Add NSString category for providing iOS6-style string drawing APIs.

ui/ios/NSString+CrStringDrawing_unittest.mm

+// Copyright 2014 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/ios/NSString+CrStringDrawing.h"
+
+#include "base/mac/scoped_nsobject.h"
+#include "base/strings/stringprintf.h"
+#include "base/strings/sys_string_conversions.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/platform_test.h"
+
+namespace {
+
+typedef PlatformTest NSStringCrStringDrawing;
+
+// These test verifies that the category methods return the same values as the
+// deprecated methods, so ignore warnings about using deprecated methods.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
+TEST_F(NSStringCrStringDrawing, SizeWithFont) {
+  NSArray* fonts = @[
+    [NSNull null],
+    [UIFont systemFontOfSize:16],
+    [UIFont boldSystemFontOfSize:10],
+    [UIFont fontWithName:@"Helvetica" size:12.0],
+  ];
+  for (UIFont* font in fonts) {
+    if ([font isEqual:[NSNull null]])
+      font = nil;
+    std::string font_tag = "with font ";
+    font_tag.append(
+        base::SysNSStringToUTF8(font ? [font description] : @"nil"));
+    EXPECT_EQ([@"" sizeWithFont:font].width,
+              [@"" cr_sizeWithFont:font].width) << font_tag;
+    EXPECT_EQ([@"" sizeWithFont:font].height,
+              [@"" cr_sizeWithFont:font].height) << font_tag;
+    EXPECT_EQ([@"Test" sizeWithFont:font].width,
+              [@"Test" cr_sizeWithFont:font].width) << font_tag;
+    EXPECT_EQ([@"Test" sizeWithFont:font].height,
+              [@"Test" cr_sizeWithFont:font].height) << font_tag;
+    EXPECT_EQ([@"你好" sizeWithFont:font].width,
+              [@"你好" cr_sizeWithFont:font].width) << font_tag;
+    EXPECT_EQ([@"你好" sizeWithFont:font].height,
+              [@"你好" cr_sizeWithFont:font].height) << font_tag;
+    NSString* long_string = @"★ This is a test string that is very long.";
+    EXPECT_EQ([long_string sizeWithFont:font].width,
+              [long_string cr_sizeWithFont:font].width) << font_tag;
+    EXPECT_EQ([long_string sizeWithFont:font].height,
+              [long_string cr_sizeWithFont:font].height) << font_tag;
+  }
+}
+#pragma clang diagnostic pop  // ignored "-Wdeprecated-declarations"
+
+TEST_F(NSStringCrStringDrawing, PixelAlignedSizeWithFont) {
+  NSArray* fonts = @[
+    [UIFont systemFontOfSize:16],
+    [UIFont boldSystemFontOfSize:10],
+    [UIFont fontWithName:@"Helvetica" size:12.0],
+  ];
+  NSArray* strings = @[
+    @"",
+    @"Test",
+    @"你好",
+    @"★ This is a test string that is very long.",
+  ];
+  for (UIFont* font in fonts) {
+    NSDictionary* attributes = @{ NSFontAttributeName : font };
+
+    for (NSString* string in strings) {
+      std::string test_tag = base::StringPrintf("for string '%s' with font %s",
+          base::SysNSStringToUTF8(string).c_str(),
+          base::SysNSStringToUTF8([font description]).c_str());
+
+      CGSize size_with_attributes = [string sizeWithAttributes:attributes];
+      CGSize size_with_pixel_aligned =
+          [string cr_pixelAlignedSizeWithFont:font];
+
+      // Verify that the pixel_aligned size is always rounded up (i.e. the size
+      // returned from sizeWithAttributes: is less than or equal to the pixel-
+      // aligned size).
+      EXPECT_LE(size_with_attributes.width,
+                size_with_pixel_aligned.width) << test_tag;
+      EXPECT_LE(size_with_attributes.height,
+                size_with_pixel_aligned.height) << test_tag;
+
+      // Verify that the pixel_aligned size is never more than a pixel different
+      // than the size returned from sizeWithAttributes:.
+      static CGFloat scale = [[UIScreen mainScreen] scale];
+      EXPECT_NEAR(size_with_attributes.width * scale,
+                  size_with_pixel_aligned.width * scale,
+                  0.9999) << test_tag;
+      EXPECT_NEAR(size_with_attributes.height * scale,
+                  size_with_pixel_aligned.height * scale,
+                  0.9999) << test_tag;
+
+      // Verify that the pixel-aligned value is pixel-aligned.
+      EXPECT_FLOAT_EQ(roundf(size_with_pixel_aligned.width * scale),
+                      size_with_pixel_aligned.width * scale) << test_tag;
+      EXPECT_FLOAT_EQ(roundf(size_with_pixel_aligned.height * scale),
+                      size_with_pixel_aligned.height * scale) << test_tag;
+    }
+  }
+}
+
+
+}  // namespace