mResult.Height ) );
g.Dispose();
g = null;
tempImage.Dispose();
tempImage = null;
}
return mResult;
}
同时我找到了解决方案：
private Image BlendImageWithWindowBackgoundColorToSize(Image pImage, float pColorOpacity)
{
Image mResult = null;
if (pImage != null)
{
ColorMatrix matrix = new ColorMatrix(new float[][]{
new float[] {1F, 0, 0, 0, 0},
new float[] {0, 1F, 0, 0, 0},
new float[] {0, 0, 1F, 0, 0},
new float[] {0, 0, 0, pColorOpacity, 0}, //opacity in rage [0 1]
new float[] {0, 0, 0, 0, 1F}});
ImageAttributes imageAttributes = new ImageAttributes();
imageAttributes.SetColorMatrix(matrix);
imageAttributes.SetWrapMode(WrapMode.TileFlipXY);
mResult = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, PixelFormat.Format32bppArgb);
Image mImgSemiTransparent = (Image)mResult.Clone();
Graphics g = Graphics.FromImage(mImgSemiTransparent);
g.CompositingMode = CompositingMode.SourceOver;
g.CompositingQuality = CompositingQuality.HighQuality;
g.DrawImage(pImage, new Rectangle(0, 0, Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height), 0, 0, pImage.Width, pImage.Height, GraphicsUnit.Pixel, imageAttributes);
Graphics gF = Graphics.FromImage(mResult);
gF.Clear(Color.Red);
gF.DrawImageUnscaled(mImgSemiTransparent, 0, 0, mImgSemiTransparent.Width, mImgSemiTransparent.Height);
}
return mResult;
}
但是，γηράσκωδ'αείπολλάδιδασκόμε回答了一些柚木（它不是我想要的）比我快四倍！ :)
private Image BlendImageWithWindowBackgoundColorToSize2(Image pImage, float pColorOpacity)
{
Image mResult = null;
Image tempImage = null; //we will set the opacity of pImage to pColorOpacity and copy
//it to tempImage
if (pImage != null)
{
Graphics g;
ColorMatrix matrix = new ColorMatrix(new float[][]{
new float[] {1F, 0, 0, 0, 0},
new float[] {0, 1F, 0, 0, 0},
new float[] {0, 0, 1F, 0, 0},
new float[] {0, 0, 0, pColorOpacity, 0}, //opacity in rage [0 1]
new float[] {0, 0, 0, 0, 1F}});
ImageAttributes imageAttributes = new ImageAttributes();
imageAttributes.SetColorMatrix(matrix);
imageAttributes.SetWrapMode(WrapMode.TileFlipXY);
tempImage = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height, PixelFormat.Format32bppArgb);
g = Graphics.FromImage(tempImage);
//g.Clear(Color.Transparent); //No need!
//setting pColorOpacity to pImage and drawing to tempImage
g.DrawImage(pImage, new Rectangle(0, 0, Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height), 0, 0, pImage.Width, pImage.Height, GraphicsUnit.Pixel, imageAttributes);
g.Dispose();
g = null;
//now we will tile the tempImage
TextureBrush texture = new TextureBrush(tempImage);
mResult = new Bitmap(Screen.PrimaryScreen.Bounds.Width,
Screen.PrimaryScreen.Bounds.Height,
PixelFormat.Format32bppArgb);
g = Graphics.FromImage(mResult);
g.Clear(myColor);
g.FillRectangle(texture, new Rectangle(0, 0, mResult.Width, mResult.Height));
g.Dispose();
g = null;
tempImage.Dispose();
tempImage = null;
}
return mResult;
}