Send in the right container block size for relative positioning.

This fixes #1757.
servo · Mar 4, 2014 · 20a4ac6 · 20a4ac6 · bors-servo · Mar 11, 2014
1 parent 4a6077c
commit 20a4ac6
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Showing 5 changed files with 65 additions and 3 deletions.
diff --git a/src/components/main/layout/box_.rs b/src/components/main/layout/box_.rs
@@ -1267,6 +1267,7 @@ impl Box {
     }
 
 
+    /// TODO: What exactly does this function return? Why is it Au(0) for GenericBox?
     pub fn content_width(&self) -> Au {
         match self.specific {
             GenericBox | IframeBox(_) => Au(0),
@@ -1300,6 +1301,13 @@ impl Box {
         }
     }
 
+    /// Return the size of the content box.
+    pub fn content_box_size(&self) -> Size2D<Au> {
+        let border_box_size = self.border_box.get().size;
+        Size2D(border_box_size.width - self.noncontent_width(),
+               border_box_size.height - self.noncontent_height())
+    }
+
     /// Split box which includes new-line character
     pub fn split_by_new_line(&self) -> SplitBoxResult {
         match self.specific {

diff --git a/src/components/main/layout/flow.rs b/src/components/main/layout/flow.rs
@@ -957,9 +957,9 @@ impl<'a> MutableFlowUtils for &'a mut Flow {
             // TODO(pradeep): Move this into a generated CB function and stuff in Flow.
             match block.box_ {
                 Some(ref box_) => {
-                    // FIXME: This should be the size of the content box (which is the
-                    // Containing Block formed by a BlockFlow), not the border box.
-                    container_block_size = box_.border_box.get().size;
+                    // The Containing Block formed by a Block for relatively
+                    // positioned descendants is the content box.
+                    container_block_size = box_.content_box_size();
 
                     abs_cb_position = if block.is_positioned() {
                         block.base.abs_position + block.generated_cb_position()

diff --git a/src/test/ref/basic.list b/src/test/ref/basic.list
@@ -44,3 +44,4 @@
 == position_fixed_simple_a.html position_fixed_simple_b.html
 == position_fixed_static_y_a.html position_fixed_static_y_b.html
 == position_relative_a.html position_relative_b.html
+== position_relative_top_percentage_a.html position_relative_top_percentage_b.html
diff --git a/src/test/ref/position_relative_top_percentage_a.html b/src/test/ref/position_relative_top_percentage_a.html
@@ -0,0 +1,25 @@
+<html>
+  <head>
+    <style>
+      #first {
+      width: 100px;
+      height: 100px;
+      border: solid 10px;
+      }
+      #rel {
+      position: relative;
+      left: 50%;
+      top: 50%;
+      width: 50px;
+      height: 50px;
+      background: green;
+      }
+    </style>
+  </head>
+  <body>
+    <div id="first">
+      <div id="rel">
+      </div>
+    </div>
+  </body>
+</html>
diff --git a/src/test/ref/position_relative_top_percentage_b.html b/src/test/ref/position_relative_top_percentage_b.html
@@ -0,0 +1,28 @@
+<html>
+  <head>
+    <style>
+      #first {
+      width: 100px;
+      height: 100px;
+      border: solid 10px;
+      }
+      .box {
+      width: 50px;
+      height: 50px;
+      }
+      #green_square {
+      height: 50px;
+      width: 50px;
+      margin-left: 50px;
+      background: green;
+      }
+    </style>
+  </head>
+  <body>
+    <div id="first">
+      <div class="box"></div>
+      <div id="green_square">
+      </div>
+    </div>
+  </body>
+</html>