chrome/common/badge_util.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/common/badge_util.h"
   6
   7 #include <cmath>
   8
   9 #include "base/logging.h"
  10 #include "base/strings/utf_string_conversions.h"
  11 #include "third_party/skia/include/core/SkPaint.h"
  12 #include "third_party/skia/include/core/SkTypeface.h"
  13 #include "ui/base/resource/resource_bundle.h"
  14 #include "ui/gfx/canvas.h"
  15 #include "ui/gfx/font.h"
  16 #include "ui/gfx/geometry/rect.h"
  17 #include "ui/gfx/geometry/size.h"
  18 #include "ui/resources/grit/ui_resources.h"
  19
  20 namespace {
  21
  22 // Different platforms need slightly different constants to look good.
  23 // TODO(devlin): Comb through these and see if they are all still needed/
  24 // appropriate.
  25 #if defined(OS_WIN)
  26 const float kTextSize = 10;
  27 // The padding between the top of the badge and the top of the text.
  28 const int kTopTextPadding = -1;
  29 #elif defined(OS_MACOSX)
  30 const float kTextSize = 9.0;
  31 const int kTopTextPadding = 0;
  32 #elif defined(OS_CHROMEOS)
  33 const float kTextSize = 8.0;
  34 const int kTopTextPadding = 1;
  35 #elif defined(OS_POSIX)
  36 const float kTextSize = 9.0;
  37 const int kTopTextPadding = 0;
  38 #endif
  39
  40 const int kPadding = 2;
  41 const int kBadgeHeight = 11;
  42 const int kMaxTextWidth = 23;
  43
  44 // The minimum width for center-aligning the badge.
  45 const int kCenterAlignThreshold = 20;
  46
  47 }  // namespace
  48
  49 namespace badge_util {
  50
  51 SkPaint* GetBadgeTextPaintSingleton() {
  52 #if defined(OS_MACOSX)
  53   const char kPreferredTypeface[] = "Helvetica Bold";
  54 #else
  55   const char kPreferredTypeface[] = "Arial";
  56 #endif
  57
  58   static SkPaint* text_paint = NULL;
  59   if (!text_paint) {
  60     text_paint = new SkPaint;
  61     text_paint->setAntiAlias(true);
  62     text_paint->setTextAlign(SkPaint::kLeft_Align);
  63
  64     skia::RefPtr<SkTypeface> typeface = skia::AdoptRef(
  65         SkTypeface::CreateFromName(kPreferredTypeface, SkTypeface::kBold));
  66     // Skia doesn't do any font fallback---if the user is missing the font then
  67     // typeface will be NULL. If we don't do manual fallback then we'll crash.
  68     if (typeface) {
  69       text_paint->setFakeBoldText(true);
  70     } else {
  71       // Fall back to the system font. We don't bold it because we aren't sure
  72       // how it will look.
  73       // For the most part this code path will only be hit on Linux systems
  74       // that don't have Arial.
  75       ResourceBundle& rb = ResourceBundle::GetSharedInstance();
  76       const gfx::Font& base_font = rb.GetFont(ResourceBundle::BaseFont);
  77       typeface = skia::AdoptRef(SkTypeface::CreateFromName(
  78           base_font.GetFontName().c_str(), SkTypeface::kNormal));
  79       DCHECK(typeface);
  80     }
  81
  82     text_paint->setTypeface(typeface.get());
  83     // |text_paint| adds its own ref. Release the ref from CreateFontName.
  84   }
  85   return text_paint;
  86 }
  87
  88 void PaintBadge(gfx::Canvas* canvas,
  89                 const gfx::Rect& bounds,
  90                 const std::string& text,
  91                 const SkColor& text_color_in,
  92                 const SkColor& background_color_in,
  93                 int icon_width) {
  94   if (text.empty())
  95     return;
  96
  97   SkColor text_color = text_color_in;
  98   if (SkColorGetA(text_color_in) == 0x00)
  99     text_color = SK_ColorWHITE;
 100
 101   SkColor background_color = background_color_in;
 102   if (SkColorGetA(background_color_in) == 0x00)
 103       background_color = SkColorSetARGB(255, 218, 0, 24);
 104
 105   canvas->Save();
 106
 107   SkPaint* text_paint = badge_util::GetBadgeTextPaintSingleton();
 108   text_paint->setColor(text_color);
 109   float scale = canvas->image_scale();
 110
 111   // Calculate text width. Font width may not be linear with respect to the
 112   // scale factor (e.g. when hinting is applied), so we need to use the font
 113   // size that canvas actually uses when drawing a text.
 114   text_paint->setTextSize(SkFloatToScalar(kTextSize) * scale);
 115   SkScalar sk_text_width_in_pixel =
 116       text_paint->measureText(text.c_str(), text.size());
 117   text_paint->setTextSize(SkFloatToScalar(kTextSize));
 118
 119   // We clamp the width to a max size. SkPaint::measureText returns the width in
 120   // pixel (as a result of scale multiplier), so convert sk_text_width_in_pixel
 121   // back to DIP (density independent pixel) first.
 122   int text_width =
 123       std::min(kMaxTextWidth,
 124                static_cast<int>(
 125                    std::ceil(SkScalarToFloat(sk_text_width_in_pixel) / scale)));
 126
 127   // Calculate badge size. It is clamped to a min width just because it looks
 128   // silly if it is too skinny.
 129   int badge_width = text_width + kPadding * 2;
 130   // Force the pixel width of badge to be either odd (if the icon width is odd)
 131   // or even otherwise. If there is a mismatch you get http://crbug.com/26400.
 132   if (icon_width != 0 && (badge_width % 2 != icon_width % 2))
 133     badge_width += 1;
 134   badge_width = std::max(kBadgeHeight, badge_width);
 135
 136   // Paint the badge background color in the right location. It is usually
 137   // right-aligned, but it can also be center-aligned if it is large.
 138   int rect_height = kBadgeHeight;
 139   int rect_y = bounds.bottom() - kBadgeHeight;
 140   int rect_width = badge_width;
 141   int rect_x = (badge_width >= kCenterAlignThreshold) ?
 142       bounds.x() + (bounds.width() - badge_width) / 2 :
 143       bounds.right() - badge_width;
 144   gfx::Rect rect(rect_x, rect_y, rect_width, rect_height);
 145
 146   SkPaint rect_paint;
 147   rect_paint.setStyle(SkPaint::kFill_Style);
 148   rect_paint.setAntiAlias(true);
 149   rect_paint.setColor(background_color);
 150   canvas->DrawRoundRect(rect, 2, rect_paint);
 151
 152   // Overlay the gradient. It is stretchy, so we do this in three parts.
 153   ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
 154   gfx::ImageSkia* gradient_left = rb.GetImageSkiaNamed(
 155       IDR_BROWSER_ACTION_BADGE_LEFT);
 156   gfx::ImageSkia* gradient_right = rb.GetImageSkiaNamed(
 157       IDR_BROWSER_ACTION_BADGE_RIGHT);
 158   gfx::ImageSkia* gradient_center = rb.GetImageSkiaNamed(
 159       IDR_BROWSER_ACTION_BADGE_CENTER);
 160
 161   canvas->DrawImageInt(*gradient_left, rect.x(), rect.y());
 162   canvas->TileImageInt(*gradient_center,
 163       rect.x() + gradient_left->width(),
 164       rect.y(),
 165       rect.width() - gradient_left->width() - gradient_right->width(),
 166       rect.height());
 167   canvas->DrawImageInt(*gradient_right,
 168       rect.right() - gradient_right->width(), rect.y());
 169
 170   // Finally, draw the text centered within the badge. We set a clip in case the
 171   // text was too large.
 172   rect.Inset(kPadding, 0);
 173   canvas->ClipRect(rect);
 174   canvas->sk_canvas()->drawText(
 175       text.c_str(), text.size(),
 176       SkFloatToScalar(rect.x() +
 177                       static_cast<float>(rect.width() - text_width) / 2),
 178       SkFloatToScalar(rect.y() + kTextSize + kTopTextPadding),
 179       *text_paint);
 180   canvas->Restore();
 181 }
 182
 183 }  // namespace badge_util