macviews: honor system control tint setting

ui/native_theme/native_theme_mac.mm

 // Copyright (c) 2013 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 "ui/native_theme/native_theme_mac.h"
 
 #import <Cocoa/Cocoa.h>
 #include <stddef.h>
 
 #include "base/mac/mac_util.h"
@@ skipping 73 matching lines @@
   // CGColorRefToSkColor will not like. But RGB is additive, so the conversion
   // is easy (RGB to grayscale is less easy).
   const CGFloat* components = CGColorGetComponents(cg_color);
   CGFloat alpha = component_count == 2 ? components[1] : 1.0;
   return SkColorSetARGB(SkScalarRoundToInt(255.0 * alpha),
                         SkScalarRoundToInt(255.0 * components[0]),
                         SkScalarRoundToInt(255.0 * components[0]),
                         SkScalarRoundToInt(255.0 * components[0]));
 }
 
+// Converts an SkColor to grayscale by flat averaging of components, preserving
+// the alpha channel.
+SkColor ColorToGrayscale(SkColor color) {
+  uint8_t component = (SkColorGetR(color) +
+                       SkColorGetG(color) +
+                       SkColorGetB(color)) / 3;

[Avi (use Gerrit), 2016/08/19 00:21:48]

Do we want to do a luminosity average here?
http://www.johndcook.com/blog/2009/08/24/algorithms-convert-color-grayscale/

[Elly Fong-Jones, 2016/08/22 18:17:57]

Hm! Originally when I tried out luminance it looked ghastly, but I figured out
that there was actually a bug in my first try, and when implemented correctly,
it actually looks better than flat average does. I changed this to use luminance
and attached some comparison screenshots to the bug.

+  return SkColorSetARGB(SkColorGetA(color), component, component, component);
+}
+
 }  // namespace
 
 namespace ui {
 
 // static
 NativeTheme* NativeTheme::GetInstanceForWeb() {
   return NativeThemeMac::instance();
 }
 
 // static
 NativeThemeMac* NativeThemeMac::instance() {
   CR_DEFINE_STATIC_LOCAL(NativeThemeMac, s_native_theme, ());
   return &s_native_theme;
 }
 
+// static
+SkColor NativeThemeMac::ApplySystemControlTint(SkColor color) {
+  if ([NSColor currentControlTint] == NSGraphiteControlTint)
+    return ColorToGrayscale(color);
+  return color;
+}
+
 SkColor NativeThemeMac::GetSystemColor(ColorId color_id) const {
   // TODO(tapted): Add caching for these, and listen for
   // NSSystemColorsDidChangeNotification.
   switch (color_id) {
     case kColorId_WindowBackground:
       return NSSystemColorToSkColor([NSColor windowBackgroundColor]);
     case kColorId_DialogBackground:
       return kDialogBackgroundColor;
     case kColorId_BubbleBackground:
       return SK_ColorWHITE;
 
     case kColorId_FocusedBorderColor:
     case kColorId_FocusedMenuButtonBorderColor:
       return NSSystemColorToSkColor([NSColor keyboardFocusIndicatorColor]);
     case kColorId_UnfocusedBorderColor:
       return NSSystemColorToSkColor([NSColor controlColor]);
 
     // Buttons and labels.
     case kColorId_ButtonBackgroundColor:
     case kColorId_ButtonHoverBackgroundColor:
     case kColorId_HoverMenuButtonBorderColor:
     case kColorId_LabelBackgroundColor:
       return NSSystemColorToSkColor([NSColor controlBackgroundColor]);
     case kColorId_ButtonEnabledColor:
     case kColorId_EnabledMenuButtonBorderColor:
     case kColorId_LabelEnabledColor:
       return NSSystemColorToSkColor([NSColor controlTextColor]);
+    case kColorId_CallToActionColor:
+      return NSSystemColorToSkColor([NSColor controlTextColor]);
     case kColorId_ButtonDisabledColor:
     case kColorId_LabelDisabledColor:
       return NSSystemColorToSkColor([NSColor disabledControlTextColor]);
     case kColorId_ButtonHighlightColor:
       // Although the NSColor documentation names "selectedControlTextColor" as
       // the color for a "text in a .. control being clicked or dragged", it
       // remains black, and text on Yosemite-style pressed buttons is white.
       return SK_ColorWHITE;
     case kColorId_ButtonHoverColor:
       return NSSystemColorToSkColor([NSColor selectedControlTextColor]);
@@ skipping 134 matching lines @@
   start_colors[ButtonBackgroundType::PRESSED] = kPressedBlueStart;
 
   ColorByState end_colors;
   end_colors[ButtonBackgroundType::DISABLED] = kGrey;
   end_colors[ButtonBackgroundType::HIGHLIGHTED] = kBlueEnd;
   end_colors[ButtonBackgroundType::NORMAL] = SK_ColorWHITE;
   end_colors[ButtonBackgroundType::PRESSED] = kPressedBlueEnd;
 
   SkColor gradient_colors[] = {start_colors[type], end_colors[type]};
 
+  for (size_t i = 0; i < arraysize(gradient_colors); ++i)
+    gradient_colors[i] = ApplySystemControlTint(gradient_colors[i]);
+
   return SkGradientShader::MakeLinear(
       gradient_points, gradient_colors, gradient_positions,
       arraysize(gradient_positions),
       SkShader::kClamp_TileMode);
 }
 
 // static
 sk_sp<SkShader> NativeThemeMac::GetButtonBorderShader(ButtonBackgroundType type,
                                                       int height) {
   using ColorByState = EnumArray<ButtonBackgroundType, SkColor>;
@@ skipping 13 matching lines @@
   top_edge[ButtonBackgroundType::PRESSED] = SkColorSetRGB(0x4f, 0x72, 0xfb);
   ColorByState bottom_edge;
   bottom_edge[ButtonBackgroundType::DISABLED] = SkColorSetRGB(0xbe, 0xbe, 0xbe);
   bottom_edge[ButtonBackgroundType::HIGHLIGHTED] =
       SkColorSetRGB(0x43, 0x52, 0xff);
   bottom_edge[ButtonBackgroundType::NORMAL] = SkColorSetRGB(0x9d, 0x9d, 0x9d);
   bottom_edge[ButtonBackgroundType::PRESSED] = SkColorSetRGB(0x3e, 0x12, 0xff);
 
   SkColor gradient_colors[] = {top_edge[type], bottom_edge[type]};
 
+  for (size_t i = 0; i < arraysize(gradient_colors); ++i)
+    gradient_colors[i] = ApplySystemControlTint(gradient_colors[i]);
+
   return SkGradientShader::MakeLinear(
       gradient_points, gradient_colors, gradient_positions,
       arraysize(gradient_positions), SkShader::kClamp_TileMode);
 }
 
 // static
 void NativeThemeMac::PaintStyledGradientButton(SkCanvas* canvas,
                                                const gfx::Rect& integer_bounds,
                                                ButtonBackgroundType type,
                                                bool round_left,
                                                bool round_right,
                                                bool focus) {
   const SkScalar kBorderThickness = 1;
   const SkScalar kFocusRingThickness = 4;
-  const SkColor kFocusRingColor = SkColorSetARGB(0x94, 0x79, 0xa7, 0xe9);
+  const SkColor kFocusRingColor = ApplySystemControlTint(
+      SkColorSetARGB(0x94, 0x79, 0xa7, 0xe9));
 
   const SkVector kNoCurve = {0, 0};
   const SkVector kCurve = {kButtonCornerRadius, kButtonCornerRadius};
   const SkVector kLeftCurves[4] = {kCurve, kNoCurve, kNoCurve, kCurve};
   const SkVector kRightCurves[4] = {kNoCurve, kCurve, kCurve, kNoCurve};
 
   const SkScalar kShadowOffsetY = 1;
   const SkColor kShadowColor = SkColorSetA(SK_ColorBLACK, 0x05);
   const double kShadowBlur = 0.0;
   const std::vector<gfx::ShadowValue> shadows(
@@ skipping 42 matching lines @@
   canvas->drawDRRect(outer_shape, shape, paint);
 }
 
 NativeThemeMac::NativeThemeMac() {
 }
 
 NativeThemeMac::~NativeThemeMac() {
 }
 
 }  // namespace ui