Merge pull request #2977 from mrobinson/scrolling

Make scrolling tick by device pixels

src/components/compositing/compositor.rs

@@ -478,11 +478,6 @@ impl IOCompositor {
         }
     }
 
-    /// The size of the content area in CSS px at the current zoom level
-    fn page_window(&self) -> TypedSize2D<PagePx, f32> {
-        self.window_size.as_f32() / self.device_pixels_per_page_px()
-    }
-
     fn send_window_size(&self) {
         let dppx = self.page_zoom * self.device_pixels_per_screen_px();
         let initial_viewport = self.window_size.as_f32() / dppx;
@@ -499,17 +494,17 @@ impl IOCompositor {
     fn scroll_layer_to_fragment_point_if_necessary(&mut self,
                                                    pipeline_id: PipelineId,
                                                    layer_id: LayerId) {
-        let page_window = self.page_window();
         let device_pixels_per_page_px = self.device_pixels_per_page_px();
+        let window_size = self.window_size.as_f32();
         let needs_recomposite = match self.scene.root {
             Some(ref mut root_layer) => {
                 self.fragment_point.take().map_or(false, |fragment_point| {
+                    let fragment_point = fragment_point * device_pixels_per_page_px.get();
                     events::move(root_layer.clone(),
                                  pipeline_id,
                                  layer_id,
                                  fragment_point,
-                                 page_window,
-                                 device_pixels_per_page_px)
+                                 window_size)
                 })
             }
             None => fail!("Compositor: Tried to scroll to fragment without root layer."),
@@ -589,17 +584,19 @@ impl IOCompositor {
                                 pipeline_id: PipelineId,
                                 layer_id: LayerId,
                                 point: Point2D<f32>) {
-        let page_window = self.page_window();
+
         let device_pixels_per_page_px = self.device_pixels_per_page_px();
+        let device_point = point * device_pixels_per_page_px.get();
+        let window_size = self.window_size.as_f32();
+
         let (ask, move): (bool, bool) = match self.scene.root {
             Some(ref layer) if layer.extra_data.borrow().pipeline.id == pipeline_id => {
                 (true,
                  events::move(layer.clone(),
                               pipeline_id,
                               layer_id,
-                              point,
-                              page_window,
-                              device_pixels_per_page_px))
+                              device_point,
+                              window_size))
             }
             Some(_) | None => {
                 self.fragment_point = Some(point);
@@ -711,7 +708,7 @@ impl IOCompositor {
             MouseWindowMouseUpEvent(_, p) => p / scale,
         };
         for layer in self.scene.root.iter() {
-            events::send_mouse_event(layer.clone(), mouse_window_event, point);
+            events::send_mouse_event(layer.clone(), mouse_window_event, point, scale);
         }
     }
 
@@ -725,20 +722,14 @@ impl IOCompositor {
     fn on_scroll_window_event(&mut self,
                               delta: TypedPoint2D<DevicePixel, f32>,
                               cursor: TypedPoint2D<DevicePixel, i32>) {
-        let scale = self.device_pixels_per_page_px();
-        // TODO: modify delta to snap scroll to pixels.
-        let page_delta = delta / scale;
-        let page_cursor = cursor.as_f32() / scale;
-        let page_window = self.page_window();
         let mut scroll = false;
-        let device_pixels_per_page_px = self.device_pixels_per_page_px();
+        let window_size = self.window_size.as_f32();
         match self.scene.root {
             Some(ref mut layer) => {
                 scroll = events::handle_scroll_event(layer.clone(),
-                                                     page_delta,
-                                                     page_cursor,
-                                                     page_window,
-                                                     device_pixels_per_page_px) || scroll;
+                                                     delta,
+                                                     cursor.as_f32(),
+                                                     window_size) || scroll;
             }
             None => { }
         }
@@ -775,7 +766,6 @@ impl IOCompositor {
         self.zoom_action = true;
         self.zoom_time = precise_time_s();
         let old_viewport_zoom = self.viewport_zoom;
-        let window_size = self.window_size.as_f32();
 
         self.viewport_zoom = ScaleFactor((self.viewport_zoom.get() * magnification).max(1.0));
         let viewport_zoom = self.viewport_zoom;
@@ -783,21 +773,19 @@ impl IOCompositor {
         self.update_zoom_transform();
 
         // Scroll as needed
-        let page_delta = TypedPoint2D(
+        let window_size = self.window_size.as_f32();
+        let page_delta: TypedPoint2D<PagePx, f32> = TypedPoint2D(
             window_size.width.get() * (viewport_zoom.inv() - old_viewport_zoom.inv()).get() * 0.5,
             window_size.height.get() * (viewport_zoom.inv() - old_viewport_zoom.inv()).get() * 0.5);
-        // TODO: modify delta to snap scroll to pixels.
-        let page_cursor = TypedPoint2D(-1f32, -1f32); // Make sure this hits the base layer
-        let page_window = self.page_window();
 
-        let device_pixels_per_page_px = self.device_pixels_per_page_px();
+        let delta = page_delta * self.device_pixels_per_page_px();
+        let cursor = TypedPoint2D(-1f32, -1f32);  // Make sure this hits the base layer.
         match self.scene.root {
             Some(ref mut layer) => {
                 events::handle_scroll_event(layer.clone(),
-                                            page_delta,
-                                            page_cursor,
-                                            page_window,
-                                            device_pixels_per_page_px);
+                                            delta,
+                                            cursor,
+                                            window_size);
             }
             None => { }
         }

src/components/compositing/compositor_data.rs

@@ -8,7 +8,6 @@ use pipeline::CompositionPipeline;
 
 use azure::azure_hl::Color;
 use geom::point::TypedPoint2D;
-use geom::scale_factor::ScaleFactor;
 use geom::size::{Size2D, TypedSize2D};
 use gfx::render_task::UnusedBufferMsg;
 use layers::layers::{Layer, LayerBufferSet};
@@ -16,7 +15,7 @@ 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 servo_util::geometry::DevicePixel;
 use std::rc::Rc;
 
 pub struct CompositorData {
@@ -26,10 +25,6 @@ pub struct CompositorData {
     /// The ID of this layer within the pipeline.
     pub id: LayerId,
 
-    /// The offset of the page due to scrolling. (0,0) is when the window sees the
-    /// top left corner of the page.
-    pub scroll_offset: TypedPoint2D<PagePx, f32>,
-
     /// The behavior of this layer when a scroll message is received.
     pub wants_scroll_events: WantsScrollEventsFlag,
 
@@ -59,7 +54,6 @@ impl CompositorData {
         let new_compositor_data = CompositorData {
             pipeline: pipeline,
             id: layer_properties.id,
-            scroll_offset: TypedPoint2D(0f32, 0f32),
             wants_scroll_events: wants_scroll_events,
             scroll_policy: layer_properties.scroll_policy,
             background_color: layer_properties.background_color,
@@ -76,15 +70,12 @@ impl CompositorData {
         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
-        // scale factor does not matter here since we are scrolling to 0 offset and
-        // 0 * n == 0.
-        let size: TypedSize2D<PagePx, f32> = Size2D::from_untyped(&layer.bounds.borrow().size);
+        // cursor position to make sure the scroll isn't propagated downwards.
+        let size: TypedSize2D<DevicePixel, f32> = Size2D::from_untyped(&layer.bounds.borrow().size);
         events::handle_scroll_event(layer.clone(),
                                     TypedPoint2D(0f32, 0f32),
                                     TypedPoint2D(-1f32, -1f32),
-                                    size,
-                                    ScaleFactor(1.0));
+                                    size);
     }
 
     pub fn find_layer_with_pipeline_and_layer_id(layer: Rc<Layer<CompositorData>>,

src/components/compositing/events.rs

@@ -6,12 +6,10 @@ use compositor_data::{CompositorData, WantsScrollEvents};
 use windowing::{MouseWindowEvent, MouseWindowClickEvent, MouseWindowMouseDownEvent};
 use windowing::MouseWindowMouseUpEvent;
 
-use geom::length::Length;
-use geom::matrix::identity;
 use geom::point::{Point2D, TypedPoint2D};
 use geom::rect::{Rect, TypedRect};
 use geom::scale_factor::ScaleFactor;
-use geom::size::TypedSize2D;
+use geom::size::{Size2D, TypedSize2D};
 use layers::layers::Layer;
 use script::dom::event::{ClickEvent, MouseDownEvent, MouseMoveEvent, MouseUpEvent};
 use script::script_task::{ScriptChan, SendEventMsg};
@@ -20,6 +18,9 @@ use servo_msg::constellation_msg::PipelineId;
 use servo_util::geometry::{DevicePixel, PagePx};
 use std::rc::Rc;
 
+
+use geom::matrix::identity;
+
 trait Clampable {
     fn clamp(&self, mn: &Self, mx: &Self) -> Self;
 }
@@ -43,10 +44,9 @@ impl Clampable for f32 {
 /// mouse is over child layers first. If a layer successfully scrolled, returns true; otherwise
 /// returns false, so a parent layer can scroll instead.
 pub fn handle_scroll_event(layer: Rc<Layer<CompositorData>>,
-                           delta: TypedPoint2D<PagePx, f32>,
-                           cursor: TypedPoint2D<PagePx, f32>,
-                           window_size: TypedSize2D<PagePx, f32>,
-                           page_to_device_pixels_scale: ScaleFactor<PagePx, DevicePixel, f32>)
+                           delta: TypedPoint2D<DevicePixel, f32>,
+                           cursor: TypedPoint2D<DevicePixel, f32>,
+                           window_size: TypedSize2D<DevicePixel, f32>)
                            -> bool {
     // If this layer doesn't want scroll events, neither it nor its children can handle scroll
     // events.
@@ -55,80 +55,80 @@ pub fn handle_scroll_event(layer: Rc<Layer<CompositorData>>,
     }
 
     // Allow children to scroll.
-    let cursor = cursor - layer.extra_data.borrow().scroll_offset;
+    let content_offset: TypedPoint2D<DevicePixel, f32> =
+        Point2D::from_untyped(&*layer.content_offset.borrow());
+    let cursor = cursor - content_offset;
     for child in layer.children().iter() {
-        let rect: TypedRect<PagePx, f32> = Rect::from_untyped(&*child.bounds.borrow());
+        let rect: TypedRect<DevicePixel, f32> = Rect::from_untyped(&*child.bounds.borrow());
         if rect.contains(&cursor) &&
            handle_scroll_event(child.clone(),
                                delta,
                                cursor - rect.origin,
-                               rect.size,
-                               page_to_device_pixels_scale) {
+                               rect.size) {
             return true
         }
     }
 
-    // This scroll event is mine!
-    // Scroll this layer!
-    let old_origin = layer.extra_data.borrow().scroll_offset.clone();
-    layer.extra_data.borrow_mut().scroll_offset = old_origin + delta;
+    clamp_scroll_offset_and_scroll_layer(layer,
+                                         content_offset.to_untyped() + delta.to_untyped(),
+                                         window_size.to_untyped())
 
-    // bounds checking
-    let page_size = layer.bounds.borrow().size;
-    let window_size = window_size.to_untyped();
-    let scroll_offset = layer.extra_data.borrow().scroll_offset.to_untyped();
+}
 
-    let min_x = (window_size.width - page_size.width).min(0.0);
-    layer.extra_data.borrow_mut().scroll_offset.x = Length(scroll_offset.x.clamp(&min_x, &0.0));
+pub fn clamp_scroll_offset_and_scroll_layer(layer: Rc<Layer<CompositorData>>,
+                                            mut new_offset: Point2D<f32>,
+                                            window_size: Size2D<f32>)
+                                            -> bool {
+    let layer_size = layer.bounds.borrow().size;
+    let min_x = (window_size.width - layer_size.width).min(0.0);
+    new_offset.x = new_offset.x.clamp(&min_x, &0.0);
 
-    let min_y = (window_size.height - page_size.height).min(0.0);
-    layer.extra_data.borrow_mut().scroll_offset.y = Length(scroll_offset.y.clamp(&min_y, &0.0));
+    let min_y = (window_size.height - layer_size.height).min(0.0);
+    new_offset.y = new_offset.y.clamp(&min_y, &0.0);
 
-    if old_origin - layer.extra_data.borrow().scroll_offset == TypedPoint2D(0f32, 0f32) {
+    if *layer.content_offset.borrow() == new_offset {
         return false
     }
 
-    let offset = layer.extra_data.borrow().scroll_offset.clone();
-    scroll(layer.clone(), offset, page_to_device_pixels_scale)
+    // 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() = new_offset;
+    scroll_layer_and_all_child_layers(layer.clone(), new_offset)
 }
 
-/// Actually scrolls the descendants of a layer that scroll. This is called by
-/// `handle_scroll_event` above when it determines that a layer wants to scroll.
-fn scroll(layer: Rc<Layer<CompositorData>>,
-          scroll_offset: TypedPoint2D<PagePx, f32>,
-          page_to_device_pixels_scale: ScaleFactor<PagePx, DevicePixel, f32>)
-          -> bool {
+fn scroll_layer_and_all_child_layers(layer: Rc<Layer<CompositorData>>,
+                                     new_offset: Point2D<f32>)
+                                     -> bool {
     let mut result = false;
 
     // Only scroll this layer if it's not fixed-positioned.
     if layer.extra_data.borrow().scroll_policy != FixedPosition {
-        // Scroll this layer!
-        layer.extra_data.borrow_mut().scroll_offset = scroll_offset;
-
-        let scroll_offset = layer.extra_data.borrow().scroll_offset.clone();
-        *layer.transform.borrow_mut() = identity().translate(scroll_offset.x.get(), scroll_offset.y.get(), 0.0);
-        *layer.content_offset.borrow_mut() = (scroll_offset * page_to_device_pixels_scale).to_untyped();
-
+        *layer.transform.borrow_mut() = identity().translate(new_offset.x, new_offset.y, 0.0);
+        *layer.content_offset.borrow_mut() = new_offset;
         result = true
     }
 
     for child in layer.children().iter() {
-        result = scroll(child.clone(), scroll_offset, page_to_device_pixels_scale) || result;
+        result |= scroll_layer_and_all_child_layers(child.clone(), new_offset);
     }
 
-    result
+    return result;
 }
 
 // Takes in a MouseWindowEvent, determines if it should be passed to children, and
 // sends the event off to the appropriate pipeline. NB: the cursor position is in
 // page coordinates.
 pub fn send_mouse_event(layer: Rc<Layer<CompositorData>>,
-                        event: MouseWindowEvent, cursor: TypedPoint2D<PagePx, f32>) {
-    let cursor = cursor - layer.extra_data.borrow().scroll_offset;
+                        event: MouseWindowEvent,
+                        cursor: TypedPoint2D<PagePx, f32>,
+                        device_pixels_per_page_px: ScaleFactor<PagePx, DevicePixel, f32>) {
+    let content_offset : TypedPoint2D<DevicePixel, f32> =
+        Point2D::from_untyped(&*layer.content_offset.borrow());
+    let cursor = cursor - (content_offset / device_pixels_per_page_px);
     for child in layer.children().iter() {
         let rect: TypedRect<PagePx, f32> = Rect::from_untyped(&*child.bounds.borrow());
         if rect.contains(&cursor) {
-            send_mouse_event(child.clone(), event, cursor - rect.origin);
+            send_mouse_event(child.clone(), event, cursor - rect.origin, device_pixels_per_page_px);
             return;
         }
     }
@@ -154,8 +154,7 @@ pub fn move(layer: Rc<Layer<CompositorData>>,
             pipeline_id: PipelineId,
             layer_id: LayerId,
             origin: Point2D<f32>,
-            window_size: TypedSize2D<PagePx, f32>,
-            page_to_device_pixels_scale: ScaleFactor<PagePx, DevicePixel, f32>)
+            window_size: TypedSize2D<DevicePixel, f32>)
             -> bool {
     // Search children for the right layer to move.
     if layer.extra_data.borrow().pipeline.id != pipeline_id ||
@@ -165,8 +164,7 @@ pub fn move(layer: Rc<Layer<CompositorData>>,
                  pipeline_id,
                  layer_id,
                  origin,
-                 window_size,
-                 page_to_device_pixels_scale)
+                 window_size)
         });
     }
 
@@ -174,25 +172,5 @@ pub fn move(layer: Rc<Layer<CompositorData>>,
         return false
     }
 
-    // Scroll this layer!
-    let old_origin = layer.extra_data.borrow().scroll_offset;
-    layer.extra_data.borrow_mut().scroll_offset = Point2D::from_untyped(&(origin * -1.0));
-
-    // bounds checking
-    let page_size = layer.bounds.borrow().size;
-    let window_size = window_size.to_untyped();
-    let scroll_offset = layer.extra_data.borrow().scroll_offset.to_untyped();
-
-    let min_x = (window_size.width - page_size.width).min(0.0);
-    layer.extra_data.borrow_mut().scroll_offset.x = Length(scroll_offset.x.clamp(&min_x, &0.0));
-    let min_y = (window_size.height - page_size.height).min(0.0);
-    layer.extra_data.borrow_mut().scroll_offset.y = Length(scroll_offset.y.clamp(&min_y, &0.0));
-
-    // check to see if we scrolled
-    if old_origin - layer.extra_data.borrow().scroll_offset == TypedPoint2D(0f32, 0f32) {
-        return false;
-    }
-
-    let offset = layer.extra_data.borrow().scroll_offset.clone();
-    scroll(layer.clone(), offset, page_to_device_pixels_scale)
+    clamp_scroll_offset_and_scroll_layer(layer, origin * -1.0, window_size.to_untyped())
 }