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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 "web/PageScaleConstraintsSet.h"
     33 
     34 #include "platform/Length.h"
     35 #include "wtf/Assertions.h"
     36 
     37 namespace blink {
     38 
     39 static const float defaultMinimumScale = 0.25f;
     40 static const float defaultMaximumScale = 5.0f;
     41 
     42 PageScaleConstraintsSet::PageScaleConstraintsSet()
     43     : m_finalConstraints(1, 1, 1)
     44     , m_lastContentsWidth(0)
     45     , m_needsReset(false)
     46     , m_constraintsDirty(false)
     47 {
     48 }
     49 
     50 PageScaleConstraints PageScaleConstraintsSet::defaultConstraints() const
     51 {
     52     return PageScaleConstraints(-1, defaultMinimumScale, defaultMaximumScale);
     53 }
     54 
     55 void PageScaleConstraintsSet::updatePageDefinedConstraints(const ViewportDescription& description, Length legacyFallbackWidth)
     56 {
     57     m_pageDefinedConstraints = description.resolve(m_viewSize, legacyFallbackWidth);
     58 
     59     m_constraintsDirty = true;
     60 }
     61 
     62 void PageScaleConstraintsSet::setUserAgentConstraints(const PageScaleConstraints& userAgentConstraints)
     63 {
     64     m_userAgentConstraints = userAgentConstraints;
     65     m_constraintsDirty = true;
     66 }
     67 
     68 PageScaleConstraints PageScaleConstraintsSet::computeConstraintsStack() const
     69 {
     70     PageScaleConstraints constraints = defaultConstraints();
     71     constraints.overrideWith(m_pageDefinedConstraints);
     72     constraints.overrideWith(m_userAgentConstraints);
     73     return constraints;
     74 }
     75 
     76 void PageScaleConstraintsSet::computeFinalConstraints()
     77 {
     78     m_finalConstraints = computeConstraintsStack();
     79 
     80     m_constraintsDirty = false;
     81 }
     82 
     83 void PageScaleConstraintsSet::adjustFinalConstraintsToContentsSize(IntSize contentsSize, int nonOverlayScrollbarWidth)
     84 {
     85     m_finalConstraints.fitToContentsWidth(contentsSize.width(), m_viewSize.width() - nonOverlayScrollbarWidth);
     86 }
     87 
     88 void PageScaleConstraintsSet::setNeedsReset(bool needsReset)
     89 {
     90     m_needsReset = needsReset;
     91     if (needsReset)
     92         m_constraintsDirty = true;
     93 }
     94 
     95 void PageScaleConstraintsSet::didChangeContentsSize(IntSize contentsSize, float pageScaleFactor)
     96 {
     97     // If a large fixed-width element expanded the size of the document late in
     98     // loading and our initial scale is not set (or set to be less than the last
     99     // minimum scale), reset the page scale factor to the new initial scale.
    100     if (contentsSize.width() > m_lastContentsWidth
    101         && pageScaleFactor == finalConstraints().minimumScale
    102         && computeConstraintsStack().initialScale < finalConstraints().minimumScale)
    103         setNeedsReset(true);
    104 
    105     m_constraintsDirty = true;
    106     m_lastContentsWidth = contentsSize.width();
    107 }
    108 
    109 static float computeDeprecatedTargetDensityDPIFactor(const ViewportDescription& description, float deviceScaleFactor)
    110 {
    111     if (description.deprecatedTargetDensityDPI == ViewportDescription::ValueDeviceDPI)
    112         return 1.0f / deviceScaleFactor;
    113 
    114     float targetDPI = -1.0f;
    115     if (description.deprecatedTargetDensityDPI == ViewportDescription::ValueLowDPI)
    116         targetDPI = 120.0f;
    117     else if (description.deprecatedTargetDensityDPI == ViewportDescription::ValueMediumDPI)
    118         targetDPI = 160.0f;
    119     else if (description.deprecatedTargetDensityDPI == ViewportDescription::ValueHighDPI)
    120         targetDPI = 240.0f;
    121     else if (description.deprecatedTargetDensityDPI != ViewportDescription::ValueAuto)
    122         targetDPI = description.deprecatedTargetDensityDPI;
    123     return targetDPI > 0 ? 160.0f / targetDPI : 1.0f;
    124 }
    125 
    126 static float getLayoutWidthForNonWideViewport(const FloatSize& deviceSize, float initialScale)
    127 {
    128     return initialScale == -1 ? deviceSize.width() : deviceSize.width() / initialScale;
    129 }
    130 
    131 static float computeHeightByAspectRatio(float width, const FloatSize& deviceSize)
    132 {
    133     return width * (deviceSize.height() / deviceSize.width());
    134 }
    135 
    136 void PageScaleConstraintsSet::didChangeViewSize(const IntSize& size)
    137 {
    138     if (m_viewSize == size)
    139         return;
    140 
    141     m_viewSize = size;
    142     m_constraintsDirty = true;
    143 }
    144 
    145 IntSize PageScaleConstraintsSet::mainFrameSize(const IntSize& contentsSize) const
    146 {
    147     // If there's no explicit minimum scale factor set, size the frame so that its width == content width
    148     // so there's no horizontal scrolling at the minimum scale.
    149     if (m_pageDefinedConstraints.minimumScale < finalConstraints().minimumScale
    150         && m_userAgentConstraints.minimumScale < finalConstraints().minimumScale
    151         && contentsSize.width()
    152         && m_viewSize.width())
    153         return IntSize(contentsSize.width(), computeHeightByAspectRatio(contentsSize.width(), m_viewSize));
    154 
    155     // If there is a minimum scale (or there's no content size yet), the frame size should match the viewport
    156     // size at minimum scale, since the viewport must always be contained by the frame.
    157     IntSize frameSize(m_viewSize);
    158     frameSize.scale(1 / finalConstraints().minimumScale);
    159     return frameSize;
    160 }
    161 
    162 void PageScaleConstraintsSet::adjustForAndroidWebViewQuirks(const ViewportDescription& description, int layoutFallbackWidth, float deviceScaleFactor, bool supportTargetDensityDPI, bool wideViewportQuirkEnabled, bool useWideViewport, bool loadWithOverviewMode, bool nonUserScalableQuirkEnabled)
    163 {
    164     if (!supportTargetDensityDPI && !wideViewportQuirkEnabled && loadWithOverviewMode && !nonUserScalableQuirkEnabled)
    165         return;
    166 
    167     const float oldInitialScale = m_pageDefinedConstraints.initialScale;
    168     if (!loadWithOverviewMode) {
    169         bool resetInitialScale = false;
    170         if (description.zoom == -1) {
    171             if (description.maxWidth.isAuto() || description.maxWidth.type() == ExtendToZoom)
    172                 resetInitialScale = true;
    173             if (useWideViewport || description.maxWidth.type() == DeviceWidth)
    174                 resetInitialScale = true;
    175         }
    176         if (resetInitialScale)
    177             m_pageDefinedConstraints.initialScale = 1.0f;
    178     }
    179 
    180     float adjustedLayoutSizeWidth = m_pageDefinedConstraints.layoutSize.width();
    181     float adjustedLayoutSizeHeight = m_pageDefinedConstraints.layoutSize.height();
    182     float targetDensityDPIFactor = 1.0f;
    183 
    184     if (supportTargetDensityDPI) {
    185         targetDensityDPIFactor = computeDeprecatedTargetDensityDPIFactor(description, deviceScaleFactor);
    186         if (m_pageDefinedConstraints.initialScale != -1)
    187             m_pageDefinedConstraints.initialScale *= targetDensityDPIFactor;
    188         if (m_pageDefinedConstraints.minimumScale != -1)
    189             m_pageDefinedConstraints.minimumScale *= targetDensityDPIFactor;
    190         if (m_pageDefinedConstraints.maximumScale != -1)
    191             m_pageDefinedConstraints.maximumScale *= targetDensityDPIFactor;
    192         if (wideViewportQuirkEnabled && (!useWideViewport || description.maxWidth.type() == DeviceWidth)) {
    193             adjustedLayoutSizeWidth /= targetDensityDPIFactor;
    194             adjustedLayoutSizeHeight /= targetDensityDPIFactor;
    195         }
    196     }
    197 
    198     if (wideViewportQuirkEnabled) {
    199         if (useWideViewport && (description.maxWidth.isAuto() || description.maxWidth.type() == ExtendToZoom) && description.zoom != 1.0f) {
    200             adjustedLayoutSizeWidth = layoutFallbackWidth;
    201             adjustedLayoutSizeHeight = computeHeightByAspectRatio(adjustedLayoutSizeWidth, m_viewSize);
    202         } else if (!useWideViewport) {
    203             const float nonWideScale = description.zoom < 1 && description.maxWidth.type() != DeviceWidth && description.maxWidth.type() != DeviceHeight ? -1 : oldInitialScale;
    204             adjustedLayoutSizeWidth = getLayoutWidthForNonWideViewport(m_viewSize, nonWideScale) / targetDensityDPIFactor;
    205             float newInitialScale = targetDensityDPIFactor;
    206             if (m_userAgentConstraints.initialScale != -1 && (description.maxWidth.type() == DeviceWidth || ((description.maxWidth.isAuto() || description.maxWidth.type() == ExtendToZoom) && description.zoom == -1))) {
    207                 adjustedLayoutSizeWidth /= m_userAgentConstraints.initialScale;
    208                 newInitialScale = m_userAgentConstraints.initialScale;
    209             }
    210             adjustedLayoutSizeHeight = computeHeightByAspectRatio(adjustedLayoutSizeWidth, m_viewSize);
    211             if (description.zoom < 1) {
    212                 m_pageDefinedConstraints.initialScale = newInitialScale;
    213                 if (m_pageDefinedConstraints.minimumScale != -1)
    214                     m_pageDefinedConstraints.minimumScale = std::min<float>(m_pageDefinedConstraints.minimumScale, m_pageDefinedConstraints.initialScale);
    215                 if (m_pageDefinedConstraints.maximumScale != -1)
    216                     m_pageDefinedConstraints.maximumScale = std::max<float>(m_pageDefinedConstraints.maximumScale, m_pageDefinedConstraints.initialScale);
    217             }
    218         }
    219     }
    220 
    221     if (nonUserScalableQuirkEnabled && !description.userZoom) {
    222         m_pageDefinedConstraints.initialScale = targetDensityDPIFactor;
    223         m_pageDefinedConstraints.minimumScale = m_pageDefinedConstraints.initialScale;
    224         m_pageDefinedConstraints.maximumScale = m_pageDefinedConstraints.initialScale;
    225         if (description.maxWidth.isAuto() || description.maxWidth.type() == ExtendToZoom || description.maxWidth.type() == DeviceWidth) {
    226             adjustedLayoutSizeWidth = m_viewSize.width() / targetDensityDPIFactor;
    227             adjustedLayoutSizeHeight = computeHeightByAspectRatio(adjustedLayoutSizeWidth, m_viewSize);
    228         }
    229     }
    230 
    231     m_pageDefinedConstraints.layoutSize.setWidth(adjustedLayoutSizeWidth);
    232     m_pageDefinedConstraints.layoutSize.setHeight(adjustedLayoutSizeHeight);
    233 }
    234 
    235 } // namespace blink
    236