Color Gradients 1-5

clrGrad_1_5.pde

color red = 0xffff0000;
color yellow = 0xffffff00;

float centerX = 256;
float centerY = 128;
float innerDiam = 32; 
float outerDiam = 512;

size(512, 256);
background(255);
noStroke();

for (float i = outerDiam; i >= innerDiam; --i) {
  fill(lerpColor(red, yellow,
    (i - innerDiam) / (outerDiam - innerDiam)));
  ellipse(centerX, centerY, i, i);
}