third_party/WebKit/Source/core/frame/PageScaleConstraints.cpp

   1 /*
   2  * Copyright (C) 2013 Google Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  *     * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *     * Redistributions in binary form must reproduce the above
  11  * copyright notice, this list of conditions and the following disclaimer
  12  * in the documentation and/or other materials provided with the
  13  * distribution.
  14  *     * Neither the name of Google Inc. nor the names of its
  15  * contributors may be used to endorse or promote products derived from
  16  * this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #include "config.h"
  32 #include "core/frame/PageScaleConstraints.h"
  33
  34 #include <algorithm>
  35
  36 namespace blink {
  37
  38 PageScaleConstraints::PageScaleConstraints()
  39     : initialScale(-1), minimumScale(-1), maximumScale(-1) { }
  40
  41 PageScaleConstraints::PageScaleConstraints(float initial, float minimum, float maximum)
  42     : initialScale(initial), minimumScale(minimum), maximumScale(maximum) { }
  43
  44 void PageScaleConstraints::overrideWith(const PageScaleConstraints& other)
  45 {
  46     if (other.initialScale != -1) {
  47         initialScale = other.initialScale;
  48         if (minimumScale != -1)
  49             minimumScale = std::min(minimumScale, other.initialScale);
  50     }
  51     if (other.minimumScale != -1)
  52         minimumScale = other.minimumScale;
  53     if (other.maximumScale != -1)
  54         maximumScale = other.maximumScale;
  55     if (!other.layoutSize.isZero())
  56         layoutSize = other.layoutSize;
  57     clampAll();
  58 }
  59
  60 float PageScaleConstraints::clampToConstraints(float pageScaleFactor) const
  61 {
  62     if (pageScaleFactor == -1)
  63         return pageScaleFactor;
  64     if (minimumScale != -1)
  65         pageScaleFactor = std::max(pageScaleFactor, minimumScale);
  66     if (maximumScale != -1)
  67         pageScaleFactor = std::min(pageScaleFactor, maximumScale);
  68     return pageScaleFactor;
  69 }
  70
  71 void PageScaleConstraints::clampAll()
  72 {
  73     if (minimumScale != -1 && maximumScale != -1)
  74         maximumScale = std::max(minimumScale, maximumScale);
  75     initialScale = clampToConstraints(initialScale);
  76 }
  77
  78 void PageScaleConstraints::fitToContentsWidth(float contentsWidth, int viewWidthNotIncludingScrollbars)
  79 {
  80     if (!contentsWidth || !viewWidthNotIncludingScrollbars)
  81         return;
  82
  83     // Clamp the minimum scale so that the viewport can't exceed the document
  84     // width.
  85     minimumScale = std::max(minimumScale, viewWidthNotIncludingScrollbars / contentsWidth);
  86
  87     clampAll();
  88 }
  89
  90 void PageScaleConstraints::resolveAutoInitialScale()
  91 {
  92     // If the initial scale wasn't defined, set it to minimum scale now that we
  93     // know the real value.
  94     if (initialScale == -1)
  95         initialScale = minimumScale;
  96
  97     clampAll();
  98 }
  99
 100 bool PageScaleConstraints::operator==(const PageScaleConstraints& other) const
 101 {
 102     return layoutSize == other.layoutSize
 103         && initialScale == other.initialScale
 104         && minimumScale == other.minimumScale
 105         && maximumScale == other.maximumScale;
 106 }
 107
 108 } // namespace blink