replaced-element-042.html (3451B)
1 <!DOCTYPE html> 2 <meta charset="utf-8"> 3 <title>CSS aspect-ratio: replaced element with box-sizing</title> 4 <link rel="help" href="https://drafts.csswg.org/css-sizing-4/#aspect-ratio"> 5 <link rel="help" href="https://drafts.csswg.org/css2/visudet.html#min-max-widths"> 6 <link rel="author" title="Oriol Brufau" href="mailto:obrufau@igalia.com"> 7 8 <style> 9 canvas { 10 box-sizing: border-box; 11 aspect-ratio: 1; 12 width: auto; 13 height: auto; 14 background: black; 15 } 16 </style> 17 18 <div id="log"></div> 19 20 <!-- 21 From https://drafts.csswg.org/css2/visudet.html#min-max-widths 22 23 > for replaced elements with an intrinsic ratio and both `width` and `height` specified as `auto`, 24 > the algorithm is as follows: 25 > 26 > Select from the table the resolved height and width values for the appropriate constraint violation. 27 > Take the max-width and max-height as max(min, max) so that min ≤ max holds true. 28 > In this table w and h stand for the results of the width and height computations 29 > ignoring the `min-width`, `min-height`, `max-width` and `max-height` properties. 30 > Normally these are the intrinsic width and height, but they may not be 31 > in the case of replaced elements with intrinsic ratios. 32 33 Note the testcases below ensure that w/h is 1 to match the provided `aspect-ratio`, 34 which didn't exist in CSS2. 35 36 Also note that `aspect-ratio: 1` refers to the border-box due to `box-sizing`, 37 so we need to perform all calculations using border-box sizes. 38 --> 39 40 <!-- 41 w = 100 + 0 = 100 42 h = 50 + 50 = 100 43 max-width = 50 44 max-height = 70 45 Constraint Violation = "(w > max-width) and (h > max-height), where (max-width/w ≤ max-height/h)" 46 Resolved Width = max-width = 50 47 Resolved Height = max(min-height, max-width * h/w) = max(0, 50*100/100) = 50 48 --> 49 <canvas width="100" height="50" style="max-width: 50px; max-height: 70px; padding-top: 50px" 50 data-expected-width="50" data-expected-height="50"></canvas> 51 52 <!-- 53 w = 50 + 50 = 100 54 h = 100 + 0 = 100 55 max-width = 70 56 max-height = 50 57 Constraint Violation = "(w > max-width) and (h > max-height), where (max-width/w > max-height/h)" 58 Resolved Width = max(min-width, max-height * w/h) = max(0, 50*100/100) = 50 59 Resolved Height = max-height = 50 60 --> 61 <canvas width="50" height="100" style="max-width: 70px; max-height: 50px; padding-left: 50px" 62 data-expected-width="50" data-expected-height="50"></canvas> 63 64 <!-- 65 w = 50 + 50 = 100 66 h = 100 + 0 = 100 67 min-width = 150 68 min-height = 175 69 Constraint Violation = "(w < min-width) and (h < min-height), where (min-width/w ≤ min-height/h)" 70 Resolved Width = min(max-width, min-height * w/h) = min(∞, 175*100/100) = 175 71 Resolved Height = min-height = 175 72 --> 73 <canvas width="50" height="100" style="min-width: 150px; min-height: 175px; padding-left: 50px" 74 data-expected-width="175" data-expected-height="175"></canvas> 75 76 <!-- 77 w = 100 + 0 = 100 78 h = 50 + 50 = 100 79 min-width = 175 80 min-height = 150 81 Constraint Violation = "(w < min-width) and (h < min-height), where (min-width/w > min-height/h)" 82 Resolved Width = min-width = 175 83 Resolved Height = min(max-height, min-width * h/w) = min(∞, 175*100/100) = 175 84 --> 85 <canvas width="100" height="50" style="min-width: 175px; min-height: 150px; padding-top: 50px" 86 data-expected-width="175" data-expected-height="175"></canvas> 87 88 <script src="/resources/testharness.js"></script> 89 <script src="/resources/testharnessreport.js"></script> 90 <script src="/resources/check-layout-th.js"></script> 91 <script> 92 checkLayout("canvas"); 93 </script>