MacViews: Add native drop shadow to dialogs on OSX < 10.10.

ui/gfx/path_mac_unittest.mm

+// 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.
+
+#import "ui/gfx/path_mac.h"
+
+#include <cmath>
+#include <vector>
+
+#import <Cocoa/Cocoa.h>
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/skia/include/core/SkRegion.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/rect_conversions.h"
+#include "ui/gfx/path.h"
+
+namespace {
+
+// Returns the point at a distance of |radius| from the point (|centre_x|,
+// |centre_y|), and angle |degrees| from the positive horizontal axis, measured
+// anti-clockwise.
+NSPoint GetRadialPoint(double radius,
+                       double degrees,
+                       double centre_x,
+                       double centre_y) {
+  const double radian = (degrees * SK_ScalarPI) / 180;
+  return NSMakePoint(centre_x + radius * std::cos(radian),
+                     centre_y + radius * std::sin(radian));
+}
+
+// Returns the area of a circle with the given |radius|.
+double CalculateCircleArea(double radius) {
+  return SK_ScalarPI * radius * radius;
+}
+
+// Returns the area of a simple polygon. |path| should represent a simple
+// polygon.
+double CalculatePolygonArea(NSBezierPath* path) {
+  // If path represents a single polygon, it will have MoveTo, followed by
+  // multiple LineTo, followed By ClosePath, followed by another MoveTo
+  // NSBezierPathElement.
+  const size_t element_count = [path elementCount];
+  NSPoint points[3];
+  std::vector<NSPoint> poly;
+
+  for (size_t i = 0; i < element_count - 1; i++) {
+    NSBezierPathElement element =
+        [path elementAtIndex:i associatedPoints:points];
+    poly.push_back(points[0]);
+    DCHECK_EQ(element,
+              i ? (i == element_count - 2 ? NSClosePathBezierPathElement
+                                          : NSLineToBezierPathElement)
+                : NSMoveToBezierPathElement);
+  }
+  DCHECK_EQ([path elementAtIndex:element_count - 1 associatedPoints:points],

[msw, 2016/02/11 23:57:37]

optional nit: you could omit associatedPoints here and the DCHECK immediately
below; the following DCHECK seems sufficient.

[karandeepb, 2016/02/12 03:45:52]

Done.

+            NSMoveToBezierPathElement);
+  DCHECK(NSEqualPoints(points[0], poly.front()));
+
+  // Shoelace Algorithm to find the area of a simple polygon.
+  DCHECK(NSEqualPoints(poly.front(), poly.back()));
+  double area = 0;
+  for (size_t i = 0; i < poly.size() - 1; i++)
+    area += poly[i].x * poly[i + 1].y - poly[i].y * poly[i + 1].x;

[msw, 2016/02/11 23:57:37]

q: don't you technically need incldue these terms once (outside the loop)?
a += poly[poly.size() - 1].x * poly[0].y - poly[0].x * poly[poly.size() - 1].y
(I'm just learning via https://en.wikipedia.org/wiki/Shoelace_formula)

[karandeepb, 2016/02/12 03:45:52]

The last point in the poly vector is the same as the first point i.e. there are
(n+1) points in the vector for an n-sided polygon. This helps eliminate the
extra terms, since these are taken care of inside the loop itself. This is the
same as the 3rd Alternative formula on wikipedia.

[msw, 2016/02/12 19:26:55]

Acknowledged.

+
+  return std::fabs(area) / 2.0;
+}
+
+// Returns the area of a rounded rectangle with the given |width|, |height| and
+// |radius|.
+double CalculateRoundedRectangleArea(double width,
+                                     double height,
+                                     double radius) {
+  const double inside_width = width - 2 * radius;
+  const double inside_height = height - 2 * radius;
+  return inside_width * inside_height +
+         2 * radius * (inside_width + inside_height) +
+         CalculateCircleArea(radius);
+}
+
+// Returns the bounding box of |path| as a gfx::Rect.

[msw, 2016/02/11 23:57:38]

nit: put this anon namespace inside gfx, and then 'gfx::' is not needed.

[karandeepb, 2016/02/12 03:45:52]

Done.

+gfx::Rect GetBoundingBox(NSBezierPath* path) {
+  const NSRect bounds = [path bounds];
+  return gfx::ToNearestRect(gfx::RectF(bounds.origin.x, bounds.origin.y,
+                                       bounds.size.width, bounds.size.height));
+}
+
+}  // namespace
+
+namespace gfx {
+
+// Check that empty NSBezierPath is returned for empty SkPath.
+TEST(CreateNSBezierPathFromSkPathTest, EmptyPath) {
+  NSBezierPath* result = CreateNSBezierPathFromSkPath(SkPath());

[msw, 2016/02/11 23:57:38]

Don't you need to release (CFRelease?) all the paths created here?
(or use base::scoped_nsobject or something similar?)

[karandeepb, 2016/02/12 03:45:52]

It is autoreleased when it is no longer in scope(at the end of an iteration of
the main runloop).

+  EXPECT_TRUE([result isEmpty]);
+}
+
+// Check that the returned NSBezierPath has the correct winding rule.
+TEST(CreateNSBezierPathFromSkPathTest, FillType) {
+  SkPath path;
+  path.setFillType(SkPath::kWinding_FillType);
+  NSBezierPath* result = CreateNSBezierPathFromSkPath(path);
+  EXPECT_EQ(NSNonZeroWindingRule, [result windingRule]);
+
+  path.setFillType(SkPath::kEvenOdd_FillType);
+  result = CreateNSBezierPathFromSkPath(path);
+  EXPECT_EQ(NSEvenOddWindingRule, [result windingRule]);
+}
+
+// Check that a path containing multiple subpaths, in this case two rectangles,
+// is correctly converted to a NSBezierPath.
+TEST(CreateNSBezierPathFromSkPathTest, TwoRectanglesPath) {
+  const SkRect rects[] = {
+      {0, 0, 50, 50}, {100, 100, 150, 150},
+  };
+  const NSPoint inside_points[] = {
+      {1, 1},     {1, 49},    {49, 49},   {49, 1},  {101, 101},
+      {101, 149}, {149, 149}, {149, 101}, {25, 25}, {125, 125}};

[msw, 2016/02/11 23:57:38]

nit: put {25, 25} after {49, 1}, bump {101, 101} to next line.

[karandeepb, 2016/02/12 03:45:51]

Done.

+  const NSPoint outside_points[] = {{-1, -1}, {-1, 51},  {51, 51},   {51, -1},

[msw, 2016/02/11 23:57:38]

EXPECT/ASSERT_EQ(arraysize(inside_points), arraysize(outside_points));

[karandeepb, 2016/02/12 03:45:52]

Done.

+                                    {99, 99}, {99, 151}, {151, 151}, {151, 99},
+                                    {75, 75}, {-5, -5}};
+  const gfx::Rect expected_bounds(0, 0, 150, 150);

[msw, 2016/02/11 23:57:38]

nit: 'gfx::' not needed

[karandeepb, 2016/02/12 03:45:52]

Done.

+
+  SkPath path;
+  path.addRect(rects[0]);
+  path.addRect(rects[1]);
+  NSBezierPath* result = CreateNSBezierPathFromSkPath(path);
+
+  // Check points near the boundary of the path and verify that they are
+  // reported correctly as being inside/outside the path.
+  for (size_t i = 0; i < arraysize(inside_points); i++) {
+    EXPECT_TRUE([result containsPoint:inside_points[i]]);
+    EXPECT_FALSE([result containsPoint:outside_points[i]]);
+  }
+
+  // Check that the returned result has the correct bounding box. GetBoundingBox
+  // rounds the coordinates to nearest integer values.
+  EXPECT_EQ(expected_bounds, GetBoundingBox(result));
+}
+
+// Test that an SKPath containing a circle is converted correctly to a
+// NSBezierPath.
+TEST(CreateNSBezierPathFromSkPathTest, CirclePath) {
+  const int kRadius = 5;
+  const int kCentreX = 10;
+  const int kCentreY = 15;
+  const double kCushion = 0.1;
+  // Expected bounding box of the circle.
+  const gfx::Rect expected_bounds(kCentreX - kRadius, kCentreY - kRadius,

[msw, 2016/02/11 23:57:38]

nit: 'gfx::' not needed

[karandeepb, 2016/02/12 03:45:51]

Done.

+                                  2 * kRadius, 2 * kRadius);
+
+  SkPath path;
+  path.addCircle(SkIntToScalar(kCentreX), SkIntToScalar(kCentreY),
+                 SkIntToScalar(kRadius));
+  NSBezierPath* result = CreateNSBezierPathFromSkPath(path);
+
+  // Check points near the boundary of the circle and verify that they are
+  // reported correctly as being inside/outside the path.
+  for (size_t deg = 0; deg < 360; deg++) {
+    NSPoint inside_point =
+        GetRadialPoint(kRadius - kCushion, deg, kCentreX, kCentreY);
+    NSPoint outside_point =
+        GetRadialPoint(kRadius + kCushion, deg, kCentreX, kCentreY);
+    EXPECT_TRUE([result containsPoint:inside_point]);
+    EXPECT_FALSE([result containsPoint:outside_point]);
+  }
+
+  // Check that the returned result has the correct bounding box. GetBoundingBox
+  // rounds the coordinates to nearest integer values.
+  EXPECT_EQ(expected_bounds, GetBoundingBox(result));
+
+  // Check area of converted path is correct upto a certain tolerance value. To

[msw, 2016/02/11 23:57:38]

nit: "up to"

[karandeepb, 2016/02/12 03:45:52]

Done.

+  // find the area of the NSBezierPath returned, flatten it i.e. convert it to a
+  // polygon.
+  [NSBezierPath setDefaultFlatness:0.01];
+  NSBezierPath* polygon = [result bezierPathByFlatteningPath];

[msw, 2016/02/11 23:57:38]

nit: delete this object at some point or use base::scoped_nsobject?

[karandeepb, 2016/02/12 03:45:51]

It is autoreleased when it is no longer in scope(at the end of an iteration of
the main runloop).

+  const double kTolerance = 0.14;
+  EXPECT_NEAR(CalculateCircleArea(kRadius), CalculatePolygonArea(polygon),
+              kTolerance);
+}
+
+// Test that an SKPath containing a rounded rectangle is converted correctly to
+// a NSBezierPath.
+TEST(CreateNSBezierPathFromSkPathTest, RoundedRectanglePath) {
+  const int kRectangleWidth = 50;
+  const int kRectangleHeight = 100;
+  const int kCornerRadius = 5;
+  const double kCushion = 0.1;
+  // Expected bounding box of the rounded rectangle.
+  const gfx::Rect expected_bounds(kRectangleWidth, kRectangleHeight);

[msw, 2016/02/11 23:57:38]

nit: 'gfx::' not needed

[karandeepb, 2016/02/12 03:45:52]

Done.

+
+  SkRRect rrect;
+  rrect.setRectXY(SkRect::MakeWH(kRectangleWidth, kRectangleHeight),
+                  kCornerRadius, kCornerRadius);
+
+  const NSPoint inside_points[] = {
+      // Bottom left corner.
+      {kCornerRadius / 2.0, kCornerRadius / 2.0},
+      // Bottom right corner.
+      {kRectangleWidth - kCornerRadius / 2.0, kCornerRadius / 2.0},
+      // Top Right corner.
+      {kRectangleWidth - kCornerRadius / 2.0,
+       kRectangleHeight - kCornerRadius / 2.0},
+      // Top left corner.
+      {kCornerRadius / 2.0, kRectangleHeight - kCornerRadius / 2.0},
+      // Bottom middle.
+      {kRectangleWidth / 2.0, kCushion},
+      // Right middle.
+      {kRectangleWidth - kCushion, kRectangleHeight / 2.0},
+      // Top middle.
+      {kRectangleWidth / 2.0, kRectangleHeight - kCushion},
+      // Left middle.
+      {kCushion, kRectangleHeight / 2.0}};
+  const NSPoint outside_points[] = {

[msw, 2016/02/11 23:57:38]

EXPECT/ASSERT_EQ(arraysize(inside_points), arraysize(outside_points));

[karandeepb, 2016/02/12 03:45:52]

Done.

+      // Bottom left corner.
+      {0, 0},
+      // Bottom right corner.
+      {kRectangleWidth, 0},
+      // Top right corner.
+      {kRectangleWidth, kRectangleHeight},
+      // Top left corner.
+      {0, kRectangleHeight},
+      // Bottom middle.
+      {kRectangleWidth / 2.0, -kCushion},
+      // Right middle.
+      {kRectangleWidth + kCushion, kRectangleHeight / 2.0},
+      // Top middle.
+      {kRectangleWidth / 2.0, kRectangleHeight + kCushion},
+      // Left middle.
+      {-kCushion, kRectangleHeight / 2.0}};
+  const size_t kNumPoints = arraysize(inside_points);
+
+  SkPath path;
+  path.addRRect(rrect);
+  NSBezierPath* result = CreateNSBezierPathFromSkPath(path);
+
+  // Check points near the boundary of the path and verify that they are
+  // reported correctly as being inside/outside the path.
+  for (size_t i = 0; i < kNumPoints; i++) {
+    EXPECT_TRUE([result containsPoint:inside_points[i]]);
+    EXPECT_FALSE([result containsPoint:outside_points[i]]);
+  }
+
+  // Check that the returned result has the correct bounding box. GetBoundingBox
+  // rounds the coordinates to nearest integer values.
+  EXPECT_EQ(expected_bounds, GetBoundingBox(result));
+
+  // Check area of converted path is correct upto a certain tolerance value. To

[msw, 2016/02/11 23:57:38]

nit: "up to"

[karandeepb, 2016/02/12 03:45:51]

Done.

+  // find the area of the NSBezierPath returned, flatten it i.e. convert it to a
+  // polygon.
+  [NSBezierPath setDefaultFlatness:0.01];
+  NSBezierPath* polygon = [result bezierPathByFlatteningPath];
+  const double kTolerance = 0.14;
+  EXPECT_NEAR(CalculateRoundedRectangleArea(kRectangleWidth, kRectangleHeight,
+                                            kCornerRadius),
+              CalculatePolygonArea(polygon), kTolerance);
+}
+
+}  // namespace gfx