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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 "PageScaleConstraints.h"
     33 
     34 namespace WebCore {
     35 
     36 PageScaleConstraints::PageScaleConstraints()
     37     : initialScale(-1), minimumScale(-1), maximumScale(-1) { }
     38 
     39 PageScaleConstraints::PageScaleConstraints(float initial, float minimum, float maximum)
     40     : initialScale(initial), minimumScale(minimum), maximumScale(maximum) { }
     41 
     42 void PageScaleConstraints::overrideWith(const PageScaleConstraints& other)
     43 {
     44     if (other.initialScale != -1) {
     45         initialScale = other.initialScale;
     46         if (minimumScale != -1)
     47             minimumScale = std::min(minimumScale, other.initialScale);
     48     }
     49     if (other.minimumScale != -1)
     50         minimumScale = other.minimumScale;
     51     if (other.maximumScale != -1)
     52         maximumScale = other.maximumScale;
     53     if (!other.layoutSize.isEmpty())
     54         layoutSize = other.layoutSize;
     55     clampAll();
     56 }
     57 
     58 float PageScaleConstraints::clampToConstraints(float pageScaleFactor) const
     59 {
     60     if (pageScaleFactor == -1)
     61         return pageScaleFactor;
     62     if (minimumScale != -1)
     63         pageScaleFactor = std::max(pageScaleFactor, minimumScale);
     64     if (maximumScale != -1)
     65         pageScaleFactor = std::min(pageScaleFactor, maximumScale);
     66     return pageScaleFactor;
     67 }
     68 
     69 void PageScaleConstraints::clampAll()
     70 {
     71     if (minimumScale != -1 && maximumScale != -1)
     72         maximumScale = std::max(minimumScale, maximumScale);
     73     initialScale = clampToConstraints(initialScale);
     74 }
     75 
     76 void PageScaleConstraints::fitToContentsWidth(float contentsWidth, int viewWidthNotIncludingScrollbars)
     77 {
     78     if (!contentsWidth || !viewWidthNotIncludingScrollbars)
     79         return;
     80 
     81     // Clamp the minimum scale so that the viewport can't exceed the document
     82     // width.
     83     minimumScale = std::max(minimumScale, viewWidthNotIncludingScrollbars / contentsWidth);
     84 
     85     // If the initial scale wasn't defined, set it to minimum scale now that we
     86     // know the real value.
     87     if (initialScale == -1)
     88         initialScale = minimumScale;
     89 
     90     clampAll();
     91 }
     92 
     93 bool PageScaleConstraints::operator==(const PageScaleConstraints& other) const
     94 {
     95     return layoutSize == other.layoutSize
     96         && initialScale == other.initialScale
     97         && minimumScale == other.minimumScale
     98         && maximumScale == other.maximumScale;
     99 }
    100 
    101 } // namespace WebCore
    102