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Fixed missing alpha blending and optimized performance.

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git-svn-id: http://svn.code.sf.net/p/greenshot/code/trunk@1718 7dccd23d-a4a3-4e1f-8c07-b4c1b4018ab4
This commit is contained in:
RKrom 2012-03-21 13:12:19 +00:00
parent 4a5e04ae23
commit 64bc855652
2 changed files with 34 additions and 40 deletions
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36
GreenshotPlugin/Core/BitmapBuffer.cs
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@ -33,6 +33,22 @@ namespace GreenshotPlugin.Core {
private static log4net.ILog LOG = log4net.LogManager.GetLogger(typeof(BitmapBuffer));
private bool clone;
private Bitmap bitmap;
private static int[] factors = new int[256];
private static int[] remainings = new int[256];
static BitmapBuffer() {
// Pre calculate for alpha blending
for (int i = 0; i < 256; i++) {
int factor = 0x10000 * i / 255;
factors[i] = factor;
remainings[i] = (0x10000 * 255) - factor;
}
}
public static Color BackgroundBlendColor {
get;
set;
}
/// <summary>
/// Get the bitmap, you will always need to dispose the returned bitmap!!
@ -309,16 +325,28 @@ namespace GreenshotPlugin.Core {
}
/// <summary>
/// Retrieve the color, without alpha, at location x,y
/// Retrieve the color, without alpha (is blended), at location x,y
/// Before the first time this is called the Lock() should be called once!
/// </summary>
/// <param name="x">X coordinate</param>
/// <param name="y">Y Coordinate</param>
/// <returns>Color</returns>
public Color GetColorAtWithoutAlpha(int x, int y) {
if(x>=0 && y>=0 && x<rect.Width && y<rect.Height) {
int offset = x*bytesPerPixel+y*stride;
return Color.FromArgb(255, pointer[rIndex+offset], pointer[gIndex+offset], pointer[bIndex+offset]);
if (x >= 0 && y >= 0 && x < rect.Width && y < rect.Height) {
int offset = x * bytesPerPixel + y * stride;
int a = (aIndex == -1) ? (byte)255 : pointer[aIndex + offset];
int red = pointer[rIndex + offset];
int green = pointer[gIndex + offset];
int blue = pointer[bIndex + offset];
if (a < 255) {
int aMult = factors[a];
int rem = remainings[a];
red = (red * rem + BackgroundBlendColor.R * aMult) >> 16;
green = (green * rem + BackgroundBlendColor.G * aMult) >> 16;
blue = (blue * rem + BackgroundBlendColor.B * aMult) >> 16;
}
return Color.FromArgb(255, red, green, blue);
} else {
return Color.Empty;
}