Thanks very much for answering some of my questions for me. Xidorn Quan writes:
> On Wed, Jul 25, 2018, at 6:29 PM, Karl Tomlinson wrote: >> Is there a plan to avoid the contrast problems we have mixing >> document colors with system colors in other widgets? >> >> e.g. If one scrollbar color is specified by the document, then >> what ensures that other parts of the scrollbar are visually >> distinct? >> >> Does the computed value of the other scrollbar color change so >> that it contrasts with the specified color? > > There are only two scrollbar color properties. If a platform has > other parts which need different colors, we would derive such > colors from the given one based on the native scheme and > constrast. Does the second sentence also apply when only one of the two properties is auto? Would the color for the auto property be derived in such as way as to hide the thumb or to make it constrast? >> I see some such code in GetScrollbarArrowColor(), but I haven't >> found something similar for track and thumb. Does something >> ensure the thumb will be visible? > > Both track and thumb are specified by the author, so no, there > is nothing ensures that thumb will be visible if the author > specifically want to hide it. I can understand that if the computed values of track and thumb match and are not auto, then a scrollbar might be hidden. I'm not clear on whether it will actually be hidden because I'm not clear on how much variation (e.g. shading) the implementation is permitted to apply to shape the colors. But my key questions are about the situation where one and only one of the two colors is auto. I'm not entirely clear what "If scrollbar-track-color computes to auto, and scrollbar-face-color is not auto, it is used to color the scrollbar track." means. I guess it means that, if only face is not auto, then the track color is the same as that of face. Is that your understanding? Would it be correct to say that the "used value" for the track property is determined from the computed value for the face property in that situation? Assuming the face and track colors match after applying this rule, then would the scrollbar be hidden, in the same way as it would when face and track colors match but neither computed value is auto. What if only track is not auto? >> What if the user has a high contrast theme for accessibility >> reasons? Does this override document colors? > > It follows the same color overriding settings that if > browser.display.document_color_use is the default value, and the > user is using high contrast theme, those properties would be > ignored during style cascading, and consequently no custom > scrollbar would be used. Sounds good, thanks. _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
