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Index › Programming Questions & Help › Syntax Questions › 2 questions regarding color of pixel
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2 questions regarding color of pixel? (Read 679 times)
pandean
2 questions regarding color of pixel?
Apr 22nd, 2010, 12:20pm  
Hi all

I am running a project and encountered some problems related to pixels. Can anyone help me?

Question 1: how to remove a color from a pixel?

pixel[1] = noFill();  // remove  its color
updatePixels();

Question 2: how to check if a pixel has no color?

if (pixel[1] is empty){
  // do this...
}

warm regards
P
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Giles
Re: 2 questions regarding color of pixel?
Reply #1 - Apr 22nd, 2010, 8:43pm  
Pixels always have a colour...I guess you want to check if the colour is the same as the background....
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Giles
Re: 2 questions regarding color of pixel?
Reply #2 - Apr 22nd, 2010, 9:55pm  
I wrote a simple example.... click to draw in white, press a key to change the background colour:

Code:

color backg = color(0, 0, 0);

void setup()
{
  size(400,400);
  background(backg);
  strokeWeight(3); 
  stroke(255,255,255);
}

void draw()
{
  
}

void mouseDragged()
{
   line(pmouseX, pmouseY, mouseX, mouseY);
}

void keyPressed()
{
  color c = color(random(255), random(255), random(255));
  loadPixels();
  for(int i=0; i<pixels.length; i++)
  {
    if(pixels[i]==backg) pixels[i]=c;
  }
  updatePixels();
  backg=c;
}
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