implement position:relative

src/components/main/layout/block.rs

@@ -13,7 +13,7 @@ use layout::model::{MaybeAuto, Specified, Auto, specified_or_none, specified};
 use layout::float_context::{FloatContext, PlacementInfo, Invalid, FloatType};
 
 use std::cell::RefCell;
-use geom::{Point2D, Rect, SideOffsets2D};
+use geom::{Point2D, Rect, SideOffsets2D, Size2D};
 use gfx::display_list::{DisplayList, DisplayListCollection};
 use servo_util::geometry::Au;
 use servo_util::geometry;
@@ -533,12 +533,13 @@ impl BlockFlow {
     pub fn build_display_list_block<E:ExtraDisplayListData>(
                                     &mut self,
                                     builder: &DisplayListBuilder,
+                                    container_block_size: &Size2D<Au>,
                                     dirty: &Rect<Au>,
                                     mut index: uint,
                                     lists: &RefCell<DisplayListCollection<E>>)
                                     -> uint {
         if self.is_float() {
-            self.build_display_list_float(builder, dirty, index, lists);
+            self.build_display_list_float(builder, container_block_size, dirty, index, lists);
             return index;
         }
 
@@ -556,16 +557,28 @@ impl BlockFlow {
 
         debug!("build_display_list_block: adding display element");
 
+        let rel_offset = match self.box_ {
+            Some(ref box_) => {
+                box_.relative_position(container_block_size)
+            },
+            None => {
+                Point2D {
+                    x: Au::new(0),
+                    y: Au::new(0),
+                }
+            }
+        };
+
         // add box that starts block context
         for box_ in self.box_.iter() {
-            box_.build_display_list(builder, dirty, self.base.abs_position, (&*self) as &Flow, index, lists);
+            box_.build_display_list(builder, dirty, self.base.abs_position + rel_offset, (&*self) as &Flow, index, lists);
         }
         // TODO: handle any out-of-flow elements
         let this_position = self.base.abs_position;
 
         for child in self.base.child_iter() {
             let child_base = flow::mut_base(*child);
-            child_base.abs_position = this_position + child_base.position.origin;
+            child_base.abs_position = this_position + child_base.position.origin + rel_offset;
         }
 
         index
@@ -574,6 +587,7 @@ impl BlockFlow {
     pub fn build_display_list_float<E:ExtraDisplayListData>(
                                     &mut self,
                                     builder: &DisplayListBuilder,
+                                    container_block_size: &Size2D<Au>,
                                     dirty: &Rect<Au>,
                                     index: uint,
                                     lists: &RefCell<DisplayListCollection<E>>)
@@ -583,8 +597,21 @@ impl BlockFlow {
             return true;
         }
 
+        // position:relative
+        let rel_offset = match self.box_ {
+            Some(ref box_) => {
+                box_.relative_position(container_block_size)
+            },
+            None => {
+                Point2D {
+                    x: Au::new(0),
+                    y: Au::new(0),
+                }
+            }
+        };
+
 
-        let offset = self.base.abs_position + self.float.get_ref().rel_pos;
+        let offset = self.base.abs_position + self.float.get_ref().rel_pos + rel_offset;
         // add box that starts block context
         for box_ in self.box_.iter() {
             box_.build_display_list(builder, dirty, offset, (&*self) as &Flow, index, lists);
@@ -596,7 +623,7 @@ impl BlockFlow {
         // go deeper into the flow tree
         for child in self.base.child_iter() {
             let child_base = flow::mut_base(*child);
-            child_base.abs_position = offset + child_base.position.origin;
+            child_base.abs_position = offset + child_base.position.origin + rel_offset;
         }
 
         false

src/components/main/layout/box_.rs

@@ -29,7 +29,7 @@ use std::cmp::ApproxEq;
 use std::num::Zero;
 use style::{ComputedValues, TElement, TNode};
 use style::computed_values::{LengthOrPercentage, LengthOrPercentageOrAuto, overflow, LPA_Auto};
-use style::computed_values::{border_style, clear, font_family, line_height};
+use style::computed_values::{border_style, clear, font_family, line_height, position};
 use style::computed_values::{text_align, text_decoration, vertical_align, visibility, white_space};
 
 use css::node_style::StyledNode;
@@ -651,6 +651,59 @@ impl Box {
             &None => {}
         }
     }
+    pub fn relative_position(&self, container_block_size: &Size2D<Au>) -> Point2D<Au> {
+        fn left_right(style: &ComputedValues,block_width: Au) -> Au {
+            // TODO(ksh8281) : consider RTL(right-to-left) culture
+            match (style.PositionOffsets.left, style.PositionOffsets.right) {
+                (LPA_Auto, _) => {
+                    -MaybeAuto::from_style(style.PositionOffsets.right, block_width)
+                        .specified_or_zero()
+                }
+                (_, _) => {
+                    MaybeAuto::from_style(style.PositionOffsets.left, block_width)
+                        .specified_or_zero()
+                }
+            }
+        }
+
+        fn top_bottom(style: &ComputedValues,block_height: Au) -> Au {
+            match (style.PositionOffsets.top, style.PositionOffsets.bottom) {
+                (LPA_Auto, _) => {
+                    -MaybeAuto::from_style(style.PositionOffsets.bottom, block_height)
+                        .specified_or_zero()
+                }
+                (_, _) => {
+                    MaybeAuto::from_style(style.PositionOffsets.top, block_height)
+                        .specified_or_zero()
+                }
+            }
+        }
+
+        let mut rel_pos: Point2D<Au> = Point2D {
+            x: Au::new(0),
+            y: Au::new(0),
+        };
+
+        if self.style().Box.position == position::relative {
+            rel_pos.x = rel_pos.x + left_right(self.style(), container_block_size.width);
+            rel_pos.y = rel_pos.y + top_bottom(self.style(), container_block_size.height);
+        }
+
+        let info = self.inline_info.borrow();
+        match info.get() {
+            &Some(ref info) => {
+                for info in info.parent_info.iter() {
+                    if info.style.get().Box.position == position::relative {
+                        rel_pos.x = rel_pos.x + left_right(info.style.get(), container_block_size.width);
+                        rel_pos.y = rel_pos.y + top_bottom(info.style.get(), container_block_size.height);
+                    }
+                }
+            },
+            &None => {}
+        }
+        rel_pos
+    }
+
     /// Always inline for SCCP.
     ///
     /// FIXME(pcwalton): Just replace with the clear type from the style module for speed?

src/components/main/layout/flow.rs

@@ -40,6 +40,7 @@ use layout::wrapper::ThreadSafeLayoutNode;
 use extra::dlist::{DList, DListIterator, MutDListIterator};
 use extra::container::Deque;
 use geom::point::Point2D;
+use geom::Size2D;
 use geom::rect::Rect;
 use gfx::display_list::{ClipDisplayItemClass, DisplayListCollection, DisplayList};
 use layout::display_list_builder::ToGfxColor;
@@ -207,6 +208,7 @@ pub trait MutableFlowUtils {
     fn build_display_lists<E:ExtraDisplayListData>(
                           self,
                           builder: &DisplayListBuilder,
+                          container_block_size: &Size2D<Au>,
                           dirty: &Rect<Au>,
                           index: uint,
                           mut list: &RefCell<DisplayListCollection<E>>)
@@ -726,14 +728,15 @@ impl<'a> MutableFlowUtils for &'a mut Flow {
     fn build_display_lists<E:ExtraDisplayListData>(
                           self,
                           builder: &DisplayListBuilder,
+                          container_block_size: &Size2D<Au>,
                           dirty: &Rect<Au>,
                           mut index: uint,
                           lists: &RefCell<DisplayListCollection<E>>)
                           -> bool {
         debug!("Flow: building display list for f{}", base(self).id);
         index = match self.class() {
-            BlockFlowClass => self.as_block().build_display_list_block(builder, dirty, index, lists),
-            InlineFlowClass => self.as_inline().build_display_list_inline(builder, dirty, index, lists),
+            BlockFlowClass => self.as_block().build_display_list_block(builder, container_block_size, dirty, index, lists),
+            InlineFlowClass => self.as_inline().build_display_list_inline(builder, container_block_size, dirty, index, lists),
         };
 
         if lists.with_mut(|lists| lists.lists[index].list.len() == 0) {
@@ -744,8 +747,21 @@ impl<'a> MutableFlowUtils for &'a mut Flow {
             let mut child_lists = DisplayListCollection::new();
             child_lists.add_list(DisplayList::new());
             let child_lists = RefCell::new(child_lists);
+            let container_block_size = match self.class() {
+                BlockFlowClass => {
+                    if self.as_block().box_.is_some() {
+                        self.as_block().box_.get_ref().position.get().size
+                    } else {
+                        base(self).position.size
+                    }
+                },
+                _ => {
+                    base(self).position.size
+                }
+            };
+
             for kid in child_iter(self) {
-                kid.build_display_lists(builder, dirty, 0u, &child_lists);
+                kid.build_display_lists(builder, &container_block_size, dirty, 0u, &child_lists);
             }
 
             let mut child_lists = Some(child_lists.unwrap());

src/components/main/layout/inline.rs

@@ -494,6 +494,7 @@ impl InlineFlow {
     pub fn build_display_list_inline<E:ExtraDisplayListData>(
                                      &self,
                                      builder: &DisplayListBuilder,
+                                     container_block_size: &Size2D<Au>,
                                      dirty: &Rect<Au>,
                                      index: uint,
                                      lists: &RefCell<DisplayListCollection<E>>)
@@ -510,7 +511,8 @@ impl InlineFlow {
                self.boxes.len());
 
         for box_ in self.boxes.iter() {
-            box_.build_display_list(builder, dirty, self.base.abs_position, (&*self) as &Flow, index, lists);
+            let rel_offset: Point2D<Au> = box_.relative_position(container_block_size);
+            box_.build_display_list(builder, dirty, self.base.abs_position + rel_offset, (&*self) as &Flow, index, lists);
         }
 
         // TODO(#225): Should `inline-block` elements have flows as children of the inline flow or

src/components/main/layout/layout_task.rs

@@ -615,7 +615,7 @@ impl LayoutTask {
                 let display_list_builder = DisplayListBuilder {
                     ctx: &layout_ctx,
                 };
-                layout_root.build_display_lists(&display_list_builder, &dirty, 0u, display_list_collection);
+                layout_root.build_display_lists(&display_list_builder, &root_size, &dirty, 0u, display_list_collection);
 
                 let display_list_collection = Arc::new(display_list_collection.unwrap());
 

src/test/ref/basic.list

@@ -26,3 +26,4 @@
 == upper_id_attr.html upper_id_attr_ref.html
 # inline_border_a.html inline_border_b.html
 == anon_block_inherit_a.html anon_block_inherit_b.html
+== position_relative_a.html position_relative_b.html

src/test/ref/inline_border_a.html

@@ -16,7 +16,7 @@
 </style>
 </head>
 <body>
-<span style="border: 10px black solid"><img width="100" style="border:10px red solid" src="inline_border.jpeg"></span>
+<span style="border: 10px black solid"><img width="100" style="border:10px red solid" src="test.jpeg"></span>
 </body>
 </html>
 

src/test/ref/position_relative_a.html

@@ -0,0 +1,17 @@
+<html>
+<head>
+<title>
+    today, weather is very cold.....
+</title>
+<style>
+    body {
+        margin: 0px;
+        padding: 0px;
+    }
+</style>
+</head>
+<body>
+<div style="width:500px;height:200px;position:relative;left:100px;top:100px" >
+    <img src="test.jpeg" style="width:100px;height:100px;"/><span style="position:relative;left:-200px;top:-100px"><img src="test.jpeg" style="position:relative;left:100px;top:100px;width:100px;height:100px"/></span></div>
+</body>
+</html>

src/test/ref/position_relative_b.html

@@ -0,0 +1,18 @@
+<html>
+<head>
+<title>
+    today, weather is very cold.....
+</title>
+<style>
+    body {
+        margin: 0px;
+        padding: 0px;
+    }
+</style>
+</head>
+<body>
+<div style="width:500px;height:200px;margin-left:100px;margin-top:100px" >
+    <img src="test.jpeg" style="width:100px;height:100px;"/>
+</div>
+</body>
+</html>