On Thu, 10 Sep 2026 17:47:40 GMT, Martin Fox <[email protected]> wrote:
>> This PR attempts to improve LCD text rendering on Windows and Linux. Changes >> include: >> >> - (Windows only) When setting up DirectWrite the code now uses the >> NATURAL_SYMMETRIC rendering mode except for very small glyphs where it uses >> NATURAL. Using NATURAL_SYMMETRIC avoids distorted glyphs at specific pixel >> sizes (see [JDK-8389632](https://bugs.openjdk.org/browse/JDK-8389632)) and >> retains the curves along the top and bottom of the glyphs. Using NATURAL at >> small sizes avoids glyphs turning very fuzzy and light. >> >> - The code is now consistently converts the colors from sRGB to a linear >> space (more or less), composites them, and then converts the result back to >> sRGB. >> >> - The shader applies a contrast equation to the LCD glyph mask which helps >> emphasize the stems. The same equation is used by Skia and probably added by >> Microsoft when they cleaned up text rendering for Chromium. BTW it’s just >> the equation for a parabola that goes through points (0, 0) and (1, 1). >> >> My testing was mostly done on a 27 inch display with a resolution of >> 2560x1440 and a screen scale of 150%. This was low enough to notice a >> difference. Resolutions higher than that (like full-on Retina) tend to hide >> a lot of sins. >> >> I recommend reading “The Raster Tragedy in Skia” which is concise but covers >> a lot of ground. It contains a section on the challenges of compositing text >> in sRGB space and also the issues getting LCD text to look dark enough >> without inflating the stems. I wish I had found this earlier in the process. >> >> --------- >> - [x] I confirm that I make this contribution in accordance with the >> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). > > Martin Fox has updated the pull request incrementally with one additional > commit since the last revision: > > Added Swing version of the cascade I added a Swing version of the cascade. Swing doesn't allow fractional font heights so it has fewer rows. Attached is a screenshot showing the Monkey Tester as it looks with this PR (to the left) and on the master branch (to the right). I find it difficult to judge the differences using screenshots. At anything other than 100% the LCD effect is lost and many image viewing apps smooth the image (I used Paint on Windows to avoid that). At 100% the PR text has more weight and is a little smoother (at least to me). <img width="573" height="430" alt="TextDiffs" src="https://github.com/user-attachments/assets/489d53d2-be6d-4ef5-850b-689b79cf8ca0"; /> ------------- PR Comment: https://git.openjdk.org/jfx/pull/2284#issuecomment-5623002359
