1 files changed, 33 insertions, 0 deletions
diff --git a/layout/reftests/css-ruby/utils.js b/layout/reftests/css-ruby/utils.js
new file mode 100644
index 0000000000..1fee84cc2d
--- /dev/null
+++ b/layout/reftests/css-ruby/utils.js
@@ -0,0 +1,33 @@
+function getBlockAxisName(elem) {
+  var wm = getComputedStyle(elem).writingMode;
+  return (!wm || wm == 'horizontal-tb') ? 'height' : 'width';
+}
+
+function getBSize(elem) {
+  return elem.getBoundingClientRect()[getBlockAxisName(elem)] + 'px';
+}
+
+function setBSize(elem, bsize) {
+  elem.style[getBlockAxisName(elem)] = bsize;
+  elem.style.lineHeight = bsize;
+}
+
+// Ruby annotations are placed based on block-axis size of inline boxes
+// instead of line box. Block-axis size of an inline box is the max
+// height of the font, while that of line box is line height. Hence we
+// sometimes need to explicitly set the block-axis size of an inline
+// box to a block to simulate the exact behavior, which is what the
+// following two functions do.
+
+function makeBSizeMatchInlineBox(block, inline) {
+  setBSize(block, getBSize(inline));
+}
+
+function makeBSizeOfParentMatch(elems) {
+  // The size change is divided into two phases to avoid
+  // triggering reflow for every element.
+  for (var elem of elems)
+    elem.dataset.bsize = getBSize(elem);
+  for (var elem of elems)
+    setBSize(elem.parentNode, elem.dataset.bsize);
+}