Fix ArrayIndexOutOfBoundsException with compact SVG arc notation

[hxrshxz]

Fixes #1244

Summary

Adds support for compact SVG arc notation where flags and coordinates are concatenated (e.g., a2 2 0 013 3 instead of a 2 2 0 0 1 3 3). Previously crashed with ArrayIndexOutOfBoundsException.

Changes

• core/src/processing/core/PShapeSVG.java: Added isCompactArcNotation() helper method to detect and parse concatenated arc flags/coordinates for both A and a commands
• core/test/processing/core/PShapeSVGPathTest.java: Added 4 test cases covering compact notation, standard notation, and edge cases

Before

Screencast.from.2025-10-15.00-31-18.mp4

After

Screencast.from.2025-10-14.23-14-15.mp4

[Copilot]

Pull Request Overview

This PR fixes an ArrayIndexOutOfBoundsException that occurred when parsing SVG arc commands with compact notation where flags and coordinates are concatenated (e.g., a2 2 0 013 3). The fix adds support for detecting and properly parsing this compact format.

Key changes:

• Added isCompactArcNotation() helper method to detect concatenated arc flags and coordinates
• Modified arc parsing logic for both absolute (A) and relative (a) commands to handle compact notation
• Added comprehensive test coverage for various compact arc notation scenarios

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
core/src/processing/core/PShapeSVG.java	Implements compact arc notation detection and parsing logic
core/test/processing/core/PShapeSVGPathTest.java	Adds test cases for compact notation, standard notation, and edge cases

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[hxrshxz]

@catilac have a look :)

[Stefterv]

Hi @hxrshxz great work! Thank you!

Looking at the tests, the one thing I would say to be missing is a step that actually checks if the parsing occurred correctly by looking at the numbers that the parser spits out, I would say just checking if the shape parses is not enough.

[hxrshxz]

Thanks @Stefterv I have added tests to verify the actual parsed endpoint values, not just that the shape doesn't crash