[anchor-position] Parse and evaluator `auto` and `auto-size` keywords
This patch adds two more anchor side keywords `auto` and `auto-size`
to the `anchor()` function, and evaluates them by converting them into
the corresponding physical sides.
This patch doesn't implement the automatic fallbacks, which will be
implemented by a follow-up patch.
Spec: https://drafts.csswg.org/css-anchor-position-1/#anchor-auto
Bug: 1412864
Change-Id: I0494ab943a07ab9916b430600d4f49235c5df084
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4602508
Commit-Queue: Koji Ishii <kojii@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Auto-Submit: Xiaocheng Hu <xiaochengh@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1155689}
diff --git a/css/css-anchor-position/anchor-position-auto-001.html b/css/css-anchor-position/anchor-position-auto-001.html
new file mode 100644
index 0000000..b5e1952
--- /dev/null
+++ b/css/css-anchor-position/anchor-position-auto-001.html
@@ -0,0 +1,71 @@
+<!DOCTYPE html>
+<title>Tests automatic anchor positioning without fallbacks</title>
+<link rel="help" href="https://drafts.csswg.org/css-anchor-position-1/#anchor-auto">
+<link rel="auto" href="mailto:xiaochengh@chromium.org">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/resources/check-layout-th.js"></script>
+<script src="support/test-common.js"></script>
+
+<style>
+body {
+ margin: 0;
+}
+
+#cb {
+ position: absolute;
+ width: 500px;
+ height: 500px;
+}
+
+#anchor {
+ margin-left: 150px;
+ margin-top: 250px;
+ width: 100px;
+ height: 100px;
+ background: orange;
+ anchor-name: --a;
+}
+
+.target {
+ position: absolute;
+ width: 100px;
+ height: 100px;
+ background: lime;
+}
+
+#target1 {
+ top: anchor(--a auto); /* should evaluate to `bottom` */
+ left: anchor(--a auto-same); /* should evaluate to `left` */
+}
+
+#target2 {
+ bottom: anchor(--a auto); /* should evaluate to `top` */
+ right: anchor(--a auto-same); /* should evaluate to `right` */
+}
+
+#target3 {
+ top: anchor(--a auto-same); /* should evaluate to `top` */
+ left: anchor(--a auto); /* should evaluate to `right` */
+}
+
+#target4 {
+ bottom: anchor(--a auto-same); /* should evaluate to `bottom` */
+ right: anchor(--a auto); /* should evaluate to `left` */
+}
+</style>
+
+<body onload="checkLayoutForAnchorPos('.target')">
+ <div id="cb">
+ <div id="anchor"></div>
+
+ <div id="target1" class="target"
+ data-offset-x="150" data-offset-y="350"></div>
+ <div id="target2" class="target"
+ data-offset-x="150" data-offset-y="150"></div>
+ <div id="target3" class="target"
+ data-offset-x="250" data-offset-y="250"></div>
+ <div id="target4" class="target"
+ data-offset-x="50" data-offset-y="250"></div>
+ </div>
+</body>
