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      1 /*
      2  * Copyright (C) 2009 Dirk Schulze <krit (at) webkit.org>
      3  * Copyright (C) 2013 Google Inc. All rights reserved.
      4  *
      5  * This library is free software; you can redistribute it and/or
      6  * modify it under the terms of the GNU Library General Public
      7  * License as published by the Free Software Foundation; either
      8  * version 2 of the License, or (at your option) any later version.
      9  *
     10  * This library is distributed in the hope that it will be useful,
     11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     13  * Library General Public License for more details.
     14  *
     15  * You should have received a copy of the GNU Library General Public License
     16  * along with this library; see the file COPYING.LIB.  If not, write to
     17  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     18  * Boston, MA 02110-1301, USA.
     19  */
     20 
     21 #ifndef Filter_h
     22 #define Filter_h
     23 
     24 #include "platform/PlatformExport.h"
     25 #include "platform/geometry/FloatRect.h"
     26 #include "platform/geometry/FloatSize.h"
     27 #include "platform/graphics/ImageBuffer.h"
     28 #include "third_party/skia/include/core/SkImageFilter.h"
     29 #include "wtf/RefCounted.h"
     30 
     31 namespace WebCore {
     32 
     33 class FilterEffect;
     34 
     35 class PLATFORM_EXPORT Filter : public RefCounted<Filter> {
     36 public:
     37     Filter(const AffineTransform& absoluteTransform)
     38     : m_absoluteTransform(absoluteTransform)
     39     , m_inverseTransform(absoluteTransform.inverse())
     40     {
     41         // Filters can only accept scaling and translating transformations, as coordinates
     42         // in most primitives are given in horizontal and vertical directions.
     43         ASSERT(!absoluteTransform.b() && !absoluteTransform.c());
     44     }
     45     virtual ~Filter() { }
     46 
     47     void setSourceImage(PassOwnPtr<ImageBuffer> sourceImage) { m_sourceImage = sourceImage; }
     48     ImageBuffer* sourceImage() { return m_sourceImage.get(); }
     49 
     50     const AffineTransform& absoluteTransform() const { return m_absoluteTransform; }
     51 
     52     void setAbsoluteTransform(const AffineTransform& absoluteTransform)
     53     {
     54         // Filters can only accept scaling and translating transformations, as coordinates
     55         // in most primitives are given in horizontal and vertical directions.
     56         ASSERT(!absoluteTransform.b() && !absoluteTransform.c());
     57         m_absoluteTransform = absoluteTransform;
     58         m_inverseTransform = absoluteTransform.inverse();
     59         m_absoluteFilterRegion = m_absoluteTransform.mapRect(m_filterRegion);
     60     }
     61     FloatPoint mapAbsolutePointToLocalPoint(const FloatPoint& point) const { return m_inverseTransform.mapPoint(point); }
     62     FloatRect mapLocalRectToAbsoluteRect(const FloatRect& rect) const { return m_absoluteTransform.mapRect(rect); }
     63     FloatRect mapAbsoluteRectToLocalRect(const FloatRect& rect) const { return m_inverseTransform.mapRect(rect); }
     64 
     65     virtual float applyHorizontalScale(float value) const
     66     {
     67         return value * m_absoluteTransform.a();
     68     }
     69     virtual float applyVerticalScale(float value) const
     70     {
     71         return value * m_absoluteTransform.d();
     72     }
     73     virtual FloatPoint3D resolve3dPoint(const FloatPoint3D& point) const { return point; }
     74 
     75     virtual IntRect sourceImageRect() const = 0;
     76 
     77     FloatRect absoluteFilterRegion() const { return m_absoluteFilterRegion; }
     78 
     79     FloatRect filterRegion() const { return m_filterRegion; }
     80     void setFilterRegion(const FloatRect& rect)
     81     {
     82         m_filterRegion = rect;
     83         m_absoluteFilterRegion = m_absoluteTransform.mapRect(m_filterRegion);
     84     }
     85 
     86     // The methods enableCache() and disableCache() are temporary, and we
     87     // should address the real issue inside skia, thus simplifying what the
     88     // clients have to know, and can remove these.
     89     // Also note that this cache should no longer be used by Blink once the
     90     // NON impl-side painting path is removed.
     91     void enableCache()
     92     {
     93         if (!m_cache)
     94             m_cache = adoptRef(SkImageFilter::Cache::Create(1));
     95         SkImageFilter::SetExternalCache(m_cache.get());
     96     }
     97 
     98     void disableCache()
     99     {
    100         SkImageFilter::SetExternalCache(0);
    101     }
    102 
    103     void removeFromCache(SkImageFilter* filter)
    104     {
    105         if (m_cache)
    106             m_cache->remove(filter);
    107     }
    108 
    109 private:
    110     OwnPtr<ImageBuffer> m_sourceImage;
    111     AffineTransform m_absoluteTransform;
    112     AffineTransform m_inverseTransform;
    113     FloatRect m_absoluteFilterRegion;
    114     FloatRect m_filterRegion;
    115     RefPtr<SkImageFilter::Cache> m_cache;
    116 };
    117 
    118 } // namespace WebCore
    119 
    120 #endif // Filter_h
    121