For Bitmap
, there is a MakeTransparent
method, is there one similar for changing one color to another?
// This sets Color.White to transparent
Bitmap myBitmap = new Bitmap(sr.Stream);
myBitmap.MakeTransparent(System.Drawing.Color.White);
Is there something that can do something like this?
Bitmap myBitmap = new Bitmap(sr.Stream);
myBitmap.ChangeColor(System.Drawing.Color.Black, System.Drawing.Color.Gray);
Lifting the code from this answer:
public static class BitmapExtensions
{
public static Bitmap ChangeColor(this Bitmap image, Color fromColor, Color toColor)
{
ImageAttributes attributes = new ImageAttributes();
attributes.SetRemapTable(new ColorMap[]
{
new ColorMap()
{
OldColor = fromColor,
NewColor = toColor,
}
}, ColorAdjustType.Bitmap);
using (Graphics g = Graphics.FromImage(image))
{
g.DrawImage(
image,
new Rectangle(Point.Empty, image.Size),
0, 0, image.Width, image.Height,
GraphicsUnit.Pixel,
attributes);
}
return image;
}
}
While I haven't benchmarked it, this should be faster than any solution that's doing GetPixel/SetPixel in a loop. It's also a bit more straightforward.
Through curiosity to Yorye Nathan's comment, This is an extension that I created by modifying http://msdn.microsoft.com/en-GB/library/ms229672(v=vs.90).aspx.
It can turn all pixels in a bitmap from one colour to another.
public static class BitmapExt
{
public static void ChangeColour(this Bitmap bmp, byte inColourR, byte inColourG, byte inColourB, byte outColourR, byte outColourG, byte outColourB)
{
// Specify a pixel format.
PixelFormat pxf = PixelFormat.Format24bppRgb;
// Lock the bitmap's bits.
Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height);
BitmapData bmpData =
bmp.LockBits(rect, ImageLockMode.ReadWrite,
pxf);
// Get the address of the first line.
IntPtr ptr = bmpData.Scan0;
// Declare an array to hold the bytes of the bitmap.
// int numBytes = bmp.Width * bmp.Height * 3;
int numBytes = bmpData.Stride * bmp.Height;
byte[] rgbValues = new byte[numBytes];
// Copy the RGB values into the array.
Marshal.Copy(ptr, rgbValues, 0, numBytes);
// Manipulate the bitmap
for (int counter = 0; counter < rgbValues.Length; counter += 3)
{
if (rgbValues[counter] == inColourR &&
rgbValues[counter + 1] == inColourG &&
rgbValues[counter + 2] == inColourB)
{
rgbValues[counter] = outColourR;
rgbValues[counter + 1] = outColourG;
rgbValues[counter + 2] = outColourB;
}
}
// Copy the RGB values back to the bitmap
Marshal.Copy(rgbValues, 0, ptr, numBytes);
// Unlock the bits.
bmp.UnlockBits(bmpData);
}
}
called by bmp.ChangeColour(0,128,0,0,0,0);
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With