Your CJK text is silently broken, and Pillow will not tell you

Rendering CJK text in Canvas and Pillow presents significant technical challenges. Unlike CSS, Canvas lacks automatic line-breaking logic, forcing developers to build custom systems that often fail silently. Similarly, Python's Pillow library introduces subtle bugs, such as incorrect font indexing in PingFang.ttc on macOS, which can lead to missing characters or typographically incorrect outputs. These issues often go unnoticed because they do not trigger stack traces, resulting in visually flawed images or posters.