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      1 /*
      2  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
      3  *
      4  * This library is free software; you can redistribute it and/or
      5  * modify it under the terms of the GNU Library General Public
      6  * License as published by the Free Software Foundation; either
      7  * version 2 of the License, or (at your option) any later version.
      8  *
      9  * This library is distributed in the hope that it will be useful,
     10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     12  * Library General Public License for more details.
     13  *
     14  * You should have received a copy of the GNU Library General Public License
     15  * along with this library; see the file COPYING.LIB.  If not, write to
     16  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     17  * Boston, MA 02110-1301, USA.
     18  */
     19 
     20 #include "config.h"
     21 
     22 #if ENABLE(SVG)
     23 #include "SVGImageBufferTools.h"
     24 
     25 #include "FrameView.h"
     26 #include "GraphicsContext.h"
     27 #include "RenderObject.h"
     28 #include "RenderSVGContainer.h"
     29 #include "RenderSVGRoot.h"
     30 
     31 namespace WebCore {
     32 
     33 static AffineTransform& currentContentTransformation()
     34 {
     35     DEFINE_STATIC_LOCAL(AffineTransform, s_currentContentTransformation, ());
     36     return s_currentContentTransformation;
     37 }
     38 
     39 void SVGImageBufferTools::calculateTransformationToOutermostSVGCoordinateSystem(const RenderObject* renderer, AffineTransform& absoluteTransform)
     40 {
     41     const RenderObject* current = renderer;
     42     ASSERT(current);
     43 
     44     absoluteTransform = currentContentTransformation();
     45     while (current) {
     46         absoluteTransform = current->localToParentTransform() * absoluteTransform;
     47         if (current->isSVGRoot())
     48             break;
     49         current = current->parent();
     50     }
     51 }
     52 
     53 bool SVGImageBufferTools::createImageBuffer(const FloatRect& absoluteTargetRect, const FloatRect& clampedAbsoluteTargetRect, OwnPtr<ImageBuffer>& imageBuffer, ColorSpace colorSpace)
     54 {
     55     IntSize imageSize(roundedImageBufferSize(clampedAbsoluteTargetRect.size()));
     56     IntSize unclampedImageSize(SVGImageBufferTools::roundedImageBufferSize(absoluteTargetRect.size()));
     57 
     58     // Don't create empty ImageBuffers.
     59     if (imageSize.isEmpty())
     60         return false;
     61 
     62     OwnPtr<ImageBuffer> image = ImageBuffer::create(imageSize, colorSpace);
     63     if (!image)
     64         return false;
     65 
     66     GraphicsContext* imageContext = image->context();
     67     ASSERT(imageContext);
     68 
     69     // Compensate rounding effects, as the absolute target rect is using floating-point numbers and the image buffer size is integer.
     70     imageContext->scale(FloatSize(unclampedImageSize.width() / absoluteTargetRect.width(), unclampedImageSize.height() / absoluteTargetRect.height()));
     71 
     72     imageBuffer = image.release();
     73     return true;
     74 }
     75 
     76 void SVGImageBufferTools::renderSubtreeToImageBuffer(ImageBuffer* image, RenderObject* item, const AffineTransform& subtreeContentTransformation)
     77 {
     78     ASSERT(item);
     79     ASSERT(image);
     80     ASSERT(image->context());
     81 
     82     PaintInfo info(image->context(), PaintInfo::infiniteRect(), PaintPhaseForeground, 0, 0, 0);
     83 
     84     AffineTransform& contentTransformation = currentContentTransformation();
     85     AffineTransform savedContentTransformation = contentTransformation;
     86     contentTransformation = subtreeContentTransformation * contentTransformation;
     87 
     88     item->layoutIfNeeded();
     89     item->paint(info, 0, 0);
     90 
     91     contentTransformation = savedContentTransformation;
     92 }
     93 
     94 void SVGImageBufferTools::clipToImageBuffer(GraphicsContext* context, const AffineTransform& absoluteTransform, const FloatRect& clampedAbsoluteTargetRect, OwnPtr<ImageBuffer>& imageBuffer)
     95 {
     96     ASSERT(context);
     97     ASSERT(imageBuffer);
     98 
     99     // The mask image has been created in the absolute coordinate space, as the image should not be scaled.
    100     // So the actual masking process has to be done in the absolute coordinate space as well.
    101     context->concatCTM(absoluteTransform.inverse());
    102     context->clipToImageBuffer(imageBuffer.get(), clampedAbsoluteTargetRect);
    103     context->concatCTM(absoluteTransform);
    104 
    105     // When nesting resources, with objectBoundingBox as content unit types, there's no use in caching the
    106     // resulting image buffer as the parent resource already caches the result.
    107     if (!currentContentTransformation().isIdentity())
    108         imageBuffer.clear();
    109 }
    110 
    111 IntSize SVGImageBufferTools::roundedImageBufferSize(const FloatSize& size)
    112 {
    113     return IntSize(static_cast<int>(lroundf(size.width())), static_cast<int>(lroundf(size.height())));
    114 }
    115 
    116 FloatRect SVGImageBufferTools::clampedAbsoluteTargetRectForRenderer(const RenderObject* renderer, const FloatRect& absoluteTargetRect)
    117 {
    118     ASSERT(renderer);
    119 
    120     const RenderSVGRoot* svgRoot = SVGRenderSupport::findTreeRootObject(renderer);
    121     FloatRect clampedAbsoluteTargetRect = absoluteTargetRect;
    122     clampedAbsoluteTargetRect.intersect(svgRoot->contentBoxRect());
    123     return clampedAbsoluteTargetRect;
    124 }
    125 
    126 }
    127 
    128 #endif // ENABLE(SVG)
    129