Merge pull request #3464 from mrobinson/scroll_offset

Allow iframes to scroll their contents

5 files changed, 104 insertions, 52 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 3c9746c4432..e04ebaa0b67 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -33,7 +33,7 @@ dependencies = [
  "freetype 0.1.0 (git+https://github.com/servo/rust-freetype#0b03da276e4bdeae2300596dabc4ccb16733ad70)",
  "geom 0.1.0 (git+https://github.com/servo/rust-geom#50a294fd997f0c6eb43e9a58ad6e227fdc2a4692)",
  "glfw 0.0.1 (git+https://github.com/servo/glfw-rs?ref=servo#7ccfaca315a43d97914e1601c90ad348ef190edf)",
- "layers 0.1.0 (git+https://github.com/servo/rust-layers#ef89918471815dfced7aaf2f1594d5469f03eab7)",
+ "layers 0.1.0 (git+https://github.com/servo/rust-layers#ed570335738913fb41fc62a024389dfa415962e8)",
  "opengles 0.1.0 (git+https://github.com/servo/rust-opengles#6776e9c07feb149d34b087039ecf6b2c143e3afc)",
  "skia-sys 0.0.20130412 (git+https://github.com/servo/skia#6d696712962fd0d41120b7a414a48417da8e6a92)",
  "xlib 0.1.0 (git+https://github.com/servo/rust-xlib#581d4faddec5188d3c3ae5307dbea28aab90644c)",
@@ -66,7 +66,7 @@ dependencies = [
  "gfx 0.0.1",
  "glfw 0.0.1 (git+https://github.com/servo/glfw-rs?ref=servo#7ccfaca315a43d97914e1601c90ad348ef190edf)",
  "glut 0.0.1 (git+https://github.com/servo/rust-glut#01af0162ea0322ad1a40d6adb023a39813605949)",
- "layers 0.1.0 (git+https://github.com/servo/rust-layers#ef89918471815dfced7aaf2f1594d5469f03eab7)",
+ "layers 0.1.0 (git+https://github.com/servo/rust-layers#ed570335738913fb41fc62a024389dfa415962e8)",
  "layout_traits 0.0.1",
  "msg 0.0.1",
  "net 0.0.1",
@@ -181,7 +181,7 @@ dependencies = [
  "freetype 0.1.0 (git+https://github.com/servo/rust-freetype#0b03da276e4bdeae2300596dabc4ccb16733ad70)",
  "geom 0.1.0 (git+https://github.com/servo/rust-geom#50a294fd997f0c6eb43e9a58ad6e227fdc2a4692)",
  "harfbuzz 0.1.0 (git+https://github.com/servo/rust-harfbuzz#ad520942cc17232e1a40cdd8a99c2905623d35f6)",
- "layers 0.1.0 (git+https://github.com/servo/rust-layers#ef89918471815dfced7aaf2f1594d5469f03eab7)",
+ "layers 0.1.0 (git+https://github.com/servo/rust-layers#ed570335738913fb41fc62a024389dfa415962e8)",
  "msg 0.0.1",
  "net 0.0.1",
  "plugins 0.0.1",
@@ -265,7 +265,7 @@ dependencies = [
 [[package]]
 name = "layers"
 version = "0.1.0"
-source = "git+https://github.com/servo/rust-layers#ef89918471815dfced7aaf2f1594d5469f03eab7"
+source = "git+https://github.com/servo/rust-layers#ed570335738913fb41fc62a024389dfa415962e8"
 dependencies = [
  "core_foundation 0.1.0 (git+https://github.com/servo/rust-core-foundation#166a601ff3e0fc3a64ca1a9090d02c8d4f22b61a)",
  "egl 0.1.0 (git+https://github.com/servo/rust-egl#88f2a13812ddbce2bf2317221663a61c31b3e220)",
@@ -321,7 +321,7 @@ dependencies = [
  "core_foundation 0.1.0 (git+https://github.com/servo/rust-core-foundation#166a601ff3e0fc3a64ca1a9090d02c8d4f22b61a)",
  "geom 0.1.0 (git+https://github.com/servo/rust-geom#50a294fd997f0c6eb43e9a58ad6e227fdc2a4692)",
  "io_surface 0.1.0 (git+https://github.com/servo/rust-io-surface#7038341220bd7e86e21118fac2cbc6bd50890e47)",
- "layers 0.1.0 (git+https://github.com/servo/rust-layers#ef89918471815dfced7aaf2f1594d5469f03eab7)",
+ "layers 0.1.0 (git+https://github.com/servo/rust-layers#ed570335738913fb41fc62a024389dfa415962e8)",
  "url 0.1.0 (git+https://github.com/servo/rust-url#bfdf809365600a7941a77524f9bb065886de3379)",
  "util 0.0.1",
 ]
diff --git a/components/compositing/compositor.rs b/components/compositing/compositor.rs
index cec9c2b7419..730db1519a3 100644
--- a/components/compositing/compositor.rs
+++ b/components/compositing/compositor.rs
@@ -9,6 +9,7 @@ use compositor_task::{SetLayerOrigin, Paint, ScrollFragmentPoint, LoadComplete};
 use compositor_task::{ShutdownComplete, ChangeRenderState, RenderMsgDiscarded};
 use constellation::SendableFrameTree;
 use events;
+use events::ScrollPositionChanged;
 use pipeline::CompositionPipeline;
 use platform::{Application, Window};
 use windowing;
@@ -24,7 +25,7 @@ use azure::azure_hl;
 use std::cmp;
 use std::time::duration::Duration;
 use geom::point::{Point2D, TypedPoint2D};
-use geom::rect::Rect;
+use geom::rect::{Rect, TypedRect};
 use geom::size::TypedSize2D;
 use geom::scale_factor::ScaleFactor;
 use gfx::render_task::{RenderChan, RenderMsg, RenderRequest, UnusedBufferMsg};
@@ -35,8 +36,8 @@ use layers::rendergl::RenderContext;
 use layers::scene::Scene;
 use opengles::gl2;
 use png;
-use servo_msg::compositor_msg::{Blank, Epoch, FixedPosition, FinishedLoading, IdleRenderState};
-use servo_msg::compositor_msg::{LayerId, ReadyState, RenderingRenderState, RenderState};
+use servo_msg::compositor_msg::{Blank, Epoch, FinishedLoading, IdleRenderState, LayerId};
+use servo_msg::compositor_msg::{ReadyState, RenderingRenderState, RenderState, Scrollable};
 use servo_msg::constellation_msg::{ConstellationChan, ExitMsg, LoadUrlMsg, NavigateMsg};
 use servo_msg::constellation_msg::{PipelineId, ResizedWindowMsg, WindowSizeData};
 use servo_msg::constellation_msg;
@@ -413,7 +414,8 @@ impl IOCompositor {
             Some(ref mut layer) => CompositorData::clear_all_tiles(layer.clone()),
             None => { }
         }
-        self.scene.root = Some(self.create_frame_tree_root_layers(frame_tree));
+        self.scene.root = Some(self.create_frame_tree_root_layers(frame_tree, None));
+        self.scene.set_root_layer_size(self.window_size.as_f32());
 
         // Initialize the new constellation channel by sending it the root window size.
         self.constellation_chan = new_constellation_chan;
@@ -421,7 +423,8 @@ impl IOCompositor {
     }
 
     fn create_frame_tree_root_layers(&mut self,
-                                     frame_tree: &SendableFrameTree)
+                                     frame_tree: &SendableFrameTree,
+                                     frame_rect: Option<TypedRect<PagePx, f32>>)
                                      -> Rc<Layer<CompositorData>> {
         // Initialize the ReadyState and RenderState for this pipeline.
         self.ready_states.insert(frame_tree.pipeline.id, Blank);
@@ -433,15 +436,22 @@ impl IOCompositor {
             id: LayerId::null(),
             rect: Rect::zero(),
             background_color: azure_hl::Color::new(0., 0., 0., 0.),
-            scroll_policy: FixedPosition,
+            scroll_policy: Scrollable,
         };
         let root_layer = CompositorData::new_layer(frame_tree.pipeline.clone(),
                                                    layer_properties,
                                                    WantsScrollEvents,
                                                    self.opts.tile_size);
 
+        match frame_rect {
+            Some(ref frame_rect) => {
+                *root_layer.bounds.borrow_mut() = frame_rect * self.device_pixels_per_page_px();
+            }
+            None => {}
+        }
+
         for kid in frame_tree.children.iter() {
-            root_layer.add_child(self.create_frame_tree_root_layers(&kid.frame_tree));
+            root_layer.add_child(self.create_frame_tree_root_layers(&kid.frame_tree, kid.rect));
         }
         return root_layer;
     }
@@ -490,7 +500,7 @@ impl IOCompositor {
         let need_new_root_layer = !self.update_layer_if_exists(layer_properties);
         if need_new_root_layer {
             let root_layer = self.find_pipeline_root_layer(layer_properties.pipeline_id);
-            CompositorData::update_layer(root_layer.clone(), layer_properties);
+            CompositorData::update_layer_except_size(root_layer.clone(), layer_properties);
 
             let root_layer_pipeline = root_layer.extra_data.borrow().pipeline.clone();
             let first_child = CompositorData::new_layer(root_layer_pipeline.clone(),
@@ -701,13 +711,15 @@ impl IOCompositor {
             self.hidpi_factor = new_hidpi_factor;
             self.update_zoom_transform();
         }
-        if self.window_size != new_size {
-            debug!("osmain: window resized to {:?}", new_size);
-            self.window_size = new_size;
-            self.send_window_size();
-        } else {
-            debug!("osmain: dropping window resize since size is still {:?}", new_size);
+
+        if self.window_size == new_size {
+            return;
         }
+
+        debug!("osmain: window resized to {:?}", new_size);
+        self.window_size = new_size;
+        self.scene.set_root_layer_size(new_size.as_f32());
+        self.send_window_size();
     }
 
     fn on_load_url_window_event(&mut self, url_string: String) {
@@ -755,7 +767,7 @@ impl IOCompositor {
                                                      delta,
                                                      cursor.as_f32(),
                                                      window_size,
-                                                     scene_scale) || scroll;
+                                                     scene_scale) == ScrollPositionChanged;
             }
             None => { }
         }
diff --git a/components/compositing/compositor_data.rs b/components/compositing/compositor_data.rs
index bbb46603f6a..ad6bcefa8fd 100644
--- a/components/compositing/compositor_data.rs
+++ b/components/compositing/compositor_data.rs
@@ -18,6 +18,7 @@ use layers::platform::surface::NativeSurfaceMethods;
 use servo_msg::compositor_msg::{Epoch, LayerId};
 use servo_msg::compositor_msg::ScrollPolicy;
 use servo_msg::constellation_msg::PipelineId;
+use servo_util::geometry::PagePx;
 use std::rc::Rc;
 
 pub struct CompositorData {
@@ -39,6 +40,10 @@ pub struct CompositorData {
     /// A monotonically increasing counter that keeps track of the current epoch.
     /// add_buffer() calls that don't match the current epoch will be ignored.
     pub epoch: Epoch,
+
+    /// The scroll offset originating from this scrolling root. This allows scrolling roots
+    /// to track their current scroll position even while their content_offset does not change.
+    pub scroll_offset: TypedPoint2D<PagePx, f32>,
 }
 
 #[deriving(PartialEq, Clone)]
@@ -60,19 +65,24 @@ impl CompositorData {
             scroll_policy: layer_properties.scroll_policy,
             background_color: layer_properties.background_color,
             epoch: layer_properties.epoch,
+            scroll_offset: TypedPoint2D(0., 0.),
         };
 
         Rc::new(Layer::new(Rect::from_untyped(&layer_properties.rect),
                            tile_size, new_compositor_data))
     }
 
-    pub fn update_layer(layer: Rc<Layer<CompositorData>>, layer_properties: LayerProperties) {
+    pub fn update_layer_except_size(layer: Rc<Layer<CompositorData>>,
+                                    layer_properties: LayerProperties) {
         layer.extra_data.borrow_mut().epoch = layer_properties.epoch;
+        layer.extra_data.borrow_mut().scroll_policy = layer_properties.scroll_policy;
         layer.extra_data.borrow_mut().background_color = layer_properties.background_color;
+        layer.contents_changed();
+    }
 
+    pub fn update_layer(layer: Rc<Layer<CompositorData>>, layer_properties: LayerProperties) {
         let size: TypedSize2D<DevicePixel, f32> = Size2D::from_untyped(&layer_properties.rect.size);
         layer.resize(size);
-        layer.contents_changed();
 
         // Call scroll for bounds checking if the page shrunk. Use (-1, -1) as the
         // cursor position to make sure the scroll isn't propagated downwards. The
@@ -82,6 +92,7 @@ impl CompositorData {
                                     TypedPoint2D(-1f32, -1f32),
                                     size,
                                     ScaleFactor(1.0) /* scene_scale */);
+        CompositorData::update_layer_except_size(layer, layer_properties);
     }
 
     pub fn find_layer_with_pipeline_and_layer_id(layer: Rc<Layer<CompositorData>>,
diff --git a/components/compositing/events.rs b/components/compositing/events.rs
index c4e86cae26a..aa1bfc6e2a3 100644
--- a/components/compositing/events.rs
+++ b/components/compositing/events.rs
@@ -8,6 +8,7 @@ use windowing::MouseWindowMouseUpEvent;
 
 use geom::length::Length;
 use geom::point::{Point2D, TypedPoint2D};
+use geom::rect::Rect;
 use geom::scale_factor::ScaleFactor;
 use geom::size::TypedSize2D;
 use layers::geometry::DevicePixel;
@@ -39,6 +40,13 @@ impl Clampable for f32 {
     }
 }
 
+#[deriving(PartialEq)]
+pub enum ScrollEventResult {
+    ScrollEventUnhandled,
+    ScrollPositionChanged,
+    ScrollPositionUnchanged,
+}
+
 /// Move the layer's descendants that don't want scroll events and scroll by a relative
 /// specified amount in page coordinates. This also takes in a cursor position to see if the
 /// mouse is over child layers first. If a layer successfully scrolled, returns true; otherwise
@@ -48,40 +56,51 @@ pub fn handle_scroll_event(layer: Rc<Layer<CompositorData>>,
                            cursor: TypedPoint2D<DevicePixel, f32>,
                            window_size: TypedSize2D<DevicePixel, f32>,
                            scale: ScaleFactor<PagePx, DevicePixel, f32>)
-                           -> bool {
+                           -> ScrollEventResult {
     // If this layer doesn't want scroll events, neither it nor its children can handle scroll
     // events.
     if layer.extra_data.borrow().wants_scroll_events != WantsScrollEvents {
-        return false
+        return ScrollEventUnhandled;
     }
 
     // Allow children to scroll.
-    let content_offset_in_page_pixels : TypedPoint2D<PagePx, f32> =
-        Point2D::from_untyped(&*layer.content_offset.borrow());
-    let content_offset : TypedPoint2D<DevicePixel, f32> = content_offset_in_page_pixels * scale;
-    let new_cursor = cursor - content_offset;
+    let scroll_offset = layer.extra_data.borrow().scroll_offset;
+    let scroll_offset_in_device_pixels = scroll_offset * scale;
+    let new_cursor = cursor - scroll_offset_in_device_pixels;
     for child in layer.children().iter() {
         let child_bounds = child.bounds.borrow();
-        if child_bounds.contains(&new_cursor) &&
-           handle_scroll_event(child.clone(),
-                               delta,
-                               new_cursor - child_bounds.origin,
-                               child_bounds.size,
-                               scale) {
-            return true
+        if child_bounds.contains(&new_cursor) {
+            let result = handle_scroll_event(child.clone(),
+                                             delta,
+                                             new_cursor - child_bounds.origin,
+                                             child_bounds.size,
+                                             scale);
+            if result != ScrollEventUnhandled {
+                return result;
+            }
         }
     }
 
-    clamp_scroll_offset_and_scroll_layer(layer, content_offset + delta, window_size, scale)
+    clamp_scroll_offset_and_scroll_layer(layer,
+                                         scroll_offset_in_device_pixels + delta,
+                                         window_size,
+                                         scale)
+}
 
+pub fn calculate_content_size_for_layer(layer: Rc<Layer<CompositorData>>)
+                                         -> TypedSize2D<DevicePixel, f32> {
+    layer.children().iter().fold(Rect::zero(),
+                                 |unioned_rect, child_rect| {
+                                    unioned_rect.union(&*child_rect.bounds.borrow())
+                                 }).size
 }
 
 pub fn clamp_scroll_offset_and_scroll_layer(layer: Rc<Layer<CompositorData>>,
                                             new_offset: TypedPoint2D<DevicePixel, f32>,
                                             window_size: TypedSize2D<DevicePixel, f32>,
                                             scale: ScaleFactor<PagePx, DevicePixel, f32>)
-                                            -> bool {
-    let layer_size = layer.bounds.borrow().size;
+                                            -> ScrollEventResult {
+    let layer_size = calculate_content_size_for_layer(layer.clone());
     let min_x = (window_size.width - layer_size.width).get().min(0.0);
     let min_y = (window_size.height - layer_size.height).get().min(0.0);
     let new_offset : TypedPoint2D<DevicePixel, f32> =
@@ -89,15 +108,24 @@ pub fn clamp_scroll_offset_and_scroll_layer(layer: Rc<Layer<CompositorData>>,
                 Length(new_offset.y.get().clamp(&min_y, &0.0)));
 
     let new_offset_in_page_px = new_offset / scale;
-    let untyped_new_offset = new_offset_in_page_px.to_untyped();
-    if *layer.content_offset.borrow() == untyped_new_offset {
-        return false
+    if layer.extra_data.borrow().scroll_offset == new_offset_in_page_px {
+        return ScrollPositionUnchanged;
     }
 
-    // FIXME: This allows the base layer to record the current content offset without
-    // updating its transform. This should be replaced with something less strange.
-    *layer.content_offset.borrow_mut() = untyped_new_offset;
-    scroll_layer_and_all_child_layers(layer.clone(), new_offset_in_page_px)
+    // The scroll offset is just a record of the scroll position of this scrolling root,
+    // but scroll_layer_and_all_child_layers actually moves the child layers.
+    layer.extra_data.borrow_mut().scroll_offset = new_offset_in_page_px;
+
+    let mut result = false;
+    for child in layer.children().iter() {
+        result |= scroll_layer_and_all_child_layers(child.clone(), new_offset_in_page_px);
+    }
+
+    if result {
+        return ScrollPositionChanged;
+    } else {
+        return ScrollPositionUnchanged;
+    }
 }
 
 fn scroll_layer_and_all_child_layers(layer: Rc<Layer<CompositorData>>,
@@ -115,8 +143,9 @@ fn scroll_layer_and_all_child_layers(layer: Rc<Layer<CompositorData>>,
         result = true
     }
 
+    let offset_for_children = new_offset + layer.extra_data.borrow().scroll_offset;
     for child in layer.children().iter() {
-        result |= scroll_layer_and_all_child_layers(child.clone(), new_offset);
+        result |= scroll_layer_and_all_child_layers(child.clone(), offset_for_children);
     }
 
     return result;
diff --git a/ports/cef/Cargo.lock b/ports/cef/Cargo.lock
index c4d77206c38..74fe836c0b3 100644
--- a/ports/cef/Cargo.lock
+++ b/ports/cef/Cargo.lock
@@ -11,7 +11,7 @@ dependencies = [
  "glfw 0.0.1 (git+https://github.com/servo/glfw-rs?ref=servo#955dbe919870b0536f79123232d87c0efe3c552e)",
  "glut 0.0.1 (git+https://github.com/servo/rust-glut#01af0162ea0322ad1a40d6adb023a39813605949)",
  "js 0.1.0 (git+https://github.com/servo/rust-mozjs#41fb0d80a5ed5614ca13a120cdb3281e599d4e04)",
- "layers 0.1.0 (git+https://github.com/servo/rust-layers#ef89918471815dfced7aaf2f1594d5469f03eab7)",
+ "layers 0.1.0 (git+https://github.com/servo/rust-layers#ed570335738913fb41fc62a024389dfa415962e8)",
 "plugins 0.0.1",
  "msg 0.0.1",
  "net 0.0.1",
@@ -45,7 +45,7 @@ dependencies = [
  "freetype 0.1.0 (git+https://github.com/servo/rust-freetype#0b03da276e4bdeae2300596dabc4ccb16733ad70)",
  "geom 0.1.0 (git+https://github.com/servo/rust-geom#50a294fd997f0c6eb43e9a58ad6e227fdc2a4692)",
  "glfw 0.0.1 (git+https://github.com/servo/glfw-rs?ref=servo#955dbe919870b0536f79123232d87c0efe3c552e)",
- "layers 0.1.0 (git+https://github.com/servo/rust-layers#ef89918471815dfced7aaf2f1594d5469f03eab7)",
+ "layers 0.1.0 (git+https://github.com/servo/rust-layers#ed570335738913fb41fc62a024389dfa415962e8)",
  "opengles 0.1.0 (git+https://github.com/servo/rust-opengles#6776e9c07feb149d34b087039ecf6b2c143e3afc)",
  "skia-sys 0.0.20130412 (git+https://github.com/servo/skia#6d696712962fd0d41120b7a414a48417da8e6a92)",
  "xlib 0.1.0 (git+https://github.com/servo/rust-xlib#581d4faddec5188d3c3ae5307dbea28aab90644c)",
@@ -78,7 +78,7 @@ dependencies = [
  "gfx 0.0.1",
  "glfw 0.0.1 (git+https://github.com/servo/glfw-rs?ref=servo#955dbe919870b0536f79123232d87c0efe3c552e)",
  "glut 0.0.1 (git+https://github.com/servo/rust-glut#01af0162ea0322ad1a40d6adb023a39813605949)",
- "layers 0.1.0 (git+https://github.com/servo/rust-layers#ef89918471815dfced7aaf2f1594d5469f03eab7)",
+ "layers 0.1.0 (git+https://github.com/servo/rust-layers#ed570335738913fb41fc62a024389dfa415962e8)",
  "layout_traits 0.0.1",
  "msg 0.0.1",
  "net 0.0.1",
@@ -193,7 +193,7 @@ dependencies = [
  "freetype 0.1.0 (git+https://github.com/servo/rust-freetype#0b03da276e4bdeae2300596dabc4ccb16733ad70)",
  "geom 0.1.0 (git+https://github.com/servo/rust-geom#50a294fd997f0c6eb43e9a58ad6e227fdc2a4692)",
  "harfbuzz 0.1.0 (git+https://github.com/servo/rust-harfbuzz#ad520942cc17232e1a40cdd8a99c2905623d35f6)",
- "layers 0.1.0 (git+https://github.com/servo/rust-layers#ef89918471815dfced7aaf2f1594d5469f03eab7)",
+ "layers 0.1.0 (git+https://github.com/servo/rust-layers#ed570335738913fb41fc62a024389dfa415962e8)",
  "plugins 0.0.1",
  "msg 0.0.1",
  "net 0.0.1",
@@ -277,7 +277,7 @@ dependencies = [
 [[package]]
 name = "layers"
 version = "0.1.0"
-source = "git+https://github.com/servo/rust-layers#ef89918471815dfced7aaf2f1594d5469f03eab7"
+source = "git+https://github.com/servo/rust-layers#ed570335738913fb41fc62a024389dfa415962e8"
 dependencies = [
  "core_foundation 0.1.0 (git+https://github.com/servo/rust-core-foundation#166a601ff3e0fc3a64ca1a9090d02c8d4f22b61a)",
  "egl 0.1.0 (git+https://github.com/servo/rust-egl#88f2a13812ddbce2bf2317221663a61c31b3e220)",
@@ -337,7 +337,7 @@ dependencies = [
  "core_foundation 0.1.0 (git+https://github.com/servo/rust-core-foundation#166a601ff3e0fc3a64ca1a9090d02c8d4f22b61a)",
  "geom 0.1.0 (git+https://github.com/servo/rust-geom#50a294fd997f0c6eb43e9a58ad6e227fdc2a4692)",
  "io_surface 0.1.0 (git+https://github.com/servo/rust-io-surface#7038341220bd7e86e21118fac2cbc6bd50890e47)",
- "layers 0.1.0 (git+https://github.com/servo/rust-layers#ef89918471815dfced7aaf2f1594d5469f03eab7)",
+ "layers 0.1.0 (git+https://github.com/servo/rust-layers#ed570335738913fb41fc62a024389dfa415962e8)",
  "url 0.1.0 (git+https://github.com/servo/rust-url#bfdf809365600a7941a77524f9bb065886de3379)",
  "util 0.0.1",
 ]