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      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/page/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.isEmpty())
     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     // If the initial scale wasn't defined, set it to minimum scale now that we
     88     // know the real value.
     89     if (initialScale == -1)
     90         initialScale = minimumScale;
     91 
     92     clampAll();
     93 }
     94 
     95 bool PageScaleConstraints::operator==(const PageScaleConstraints& other) const
     96 {
     97     return layoutSize == other.layoutSize
     98         && initialScale == other.initialScale
     99         && minimumScale == other.minimumScale
    100         && maximumScale == other.maximumScale;
    101 }
    102 
    103 } // namespace blink
    104