https://bugs.documentfoundation.org/show_bug.cgi?id=156685
--- Comment #9 from Myndex <m...@andysomers.com> --- Hi Regina, Heiko, Rafael, Sorry for my delay in response, and sorry this is causing trouble from the other bug being fixed. To highlight the importance of corrections for the underlying issues: For color RGB(114,159,207), white is higher contrast than black. Depending on the size of the font this can be quite important to readability and visual accessibility. FWIW I have been practically unable to use LibreOffice because of how text colors are unreadable when my OS is in dark mode, so getting some of these issues corrected is important for the LibreOffice UX overall. The present bug Instead of lowering the threshold, could the default blue be lightened? That seems like a proactive step in the right direction. Notes on contrast & methods: The WCAG 2 contrast math is incorrect, particularly for dark colors. An APCA-based calculator gives useful results over the visual range. https://www.myndex.com/APCA/ If the auto color is ONLY white or back, then changing the math is not needed (probably). The existing but archaic method is fine for a single flip point. The 156 came from testing and aligning with perceptually uniform methods, and exactitude is not needed. RGB(114,159,207) with black text rates a contrast of Lc 50, which is lower than ideal, okay for larger / bolder fonts (32px normal, 21px bold) if readability is important. RGB(114,159,207) is close to contrast center, so it's perhaps black text is not a show-stopper, but white text has about 15%-20% more readable contrast. Perception and Flips To keep text black with a perceptually similar blue, rgb(125,179,232) is a reasonable minimum, rgb(135,197,255) is better for black text, and rgb(158,206,255) is preferred for smaller black text. Dark mode (white text) perceptually uniform inversions: rgb(112,155,201) reasonable minimum rgb(96,136,178) better for white text rgb(90,125,156) preferred for smaller white text Thank you for reading Andy -- You are receiving this mail because: You are the assignee for the bug.
