RFR: 8017266: Background is painted taller than needed for styled text.

[Alexander Zuev]

On Thu, 23 Oct 2025 03:19:06 GMT, Prasanta Sadhukhan <psadhukhan at openjdk.org> wrote:

> GlyphView.paint() draws background bounding the passed Shape, while the span reserved for the superscripted text is taller than the height of the glyphs so it is better to use the painter.getHeight() instead of alloc.height to fill the actual glyphs boundary
> 
> Before fix
> <img width="103" height="93" alt="image" src="https://github.com/user-attachments/assets/e673d214-13c7-4a42-8f55-cfd654e5a978" />
> 
> 
> With fix
> <img width="110" height="86" alt="image" src="https://github.com/user-attachments/assets/c13377a6-b4ac-406c-a153-a55c0b9a917b" />
> 
> No regressions is observed in CI..A manual verification test is provided..

The only problem i have with this fix is that after it the background and the selection are painted differently while before the fix they were painted the same shape.
<img width="59" height="33" alt="noselect" src="https://github.com/user-attachments/assets/478f7ee5-2608-4a6d-b893-2356f9481457" />
<img width="61" height="37" alt="select" src="https://github.com/user-attachments/assets/4b43e453-8d10-4bce-a27e-89e3c9d4923e" />

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PR Comment: https://git.openjdk.org/jdk/pull/27947#issuecomment-3438052314