Multiple DPI Tracking for ScreenWin

ui/gfx/win/rect_util.h

+// Copyright 2016 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.
+
+#ifndef UI_GFX_WIN_RECT_UTIL_H_
+#define UI_GFX_WIN_RECT_UTIL_H_
+
+#include <stdint.h>
+
+#include "ui/gfx/gfx_export.h"
+
+namespace gfx {
+
+class Rect;
+
+namespace win {
+
+enum class RectEdge {
+  BOTTOM = 0,
+  LEFT = 1,
+  TOP = 2,
+  RIGHT = 3,
+  NONE = 4,
+};
+
+// Returns |ref|'s RectEdge touching |test|.
+RectEdge GFX_EXPORT RectTouch(gfx::Rect ref, gfx::Rect test);

[scottmg, 2016/02/09 20:21:36]

"RectTouch" is a bit terse. Mostly, I'd expect it to return bool.

Not coming up with a better name though. "TouchingEdgeForRect" or
"TouchingEdgeBetweenRects"

[scottmg, 2016/02/09 20:21:36]

The GFX_EXPORTs normally go before the return type.

[robliao, 2016/02/10 22:50:03]

Done and renamed to FindTouchingRectEdge.

+
+// Returns a scaled and positioned rect based off of target_rect and context.
+// The reference rectangle and target rectangle may scale at different rates.
+// This function attempts to preserve the relative positioning of the target
+// rectangle with respect to the scaled rectangle in the face of differing
+// scale factors.
+//
+// Examples:
+// +--------------+              Since both rectangles are of the same
+// |              |              scale factor, positions and sizes
+// |              |              remain the same.
+// |    REF 1x    +----------+
+// |              |          |
+// +--------------+    1x    |
+//                |          |
+//                +----------+
+//
+// Original
+// +--------------+              The 2x rectangle is scaled down while
+// |              |              maintaining a similar neighboring relationship
+// |              |              with the 1x rectangle.
+// |    REF 1x    +----------+
+// |              |          |
+// +--------------+    2x    |
+//                |          |
+//                +----------+
+// Scaled
+// +--------------+
+// |              |
+// |              |
+// |    REF 1x    |
+// |              +-----+
+// +--------------+  2x |
+//                +-----+
+gfx::Rect GFX_EXPORT ScaleAndPositionRect(gfx::Rect ref_scaled_rect,
+                                          gfx::Rect ref_original_rect,
+                                          gfx::Rect target_rect,
+                                          float target_scale_factor);
+
+// Returns the squared distance between two rects.

[scottmg, 2016/02/09 20:21:36]

A little more explanation here, it isn't obvious what "squared distance between
two rects" means.

[robliao, 2016/02/10 22:50:03]

Done and added some ASCII art.

+int64_t GFX_EXPORT SquaredDistanceBetweenRects(gfx::Rect ref, gfx::Rect rect);
+
+}  // namespace win
+}  // namespace gfx
+
+#endif  // UI_GFX_WIN_RECT_UTIL_H_