Using GetPixel and SetPixel is easy but very slow so I'm trying to using LockBits.
I have this method I did long time ago to compare between two images:
public static Bitmap FastComparison(Bitmap bmp1,Bitmap bmp2)
{
tolerancenumeric = 15;
int tolerance = tolerancenumeric * tolerancenumeric +
tolerancenumeric * tolerancenumeric +
tolerancenumeric * tolerancenumeric; //dr * dr + dg * dg + db * db;
bmp3 = new Bitmap(512,512);
PixelFormat pxf = PixelFormat.Format24bppRgb;
Rectangle rect = new Rectangle(0, 0, bmp1.Width, bmp1.Height);
BitmapData bmpData1 = bmp1.LockBits(rect, ImageLockMode.ReadWrite, pxf);
BitmapData bmpData2 = bmp2.LockBits(rect, ImageLockMode.ReadWrite, pxf);
BitmapData bmpData3 = bmp3.LockBits(rect, ImageLockMode.ReadWrite, pxf);
IntPtr ptr1 = bmpData1.Scan0;
IntPtr ptr2 = bmpData2.Scan0;
IntPtr ptr3 = bmpData3.Scan0;
int numBytes = bmpData1.Stride * bmp1.Height;
byte[] rgbValues1 = new byte[numBytes];
Marshal.Copy(ptr1, rgbValues1, 0, numBytes);
bmp1.UnlockBits(bmpData1);
byte[] rgbValues2 = new byte[numBytes];
Marshal.Copy(ptr2, rgbValues2, 0, numBytes);
bmp2.UnlockBits(bmpData2);
for (int counter = 0; counter < rgbValues1.Length; counter += 3)
{
int dr, dg, db;
dr = (int)rgbValues2[counter] - (int)rgbValues1[counter];
dg = (int)rgbValues2[counter + 1] - (int)rgbValues1[counter + 1];
db = (int)rgbValues2[counter + 2] - (int)rgbValues1[counter + 2];
int error = dr * dr + dg * dg + db * db;
int y, x;
y = (counter / 3) / 512;
x = (counter - y * 512 * 3)/3;
if ((x == 479) && (y == 474))
{
Byte r1, g1, b1, r2, g2, b2;
r1 = rgbValues1[counter];
b1 = rgbValues1[counter+1];
g1 = rgbValues1[counter+2];
r2 = rgbValues2[counter];
b2 = rgbValues2[counter+1];
g2 = rgbValues2[counter+2];
}
if (error < tolerance)
{
rgbValues1[counter] = 0;
rgbValues1[counter + 1] = 0;
rgbValues1[counter + 2] = 0;
}
}
Marshal.Copy(rgbValues1, 0, ptr3, numBytes);
bmp3.UnlockBits(bmpData3);
return bmp3;
}
But now I want to use also LockBits but with one image and to color all the pixels that are not black in yellow.
I started new method:
public Bitmap ChangeColors(Bitmap bmp1)
{
bmpColors = new Bitmap(512, 512);
PixelFormat pxf = PixelFormat.Format24bppRgb;
Rectangle rect = new Rectangle(0, 0, bmp1.Width, bmp1.Height);
BitmapData bmpData1 = bmp1.LockBits(rect, ImageLockMode.ReadWrite, pxf);
IntPtr ptr1 = bmpData1.Scan0;
int numBytes = bmpData1.Stride * bmp1.Height;
byte[] rgbValues1 = new byte[numBytes];
Marshal.Copy(ptr1, rgbValues1, 0, numBytes);
bmp1.UnlockBits(bmpData1);
for (int counter = 0; counter < rgbValues1.Length; counter += 3)
{
int y, x;
y = (counter / 3) / 512;
x = (counter - y * 512 * 3) / 3;
Byte r1, g1, b1;
r1 = rgbValues1[counter];
b1 = rgbValues1[counter + 1];
g1 = rgbValues1[counter + 2];
}
return bmpColors;
}
But not sure how to make it so the bitmap bmpColors will be the original one but with all pixels that are not black in yellow.
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