private void FilterPixelsBilinear(FastBitmap source, FastBitmap destination, int width, int height, Int32Rect transformedSpace)
{
int srcWidth = width;
int srcHeight = height;
int srcWidth1 = width - 1;
int srcHeight1 = height - 1;
int outWidth = transformedSpace.Width;
int outHeight = transformedSpace.Height;
int outX = transformedSpace.X;
int outY = transformedSpace.Y;
for (int y = 0; y < outHeight; y++)
{
for (int x = 0; x < outWidth; x++)
{
Point output = TransformInverse(outX + x, outY + y);
int srcX = (int)Math.Floor(output.X);
int srcY = (int)Math.Floor(output.Y);
double xWeight = output.X - srcX;
double yWeight = output.Y - srcY;
Color nw, ne, sw, se;
if (srcX >= 0 && srcX < srcWidth1 && srcY >= 0 && srcY < srcHeight1)
{
// Easy case, all corners are in the image
nw = source[srcX, srcY];
ne = source[srcX + 1, srcY];
sw = source[srcX, srcY + 1];
se = source[srcX + 1, srcY + 1];
}
else
{
// Some of the corners are off the image
nw = GetPixel(source, srcX, srcY, srcWidth, srcHeight);
ne = GetPixel(source, srcX + 1, srcY, srcWidth, srcHeight);
sw = GetPixel(source, srcX, srcY + 1, srcWidth, srcHeight);
se = GetPixel(source, srcX + 1, srcY + 1, srcWidth, srcHeight);
}
destination[x, y] = ImageMath.BilinearInterpolate(xWeight, yWeight, nw, ne, sw, se);
}
}
}
private Color GetPixel(FastBitmap bitmap, int x, int y, int width, int height)
{
if (x < 0 || x >= width || y < 0 || y >= height)
{
switch (EdgeAction)
{
case EdgeAction.Wrap:
return(bitmap[ImageMath.Mod(x, width), ImageMath.Mod(y, height)]);
case EdgeAction.Clamp:
return(bitmap[ImageMath.Clamp(x, 0, width - 1), ImageMath.Clamp(y, 0, height - 1)]);
case EdgeAction.RgbClamp:
{
Color edgeColour = bitmap[ImageMath.Clamp(x, 0, width - 1), ImageMath.Clamp(y, 0, height - 1)];
return(Color.FromArgb(0, edgeColour.R, edgeColour.G, edgeColour.B));
}
case EdgeAction.Zero:
return(Colors.Transparent);
}
}
return(bitmap[x, y]);
}
