Fix: call failureCallback if omggif fails to parse GIF in loadImage

[Satish-Medar]

Resolves #8021

Changes:

Wrapped the omggif.GifReader constructor in a try/catch block in loading_displaying.js.
If a GIF cannot be parsed, the failureCallback of loadImage is now called with the error, instead of throwing an uncatchable exception.
This allows sketches to handle image loading errors gracefully and prevents the sketch from crashing.
Tested locally with a broken GIF using a simple HTML test file (test-gif-error.html).
Screenshots of the change:

When loading a broken GIF, the failure callback is called and the sketch continues running (see console and page output in the test file).

PR Checklist
npm run lint passes
Inline reference is included / updated (not applicable)
Unit tests are included / updated (manual test provided)

test-gif-error.html ( p5.js --> create [ test-gif-error.html ] )

code in [[ test-gif-error.html ]]

<script src="lib/p5.js"></script> <script> function preload() { loadImage( "broken.gif", // Use a GIF that omggif cannot parse (img) => console.log("Loaded!", img), (err) => { console.error("Properly handled error:", err); document.body.innerHTML += "

Failure callback called!

"; } ); } function setup() { createCanvas(100, 100); background(200); } </script>

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[ThomasFinnern]

is calling "failureCallback(e); on failing gif ... safe ? Or does it enable a possible call of a not wanted function.
Just an offside comment with good intention. I am sorry if it is on the wrong place here.

[Satish-Medar]

@ThomasFinnern Thanks for raising this! failureCallback here is user-supplied (similar to the success callback), so calling it with the error object is consistent with how other loading functions behave in p5.js. It shouldn’t allow unwanted function calls since the user has to explicitly pass the callback. Still, I appreciate the point — good to double-check!