[win] Ensure the app launcher always comes up on screen.

chrome/browser/ui/views/app_list/app_list_controller_win.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.
 
 #include <sstream>
 
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/lazy_instance.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 522 matching lines @@
     return false;
 
   RECT win_rect;
   if (!GetWindowRect(taskbar_hwnd, &win_rect))
     return false;
 
   *rect = gfx::Rect(win_rect);
   return true;
 }
 
-// Used to position the view relative to a point, which requires |anchor| to be
-// in the center of the desired view location. This helper function updates
-// |anchor| thus, using the location of the point in |point|, the distance
-// to move the view from |point| in |offset|, and the direction to move
-// represented in |direction|.
-// To position relative to a screen corner, the absolute values of |direction|.x
-// and |direction.y| should both be 1. To position relative to some point on the
-// taskbar, one of the absolute values of |direction.x| and |direction.y| should
-// be 1 and the other 0.
-void FloatFromPoint(const gfx::Point& point,
-                    const gfx::Size& offset,
-                    const gfx::Point& direction,
-                    gfx::Point* anchor) {
-  anchor->set_x(point.x() + direction.x() * offset.width());
-  anchor->set_y(point.y() + direction.y() * offset.height());
+gfx::Point FindReferencePoint(const gfx::Display& display,
+                              gfx::Point* anchor) {

[tapted, 2013/02/27 11:58:48]

i think |anchor| can be const reference now

[benwells, 2013/02/27 22:35:42]

Yeah, and in the next function. Done.

+  const int kSnapDistance = 50;
+
+  // If we can't find the taskbar, snap to the bottom left.
+  // If the display size is the same as the work area, and does not contain the
+  // taskbar, either the taskbar is hidden or on another monitor, so just snap
+  // to the bottom left.
+  gfx::Rect taskbar_rect;
+  if (!GetTaskbarRect(&taskbar_rect) ||
+      (display.work_area() == display.bounds() &&
+          !display.work_area().Contains(taskbar_rect))) {
+    return display.work_area().bottom_left();
+  }
+
+  // Snap to the taskbar edge. If the cursor is greater than kSnapDistance away,
+  // also move to the left (for horizontal taskbars) or top (for vertical).
+  const gfx::Rect& screen_rect = display.bounds();
+  // First handle taskbar on bottom.
+  if (taskbar_rect.width() == screen_rect.width()) {
+    if (taskbar_rect.bottom() == screen_rect.bottom()) {
+      if (taskbar_rect.y() - anchor->y() > kSnapDistance)
+        return gfx::Point(screen_rect.x(), taskbar_rect.y());
+
+      return gfx::Point(anchor->x(), taskbar_rect.y());
+    }
+
+    // Now try on the top.
+    if (anchor->y() - taskbar_rect.bottom() > kSnapDistance)
+      return gfx::Point(screen_rect.x(), taskbar_rect.bottom());
+
+    return gfx::Point(anchor->x(), taskbar_rect.bottom());
+  }
+
+  // Now try the left.
+  if (taskbar_rect.x() == screen_rect.x()) {
+    if (anchor->x() - taskbar_rect.right() > kSnapDistance)
+      return gfx::Point(taskbar_rect.right(), screen_rect.y());
+
+    return gfx::Point(taskbar_rect.right(), anchor->y());
+  }
+
+  // Finally, try the right.
+  if (taskbar_rect.x() - anchor->x() > kSnapDistance)
+    return gfx::Point(taskbar_rect.x(), screen_rect.y());
+
+  return gfx::Point(taskbar_rect.x(), anchor->y());
 }
 
 void AppListController::SnapArrowLocationToTaskbarEdge(
     const gfx::Display& display,
     gfx::Point* anchor) {
-  const int kSnapDistance = 50;
-  const int kSnapOffset = 5;
+  const int kSnapOffset = 3;
 
-  gfx::Rect taskbar_rect;
-  gfx::Size float_offset = current_view_->GetPreferredSize();
-  float_offset.set_width(float_offset.width() / 2);
-  float_offset.set_height(float_offset.height() / 2);
-  float_offset.Enlarge(kSnapOffset, kSnapOffset);
+  gfx::Rect bounds_rect(display.work_area());
+  gfx::Size view_size(current_view_->GetPreferredSize());
+  bounds_rect.Inset(view_size.width() / 2 + kSnapOffset,
+                    view_size.height() / 2 + kSnapOffset);
 
-  // If we can't find the taskbar, snap to the bottom left.
-  // If the display size is the same as the work area, and does not contain the
-  // taskbar, either the taskbar is hidden or on another monitor, so just snap
-  // to the bottom left.
-  if (!GetTaskbarRect(&taskbar_rect) ||
-      (display.work_area() == display.bounds() &&
-          !display.work_area().Contains(taskbar_rect))) {
-    FloatFromPoint(display.work_area().bottom_left(),
-                   float_offset,
-                   gfx::Point(1, -1),
-                   anchor);
-    return;
-  }
-
-  const gfx::Rect& screen_rect = display.bounds();
-
-  // Snap to the taskbar edge. If the cursor is greater than kSnapDistance away,
-  // also move to the left (for horizontal taskbars) or top (for vertical).
-
-  // First handle taskbar on bottom.
-  if (taskbar_rect.width() == screen_rect.width()) {
-    if (taskbar_rect.bottom() == screen_rect.bottom()) {
-      if (taskbar_rect.y() - anchor->y() > kSnapDistance) {
-        FloatFromPoint(gfx::Point(screen_rect.x(), taskbar_rect.y()),
-                       float_offset,
-                       gfx::Point(1, -1),
-                       anchor);
-        return;
-      }
-
-      FloatFromPoint(gfx::Point(anchor->x(), taskbar_rect.y()),
-                     float_offset,
-                     gfx::Point(0, -1),
-                     anchor);
-      return;
-    }
-
-    // Now try on the top.
-    if (anchor->y() - taskbar_rect.bottom() > kSnapDistance) {
-      FloatFromPoint(gfx::Point(screen_rect.x(), taskbar_rect.bottom()),
-                     float_offset,
-                     gfx::Point(1, 1),
-                     anchor);
-      return;
-    }
-
-    FloatFromPoint(gfx::Point(anchor->x(), taskbar_rect.bottom()),
-                   float_offset,
-                   gfx::Point(0, 1),
-                   anchor);
-    return;
-  }
-
-  // Now try the left.
-  if (taskbar_rect.x() == screen_rect.x()) {
-    if (anchor->x() - taskbar_rect.right() > kSnapDistance) {
-      FloatFromPoint(gfx::Point(taskbar_rect.right(), screen_rect.y()),
-                     float_offset,
-                     gfx::Point(1, 1),
-                     anchor);
-      return;
-    }
-
-    FloatFromPoint(gfx::Point(taskbar_rect.right(), anchor->y()),
-                   float_offset,
-                   gfx::Point(1, 0),
-                   anchor);
-    return;
-  }
-
-  // Finally, try the right.
-  if (taskbar_rect.x() - anchor->x() > kSnapDistance) {
-    FloatFromPoint(gfx::Point(taskbar_rect.x(), screen_rect.y()),
-                   float_offset,
-                   gfx::Point(-1, 1),
-                   anchor);
-    return;
-  }
-
-  FloatFromPoint(gfx::Point(taskbar_rect.x(), anchor->y()),
-                 float_offset,
-                 gfx::Point(-1, 0),
-                 anchor);
+  gfx::Point ref_point(FindReferencePoint(display, anchor));
+  anchor->SetPoint(ref_point.x(), ref_point.y());

[tapted, 2013/02/27 11:58:48]

I don't... think default assignment operator has been hidden, so I'd probably go
for 

*anchor = FindReferencePoint(..);

but there might be a different prevailing style/opinion in Chrome.

[benwells, 2013/02/27 22:35:42]

Yep, good one.

+  anchor->ClampToMin(bounds_rect.origin());

[tapted, 2013/02/27 11:58:48]

ah, origin - of course ;). (Cocoa has had me thinking upside-down)

+  anchor->ClampToMax(bounds_rect.bottom_right());
 }
 
 void AppListController::UpdateArrowPositionAndAnchorPoint(
     const gfx::Point& cursor) {
   gfx::Point anchor(cursor);
   gfx::Screen* screen =
       gfx::Screen::GetScreenFor(current_view_->GetWidget()->GetNativeView());
   gfx::Display display = screen->GetDisplayNearestPoint(anchor);
 
   SnapArrowLocationToTaskbarEdge(display, &anchor);
@@ skipping 210 matching lines @@
 
 Profile* GetCurrentAppListProfile() {
   return GetCurrentAppListController()->profile();
 }
 
 bool IsAppListVisible() {
   return GetCurrentAppListController()->IsAppListVisible();
 }
 
 }  // namespace chrome