| <!DOCTYPE html> |
| <meta charset="utf-8"> |
| <title>CSS aspect-ratio: replaced element with box-sizing</title> |
| <link rel="help" href="https://drafts.csswg.org/css-sizing-4/#aspect-ratio"> |
| <link rel="help" href="https://drafts.csswg.org/css2/visudet.html#min-max-widths"> |
| <link rel="author" title="Oriol Brufau" href="mailto:[email protected]"> |
| |
| <style> |
| canvas { |
| box-sizing: border-box; |
| aspect-ratio: 1; |
| width: auto; |
| height: auto; |
| background: black; |
| } |
| </style> |
| |
| <div id="log"></div> |
| |
| <!-- |
| From https://drafts.csswg.org/css2/visudet.html#min-max-widths |
| |
| > for replaced elements with an intrinsic ratio and both `width` and `height` specified as `auto`, |
| > the algorithm is as follows: |
| > |
| > Select from the table the resolved height and width values for the appropriate constraint violation. |
| > Take the max-width and max-height as max(min, max) so that min ≤ max holds true. |
| > In this table w and h stand for the results of the width and height computations |
| > ignoring the `min-width`, `min-height`, `max-width` and `max-height` properties. |
| > Normally these are the intrinsic width and height, but they may not be |
| > in the case of replaced elements with intrinsic ratios. |
| |
| Note the testcases below ensure that w/h is 1 to match the provided `aspect-ratio`, |
| which didn't exist in CSS2. |
| |
| Also note that `aspect-ratio: 1` refers to the border-box due to `box-sizing`, |
| so we need to perform all calculations using border-box sizes. |
| --> |
| |
| <!-- |
| w = 100 + 0 = 100 |
| h = 50 + 50 = 100 |
| max-width = 50 |
| max-height = 70 |
| Constraint Violation = "(w > max-width) and (h > max-height), where (max-width/w ≤ max-height/h)" |
| Resolved Width = max-width = 50 |
| Resolved Height = max(min-height, max-width * h/w) = max(0, 50*100/100) = 50 |
| --> |
| <canvas width="100" height="50" style="max-width: 50px; max-height: 70px; padding-top: 50px" |
| data-expected-width="50" data-expected-height="50"></canvas> |
| |
| <!-- |
| w = 50 + 50 = 100 |
| h = 100 + 0 = 100 |
| max-width = 70 |
| max-height = 50 |
| Constraint Violation = "(w > max-width) and (h > max-height), where (max-width/w > max-height/h)" |
| Resolved Width = max(min-width, max-height * w/h) = max(0, 50*100/100) = 50 |
| Resolved Height = max-height = 50 |
| --> |
| <canvas width="50" height="100" style="max-width: 70px; max-height: 50px; padding-left: 50px" |
| data-expected-width="50" data-expected-height="50"></canvas> |
| |
| <!-- |
| w = 50 + 50 = 100 |
| h = 100 + 0 = 100 |
| min-width = 150 |
| min-height = 175 |
| Constraint Violation = "(w < min-width) and (h < min-height), where (min-width/w ≤ min-height/h)" |
| Resolved Width = min(max-width, min-height * w/h) = min(∞, 175*100/100) = 175 |
| Resolved Height = min-height = 175 |
| --> |
| <canvas width="50" height="100" style="min-width: 150px; min-height: 175px; padding-left: 50px" |
| data-expected-width="175" data-expected-height="175"></canvas> |
| |
| <!-- |
| w = 100 + 0 = 100 |
| h = 50 + 50 = 100 |
| min-width = 175 |
| min-height = 150 |
| Constraint Violation = "(w < min-width) and (h < min-height), where (min-width/w > min-height/h)" |
| Resolved Width = min-width = 175 |
| Resolved Height = min(max-height, min-width * h/w) = min(∞, 175*100/100) = 175 |
| --> |
| <canvas width="100" height="50" style="min-width: 175px; min-height: 150px; padding-top: 50px" |
| data-expected-width="175" data-expected-height="175"></canvas> |
| |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <script src="/resources/check-layout-th.js"></script> |
| <script> |
| checkLayout("canvas"); |
| </script> |
