graphics/cairo/ImageBufferCairo.cpp

/*
 * Copyright (C) 2006 Nikolas Zimmermann <zimmermann (at) kde.org>
 * Copyright (C) 2007 Holger Hans Peter Freyther <zecke (at) selfish.org>
 * Copyright (C) 2008, 2009 Dirk Schulze <krit (at) webkit.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "ImageBuffer.h"

#include "Base64.h"
#include "BitmapImage.h"
#include "Color.h"
#include "GraphicsContext.h"
#include "ImageData.h"
#include "MIMETypeRegistry.h"
#include "Pattern.h"
#include "PlatformString.h"

#include <cairo.h>
#include <wtf/Vector.h>
#include <math.h>

using namespace std;

// Cairo doesn't provide a way to copy a cairo_surface_t.
// See http://lists.cairographics.org/archives/cairo/2007-June/010877.html
// Once cairo provides the way, use the function instead of this.
static inline cairo_surface_t* copySurface(cairo_surface_t* surface)
{
    cairo_format_t format = cairo_image_surface_get_format(surface);
    int width = cairo_image_surface_get_width(surface);
    int height = cairo_image_surface_get_height(surface);
    cairo_surface_t* newsurface = cairo_image_surface_create(format, width, height);

    cairo_t* cr = cairo_create(newsurface);
    cairo_set_source_surface(cr, surface, 0, 0);
    cairo_set_operator(cr, CAIRO_OPERATOR_SOURCE);
    cairo_paint(cr);
    cairo_destroy(cr);

    return newsurface;
}

namespace WebCore {

ImageBufferData::ImageBufferData(const IntSize& size)
    : m_surface(0)
{
}

ImageBuffer::ImageBuffer(const IntSize& size, ImageColorSpace imageColorSpace, bool& success)
    : m_data(size)
    , m_size(size)
{
    success = false;  // Make early return mean error.
    m_data.m_surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32,
                                                  size.width(),
                                                  size.height());
    if (cairo_surface_status(m_data.m_surface) != CAIRO_STATUS_SUCCESS)
        return;  // create will notice we didn't set m_initialized and fail.

    cairo_t* cr = cairo_create(m_data.m_surface);
    m_context.set(new GraphicsContext(cr));
    cairo_destroy(cr);  // The context is now owned by the GraphicsContext.
    success = true;
}

ImageBuffer::~ImageBuffer()
{
    cairo_surface_destroy(m_data.m_surface);
}

GraphicsContext* ImageBuffer::context() const
{
    return m_context.get();
}

Image* ImageBuffer::image() const
{
    if (!m_image) {
        // It's assumed that if image() is called, the actual rendering to the
        // GraphicsContext must be done.
        ASSERT(context());

        // This creates a COPY of the image and will cache that copy. This means
        // that if subsequent operations take place on the context, neither the
        // currently-returned image, nor the results of future image() calls,
        // will contain that operation.
        //
        // This seems silly, but is the way the CG port works: image() is
        // intended to be used only when rendering is "complete."
        cairo_surface_t* newsurface = copySurface(m_data.m_surface);

        // BitmapImage will release the passed in surface on destruction
        m_image = BitmapImage::create(newsurface);
    }
    return m_image.get();
}

void ImageBuffer::platformTransformColorSpace(const Vector<int>& lookUpTable)
{
    ASSERT(cairo_surface_get_type(m_data.m_surface) == CAIRO_SURFACE_TYPE_IMAGE);

    unsigned char* dataSrc = cairo_image_surface_get_data(m_data.m_surface);
    int stride = cairo_image_surface_get_stride(m_data.m_surface);
    for (int y = 0; y < m_size.height(); ++y) {
        unsigned* row = reinterpret_cast<unsigned*>(dataSrc + stride * y);
        for (int x = 0; x < m_size.width(); x++) {
            unsigned* pixel = row + x;
            Color pixelColor = colorFromPremultipliedARGB(*pixel);
            pixelColor = Color(lookUpTable[pixelColor.red()],
                               lookUpTable[pixelColor.green()],
                               lookUpTable[pixelColor.blue()],
                               pixelColor.alpha());
            *pixel = premultipliedARGBFromColor(pixelColor);
        }
    }
    cairo_surface_mark_dirty_rectangle (m_data.m_surface, 0, 0, m_size.width(), m_size.height());
}

template <Multiply multiplied>
PassRefPtr<ImageData> getImageData(const IntRect& rect, const ImageBufferData& data, const IntSize& size)
{
    ASSERT(cairo_surface_get_type(data.m_surface) == CAIRO_SURFACE_TYPE_IMAGE);

    PassRefPtr<ImageData> result = ImageData::create(rect.width(), rect.height());
    unsigned char* dataSrc = cairo_image_surface_get_data(data.m_surface);
    unsigned char* dataDst = result->data()->data()->data();

    if (rect.x() < 0 || rect.y() < 0 || (rect.x() + rect.width()) > size.width() || (rect.y() + rect.height()) > size.height())
        memset(dataDst, 0, result->data()->length());

    int originx = rect.x();
    int destx = 0;
    if (originx < 0) {
        destx = -originx;
        originx = 0;
    }
    int endx = rect.x() + rect.width();
    if (endx > size.width())
        endx = size.width();
    int numColumns = endx - originx;

    int originy = rect.y();
    int desty = 0;
    if (originy < 0) {
        desty = -originy;
        originy = 0;
    }
    int endy = rect.y() + rect.height();
    if (endy > size.height())
        endy = size.height();
    int numRows = endy - originy;

    int stride = cairo_image_surface_get_stride(data.m_surface);
    unsigned destBytesPerRow = 4 * rect.width();

    unsigned char* destRows = dataDst + desty * destBytesPerRow + destx * 4;
    for (int y = 0; y < numRows; ++y) {
        unsigned* row = reinterpret_cast<unsigned*>(dataSrc + stride * (y + originy));
        for (int x = 0; x < numColumns; x++) {
            int basex = x * 4;
            unsigned* pixel = row + x + originx;
            Color pixelColor;
            if (multiplied == Unmultiplied)
                pixelColor = colorFromPremultipliedARGB(*pixel);
            else
                pixelColor = Color(*pixel);
            destRows[basex]     = pixelColor.red();
            destRows[basex + 1] = pixelColor.green();
            destRows[basex + 2] = pixelColor.blue();
            destRows[basex + 3] = pixelColor.alpha();
        }
        destRows += destBytesPerRow;
    }

    return result;
}

PassRefPtr<ImageData> ImageBuffer::getUnmultipliedImageData(const IntRect& rect) const
{
    return getImageData<Unmultiplied>(rect, m_data, m_size);
}

PassRefPtr<ImageData> ImageBuffer::getPremultipliedImageData(const IntRect& rect) const
{
    return getImageData<Premultiplied>(rect, m_data, m_size);
}

template <Multiply multiplied>
void putImageData(ImageData*& source, const IntRect& sourceRect, const IntPoint& destPoint, ImageBufferData& data, const IntSize& size)
{
    ASSERT(cairo_surface_get_type(data.m_surface) == CAIRO_SURFACE_TYPE_IMAGE);

    unsigned char* dataDst = cairo_image_surface_get_data(data.m_surface);

    ASSERT(sourceRect.width() > 0);
    ASSERT(sourceRect.height() > 0);

    int originx = sourceRect.x();
    int destx = destPoint.x() + sourceRect.x();
    ASSERT(destx >= 0);
    ASSERT(destx < size.width());
    ASSERT(originx >= 0);
    ASSERT(originx <= sourceRect.right());

    int endx = destPoint.x() + sourceRect.right();
    ASSERT(endx <= size.width());

    int numColumns = endx - destx;

    int originy = sourceRect.y();
    int desty = destPoint.y() + sourceRect.y();
    ASSERT(desty >= 0);
    ASSERT(desty < size.height());
    ASSERT(originy >= 0);
    ASSERT(originy <= sourceRect.bottom());

    int endy = destPoint.y() + sourceRect.bottom();
    ASSERT(endy <= size.height());
    int numRows = endy - desty;

    unsigned srcBytesPerRow = 4 * source->width();
    int stride = cairo_image_surface_get_stride(data.m_surface);

    unsigned char* srcRows = source->data()->data()->data() + originy * srcBytesPerRow + originx * 4;
    for (int y = 0; y < numRows; ++y) {
        unsigned* row = reinterpret_cast<unsigned*>(dataDst + stride * (y + desty));
        for (int x = 0; x < numColumns; x++) {
            int basex = x * 4;
            unsigned* pixel = row + x + destx;
            Color pixelColor(srcRows[basex],
                    srcRows[basex + 1],
                    srcRows[basex + 2],
                    srcRows[basex + 3]);
            if (multiplied == Unmultiplied)
                *pixel = premultipliedARGBFromColor(pixelColor);
            else
                *pixel = pixelColor.rgb();
        }
        srcRows += srcBytesPerRow;
    }
    cairo_surface_mark_dirty_rectangle (data.m_surface,
                                        destx, desty,
                                        numColumns, numRows);
}

void ImageBuffer::putUnmultipliedImageData(ImageData* source, const IntRect& sourceRect, const IntPoint& destPoint)
{
    putImageData<Unmultiplied>(source, sourceRect, destPoint, m_data, m_size);
}

void ImageBuffer::putPremultipliedImageData(ImageData* source, const IntRect& sourceRect, const IntPoint& destPoint)
{
    putImageData<Premultiplied>(source, sourceRect, destPoint, m_data, m_size);
}

static cairo_status_t writeFunction(void* closure, const unsigned char* data, unsigned int length)
{
    Vector<char>* in = reinterpret_cast<Vector<char>*>(closure);
    in->append(data, length);
    return CAIRO_STATUS_SUCCESS;
}

String ImageBuffer::toDataURL(const String& mimeType) const
{
    cairo_surface_t* image = cairo_get_target(context()->platformContext());
    if (!image)
        return "data:,";

    String actualMimeType("image/png");
    if (MIMETypeRegistry::isSupportedImageMIMETypeForEncoding(mimeType))
        actualMimeType = mimeType;

    Vector<char> in;
    // Only PNG output is supported for now.
    cairo_surface_write_to_png_stream(image, writeFunction, &in);

    Vector<char> out;
    base64Encode(in, out);

    return "data:" + actualMimeType + ";base64," + String(out.data(), out.size());
}

} // namespace WebCore