Should P5.Graphics support set() with another P5.Graphics?

[KevinWorkman]

Nature of issue?

• [X] Found a bug

Most appropriate sub-area of p5.js?

• [X] Color
• createGraphics()
• set()

Which platform were you using when you encountered this?

• [X] Desktop/Laptop

Details about the bug:

• p5.js version: 0.6.1 (using the alpha web editor)
• Web browser and version: Chrome 67.0.3396.62
• Operating System: Linux
• Steps to reproduce this:

From this Stack Overflow question.

It appears that the set() function does not work with P5.Graphics values. Is this expected?

let redRect;

function setup() {
  createCanvas(100,100);
  redRect = createGraphics(100,100);
  redRect.fill(255, 0, 0);
  redRect.rect(20,20,40,40);

  const blueRect = createGraphics(20, 20);
  blueRect.background(0, 0, 255);
  redRect.set(30, 30, blueRect);
  redRect.updatePixels();
}

function draw() {
  background(0, 255, 0);
  image(redRect,0,0);
}

I would expect this to create a graphics that contains a red rectangle, and then draw a blue rectangle to that first graphics. Instead, only a single pixel is set, and it's set to transparent?

[Ajayneethikannan]

I think that this feature should be present . The reason why it is setting a single transparent pixel is the current set method checks whether the third parameter imgOrCol is an p5.Image instance or a color value. In case it is neither if them, it sets the value of the pixel mentioned as [0, 0, 0, 0]. We can check its implementation here .

We can check if the imgOrCol parameter is p5.Image instance or p5.Graphics instance, then we can set the pixels of one p5.Graphics instance from another.

Also , if we pass a image as the third parameter set(x, y, image) the image fills the entire canvas from x, y onwards. Is this the intended behavior ?
Should we pass the height and width here as

this.drawingContext.drawImage(imgOrCol.canvas, x, y, imgOrCol.width, imgOrCol.height);

Would love your suggestions , Thank you!