chrome/browser/ui/ntp_background_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/browser/ui/ntp_background_util.h"
   6
   7 #include <cmath>
   8
   9 #include "base/logging.h"
  10 #include "chrome/browser/themes/theme_properties.h"
  11 #include "grit/theme_resources.h"
  12 #include "ui/base/theme_provider.h"
  13 #include "ui/gfx/canvas.h"
  14 #include "ui/gfx/image/image_skia.h"
  15 #include "ui/gfx/rect.h"
  16 #include "ui/gfx/skia_util.h"
  17
  18 namespace {
  19
  20 void PaintThemeBackground(
  21     gfx::Canvas* canvas, gfx::ImageSkia* ntp_background, int tiling,
  22     int alignment, const gfx::Rect& area, int tab_contents_height) {
  23   int x_pos = 0;
  24   int y_pos = 0;
  25   int width = area.width() + ntp_background->width();
  26   int height = area.height() + ntp_background->height();
  27
  28   if (alignment & ThemeProperties::ALIGN_BOTTOM) {
  29     y_pos += area.height() + tab_contents_height - ntp_background->height();
  30   } else if (alignment & ThemeProperties::ALIGN_TOP) {
  31     // no op
  32   } else {  // ALIGN_CENTER
  33     y_pos += std::floor(area.height() + tab_contents_height / 2.0 -
  34         ntp_background->height() / 2.0 + 0.5);
  35   }
  36
  37   if (alignment & ThemeProperties::ALIGN_RIGHT) {
  38     x_pos += area.width() - ntp_background->width();
  39   } else if (alignment & ThemeProperties::ALIGN_LEFT) {
  40     // no op
  41   } else {  // ALIGN_CENTER
  42     x_pos +=
  43         std::floor(area.width() / 2.0 - ntp_background->width() / 2.0 + 0.5);
  44   }
  45
  46   if (tiling != ThemeProperties::REPEAT &&
  47       tiling != ThemeProperties::REPEAT_X) {
  48     width = ntp_background->width();
  49   } else if (x_pos > 0) {
  50     x_pos = x_pos % ntp_background->width() - ntp_background->width();
  51   }
  52
  53   if (tiling != ThemeProperties::REPEAT &&
  54       tiling != ThemeProperties::REPEAT_Y) {
  55     height = ntp_background->height();
  56   } else if (y_pos > 0) {
  57     y_pos = y_pos % ntp_background->height() - ntp_background->height();
  58   }
  59
  60   x_pos += area.x();
  61   y_pos += area.y();
  62
  63   canvas->TileImageInt(*ntp_background, x_pos, y_pos, width, height);
  64 }
  65
  66 }  // namespace
  67
  68 // static
  69 void NtpBackgroundUtil::PaintBackgroundDetachedMode(ui::ThemeProvider* tp,
  70                                                     gfx::Canvas* canvas,
  71                                                     const gfx::Rect& area,
  72                                                     int tab_contents_height) {
  73   // Draw the background to match the new tab page.
  74   canvas->FillRect(area, tp->GetColor(ThemeProperties::COLOR_NTP_BACKGROUND));
  75
  76   if (tp->HasCustomImage(IDR_THEME_NTP_BACKGROUND)) {
  77     int tiling = tp->GetDisplayProperty(ThemeProperties::NTP_BACKGROUND_TILING);
  78     int alignment = tp->GetDisplayProperty(
  79         ThemeProperties::NTP_BACKGROUND_ALIGNMENT);
  80     gfx::ImageSkia* ntp_background =
  81         tp->GetImageSkiaNamed(IDR_THEME_NTP_BACKGROUND);
  82
  83     PaintThemeBackground(
  84         canvas, ntp_background, tiling, alignment, area, tab_contents_height);
  85   }
  86 }