https://bugs.kde.org/show_bug.cgi?id=403868
--- Comment #6 from Dominik Haumann <dhaum...@kde.org> --- Background: The rendering pipeline in Kate (KateRenderer) is line based: if a line needs to be drawn, the following happens: 1. We fill the line rect with the background color. 2. We collect range data such as a selection and paint this background data over the background 3. The foreground text is drawn. The problem of this approach is that many fonts have characters such as _ that are layouted such that they are painted into the next line. However, when the next line is painted, the background fill overpaints these characters again. In other words: the current painting algo is inherently broken. A proper fix would be to have several layers, and then blit one over the other. Our hack/workaround in the past was for line N to also again draw text of line N-1 and N+1 with clipping for line N. This clipping leads to the bug that the very last line misses characters such as _, since there is no line N+1. Now this bug report tells us we still have issues with overpainting. If anyone wants ti have a look, the above info may help to understand what's going on in the code, maybe someone finds a good fix? -- You are receiving this mail because: You are watching all bug changes.
