Mixing two colors

[Elias Montoya]

I am doing something simple but i have never done it. I would like to have a
function like this:

FUNCTION MixColors(Color1 AS DWORD, Color2 AS DWORD) AS DWORD

FUNCTION = ??????

END FUNCTION

WHat i want to do is to, for example mix blue with red and have purple.
But since i have never done this, i dont know how.

Thanx in advance!

[Chris Boss]

#COMPILE EXE
#DIM ALL
FUNCTION PBMAIN () AS LONG
' compare the values of the function and the correct mix value
MSGBOX STR$(MixRGB(RGB(64,32,48),RGB(255,128,64)))+" "+STR$(RGB(160,80,56))
    
END FUNCTION
FUNCTION MixRGB(BYVAL RGB1&, BYVAL RGB2&) AS LONG
     LOCAL B1 AS BYTE PTR, B2 AS BYTE PTR
     B1=VARPTR(RGB1&)
     B2=VARPTR(RGB2&)
     @B1=(@[email protected])/2
     INCR B1
     INCR B2
     @B1=(@[email protected])/2
     INCR B1
     INCR B2
     @B1=(@[email protected])/2
     FUNCTION=RGB1&
END FUNCTION

[Paul Dixon]

Elias,
there are faster ways but this one is may be easier to follow:

'PBCC5.01/PBWin9.01 function
%RedMask   = &h000000ff
%GreenMask = &h0000ff00
%BlueMask  = &h00ff0000  

FUNCTION MixColors(Color1 AS DWORD, Color2 AS DWORD) AS DWORD
LOCAL red1,red2,red3,green1,green2,green3,blue1,blue2,blue3 AS LONG

'extract the red, green and blue components of each colour
red1  = color1 AND %RedMask
green1= color1 AND %GreenMask
blue1 = color1 AND %BlueMask
red2  = color2 AND %RedMask
green2= color2 AND %GreenMask
blue2 = color2 AND %BlueMask

'add the individual components together but don't allow it to exceed 1 byte.
'if the sum is greater than the mask then return the mask instead as it represents the fullest value of that colour
red3   =  MIN (red1   + red2,   %RedMask)      
green3 =  MIN (green1 + green2, %GreenMask)
blue3  =  MIN (blue1  + blue2,  %BlueMask)

'combine the 3 colours together
FUNCTION = red3 + green3 + blue3

END FUNCTION

[Elias Montoya]

Thank you Chris and Paul. Ill try it.

[Paul Dixon]

I see Chris is averaging the colours where my code adds them. I suppose either could be taken as "mixing".

Paul.

[Chris Boss]

To mix colors requires adding each byte value (red, green or blue) and then diving by 2 (average).

To mix means to "blend" the colors.

For example if one mixes white and black, you should get a gray in between.

0,0,0

mixed with 255,255,255

should be 128,128,128

Gray.

Alphablending is similiar, except one defines a percentage for each color.

[Paul Dixon]

Chris,
I looked at "mixing" the way I'd look at combining light, not the way I'd look at combining paint.
With paint, there is a maximum brightness for any colour and when you add anythng else you reduce the overall brightness.
With light, when you add another colour then you add to the overall brightness until it saturates.

If you add red paint and blue paint you get a darker colour, that's the way your mixing would do it.
If you add red light and blue light you get a lighter colour, that's the way my mixing would do it.

I don't know what Elias wants when he mixes coulours but he now has a choice.

Paul.

[Chris Boss]

I modified the routine to alphablend the colors. A percentage paramater is added. If the percentage is say 75 (for 75%) then color 1 imakes up 75% of the mixture while color makes up 25% of the mixture.

#COMPILE EXE
#DIM ALL
FUNCTION PBMAIN () AS LONG
' compare the values of the function and the correct mix value
MSGBOX STR$(MixRGB(RGB(64,32,48),RGB(255,128,64),50))+" "+STR$(RGB(160,80,56))
MSGBOX STR$(MixRGB(RGB(0,0,0),RGB(255,255,255),25))+" "+STR$(RGB(191,191,191))

END FUNCTION
' alpha& paramater is from 0 to 100 and is the percentage of color 1 to be used
' in blending the colors. If color 1 is 25% then color 2 is 75%
FUNCTION MixRGB(BYVAL RGB1&, BYVAL RGB2&, BYVAL Alpha&) AS LONG
     LOCAL B1 AS BYTE PTR, B2 AS BYTE PTR
     LOCAL Alpha1!, Alpha2!
     B1=VARPTR(RGB1&)
     B2=VARPTR(RGB2&)
     IF Alpha&<0 THEN Alpha&=0
     IF Alpha&>100 THEN Alpha&=100
     Alpha1!=Alpha&/100
     Alpha2!=(100-Alpha&)/100
     @B1=(@B1*Alpha1!)+(@B2*Alpha2!)
     INCR B1
     INCR B2
     @B1=(@B1*Alpha1!)+(@B2*Alpha2!)
     INCR B1
     INCR B2
     @B1=(@B1*Alpha1!)+(@B2*Alpha2!)
     FUNCTION=RGB1&
END FUNCTION

[Chris Boss]

Paul,

Most of the time mixing of two colors means mixing of pigment, not light.

If you look at my alphablending example, something like this would be used in alphablending bitmaps (albiet a faster version of course).

[Guy Dombrowski]

Color tool

Here is a nice little program by Werner Henning from Berlin to help you choose a nice group of colors.
It is called Pick_RGB_Color.
Search in Werner's post for the source.
You can also simply use it as a quick reminder of all those color names.
Very handy if you have 2 monitors.

[Gösta H. Lovgren-2]

Here is a nice little program by Werner Henning from Berlin to help you choose a nice group of colors.
It is called Pick_RGB_Color.
Search in Werner's post for the source.

Do you have a link to this code? It would be appreciated. I tried searching several different ways. Thx.

=======================================
"Looking foolish does the spirit good."
John Updike
=======================================

[Guy Dombrowski]

Here it is Gosta

http://www.powerbasic.com/support/pbforums/showthread.php?t=40144

[Guy Dombrowski]

Pick_RGB_Color.bas

And here is the version I improved a bit


You had to search in all Werner Henning's posts

[Gösta H. Lovgren-2]

And here is the version I improved a bit

This doesn't put anything in the Clipboard (running in PNWin9, not CC).

You had to search in all Werner Henning's posts

A search for "Werner Henning" only shows this thread.

{Later} I have been looking at the code and I am puzzled, Guy. I see a lot of equates (ie "%RGB_INDIANRED, %RGB_LIGHTCORAL, %RGB_SALMON,") but can't find where they are assigned.
'

'PBWIN 9.01 - WinApi 05/2008 - XP Pro SP3
#Compile Exe                                
#Dim All 
#Optimize SPEED  'Fly baby Fly!!!
#Debug Display On '<<<<<<<<<<<<<<< Remember to turn off for production code
 
Function PBMain         
 ? Str$(%RGB_INDIANRED)
End Function 
'

Obviously they are assigned by PB but I've never seen them before.

=====================================
Diligence is the mother of good luck.
Ben Franklin
=====================================


============================================
A little sincerity is a dangerous thing,
and a great deal of it is absolutely fatal.
Oscar Wilde
============================================

[Rodney Hicks]

Gösta
Look in PBWIN 9.0 help as follows:

Contents-Programming Reference-Data Types-Constants-Built in RGB Color Equates

Or page 75 of the printed PBWin manual.

What I find interesting is that this says it was originally written in PBCC 5.0 and works once there then the process stayed running on my machine, and the next time I tried to run it, it gives me the undefined equate error on the first ARRAY ASSIGN state with the colour equates.

I didn't check the copy to clipboard feature but the rest of it runs fine in PBWIN 9.0.

Also a curiosity, albeit extremely minor at this point, is the fact that these Built in Colour Equates are not available in PBCC 5.0.

[Guy Dombrowski]

Built In RGB Color Equates

There is a little bug in the Help file of PB/CC 5.01
If you try to access that item the link will not work but if you go to the Built In String Equate and then use the link at the bottom, you will get there.

[Michael Mattias]

This board is not an official communications venue.

Please report bugs directly to the official bug-reporting address, [email protected].

[Gösta H. Lovgren-2]

Gösta
Look in PBWIN 9.0 help as follows:
Or page 75 of the printed PBWin manual.

RTFM, huh? Who'da thot? Thanks Rod.

What I find interesting is that this says it was originally written in PBCC 5.0 and works once there then the process stayed running on my machine, and the next time I tried to run it, it gives me the undefined equate error on the first ARRAY ASSIGN state with the colour equates.

I didn't check the copy to clipboard feature but the rest of it runs fine in PBWIN 9.0.

A problem I have is it doesn't fit on my screen right, getting the colors all to display. Another is that it doesn't End cleanly. I have to ACD. I just figured it needed a Dalog End somewhere. (Haven't looked it closer yet.)

Great to find those equates though. I wonder how many other goodies PB is hiding?

================================
"Glory is fleeting,
but obscurity is forever."
Napoleon Bonaparte (1769-1821)
================================

[Rodney Hicks]

It turns out that I was looking in PBCC 5.0. Downloaded but did not install PBCC 5.01, probably because of time constraints.
I thought I was using PBCC 5.01.

[Dave Biggs]

A problem I have is it doesn't fit on my screen right, getting the colors all to display

Try changing the font eg. $fontname1 = "Terminal" ?

BTW There are more named color equates here..

http://www.powerbasic.com/support/pbforums/showthread.php?p=316485