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      1 /*
      2  * Copyright (C) 1999 Lars Knoll (knoll (at) kde.org)
      3  *           (C) 1999 Antti Koivisto (koivisto (at) kde.org)
      4  *           (C) 2001 Dirk Mueller (mueller (at) kde.org)
      5  *           (C) 2006 Alexey Proskuryakov (ap (at) webkit.org)
      6  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
      7  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
      8  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
      9  * Copyright (C) 2012-2013 Intel Corporation. All rights reserved.
     10  *
     11  * This library is free software; you can redistribute it and/or
     12  * modify it under the terms of the GNU Library General Public
     13  * License as published by the Free Software Foundation; either
     14  * version 2 of the License, or (at your option) any later version.
     15  *
     16  * This library is distributed in the hope that it will be useful,
     17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     19  * Library General Public License for more details.
     20  *
     21  * You should have received a copy of the GNU Library General Public License
     22  * along with this library; see the file COPYING.LIB.  If not, write to
     23  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     24  * Boston, MA 02110-1301, USA.
     25  *
     26  */
     27 
     28 #include "config.h"
     29 #include "core/dom/ViewportDescription.h"
     30 
     31 using namespace std;
     32 
     33 namespace WebCore {
     34 
     35 static const float& compareIgnoringAuto(const float& value1, const float& value2, const float& (*compare) (const float&, const float&))
     36 {
     37     if (value1 == ViewportDescription::ValueAuto)
     38         return value2;
     39 
     40     if (value2 == ViewportDescription::ValueAuto)
     41         return value1;
     42 
     43     return compare(value1, value2);
     44 }
     45 
     46 float ViewportDescription::resolveViewportLength(const Length& length, const FloatSize& initialViewportSize, Direction direction)
     47 {
     48     if (length.isAuto())
     49         return ViewportDescription::ValueAuto;
     50 
     51     if (length.isFixed())
     52         return length.getFloatValue();
     53 
     54     if (length.type() == ExtendToZoom)
     55         return ViewportDescription::ValueExtendToZoom;
     56 
     57     if ((length.type() == Percent && direction == Horizontal) || length.type() == ViewportPercentageWidth)
     58         return initialViewportSize.width() * length.getFloatValue() / 100.0f;
     59 
     60     if ((length.type() == Percent && direction == Vertical) || length.type() == ViewportPercentageHeight)
     61         return initialViewportSize.height() * length.getFloatValue() / 100.0f;
     62 
     63     if (length.type() == ViewportPercentageMin)
     64         return min(initialViewportSize.width(), initialViewportSize.height()) * length.viewportPercentageLength() / 100.0f;
     65 
     66     if (length.type() == ViewportPercentageMax)
     67         return max(initialViewportSize.width(), initialViewportSize.height()) * length.viewportPercentageLength() / 100.0f;
     68 
     69     ASSERT_NOT_REACHED();
     70     return ViewportDescription::ValueAuto;
     71 }
     72 
     73 PageScaleConstraints ViewportDescription::resolve(const FloatSize& initialViewportSize) const
     74 {
     75     float resultWidth = ValueAuto;
     76     float resultMaxWidth = resolveViewportLength(maxWidth, initialViewportSize, Horizontal);
     77     float resultMinWidth = resolveViewportLength(minWidth, initialViewportSize, Horizontal);
     78     float resultHeight = ValueAuto;
     79     float resultMaxHeight = resolveViewportLength(maxHeight, initialViewportSize, Vertical);
     80     float resultMinHeight = resolveViewportLength(minHeight, initialViewportSize, Vertical);
     81 
     82     float resultZoom = zoom;
     83     float resultMinZoom = minZoom;
     84     float resultMaxZoom = maxZoom;
     85     float resultUserZoom = userZoom;
     86 
     87     // 1. Resolve min-zoom and max-zoom values.
     88     if (resultMinZoom != ViewportDescription::ValueAuto && resultMaxZoom != ViewportDescription::ValueAuto)
     89         resultMaxZoom = max(resultMinZoom, resultMaxZoom);
     90 
     91     // 2. Constrain zoom value to the [min-zoom, max-zoom] range.
     92     if (resultZoom != ViewportDescription::ValueAuto)
     93         resultZoom = compareIgnoringAuto(resultMinZoom, compareIgnoringAuto(resultMaxZoom, resultZoom, min), max);
     94 
     95     float extendZoom = compareIgnoringAuto(resultZoom, resultMaxZoom, min);
     96 
     97     // 3. Resolve non-"auto" lengths to pixel lengths.
     98     if (extendZoom == ViewportDescription::ValueAuto) {
     99         if (resultMaxWidth == ViewportDescription::ValueExtendToZoom)
    100             resultMaxWidth = ViewportDescription::ValueAuto;
    101 
    102         if (resultMaxHeight == ViewportDescription::ValueExtendToZoom)
    103             resultMaxHeight = ViewportDescription::ValueAuto;
    104 
    105         if (resultMinWidth == ViewportDescription::ValueExtendToZoom)
    106             resultMinWidth = resultMaxWidth;
    107 
    108         if (resultMinHeight == ViewportDescription::ValueExtendToZoom)
    109             resultMinHeight = resultMaxHeight;
    110     } else {
    111         float extendWidth = initialViewportSize.width() / extendZoom;
    112         float extendHeight = initialViewportSize.height() / extendZoom;
    113 
    114         if (resultMaxWidth == ViewportDescription::ValueExtendToZoom)
    115             resultMaxWidth = extendWidth;
    116 
    117         if (resultMaxHeight == ViewportDescription::ValueExtendToZoom)
    118             resultMaxHeight = extendHeight;
    119 
    120         if (resultMinWidth == ViewportDescription::ValueExtendToZoom)
    121             resultMinWidth = compareIgnoringAuto(extendWidth, resultMaxWidth, max);
    122 
    123         if (resultMinHeight == ViewportDescription::ValueExtendToZoom)
    124             resultMinHeight = compareIgnoringAuto(extendHeight, resultMaxHeight, max);
    125     }
    126 
    127     // 4. Resolve initial width from min/max descriptors.
    128     if (resultMinWidth != ViewportDescription::ValueAuto || resultMaxWidth != ViewportDescription::ValueAuto)
    129         resultWidth = compareIgnoringAuto(resultMinWidth, compareIgnoringAuto(resultMaxWidth, initialViewportSize.width(), min), max);
    130 
    131     // 5. Resolve initial height from min/max descriptors.
    132     if (resultMinHeight != ViewportDescription::ValueAuto || resultMaxHeight != ViewportDescription::ValueAuto)
    133         resultHeight = compareIgnoringAuto(resultMinHeight, compareIgnoringAuto(resultMaxHeight, initialViewportSize.height(), min), max);
    134 
    135     // 6-7. Resolve width value.
    136     if (resultWidth == ViewportDescription::ValueAuto) {
    137         if (resultHeight == ViewportDescription::ValueAuto || !initialViewportSize.height())
    138             resultWidth = initialViewportSize.width();
    139         else
    140             resultWidth = resultHeight * (initialViewportSize.width() / initialViewportSize.height());
    141     }
    142 
    143     // 8. Resolve height value.
    144     if (resultHeight == ViewportDescription::ValueAuto) {
    145         if (!initialViewportSize.width())
    146             resultHeight = initialViewportSize.height();
    147         else
    148             resultHeight = resultWidth * initialViewportSize.height() / initialViewportSize.width();
    149     }
    150 
    151     // Resolve initial-scale value.
    152     if (resultZoom == ViewportDescription::ValueAuto) {
    153         if (resultWidth != ViewportDescription::ValueAuto && resultWidth > 0)
    154             resultZoom = initialViewportSize.width() / resultWidth;
    155         if (resultHeight != ViewportDescription::ValueAuto && resultHeight > 0) {
    156             // if 'auto', the initial-scale will be negative here and thus ignored.
    157             resultZoom = max<float>(resultZoom, initialViewportSize.height() / resultHeight);
    158         }
    159     }
    160 
    161     // If user-scalable = no, lock the min/max scale to the computed initial
    162     // scale.
    163     if (!resultUserZoom)
    164         resultMinZoom = resultMaxZoom = resultZoom;
    165 
    166     // Only set initialScale to a value if it was explicitly set.
    167     if (zoom == ViewportDescription::ValueAuto)
    168         resultZoom = ViewportDescription::ValueAuto;
    169 
    170     PageScaleConstraints result;
    171     result.minimumScale = resultMinZoom;
    172     result.maximumScale = resultMaxZoom;
    173     result.initialScale = resultZoom;
    174     result.layoutSize.setWidth(resultWidth);
    175     result.layoutSize.setHeight(resultHeight);
    176     return result;
    177 }
    178 
    179 } // namespace WebCore
    180