Source/WebCore/platform/graphics/cg/PDFDocumentImage.cpp

/*
 * Copyright (C) 2004, 2005, 2006, 2013 Apple Inc.  All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
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#define _USE_MATH_DEFINES 1
#include "config.h"
#include "PDFDocumentImage.h"

#if USE(CG)

#if PLATFORM(IOS)
#include <CoreGraphics/CoreGraphics.h>
#include <ImageIO/ImageIO.h>
#endif

#include "GraphicsContext.h"
#include "ImageBuffer.h"
#include "ImageObserver.h"
#include "IntRect.h"
#include "Length.h"
#include "SharedBuffer.h"
#include <CoreGraphics/CGContext.h>
#include <CoreGraphics/CGPDFDocument.h>
#include <wtf/MathExtras.h>
#include <wtf/RetainPtr.h>

#if !PLATFORM(COCOA)
#include "ImageSourceCG.h"
#endif

namespace WebCore {

PDFDocumentImage::PDFDocumentImage(ImageObserver* observer)
    : Image(observer)
    , m_cachedBytes(0)
    , m_rotationDegrees(0)
    , m_hasPage(false)
{
}

PDFDocumentImage::~PDFDocumentImage()
{
}

String PDFDocumentImage::filenameExtension() const
{
    return "pdf";
}

FloatSize PDFDocumentImage::size() const
{
    FloatSize expandedCropBoxSize = FloatSize(expandedIntSize(m_cropBox.size()));

    if (m_rotationDegrees == 90 || m_rotationDegrees == 270)
        return expandedCropBoxSize.transposedSize();
    return expandedCropBoxSize;
}

void PDFDocumentImage::computeIntrinsicDimensions(Length& intrinsicWidth, Length& intrinsicHeight, FloatSize& intrinsicRatio)
{
    // FIXME: If we want size negotiation with PDF documents as-image, this is the place to implement it (https://bugs.webkit.org/show_bug.cgi?id=12095).
    Image::computeIntrinsicDimensions(intrinsicWidth, intrinsicHeight, intrinsicRatio);
    intrinsicRatio = FloatSize();
}

bool PDFDocumentImage::dataChanged(bool allDataReceived)
{
    ASSERT(!m_document);
    if (allDataReceived && !m_document) {
        createPDFDocument();

        if (pageCount()) {
            m_hasPage = true;
            computeBoundsForCurrentPage();
        }
    }
    return m_document; // Return true if size is available.
}

bool PDFDocumentImage::cacheParametersMatch(GraphicsContext& context, const FloatRect& dstRect, const FloatRect& srcRect) const
{
    if (dstRect.size() != m_cachedDestinationSize)
        return false;

    if (srcRect != m_cachedSourceRect)
        return false;

    AffineTransform::DecomposedType decomposedTransform;
    context.getCTM(GraphicsContext::DefinitelyIncludeDeviceScale).decompose(decomposedTransform);

    AffineTransform::DecomposedType cachedDecomposedTransform;
    m_cachedTransform.decompose(cachedDecomposedTransform);
    if (decomposedTransform.scaleX != cachedDecomposedTransform.scaleX || decomposedTransform.scaleY != cachedDecomposedTransform.scaleY)
        return false;

    return true;
}

static void transformContextForPainting(GraphicsContext& context, const FloatRect& dstRect, const FloatRect& srcRect)
{
    float hScale = dstRect.width() / srcRect.width();
    float vScale = dstRect.height() / srcRect.height();

    if (hScale != vScale) {
        float minimumScale = std::max((dstRect.width() - 0.5) / srcRect.width(), (dstRect.height() - 0.5) / srcRect.height());
        float maximumScale = std::min((dstRect.width() + 0.5) / srcRect.width(), (dstRect.height() + 0.5) / srcRect.height());

        // If the difference between the two scales is due to integer rounding of image sizes,
        // use the smaller of the two original scales to ensure that the image fits inside the
        // space originally allocated for it.
        if (minimumScale <= maximumScale) {
            hScale = std::min(hScale, vScale);
            vScale = hScale;
        }
    }

    context.translate(srcRect.x() * hScale, srcRect.y() * vScale);
    context.scale(FloatSize(hScale, -vScale));
    context.translate(0, -srcRect.height());
}

void PDFDocumentImage::updateCachedImageIfNeeded(GraphicsContext& context, const FloatRect& dstRect, const FloatRect& srcRect)
{
#if PLATFORM(IOS)
    // On iOS, some clients use low-quality image interpolation always, which throws off this optimization,
    // as we never get the subsequent high-quality paint. Since live resize is rare on iOS, disable the optimization.
    // FIXME (136593): It's also possible to do the wrong thing here if CSS specifies low-quality interpolation via the "image-rendering"
    // property, on all platforms. We should only do this optimization if we're actually in a ImageQualityController live resize,
    // and are guaranteed to do a high-quality paint later.
    bool repaintIfNecessary = true;
#else
    // If we have an existing image, reuse it if we're doing a low-quality paint, even if cache parameters don't match;
    // we'll rerender when we do the subsequent high-quality paint.
    InterpolationQuality interpolationQuality = context.imageInterpolationQuality();
    bool repaintIfNecessary = interpolationQuality != InterpolationNone && interpolationQuality != InterpolationLow;
#endif

    if (!m_cachedImageBuffer || (!cacheParametersMatch(context, dstRect, srcRect) && repaintIfNecessary)) {
        m_cachedImageBuffer = context.createCompatibleBuffer(FloatRect(enclosingIntRect(dstRect)).size());
        if (!m_cachedImageBuffer)
            return;
        GraphicsContext& bufferContext = m_cachedImageBuffer->context();

        transformContextForPainting(bufferContext, dstRect, srcRect);
        drawPDFPage(bufferContext);

        m_cachedTransform = context.getCTM(GraphicsContext::DefinitelyIncludeDeviceScale);
        m_cachedDestinationSize = dstRect.size();
        m_cachedSourceRect = srcRect;

        IntSize internalSize = m_cachedImageBuffer->internalSize();
        size_t oldCachedBytes = m_cachedBytes;
        m_cachedBytes = internalSize.width() * internalSize.height() * 4;

        if (imageObserver())
            imageObserver()->decodedSizeChanged(this, safeCast<int>(m_cachedBytes) - safeCast<int>(oldCachedBytes));
    }
}

void PDFDocumentImage::draw(GraphicsContext& context, const FloatRect& dstRect, const FloatRect& srcRect, ColorSpace, CompositeOperator op, BlendMode, ImageOrientationDescription)
{
    if (!m_document || !m_hasPage)
        return;

    updateCachedImageIfNeeded(context, dstRect, srcRect);

    {
        GraphicsContextStateSaver stateSaver(context);
        context.setCompositeOperation(op);

        if (m_cachedImageBuffer)
            context.drawImageBuffer(*m_cachedImageBuffer, ColorSpaceDeviceRGB, dstRect);
        else {
            transformContextForPainting(context, dstRect, srcRect);
            drawPDFPage(context);
        }
    }

    if (imageObserver())
        imageObserver()->didDraw(this);
}

void PDFDocumentImage::destroyDecodedData(bool)
{
    m_cachedImageBuffer = nullptr;

    if (imageObserver())
        imageObserver()->decodedSizeChanged(this, -safeCast<int>(m_cachedBytes));

    m_cachedBytes = 0;
}

#if !USE(PDFKIT_FOR_PDFDOCUMENTIMAGE)

void PDFDocumentImage::createPDFDocument()
{
    RetainPtr<CGDataProviderRef> dataProvider = adoptCF(CGDataProviderCreateWithCFData(data()->createCFData().get()));
    m_document = adoptCF(CGPDFDocumentCreateWithProvider(dataProvider.get()));
}

void PDFDocumentImage::computeBoundsForCurrentPage()
{
    ASSERT(pageCount() > 0);
    CGPDFPageRef cgPage = CGPDFDocumentGetPage(m_document.get(), 1);
    CGRect mediaBox = CGPDFPageGetBoxRect(cgPage, kCGPDFMediaBox);

    // Get crop box (not always there). If not, use media box.
    CGRect r = CGPDFPageGetBoxRect(cgPage, kCGPDFCropBox);
    if (!CGRectIsEmpty(r))
        m_cropBox = r;
    else
        m_cropBox = mediaBox;

    m_rotationDegrees = CGPDFPageGetRotationAngle(cgPage);
}

unsigned PDFDocumentImage::pageCount() const
{
    return CGPDFDocumentGetNumberOfPages(m_document.get());
}

static void applyRotationForPainting(GraphicsContext& context, FloatSize size, int rotationDegrees)
{
    if (rotationDegrees == 90)
        context.translate(0, size.height());
    else if (rotationDegrees == 180)
        context.translate(size.width(), size.height());
    else if (rotationDegrees == 270)
        context.translate(size.width(), 0);

    context.rotate(-deg2rad(static_cast<float>(rotationDegrees)));
}

void PDFDocumentImage::drawPDFPage(GraphicsContext& context)
{
    applyRotationForPainting(context, size(), m_rotationDegrees);

    context.translate(-m_cropBox.x(), -m_cropBox.y());

    // CGPDF pages are indexed from 1.
    CGContextDrawPDFPage(context.platformContext(), CGPDFDocumentGetPage(m_document.get(), 1));
}

#endif // !USE(PDFKIT_FOR_PDFDOCUMENTIMAGE)

}

#endif // USE(CG)