I have a sketch that spans 2 screens with the size of 3286 x 1080 pixels with following break-outs:

1. Screen 1 : 1920 x 1080 px

2. Screen 2 : 1366 x 768 px

When the app runs, it will display a background that is the same size as the sketch. The sketch would then save a portion of the image into a file. My problem is in the output file, there's a visible blue line which seems to come out of nowhere. Here's my sketch with unrelated code removed:

import processing.opengl.*;

PImage bg;

1. void setup() {
2.     size(3286, 1080, OPENGL);
3.     frameRate(30);
4.     bg                  = loadImage("bg.png");
5. }
6. 
   
7. void draw() {
8.     background(bg);
9. 
   
10.     PImage noteImg      = get(2309, 138, 589, 538);
11.     String filename     = "test.png";
12.     noteImg.save(savePath("data/" + filename));
13.     noLoop();
14. }

Here's the bg image:

And here's the output image: