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