Detecting RED, GREEN & BLue in pixels

[kevin]

 This little example shows how you can detect if a pixel RGB colour has any RED, GREEN or BLUE in it

PlayBASIC Code: [Select]

 Do
   cls 0

   CircleC 100,100,50,true,Rgb(255,0,0)

   CircleC 200,100,50,true,Rgb(0,255,0)

   CircleC 300,100,50,true,Rgb(0,0,255)


   CircleC 100,200,50,true,Rgb(155,100,0)

   CircleC 200,200,50,true,Rgb(0,255,233)

   CircleC 300,200,50,true,Rgb(255,255,255)


   mx=mousex()
   my=mousey()

   if IsColourRed(mx,my)=false
         Print "No RED in this pixel"
   else
         Print "Yep, this pixel has BLUE in it"
   endif   

   if IsColourGreen(mx,my)=false
         Print "No GREEN in this pixel"
   else
         Print "Yep, this pixel has GREEN in it"
   endif   


   if IsColourBlue(mx,my)=false
         Print "No BLUE in this pixel"
   else
         Print "Yep, this pixel has BLUE in it"
   endif   


   Sync
loop




Function  IsColourRed(Xpos,Ypos)
   ; Grab the Pixel
   ThisPixel=Point(xpos,Ypos)

   ; check if it's RED level is above 0  
   if rgbR(ThisPixel)>0
      result=true
   endif      
                  
EndFunction result


Function  IsColourGreen(Xpos,Ypos)
   if rgbG(Point(xpos,Ypos))>0 then    result=1
EndFunction result

Function  IsColourBlue(Xpos,Ypos)
   if rgbG(Point(xpos,Ypos))>0 then    result=1
EndFunction result