[css-borders-4] Define border/shadow rendering for corner-shape
#12175
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Specific comments scattered in. Generally, tho, I can't actually follow the algorithm and am confused by several details, and it handwaves several operations that might be obvious when you're "in the code", but aren't clear from my perspective as a relative outsider.
css-borders-4/Overview.bs
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| 1. If |s| is equal or less than -1, return <code>0, -|w|</code>. | ||
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| Note: Because of the above clamping, when the shape is more convex than a ''corner-shape/round'' or more concave than a ''corner-shape-scoop'', | ||
| the inner curve cannot would appear to have a "belly" towards the middle, as it cannot remain constant while maintaining the same curvature. |
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"cannot would" needs fixing, but I'm not 100% certain what it's trying to say.
css-borders-4/Overview.bs
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| To compute the inner path of a corner: | ||
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| 1. Let |adjustedX|, |adjustedY| be the result of the [=adjusted untrimmed inner top-left corner starting point=] steps, | ||
| modified to consider the corresponding 'border-width' and 'corner-shape' values at the start and end of a path`. |
css-borders-4/Overview.bs
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| 1. Let |adjustedX|, |adjustedY| be the result of the [=adjusted untrimmed inner top-left corner starting point=] steps, | ||
| modified to consider the corresponding 'border-width' and 'corner-shape' values at the start and end of a path`. | ||
| 1. Create a path based on the [=canonical superellipse formula=], with the outer corner as the center, starting from |adjustedX| and ending at |adjustedY|. |
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I don't really understand what this is saying. I'm particularly confused by what the "starting from... ending from..." part means; it doesn't match what I thought those variables were for. They're x and y coordinates of a point; how do you "start" and "end" at them individually?
css-borders-4/Overview.bs
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| modified to consider the corresponding 'border-width' and 'corner-shape' values at the start and end of a path`. | ||
| 1. Create a path based on the [=canonical superellipse formula=], with the outer corner as the center, starting from |adjustedX| and ending at |adjustedY|. | ||
| User agents MAY create an approximation of this path rather than try to follow the formula precisely, for performance reasons. | ||
| 1. Trim the resulting path so that it starts at a point that has a 'border-width' distance from the outer. |
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Also not sure what this is actually telling me to do. :(
css-borders-4/Overview.bs
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| This is illustrated in the following chart: | ||
| <figure> | ||
| <img src="images/corner-shape-border.svg" |
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This could use some details of where the points/etc calculated by the above algorithms are.
Is the hull calculated in the above algorithms in some way?
Fair! I redid the whole thing with more explanations and a rigorous algorithm. PTAL! |
Based on this resolution
Added detailed algorithms, explanation, and a chart.
Closes #11610
Closes #11767