scale() has unintended behavior with negative values when used in conjunction with image() ~~scale() is broken for negative values~~

Most appropriate sub-area of p5.js?

• Accessibility
• Color
• Core/Environment/Rendering
• Data
• DOM
• Events
• Image
• IO
• [x ] Math
• Typography
• Utilities
• WebGL
• Build Process
• Unit Testing
• Internalization
• Friendly Errors
• Other (specify if possible)

p5.js version

1.5.0

Web browser and version

Chrome 108.0.5359.125 64bit

Operating System

Windows 11

Steps to reproduce this

Steps:

use the following code in editor.p5js.org and notice that the right side of the screen is not properly mirrored despite usage of scale(-1, 1).

Many answers on StackOverflow suggest this and show it working but it is seemingly broken on new releases? Repro's locally for me

Snippet:

This snippet fills the main canvas with blue on the left and red on the right along with a random squiggle drawn (to be able to tell if it's properly mirroring or not)

This code DOES copy the red right side of the canvas to the left but does so without properly mirroring (ignoring the negative value passed into scale())

let canvas;

function setup() {
  createCanvas(400, 400);
  canvas = createGraphics(width, height);
  noStroke();
  canvas.noStroke();
  
  background(255);
  
  // fill left with blue
  fill(0, 0, 255);
  rect(0, 0, width/2, height);
  
  // fill right with red
  fill(255, 0, 0);
  rect(width/2, 0, width/2, height);
  
  // draw random squiggle in black to be able to test for mirroring properly
  push();
  strokeWeight(5);
  stroke(0);
  translate(width/2, height/2);
  beginShape();
  for (let i = 0; i < 150; i++) {
    let angle = map(i, 0, 150, 0, TWO_PI);
    let x = sin(angle) * random(width/2);
    let y = cos(angle) * random(height/2);
    vertex(x, y);
  }
  endShape();
  pop();
}

function draw() {
  // NOTE: this still doesn't work properly when wrapped with push()/pop()
  copy(width/2, 0, width/2, height, 0, 0, width/2, height); 
  scale(-1, 1); // **seemingly broken line**
  image(canvas, 0, 0, width/2, height, width/2, 0, -width/2, height);
  noLoop();
}

output of this script looks like this but should have the left side of the canvas mirrored across the y axis

Start by running the provided sketch in editor.p5js.org or locally with p5.js 1.5.0, focusing on the scale(-1, 1) and image() calls in draw(). Trace the scale and image rendering entry points to determine why the negative value is not mirrored. Done means the red canvas region and random squiggle are correctly mirrored across the y axis while preserving the existing behavior.