public static void Blit(LockedBitmap source, LockedBitmap target, System.Drawing.Rectangle srcRect, int destX, int destY)
{
for (int sx = srcRect.X, dx = destX; sx < srcRect.X + srcRect.Width; sx++, dx++)
{
for (int sy = srcRect.Y, dy = destY; sy < srcRect.Y + srcRect.Height; sy++, dy++)
{
Color sourcePixel = source.GetPixel(sx, sy);
target.SetPixel(dx, dy, sourcePixel);
}
}
}
public LockedBitmap DownScale(int newWidth, int newHeight)
{
LockedBitmap newBitmap = new LockedBitmap(new Bitmap(newWidth, newHeight, Source.PixelFormat));
if (Source.PixelFormat != PixelFormat.Format32bppArgb)
{
throw new Exception("DownsScale32 only works on 32 bit images");
}
float xscale = (float)Data.Width / newWidth;
float yscale = (float)Data.Height / newHeight;
byte r = 0, g = 0, b = 0, a = 0;
float summedR = 0f;
float summedG = 0f;
float summedB = 0f;
float summedA = 0f;
int left, right, top, bottom; //the area of old pixels covered by the new bitmap
float targetStartX, targetEndX;
float targetStartY, targetEndY;
float leftF, rightF, topF, bottomF; //edges of new pixel in old pixel coords
float weight;
float weightScale = xscale * yscale;
float totalColourWeight = 0f;
for (int m = 0; m < newHeight; m++)
{
for (int n = 0; n < newWidth; n++)
{
leftF = n * xscale;
rightF = (n + 1) * xscale;
topF = m * yscale;
bottomF = (m + 1) * yscale;
left = (int)leftF;
right = (int)rightF;
top = (int)topF;
bottom = (int)bottomF;
if (left < 0)
{
left = 0;
}
if (top < 0)
{
top = 0;
}
if (right >= Data.Width)
{
right = Data.Width - 1;
}
if (bottom >= Data.Height)
{
bottom = Data.Height - 1;
}
summedR = 0f;
summedG = 0f;
summedB = 0f;
summedA = 0f;
totalColourWeight = 0f;
for (int j = top; j <= bottom; j++)
{
for (int i = left; i <= right; i++)
{
targetStartX = Math.Max(leftF, i);
targetEndX = Math.Min(rightF, i + 1);
targetStartY = Math.Max(topF, j);
targetEndY = Math.Min(bottomF, j + 1);
weight = (targetEndX - targetStartX) * (targetEndY - targetStartY);
Color newColors = GetPixel(i, j);
r = newColors.R;
g = newColors.G;
b = newColors.B;
a = newColors.A;
summedA += weight * a;
if (a != 0)
{
summedR += weight * r;
summedG += weight * g;
summedB += weight * b;
totalColourWeight += weight;
}
}
}
summedR /= totalColourWeight;
summedG /= totalColourWeight;
summedB /= totalColourWeight;
summedA /= weightScale;
if (summedR < 0)
{
summedR = 0f;
}
if (summedG < 0)
{
summedG = 0f;
}
if (summedB < 0)
{
summedB = 0f;
}
if (summedA < 0)
{
summedA = 0f;
}
if (summedR >= 256)
{
summedR = 255;
}
if (summedG >= 256)
{
summedG = 255;
}
if (summedB >= 256)
{
summedB = 255;
}
if (summedA >= 256)
{
summedA = 255;
}
newBitmap.SetPixel(n, m, new Color((int)summedR, (int)summedG, (int)summedB, (int)summedA));
}
}
// Unlock old bitmap
UnlockBits();
return(newBitmap);
}