Implements core logic for Pixel Canvas

ui/views/view.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #define _USE_MATH_DEFINES // For VC++ to get M_PI. This has to be first.
 
 #include "ui/views/view.h"
 
 #include <algorithm>
 #include <cmath>
@@ skipping 827 matching lines @@
 
   if (layer()) {
     layer()->SchedulePaint(rect);
   } else if (parent_) {
     // Translate the requested paint rect to the parent's coordinate system
     // then pass this notification up to the parent.
     parent_->SchedulePaintInRect(ConvertRectToParent(rect));
   }
 }
 
-void View::Paint(const ui::PaintContext& parent_context) {
+void View::Paint(const PaintInfo& parent_paint_info) {
   if (!ShouldPaint())
     return;
 
-  ui::PaintContext context(parent_context, GetPaintContextOffset());
+  const gfx::Rect& parent_bounds = !parent()
+                                       ? GetPaintRecordingBounds()
+                                       : parent()->GetPaintRecordingBounds();
 
+  PaintInfo paint_info(parent_paint_info, GetPaintRecordingBounds(),
+                       parent_bounds, GetPaintScaleType());
+
+  const ui::PaintContext& context = paint_info.context();
   bool is_invalidated = true;
-  if (context.CanCheckInvalid()) {
+  if (paint_info.context().CanCheckInvalid()) {
 #if DCHECK_IS_ON()
-    gfx::Vector2d offset;
-    context.Visited(this);
-    View* view = this;
-    while (view->parent() && !view->layer()) {
-      DCHECK(view->GetTransform().IsIdentity());
-      offset += view->GetMirroredPosition().OffsetFromOrigin();
-      view = view->parent();
+    if (!context.is_pixel_canvas()) {

[sky, 2017/07/26 22:12:12]

Why is this only done for !pixel_canvas?

[malaykeshav, 2017/07/28 01:24:38]

With pixel canvas, the context.PaintOffset() returns the offset in pixels. This
cannot be compared with the DIP offset stored in views.

+      gfx::Vector2d offset;
+      context.Visited(this);
+      View* view = this;
+      while (view->parent() && !view->layer()) {
+        DCHECK(view->GetTransform().IsIdentity());
+        offset += view->GetMirroredPosition().OffsetFromOrigin();
+        view = view->parent();
+      }
+      // The offset in the PaintContext should be the offset up to the paint
+      // root, which we compute and verify here.
+      DCHECK_EQ(context.PaintOffset().x(), offset.x());
+      DCHECK_EQ(context.PaintOffset().y(), offset.y());
+      // The above loop will stop when |view| is the paint root, which should be
+      // the root of the current paint walk, as verified by storing the root in
+      // the PaintContext.
+      DCHECK_EQ(context.RootVisited(), view);
     }
-    // The offset in the PaintContext should be the offset up to the paint root,
-    // which we compute and verify here.
-    DCHECK_EQ(context.PaintOffset().x(), offset.x());
-    DCHECK_EQ(context.PaintOffset().y(), offset.y());
-    // The above loop will stop when |view| is the paint root, which should be
-    // the root of the current paint walk, as verified by storing the root in
-    // the PaintContext.
-    DCHECK_EQ(context.RootVisited(), view);
 #endif
 
     // If the View wasn't invalidated, don't waste time painting it, the output
     // would be culled.
-    is_invalidated = context.IsRectInvalid(GetLocalBounds());
+    is_invalidated =
+        context.IsRectInvalid(gfx::Rect(paint_info.paint_recording_size()));
   }
 
   TRACE_EVENT1("views", "View::Paint", "class", GetClassName());
 
   // If the view is backed by a layer, it should paint with itself as the origin
   // rather than relative to its parent.
   // TODO(danakj): Rework clip and transform recorder usage here to use
   // std::optional once we can do so.
-  ui::ClipRecorder clip_recorder(parent_context);
+  ui::ClipRecorder clip_recorder(parent_paint_info.context());
   if (!layer()) {
     // Set the clip rect to the bounds of this View, or |clip_path_| if it's
     // been set. Note that the X (or left) position we pass to ClipRect takes
     // into consideration whether or not the View uses a right-to-left layout so
     // that we paint the View in its mirrored position if need be.
     if (clip_path_.isEmpty()) {
-      clip_recorder.ClipRect(GetMirroredBounds());
+      clip_recorder.ClipRect(gfx::Rect(paint_info.paint_recording_size()) +
+                             paint_info.offset_from_parent());
     } else {
       gfx::Path clip_path_in_parent = clip_path_;
-      clip_path_in_parent.offset(GetMirroredX(), y());
+
+      // Transform |clip_path_| from local space to parent recording space.
+      gfx::Transform to_parent_recording_space;
+
+      gfx::PointF recording_scale = paint_info.paint_recording_scale();
+      to_parent_recording_space.Scale(SkFloatToScalar(recording_scale.x()),
+                                      SkFloatToScalar(recording_scale.y()));
+      to_parent_recording_space.Translate(paint_info.offset_from_parent());
+
+      clip_path_in_parent.transform(to_parent_recording_space.matrix());
       clip_recorder.ClipPathWithAntiAliasing(clip_path_in_parent);
     }
   }
 
   ui::TransformRecorder transform_recorder(context);
-  SetupTransformRecorderForPainting(&transform_recorder);
+  SetupTransformRecorderForPainting(&transform_recorder,
+                                    paint_info.offset_from_parent());
 
   // Note that the cache is not aware of the offset of the view
   // relative to the parent since painting is always done relative to
   // the top left of the individual view.
-  if (is_invalidated || !paint_cache_.UseCache(context, size())) {
-    ui::PaintRecorder recorder(context, size(), &paint_cache_);
+  if (is_invalidated ||
+      !paint_cache_.UseCache(context, paint_info.paint_recording_size())) {
+    ui::PaintRecorder recorder(context, paint_info.paint_recording_size(),
+                               paint_info.paint_recording_scale(),
+                               &paint_cache_);
     gfx::Canvas* canvas = recorder.canvas();
     gfx::ScopedRTLFlipCanvas scoped_canvas(canvas, width(),
                                            flip_canvas_on_paint_for_rtl_ui_);
 
     // Delegate painting the contents of the View to the virtual OnPaint method.
     OnPaint(canvas);
   }
 
   // View::Paint() recursion over the subtree.
-  PaintChildren(context);
+  PaintChildren(paint_info);
 }
 
 void View::SetBackground(std::unique_ptr<Background> b) {
   background_ = std::move(b);
 }
 
 void View::SetBorder(std::unique_ptr<Border> b) {
   border_ = std::move(b);
 }
 
@@ skipping 607 matching lines @@
       RegisterPendingAccelerators();
   }
 }
 
 void View::AddedToWidget() {}
 
 void View::RemovedFromWidget() {}
 
 // Painting --------------------------------------------------------------------
 
-void View::PaintChildren(const ui::PaintContext& context) {
+void View::PaintChildren(const PaintInfo& paint_info) {
   TRACE_EVENT1("views", "View::PaintChildren", "class", GetClassName());
-  RecursivePaintHelper(&View::Paint, context);
+  RecursivePaintHelper(&View::Paint, paint_info);
 }
 
 void View::OnPaint(gfx::Canvas* canvas) {
   TRACE_EVENT1("views", "View::OnPaint", "class", GetClassName());
   OnPaintBackground(canvas);
   OnPaintBorder(canvas);
 }
 
 void View::OnPaintBackground(gfx::Canvas* canvas) {
   if (background_) {
@@ skipping 251 matching lines @@
   // and for different display density.
   return kDefaultHorizontalDragThreshold;
 }
 
 int View::GetVerticalDragThreshold() {
   // TODO(jennyz): This value may need to be adjusted for different platforms
   // and for different display density.
   return kDefaultVerticalDragThreshold;
 }
 
+PaintInfo::ScaleType View::GetPaintScaleType() const {
+  return PaintInfo::ScaleType::kScaleToFit;
+}
+
 // Debugging -------------------------------------------------------------------
 
 #if !defined(NDEBUG)
 
 std::string View::PrintViewGraph(bool first) {
   return DoPrintViewGraph(first, this);
 }
 
 std::string View::DoPrintViewGraph(bool first, View* view_with_children) {
   // 64-bit pointer = 16 bytes of hex + "0x" + '\0' = 19.
@@ skipping 132 matching lines @@
     // Translate the requested paint rect to the parent's coordinate system
     // then pass this notification up to the parent.
     parent_->SchedulePaintInRect(ConvertRectToParent(GetLocalBounds()));
   }
 }
 
 bool View::ShouldPaint() const {
   return visible_ && !size().IsEmpty();
 }
 
-gfx::Vector2d View::GetPaintContextOffset() const {
-  // If the View has a layer() then it is a paint root. Otherwise, we need to
-  // add the offset from the parent into the total offset from the paint root.
+gfx::Rect View::GetPaintRecordingBounds() const {
+  // If the View has a layer() then it is a paint root and no offset information
+  // is needed. Otherwise, we need bounds that includes an offset from the
+  // parent to add to the total offset from the paint root.
   DCHECK(layer() || parent() || origin() == gfx::Point());
-  return layer() ? gfx::Vector2d() : GetMirroredPosition().OffsetFromOrigin();
+  return layer() ? GetLocalBounds() : GetMirroredBounds();
 }
 
 void View::SetupTransformRecorderForPainting(
-    ui::TransformRecorder* recorder) const {
+    ui::TransformRecorder* recorder,
+    const gfx::Vector2d& offset_from_parent) const {
   // If the view is backed by a layer, it should paint with itself as the origin
   // rather than relative to its parent.
   if (layer())
     return;
 
   // Translate the graphics such that 0,0 corresponds to where this View is
   // located relative to its parent.
   gfx::Transform transform_from_parent;
-  gfx::Vector2d offset_from_parent = GetMirroredPosition().OffsetFromOrigin();
   transform_from_parent.Translate(offset_from_parent.x(),
                                   offset_from_parent.y());
-  transform_from_parent.PreconcatTransform(GetTransform());
   recorder->Transform(transform_from_parent);
 }
 
-void View::RecursivePaintHelper(void (View::*func)(const ui::PaintContext&),
-                                const ui::PaintContext& context) {
+void View::RecursivePaintHelper(void (View::*func)(const PaintInfo&),
+                                const PaintInfo& info) {
   View::Views children = GetChildrenInZOrder();
   DCHECK_EQ(child_count(), static_cast<int>(children.size()));
   for (auto* child : children) {
     if (!child->layer())
-      (child->*func)(context);
+      (child->*func)(info);
   }
 }
 
 void View::PaintFromPaintRoot(const ui::PaintContext& parent_context) {
-  Paint(parent_context);
+  PaintInfo paint_info(parent_context, layer() ? layer()->size() : size());
+  Paint(paint_info);
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kDrawViewBoundsRects))
-    PaintDebugRects(parent_context);
+    PaintDebugRects(paint_info);
 }
 
-void View::PaintDebugRects(const ui::PaintContext& parent_context) {
+void View::PaintDebugRects(const PaintInfo& parent_paint_info) {
   if (!ShouldPaint())
     return;
 
-  ui::PaintContext context(parent_context, GetPaintContextOffset());
+  const gfx::Rect& parent_bounds = (layer() || !parent())
+                                       ? GetPaintRecordingBounds()
+                                       : parent()->GetPaintRecordingBounds();
+  PaintInfo paint_info(parent_paint_info, GetPaintRecordingBounds(),
+                       parent_bounds, GetPaintScaleType());
+
+  const ui::PaintContext& context = paint_info.context();
+
   ui::TransformRecorder transform_recorder(context);
-  SetupTransformRecorderForPainting(&transform_recorder);
+  SetupTransformRecorderForPainting(&transform_recorder,
+                                    paint_info.offset_from_parent());
 
-  RecursivePaintHelper(&View::PaintDebugRects, context);
+  RecursivePaintHelper(&View::PaintDebugRects, paint_info);
 
   // Draw outline rects for debugging.
-  ui::PaintRecorder recorder(context, size());
+  ui::PaintRecorder recorder(context, paint_info.paint_recording_size(),
+                             paint_info.paint_recording_scale(), &paint_cache_);
   gfx::Canvas* canvas = recorder.canvas();
   const float scale = canvas->UndoDeviceScaleFactor();
   gfx::RectF outline_rect(ScaleToEnclosedRect(GetLocalBounds(), scale));
   outline_rect.Inset(0.5f, 0.5f);
   const SkColor color = SkColorSetARGB(0x30, 0xff, 0, 0);
   canvas->DrawRect(outline_rect, color);
 }
 
 // Tree operations -------------------------------------------------------------
 
@@ skipping 643 matching lines @@
   // Message the RootView to do the drag and drop. That way if we're removed
   // the RootView can detect it and avoid calling us back.
   gfx::Point widget_location(event.location());
   ConvertPointToWidget(this, &widget_location);
   widget->RunShellDrag(this, data, widget_location, drag_operations, source);
   // WARNING: we may have been deleted.
   return true;
 }
 
 }  // namespace views