Multiple DPI Tracking for ScreenWin

ui/gfx/win/rect_util.h

Index: ui/gfx/win/rect_util.h
diff --git a/ui/gfx/win/rect_util.h b/ui/gfx/win/rect_util.h
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+// 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|.
+// Returns RectEdge::NONE if |ref| and |test| do not touch.
+// At corners, the bottom corners are clamped to BOTTOM, the upper left corner
+// is clamped to LEFT and the upper right corner is clamped to TOP.
+GFX_EXPORT RectEdge FindTouchingRectEdge(const gfx::Rect& ref,
+                                         const gfx::Rect& test);
+
+// Returns a scaled and position rect from |unscaled_rect|, positioned against
+// |ref_scaled_rect| based off of the original edge positioning on
+// |ref_unscaled_rect|, and downscaled by |unscaled_rect_scale_factor|.
+// As such, |unscaled_rect| and |ref_unscaled_rect| must be touching rectangles.
+//
+// Examples:
+// Scaled and Unscaled Coordinates
+// +--------------+              Since both rectangles are of the same scale
+// |              |              factor, relative positions remain the same.
+// |              |
+// |    REF 1x    +----------+
+// |              |          |
+// +--------------+    1x    |
+//                |          |
+//                +----------+
+//
+// Unscaled Coordinates
+// +--------------+              The 2x rectangle is scaled down while
+// |              |              maintaining a similar neighboring relationship
+// |              |              with the REF 1x rectangle.
+// |    REF 1x    +----------+
+// |              |          |
+// +--------------+    2x    |
+//                |          |
+//                +----------+
+// Scaled Coordinates
+// +--------------+
+// |              |
+// |              |
+// |    REF 1x    |
+// |              +-----+
+// +--------------+  2x |
+//                +-----+
+//
+// Unscaled Coordinates
+// +--------------+              The reference rectangle has been scaled by 2x
+// |              |              from |ref_unscaled_rect| to |ref_scaled_rect|.
+// |              |              ScaleAndPositionRect maintains the same
+// |    REF 2x    +----------+   relative positioning of the unscaled rect in
+// |              |          |   the scaled coordinate space.
+// |              |          |
+// |              |    1x    |
+// +--------------+          |
+//                |          |
+//                +----------+
+// Scaled Coordinates
+// +-------+
+// |       |
+// | REF 2x+----------+
+// |       |          |
+// +-------+          |
+//         |    1x    |
+//         |          |
+//         |          |
+//         +----------+
+GFX_EXPORT gfx::Rect ScaleAndPositionRect(const gfx::Rect& ref_scaled_rect,
+                                          const gfx::Rect& ref_unscaled_rect,
+                                          const gfx::Rect& unscaled_rect,
+                                          float unscaled_rect_scale_factor);
+
+// Returns the squared distance between two rects.
+// The distance between two rects is the length of the shortest segment that can
+// be drawn between two rectangles. This segment generally connects two opposing
+// corners between rectangles like this...
+//
+// +----------+
+// |          |
+// +----------+
+//             \  <--- Shortest Segment
+//              \
+//               +---+
+//               |   |
+//               |   |
+//               +---+
+//
+// For rectangles that share coordinates within the same axis, that generally
+// means the segment is parallel to the axis and perpendicular to the edges.
+//
+//                 One of many shortest segments
+//  +----------+  /                            \    +--------+
+//  |          |  |                             \   |        |
+//  |          |  V  +---+                       \  +--------+
+//  |          |-----|   |                        \-->|
+//  +----------+     |   |                            +----+
+//                   |   |                            |    |
+//                   +---+                            +----+
+//
+// For rectangles that intersect each other, the distance is 0.
+//
+// The squared distance is used to avoid taking the square root as the common
+// usage is to compare distances greater than 1 unit.
+GFX_EXPORT int64_t SquaredDistanceBetweenRects(const gfx::Rect& ref,
+                                               const gfx::Rect& rect);
+
+}  // namespace win
+}  // namespace gfx
+
+#endif  // UI_GFX_WIN_RECT_UTIL_H_