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 <cmath> 6 7 #include "content/public/common/page_zoom.h" 8 9 namespace content { 10 11 const double kMinimumZoomFactor = 0.25; 12 const double kMaximumZoomFactor = 5.0; 13 const double kEpsilon = 0.001; 14 const double kTextSizeMultiplierRatio = 1.2; 15 ZoomValuesEqual(double value_a,double value_b)16bool ZoomValuesEqual(double value_a, double value_b) { 17 return (std::fabs(value_a - value_b) <= kEpsilon); 18 } 19 ZoomLevelToZoomFactor(double zoom_level)20double ZoomLevelToZoomFactor(double zoom_level) { 21 return std::pow(kTextSizeMultiplierRatio, zoom_level); 22 } 23 ZoomFactorToZoomLevel(double factor)24double ZoomFactorToZoomLevel(double factor) { 25 return std::log(factor) / std::log(kTextSizeMultiplierRatio); 26 } 27 28 } // namespace content 29