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      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/chrome_page_zoom.h"
      6 
      7 #include <algorithm>
      8 #include <cmath>
      9 
     10 #include "base/prefs/pref_service.h"
     11 #include "chrome/browser/chrome_page_zoom_constants.h"
     12 #include "chrome/browser/profiles/profile.h"
     13 #include "chrome/common/pref_names.h"
     14 #include "content/public/browser/render_view_host.h"
     15 #include "content/public/browser/user_metrics.h"
     16 #include "content/public/browser/web_contents.h"
     17 #include "content/public/common/page_zoom.h"
     18 #include "content/public/common/renderer_preferences.h"
     19 
     20 using content::UserMetricsAction;
     21 
     22 namespace chrome_page_zoom {
     23 
     24 enum PageZoomValueType {
     25   PAGE_ZOOM_VALUE_TYPE_FACTOR,
     26   PAGE_ZOOM_VALUE_TYPE_LEVEL,
     27 };
     28 
     29 std::vector<double> PresetZoomValues(PageZoomValueType value_type,
     30                                      double custom_value) {
     31   // Generate a vector of zoom values from an array of known preset
     32   // factors. The values in content::kPresetZoomFactors will already be in
     33   // sorted order.
     34   std::vector<double> zoom_values;
     35   bool found_custom = false;
     36   for (size_t i = 0; i < kPresetZoomFactorsSize; i++) {
     37     double zoom_value = kPresetZoomFactors[i];
     38     if (value_type == PAGE_ZOOM_VALUE_TYPE_LEVEL)
     39       zoom_value = content::ZoomFactorToZoomLevel(zoom_value);
     40     if (content::ZoomValuesEqual(zoom_value, custom_value))
     41       found_custom = true;
     42     zoom_values.push_back(zoom_value);
     43   }
     44   // If the preset array did not contain the custom value, append it to the
     45   // vector and then sort.
     46   double min = value_type == PAGE_ZOOM_VALUE_TYPE_LEVEL ?
     47       content::ZoomFactorToZoomLevel(content::kMinimumZoomFactor) :
     48       content::kMinimumZoomFactor;
     49   double max = value_type == PAGE_ZOOM_VALUE_TYPE_LEVEL ?
     50       content::ZoomFactorToZoomLevel(content::kMaximumZoomFactor) :
     51       content::kMaximumZoomFactor;
     52   if (!found_custom && custom_value > min && custom_value < max) {
     53     zoom_values.push_back(custom_value);
     54     std::sort(zoom_values.begin(), zoom_values.end());
     55   }
     56   return zoom_values;
     57 }
     58 
     59 std::vector<double> PresetZoomFactors(double custom_factor) {
     60   return PresetZoomValues(PAGE_ZOOM_VALUE_TYPE_FACTOR, custom_factor);
     61 }
     62 
     63 std::vector<double> PresetZoomLevels(double custom_level) {
     64   return PresetZoomValues(PAGE_ZOOM_VALUE_TYPE_LEVEL, custom_level);
     65 }
     66 
     67 void Zoom(content::WebContents* web_contents, content::PageZoom zoom) {
     68   content::RenderViewHost* host = web_contents->GetRenderViewHost();
     69   double current_zoom_level = web_contents->GetZoomLevel();
     70   double default_zoom_level =
     71       Profile::FromBrowserContext(web_contents->GetBrowserContext())->
     72           GetPrefs()->GetDouble(prefs::kDefaultZoomLevel);
     73 
     74   if (zoom == content::PAGE_ZOOM_RESET) {
     75     host->SetZoomLevel(default_zoom_level);
     76     content::RecordAction(UserMetricsAction("ZoomNormal"));
     77     return;
     78   }
     79 
     80   // Generate a vector of zoom levels from an array of known presets along with
     81   // the default level added if necessary.
     82   std::vector<double> zoom_levels = PresetZoomLevels(default_zoom_level);
     83 
     84   if (zoom == content::PAGE_ZOOM_OUT) {
     85     // Iterate through the zoom levels in reverse order to find the next
     86     // lower level based on the current zoom level for this page.
     87     for (std::vector<double>::reverse_iterator i = zoom_levels.rbegin();
     88          i != zoom_levels.rend(); ++i) {
     89       double zoom_level = *i;
     90       if (content::ZoomValuesEqual(zoom_level, current_zoom_level))
     91         continue;
     92       if (zoom_level < current_zoom_level) {
     93         host->SetZoomLevel(zoom_level);
     94         content::RecordAction(UserMetricsAction("ZoomMinus"));
     95         return;
     96       }
     97       content::RecordAction(UserMetricsAction("ZoomMinus_AtMinimum"));
     98     }
     99   } else {
    100     // Iterate through the zoom levels in normal order to find the next
    101     // higher level based on the current zoom level for this page.
    102     for (std::vector<double>::const_iterator i = zoom_levels.begin();
    103          i != zoom_levels.end(); ++i) {
    104       double zoom_level = *i;
    105       if (content::ZoomValuesEqual(zoom_level, current_zoom_level))
    106         continue;
    107       if (zoom_level > current_zoom_level) {
    108         host->SetZoomLevel(zoom_level);
    109         content::RecordAction(UserMetricsAction("ZoomPlus"));
    110         return;
    111       }
    112     }
    113     content::RecordAction(UserMetricsAction("ZoomPlus_AtMaximum"));
    114   }
    115 }
    116 
    117 }  // namespace chrome_page_zoom
    118