public void MakeTransparent(Color transparentColor)
{
// FIXME: Make sure we have an alpha channel
//MakeSureWeHaveAnAlphaChannel ();
var colorValues = transparentColor.ElementsRGBA();
// Lock the bitmap's bits.
Rectangle rect = new Rectangle(0, 0, Width, Height);
var bmpData = LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite,
pixelFormat);
var alpha = Color.Transparent.A;
var red = Color.Transparent.R;
var green = Color.Transparent.G;
var blue = Color.Transparent.B;
byte alphar = Color.Transparent.A;
byte redr = Color.Transparent.R;
byte greenr = Color.Transparent.G;
byte bluer = Color.Transparent.B;
bool match = false;
var pixelSize = GetBitsPerPixel(pixelFormat) / 8;
unsafe
{
for (int y = 0; y < Height; y++)
{
byte *row = (byte *)bmpData.Scan0 + (y * bmpData.Stride);
for (int x = 0; x < bmpData.Stride; x = x + pixelSize)
{
redr = row [x + 2];;
greenr = row [x + 1];
bluer = row [x];
alphar = row [x + 3];
match = false;
if (row [x + 2] == colorValues [0] && row [x + 1] == colorValues [1] &&
row [x] == colorValues [2] && row [x + 3] == colorValues [3])
{
match = true;
}
if (match)
{
// we process bgra
row [x] = blue;
row [x + 1] = green;
row [x + 2] = red;
if (pixelSize == 4)
{
row [x + 3] = alpha;
}
}
}
}
}
// Unlock the bits.
UnlockBits(bmpData);
}
