通过在Processing中反转颜色来绘制形状

Question

我想在Processing中绘制圆圈，而不是通过绘制特定颜色的圆圈本身，而是通过反转每个圆圈占据的每个像素。以下是我想要的效果：

除了跟踪像素值矩阵之外，有没有办法在Processing中有效地实现这些目标，希望有内置的功能？

Answer 1

您应该可以通过将blendMode()设置为DIFFERENCE来轻松实现这一目标：

void setup(){
  size(400,400);
  background(0);
  noStroke();
  //change blend mode to difference
  blendMode(DIFFERENCE);
  //draw circles
  for(int i = 0 ; i < 10; i++){
    float diameter = random(50,200);
    ellipse(random(width * .35,width * .65),random(height * .2,height * .8),diameter,diameter);
  }
}
//the code bellow is just to redraw on click
void draw(){}
void mouseReleased(){
  setup();
}

这是预览：

你可以实际运行一个快速演示（点击重绘）：

function setup(){
  createCanvas(400,400);
  background(0);
  noStroke();
  //change blend mode to difference
  blendMode(DIFFERENCE);
  //draw circles
  for(var i = 0 ; i < 10; i++){
    var diameter = random(50,200);
    ellipse(random(width * .35,width * .65),random(height * .2,height * .8),diameter,diameter);
  }
}
//the code bellow is just to redraw on click
function draw(){}
function mouseReleased(){
  setup();
}

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