[RESOLVED] i want to increase the darkness of a color ?

[maged]

Dear all,
i have a color variable that contains of course a color value, how can i increase the blue degree of the color by a certain value.

for example i have a degree of blue and i want to make it darker.

i think to make it darker and retain the original color i will have to increase the three rgb components the exact value. but how can i do this ???


thank you

rgds

[Jehannum]

This should work. It's just the opposite of a brightness adjuster that I use.

Subtract a value from each pixel's colour components (red, green, and blue). The bigger darknessVal, the darker the image will become.

Dim pixelColour As Color
Dim x,y As Integer
Dim darknessVal as Byte
...
For x = 0 to PhotoBmp.Width - 1
   For y = 0 to PhotoBmp.Height - 1
      pixelColour = photoBmp.GetPixel(x, y)
 
      red = pixelColour.R - darknessVal
      green = pixelColour.G - darknessVal
      blue = pixelColour.B - darknessVal
 
      pixelColour = Color.FromArgb(red, green, blue)
      photoBmp.SetPixel(x, y, pixelColour)
   Next
Next

But don't forget NOT to let red, green, or blue go below 0 after the subtraction. I didn't include the error checking code for reasons of clarity.

Bear in mind this is my first attempt at answering a question, and I'm a beginner myself.

[Jehannum]

I think you can see how to increased the blueness of an image.

The bigger bluenessVal, the bluer the image will become.

...
blue = pixelColour.B + bluenessVal
...

In a similar loop to the above, but leaving the other colour values alone.

[maged]

thank you for answering

why did u assume that i am trying to darken an image ??? i dint say that

i have a color variable and i want to make it darker.

but in any case your code will work in all cases

thank you very much for the code, and cu around

rgds