path: root/WebCore/rendering/RenderImage.cpp

/*
 * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
 *           (C) 1999 Antti Koivisto (koivisto@kde.org)
 *           (C) 2000 Dirk Mueller (mueller@kde.org)
 *           (C) 2006 Allan Sandfeld Jensen (kde@carewolf.com)
 *           (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
 * Copyright (C) 2003, 2004, 2005, 2006, 2008, 2009, 2010 Apple Inc. All rights reserved.
 * Copyright (C) 2010 Google Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#include "config.h"
#include "RenderImage.h"

#include "Frame.h"
#include "GraphicsContext.h"
#include "HTMLAreaElement.h"
#include "HTMLCollection.h"
#include "HTMLImageElement.h"
#include "HTMLInputElement.h"
#include "HTMLMapElement.h"
#include "HTMLNames.h"
#include "HitTestResult.h"
#include "Page.h"
#include "RenderLayer.h"
#include "RenderTheme.h"
#include "RenderView.h"
#include "SelectionController.h"
#include <wtf/CurrentTime.h>
#include <wtf/UnusedParam.h>

#ifdef ANDROID_LAYOUT
#include "Settings.h"
#endif

#if ENABLE(WML)
#include "WMLImageElement.h"
#include "WMLNames.h"
#endif

using namespace std;

namespace WebCore {

using namespace HTMLNames;

RenderImage::RenderImage(Node* node)
    : RenderReplaced(node, IntSize(0, 0))
{
    updateAltText();

    view()->frameView()->setIsVisuallyNonEmpty();
}

RenderImage::~RenderImage()
{
    ASSERT(m_imageResource);
    m_imageResource->shutdown();
}

void RenderImage::setImageResource(PassOwnPtr<RenderImageResource> imageResource)
{
    ASSERT(!m_imageResource);
    m_imageResource = imageResource;
    m_imageResource->initialize(this);
}

// If we'll be displaying either alt text or an image, add some padding.
static const unsigned short paddingWidth = 4;
static const unsigned short paddingHeight = 4;

// Alt text is restricted to this maximum size, in pixels.  These are
// signed integers because they are compared with other signed values.
static const int maxAltTextWidth = 1024;
static const int maxAltTextHeight = 256;

// Sets the image height and width to fit the alt text.  Returns true if the
// image size changed.
bool RenderImage::setImageSizeForAltText(CachedImage* newImage /* = 0 */)
{
    int imageWidth = 0;
    int imageHeight = 0;
  
    // If we'll be displaying either text or an image, add a little padding.
    if (!m_altText.isEmpty() || newImage) {
        imageWidth = paddingWidth;
        imageHeight = paddingHeight;
    }
  
    if (newImage && newImage->image()) {
        // imageSize() returns 0 for the error image.  We need the true size of the
        // error image, so we have to get it by grabbing image() directly.
        imageWidth += newImage->image()->width() * style()->effectiveZoom();
        imageHeight += newImage->image()->height() * style()->effectiveZoom();
    }
  
    // we have an alt and the user meant it (its not a text we invented)
    if (!m_altText.isEmpty()) {
        const Font& font = style()->font();
        imageWidth = max(imageWidth, min(font.width(TextRun(m_altText.characters(), m_altText.length())), maxAltTextWidth));
        imageHeight = max(imageHeight, min(font.height(), maxAltTextHeight));
    }
  
    IntSize imageSize = IntSize(imageWidth, imageHeight);
    if (imageSize == intrinsicSize())
        return false;

    setIntrinsicSize(imageSize);
    return true;
}

void RenderImage::imageChanged(WrappedImagePtr newImage, const IntRect* rect)
{
    if (documentBeingDestroyed())
        return;

    if (hasBoxDecorations() || hasMask())
        RenderReplaced::imageChanged(newImage, rect);

    if (newImage != m_imageResource->imagePtr() || !newImage)
        return;

    bool imageSizeChanged = false;

    // Set image dimensions, taking into account the size of the alt text.
    if (m_imageResource->errorOccurred())
        imageSizeChanged = setImageSizeForAltText(m_imageResource->cachedImage());

    bool shouldRepaint = true;

    // Image dimensions have been changed, see what needs to be done
    if (m_imageResource->imageSize(style()->effectiveZoom()) != intrinsicSize() || imageSizeChanged) {
        if (!m_imageResource->errorOccurred())
            setIntrinsicSize(m_imageResource->imageSize(style()->effectiveZoom()));

        // In the case of generated image content using :before/:after, we might not be in the
        // render tree yet.  In that case, we don't need to worry about check for layout, since we'll get a
        // layout when we get added in to the render tree hierarchy later.
        if (containingBlock()) {
            // lets see if we need to relayout at all..
            int oldwidth = width();
            int oldheight = height();
            if (!prefWidthsDirty())
                setPrefWidthsDirty(true);
            calcWidth();
            calcHeight();

            if (imageSizeChanged || width() != oldwidth || height() != oldheight) {
                shouldRepaint = false;
                if (!selfNeedsLayout())
                    setNeedsLayout(true);
            }

            setWidth(oldwidth);
            setHeight(oldheight);
        }
    }

    if (shouldRepaint) {
        IntRect repaintRect;
        if (rect) {
            // The image changed rect is in source image coordinates (pre-zooming),
            // so map from the bounds of the image to the contentsBox.
            repaintRect = enclosingIntRect(mapRect(*rect, FloatRect(FloatPoint(), m_imageResource->imageSize(1.0f)), contentBoxRect()));
            // Guard against too-large changed rects.
            repaintRect.intersect(contentBoxRect());
        } else
            repaintRect = contentBoxRect();
        
        repaintRectangle(repaintRect);

#if USE(ACCELERATED_COMPOSITING)
        if (hasLayer()) {
            // Tell any potential compositing layers that the image needs updating.
            layer()->rendererContentChanged();
        }
#endif
    }
}

void RenderImage::notifyFinished(CachedResource* newImage)
{
    if (documentBeingDestroyed())
        return;

#if USE(ACCELERATED_COMPOSITING)
    if (newImage == m_imageResource->cachedImage() && hasLayer()) {
        // tell any potential compositing layers
        // that the image is done and they can reference it directly.
        layer()->rendererContentChanged();
    }
#else
    UNUSED_PARAM(newImage);
#endif
}

void RenderImage::paintReplaced(PaintInfo& paintInfo, int tx, int ty)
{
    int cWidth = contentWidth();
    int cHeight = contentHeight();
    int leftBorder = borderLeft();
    int topBorder = borderTop();
    int leftPad = paddingLeft();
    int topPad = paddingTop();

    GraphicsContext* context = paintInfo.context;

    if (!m_imageResource->hasImage() || m_imageResource->errorOccurred()) {
        if (paintInfo.phase == PaintPhaseSelection)
            return;

        if (cWidth > 2 && cHeight > 2) {
            // Draw an outline rect where the image should be.
#ifdef ANDROID_FIX // see http://b/issue?id=2052757
            context->save();
#endif
            context->setStrokeStyle(SolidStroke);
            context->setStrokeColor(Color::lightGray, style()->colorSpace());
            context->setFillColor(Color::transparent, style()->colorSpace());
            context->drawRect(IntRect(tx + leftBorder + leftPad, ty + topBorder + topPad, cWidth, cHeight));
#ifdef ANDROID_FIX // see http://b/issue?id=2052757
            context->restore();
#endif

            bool errorPictureDrawn = false;
            int imageX = 0;
            int imageY = 0;
            // When calculating the usable dimensions, exclude the pixels of
            // the ouline rect so the error image/alt text doesn't draw on it.
            int usableWidth = cWidth - 2;
            int usableHeight = cHeight - 2;

            Image* image = m_imageResource->image();

            if (m_imageResource->errorOccurred() && !image->isNull() && usableWidth >= image->width() && usableHeight >= image->height()) {
                // Center the error image, accounting for border and padding.
                int centerX = (usableWidth - image->width()) / 2;
                if (centerX < 0)
                    centerX = 0;
                int centerY = (usableHeight - image->height()) / 2;
                if (centerY < 0)
                    centerY = 0;
                imageX = leftBorder + leftPad + centerX + 1;
                imageY = topBorder + topPad + centerY + 1;
                context->drawImage(image, style()->colorSpace(), IntPoint(tx + imageX, ty + imageY));
                errorPictureDrawn = true;
            }

            if (!m_altText.isEmpty()) {
                String text = document()->displayStringModifiedByEncoding(m_altText);
                context->setFillColor(style()->visitedDependentColor(CSSPropertyColor), style()->colorSpace());
                int ax = tx + leftBorder + leftPad;
                int ay = ty + topBorder + topPad;
                const Font& font = style()->font();
                int ascent = font.ascent();

                // Only draw the alt text if it'll fit within the content box,
                // and only if it fits above the error image.
                TextRun textRun(text.characters(), text.length());
                int textWidth = font.width(textRun);
                if (errorPictureDrawn) {
                    if (usableWidth >= textWidth && font.height() <= imageY)
                        context->drawText(style()->font(), textRun, IntPoint(ax, ay + ascent));
                } else if (usableWidth >= textWidth && cHeight >= font.height())
                    context->drawText(style()->font(), textRun, IntPoint(ax, ay + ascent));
            }
        }
    } else if (m_imageResource->hasImage() && cWidth > 0 && cHeight > 0) {
        Image* img = m_imageResource->image(cWidth, cHeight);
        if (!img || img->isNull())
            return;

#if PLATFORM(MAC)
        if (style()->highlight() != nullAtom && !paintInfo.context->paintingDisabled())
            paintCustomHighlight(tx - x(), ty - y(), style()->highlight(), true);
#endif

        IntSize contentSize(cWidth, cHeight);
        IntRect rect(IntPoint(tx + leftBorder + leftPad, ty + topBorder + topPad), contentSize);
        paintIntoRect(context, rect);
    }
}

void RenderImage::paint(PaintInfo& paintInfo, int tx, int ty)
{
    RenderReplaced::paint(paintInfo, tx, ty);
    
    if (paintInfo.phase == PaintPhaseOutline)
        paintFocusRings(paintInfo, style());
}
    
void RenderImage::paintFocusRings(PaintInfo& paintInfo, const RenderStyle* style)
{
    // Don't draw focus rings if printing.
    if (document()->printing() || !frame()->selection()->isFocusedAndActive())
        return;
    
    if (paintInfo.context->paintingDisabled() && !paintInfo.context->updatingControlTints())
        return;

    HTMLMapElement* mapElement = imageMap();
    if (!mapElement)
        return;
    
    Document* document = mapElement->document();
    if (!document)
        return;
    
    Node* focusedNode = document->focusedNode();
    if (!focusedNode)
        return;
    
    RefPtr<HTMLCollection> areas = mapElement->areas();
    unsigned numAreas = areas->length();
    
    // FIXME: Clip the paths to the image bounding box.
    for (unsigned k = 0; k < numAreas; ++k) {
        HTMLAreaElement* areaElement = static_cast<HTMLAreaElement*>(areas->item(k));
        if (focusedNode != areaElement)
            continue;
        
        Vector<Path> focusRingPaths;
        focusRingPaths.append(areaElement->getPath(this));
        paintInfo.context->drawFocusRing(focusRingPaths, style->outlineWidth(), style->outlineOffset(), style->visitedDependentColor(CSSPropertyOutlineColor));
        break;
    }
}
    
void RenderImage::paintIntoRect(GraphicsContext* context, const IntRect& rect)
{
    if (!m_imageResource->hasImage() || m_imageResource->errorOccurred() || rect.width() <= 0 || rect.height() <= 0)
        return;

    Image* img = m_imageResource->image(rect.width(), rect.height());
    if (!img || img->isNull())
        return;

    HTMLImageElement* imageElt = (node() && node()->hasTagName(imgTag)) ? static_cast<HTMLImageElement*>(node()) : 0;
    CompositeOperator compositeOperator = imageElt ? imageElt->compositeOperator() : CompositeSourceOver;
    bool useLowQualityScaling = shouldPaintAtLowQuality(context, m_imageResource->image(), rect.size());
    context->drawImage(m_imageResource->image(rect.width(), rect.height()), style()->colorSpace(), rect, compositeOperator, useLowQualityScaling);
}

int RenderImage::minimumReplacedHeight() const
{
    return m_imageResource->errorOccurred() ? intrinsicSize().height() : 0;
}

HTMLMapElement* RenderImage::imageMap() const
{
    HTMLImageElement* i = node() && node()->hasTagName(imgTag) ? static_cast<HTMLImageElement*>(node()) : 0;
    return i ? i->document()->getImageMap(i->fastGetAttribute(usemapAttr)) : 0;
}

bool RenderImage::nodeAtPoint(const HitTestRequest& request, HitTestResult& result, int x, int y, int tx, int ty, HitTestAction hitTestAction)
{
    HitTestResult tempResult(result.point(), result.padding());
    bool inside = RenderReplaced::nodeAtPoint(request, tempResult, x, y, tx, ty, hitTestAction);

    if (tempResult.innerNode() && node()) {
        if (HTMLMapElement* map = imageMap()) {
            IntRect contentBox = contentBoxRect();
            float zoom = style()->effectiveZoom();
            int mapX = lroundf((x - tx - this->x() - contentBox.x()) / zoom);
            int mapY = lroundf((y - ty - this->y() - contentBox.y()) / zoom);
            if (map->mapMouseEvent(mapX, mapY, contentBox.size(), tempResult))
                tempResult.setInnerNonSharedNode(node());
        }
    }

    if (!inside && result.isRectBasedTest())
        result.append(tempResult);
    if (inside)
        result = tempResult;
    return inside;
}

void RenderImage::updateAltText()
{
    if (!node())
        return;

    if (node()->hasTagName(inputTag))
        m_altText = static_cast<HTMLInputElement*>(node())->altText();
    else if (node()->hasTagName(imgTag))
        m_altText = static_cast<HTMLImageElement*>(node())->altText();
#if ENABLE(WML)
    else if (node()->hasTagName(WMLNames::imgTag))
        m_altText = static_cast<WMLImageElement*>(node())->altText();
#endif
}

bool RenderImage::isWidthSpecified() const
{
    switch (style()->width().type()) {
        case Fixed:
        case Percent:
            return true;
        case Auto:
        case Relative: // FIXME: Shouldn't this case return true?
        case Static:
        case Intrinsic:
        case MinIntrinsic:
            return false;
    }
    ASSERT(false);
    return false;
}

bool RenderImage::isHeightSpecified() const
{
    switch (style()->height().type()) {
        case Fixed:
        case Percent:
            return true;
        case Auto:
        case Relative: // FIXME: Shouldn't this case return true?
        case Static:
        case Intrinsic:
        case MinIntrinsic:
            return false;
    }
    ASSERT(false);
    return false;
}

int RenderImage::calcReplacedWidth(bool includeMaxWidth) const
{
    if (m_imageResource->imageHasRelativeWidth())
        if (RenderObject* cb = isPositioned() ? container() : containingBlock()) {
            if (cb->isBox())
                m_imageResource->setImageContainerSize(IntSize(toRenderBox(cb)->availableWidth(), toRenderBox(cb)->availableHeight()));
        }

    int width;
    if (isWidthSpecified())
        width = calcReplacedWidthUsing(style()->width());
    else if (m_imageResource->usesImageContainerSize())
        width = m_imageResource->imageSize(style()->effectiveZoom()).width();
    else if (m_imageResource->imageHasRelativeWidth())
        width = 0; // If the image is relatively-sized, set the width to 0 until there is a set container size.
    else
        width = calcAspectRatioWidth();

    int minW = calcReplacedWidthUsing(style()->minWidth());
    int maxW = !includeMaxWidth || style()->maxWidth().isUndefined() ? width : calcReplacedWidthUsing(style()->maxWidth());

#ifdef ANDROID_LAYOUT
    width = max(minW, min(width, maxW));
    // in SSR mode, we will fit the image to its container width
    if (document()->settings()->layoutAlgorithm() == Settings::kLayoutSSR) {
        int cw = containingBlockWidthForContent();
        if (cw && width>cw)
            width = cw;
    }
    return width;
#else
    return max(minW, min(width, maxW));
#endif
}

int RenderImage::calcReplacedHeight() const
{
    int height;
    if (isHeightSpecified())
        height = calcReplacedHeightUsing(style()->height());
    else if (m_imageResource->usesImageContainerSize())
        height = m_imageResource->imageSize(style()->effectiveZoom()).height();
    else if (m_imageResource->imageHasRelativeHeight())
        height = 0; // If the image is relatively-sized, set the height to 0 until there is a set container size.
    else
        height = calcAspectRatioHeight();

    int minH = calcReplacedHeightUsing(style()->minHeight());
    int maxH = style()->maxHeight().isUndefined() ? height : calcReplacedHeightUsing(style()->maxHeight());

#ifdef ANDROID_LAYOUT
    height = max(minH, min(height, maxH));
    // in SSR mode, we will fit the image to its container width
    if (height && document()->settings()->layoutAlgorithm() == Settings::kLayoutSSR) {
        int width;
        if (isWidthSpecified())
            width = calcReplacedWidthUsing(style()->width());
        else
            width = calcAspectRatioWidth();
        int minW = calcReplacedWidthUsing(style()->minWidth());
        int maxW = style()->maxWidth().value() == undefinedLength ? width :
            calcReplacedWidthUsing(style()->maxWidth());
        width = max(minW, min(width, maxW));

        int cw = containingBlockWidthForContent();
        if (cw && width && width > cw)
            height = cw * height / width;   // preserve aspect ratio
    }
    return height;
#else
    return max(minH, min(height, maxH));
#endif
}

int RenderImage::calcAspectRatioWidth() const
{
    IntSize size = intrinsicSize();
    if (!size.height())
        return 0;
    if (!m_imageResource->hasImage() || m_imageResource->errorOccurred())
        return size.width(); // Don't bother scaling.
    return RenderBox::calcReplacedHeight() * size.width() / size.height();
}

int RenderImage::calcAspectRatioHeight() const
{
    IntSize size = intrinsicSize();
    if (!size.width())
        return 0;
    if (!m_imageResource->hasImage() || m_imageResource->errorOccurred())
        return size.height(); // Don't bother scaling.
    return RenderBox::calcReplacedWidth() * size.height() / size.width();
}

} // namespace WebCore