RGB separation

[bdiscount]

How do you separate the RGB from the number you get from getpixel. Is it done bitwise?

[specci48]

Hi bdiscount,

since there is no build-in feature for that, you have to do this manually with an own sub. You can use something like this:

Sub Globals
    red = 0
    green = 0
    black = 0    
End Sub

Sub App_Start
    ...
    Color2RGB(bitmap1.GetPixel1(w,h))
    ...        
End Sub

Sub Color2RGB(color)
    colorNum = color + 16777216
    red = Int(colorNum / 65536)        
    green = Int((colorNum - red * 65536) / 256)    
    black = colorNum - red * 65536 - green * 256
End Sub

specci48

[bdiscount]

Thanks specci48 I will try and incorporate it in my program.

[Cableguy]

Just a minor rectification...
It's Red, Green, Blue (not Black)

[willisgt]

Specci, what purpose does this serve:

colorNum = color + 16777216

Gary

[Cableguy]

Originally Posted by specci48

Hi bdiscount,


Color2RGB(bitmap1.GetPixel1(w,h))

This calls the Clor2RGB sub passing the pixel(x,y) color value

Sub Color2RGB(color)
colorNum = color + 16777216
red = Int(colorNum / 65536)
green = Int((colorNum - red * 65536) / 256)
black = colorNum - red * 65536 - green * 256
End Sub[/code]

Color2RGB takes the color value obtained from the pixel and converts it to an RGB value....

In the desktop, RGB has an extra value (chanel) Alpha (opacity), so it becomes ARGB... The 16777216 I'm gessing is to workaround this issue, asuming the full opacity value...

[specci48]

... translation error ... keep the blue and cancel the black ...

Originally Posted by willisgt

Specci, what purpose does this serve:

colorNum = color + 16777216

This changes the original (negative) value into a positive format. If you code this

a = Rgb(0,0,0)
b = Rgb(255,255,255)

a gets the value -16777216 and b gets the value -1.


specci48

[bdiscount]

specci
your formula doesn't give me the correct rgb
I have a grey r=192 g = 192 b = 192

when I get pixel I get 3749946 on the device (only place I work.) 3749946/65536 =57.219 (red)
3749946 + 16777216 = 20527162 / 65536 = 313.219(red)

Have got it wrong?

[specci48]

Since Erel has confirmed this code to be correct (http://www.basic4ppc.com/forum/showt...ighlight=green) I don't know where you are going wrong...

What device are you using? Can you post a small example?


specci48

[agraham]

Originally Posted by bdiscount

Have got it wrong?

Have you missed a minus sign?

-3749946 gives R=198, G=199, B=198, which could be a correct approximation for R=192, G=192, B=192 as your device probably only supports something like 64K colours rather than the full 8bits on each colour.