diff --git a/src/components/main/layout/block.rs b/src/components/main/layout/block.rs
index 8486d5225be..212441c8798 100644
--- a/src/components/main/layout/block.rs
+++ b/src/components/main/layout/block.rs
@@ -312,17 +312,86 @@ impl BlockFlowData {
}
}
}
+
+ let mut collapsible = Au(0);
+ let mut collapsing = Au(0);
+ let mut margin_top = Au(0);
+ let mut margin_bottom = Au(0);
+ let mut top_margin_collapsible = false;
+ let mut bottom_margin_collapsible = false;
+ let mut first_inflow = true;
+ for &box in self.box.iter() {
+ do box.with_model |model| {
+ if !self.is_root && model.border.top == Au(0) && model.padding.top == Au(0) {
+ collapsible = model.margin.top;
+ top_margin_collapsible = true;
+ }
+ if !self.is_root && model.border.bottom == Au(0) && model.padding.bottom == Au(0) {
+ bottom_margin_collapsible = true;
+ }
+ margin_top = model.margin.top;
+ margin_bottom = model.margin.bottom;
+ }
+ }
for kid in self.common.child_iter() {
+ match *kid {
+ BlockFlow(ref info) => {
+ for &box in info.box.iter() {
+ do box.with_model |model| {
+ // The top margin collapses with its first in-flow block-level child's
+ // top margin if the parent has no top boder, no top padding.
+ if first_inflow && top_margin_collapsible {
+ // If top-margin of parent is less than top-margin of its first child,
+ // the parent box goes down until its top is aligned with the child.
+ if margin_top < model.margin.top {
+ // TODO: The position of child floats should be updated and this
+ // would influence clearance as well. See #725
+ let extra_margin = model.margin.top - margin_top;
+ top_offset = top_offset + extra_margin;
+ margin_top = model.margin.top;
+ }
+ }
+ // The bottom margin of an in-flow block-level element collapses
+ // with the top margin of its next in-flow block-level sibling.
+ collapsing = geometry::min(model.margin.top, collapsible);
+ collapsible = model.margin.bottom;
+ }
+ }
+ first_inflow = false;
+ }
+ // Margins between a floated box and any other box do not collapse.
+ _ => {
+ collapsing = Au(0);
+ }
+ }
+
do kid.with_mut_base |child_node| {
+ cur_y = cur_y - collapsing;
child_node.position.origin.y = cur_y;
cur_y = cur_y + child_node.position.size.height;
};
}
+ // The bottom margin collapses with its last in-flow block-level child's bottom margin
+ // if the parent has no bottom boder, no bottom padding.
+ collapsing = if bottom_margin_collapsible {
+ if margin_bottom < collapsible {
+ margin_bottom = collapsible;
+ }
+ collapsible
+ } else {
+ Au(0)
+ };
+
+ // TODO: A box's own margins collapse if the 'min-height' property is zero, and it has neither
+ // top or bottom borders nor top or bottom padding, and it has a 'height' of either 0 or 'auto',
+ // and it does not contain a line box, and all of its in-flow children's margins (if any) collapse.
+
+
let mut height = if self.is_root {
Au::max(ctx.screen_size.size.height, cur_y)
} else {
- cur_y - top_offset
+ cur_y - top_offset - collapsing
};
for &box in self.box.iter() {
@@ -336,13 +405,17 @@ impl BlockFlowData {
self.box.map(|&box| {
do box.with_mut_base |base| {
//The associated box is the border box of this flow
+ base.model.margin.top = margin_top;
+ base.model.margin.bottom = margin_bottom;
+
base.position.origin.y = clearance + base.model.margin.top;
noncontent_height = base.model.padding.top + base.model.padding.bottom +
base.model.border.top + base.model.border.bottom;
base.position.size.height = height + noncontent_height;
- noncontent_height = noncontent_height + clearance + base.model.margin.top + base.model.margin.bottom;
+ noncontent_height = noncontent_height + clearance +
+ base.model.margin.top + base.model.margin.bottom;
}
});
diff --git a/src/test/ref/basic.list b/src/test/ref/basic.list
index e9140ef13d4..3a4742786b3 100644
--- a/src/test/ref/basic.list
+++ b/src/test/ref/basic.list
@@ -1,2 +1,3 @@
== basic_width_px.html basic_width_em.html
== hello_a.html hello_b.html
+== margin_a.html margin_b.html
diff --git a/src/test/ref/margin_a.html b/src/test/ref/margin_a.html
new file mode 100644
index 00000000000..fb477aa30d9
--- /dev/null
+++ b/src/test/ref/margin_a.html
@@ -0,0 +1,74 @@
+
+
+ margin
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/src/test/ref/margin_b.html b/src/test/ref/margin_b.html
new file mode 100644
index 00000000000..ac8f3fa9b7c
--- /dev/null
+++ b/src/test/ref/margin_b.html
@@ -0,0 +1,74 @@
+
+
+ margin
+
+
+
+
+
+
+
+
+
+
+
+