I'm rendering text using FormattedText, but there does appear to be any way to perform per-char hit testing on the rendered output. It's read-only, so I basically only need selection, no editing.
I'd use RichTextBox or similar, but I need to output text based on control codes embed in the text itself, so they don't always nest, which makes building the right Inline elements very complex. I'm also a bit worried about performance with that solution; I have a large number of lines, and new lines are appended often.
I've looked at GlyphRun, it appears I could get hit-testing from it or a related class, but I'd be reimplementing a lot of functionality, and it seems like there should be a simpler way...
Does anyone know of a good way to implement this?
The best way is to design a good data structure for storing your text and which also considers hit-testing. One example could be to split the text into blocks (words, lines or paragraphs depending on what you need). Then each such block should have a bounding-box which should be recomputed in any formatting operations. Also consider caret positions in your design.
Once you have such facility it becomes very easy to do hit-testing, just use the bounding boxes. It will also help in subsequent operations like highlighting a particular portion of text.