1// Copyright (c) 2011 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 "base/logging.h"
8#include "base/utf_string_conversions.h"
9#include "third_party/skia/include/core/SkPaint.h"
10#include "third_party/skia/include/core/SkTypeface.h"
11#include "ui/base/resource/resource_bundle.h"
12#include "ui/gfx/canvas_skia.h"
13#include "ui/gfx/font.h"
14
15namespace badge_util {
16
17SkPaint* GetBadgeTextPaintSingleton() {
18#if defined(OS_MACOSX)
19  const char kPreferredTypeface[] = "Helvetica Bold";
20#else
21  const char kPreferredTypeface[] = "Arial";
22#endif
23
24  static SkPaint* text_paint = NULL;
25  if (!text_paint) {
26    text_paint = new SkPaint;
27    text_paint->setAntiAlias(true);
28    text_paint->setTextAlign(SkPaint::kLeft_Align);
29
30    SkTypeface* typeface = SkTypeface::CreateFromName(
31        kPreferredTypeface, SkTypeface::kBold);
32    // Skia doesn't do any font fallback---if the user is missing the font then
33    // typeface will be NULL. If we don't do manual fallback then we'll crash.
34    if (typeface) {
35      text_paint->setFakeBoldText(true);
36    } else {
37      // Fall back to the system font. We don't bold it because we aren't sure
38      // how it will look.
39      // For the most part this code path will only be hit on Linux systems
40      // that don't have Arial.
41      ResourceBundle& rb = ResourceBundle::GetSharedInstance();
42      const gfx::Font& base_font = rb.GetFont(ResourceBundle::BaseFont);
43      typeface = SkTypeface::CreateFromName(
44          UTF16ToUTF8(base_font.GetFontName()).c_str(), SkTypeface::kNormal);
45      DCHECK(typeface);
46    }
47
48    text_paint->setTypeface(typeface);
49    // |text_paint| adds its own ref. Release the ref from CreateFontName.
50    typeface->unref();
51  }
52  return text_paint;
53}
54
55SkBitmap DrawBadgeIconOverlay(const SkBitmap& icon,
56                              float font_size,
57                              const string16& text,
58                              const string16& fallback) {
59  const int kMinPadding = 1;
60
61  // Calculate the proper style/text overlay to render on the badge.
62  SkPaint* paint = badge_util::GetBadgeTextPaintSingleton();
63  paint->setTextSize(SkFloatToScalar(font_size));
64  paint->setColor(SK_ColorWHITE);
65
66  std::string badge_text = UTF16ToUTF8(text);
67
68  // See if the text will fit - otherwise use a default.
69  SkScalar text_width = paint->measureText(badge_text.c_str(),
70                                           badge_text.size());
71
72  if (SkScalarRound(text_width) > (icon.width() - kMinPadding * 2)) {
73    // String is too large - use the alternate text.
74    badge_text = UTF16ToUTF8(fallback);
75    text_width = paint->measureText(badge_text.c_str(), badge_text.size());
76  }
77
78  // When centering the text, we need to make sure there are an equal number
79  // of pixels on each side as otherwise the text looks off-center. So if the
80  // padding would be uneven, clip one pixel off the right side.
81  int badge_width = icon.width();
82  if ((SkScalarRound(text_width) % 1) != (badge_width % 1))
83    badge_width--;
84
85  // Render the badge bitmap and overlay into a canvas.
86  scoped_ptr<gfx::CanvasSkia> canvas(
87      new gfx::CanvasSkia(badge_width, icon.height(), false));
88  canvas->DrawBitmapInt(icon, 0, 0);
89
90  // Draw the text overlay centered horizontally and vertically. Skia expects
91  // us to specify the lower left coordinate of the text box, which is why we
92  // add 'font_size - 1' to the height.
93  SkScalar x = (badge_width - text_width)/2;
94  SkScalar y = (icon.height() - font_size)/2 + font_size - 1;
95  canvas->drawText(badge_text.c_str(), badge_text.size(), x, y, *paint);
96
97  // Return the generated image.
98  return canvas->ExtractBitmap();
99}
100
101}  // namespace badge_util
102