1/*
2 * Copyright (C) 2009 Dirk Schulze <krit@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 "wtf/RefCounted.h"
29
30namespace blink {
31
32class PLATFORM_EXPORT Filter : public RefCounted<Filter> {
33public:
34    Filter(const AffineTransform& absoluteTransform)
35    : m_absoluteTransform(absoluteTransform)
36    , m_inverseTransform(absoluteTransform.inverse())
37    {
38        // Filters can only accept scaling and translating transformations, as coordinates
39        // in most primitives are given in horizontal and vertical directions.
40        ASSERT(!absoluteTransform.b() && !absoluteTransform.c());
41    }
42    virtual ~Filter() { }
43
44    void setSourceImage(PassOwnPtr<ImageBuffer> sourceImage) { m_sourceImage = sourceImage; }
45    ImageBuffer* sourceImage() { return m_sourceImage.get(); }
46
47    const AffineTransform& absoluteTransform() const { return m_absoluteTransform; }
48
49    void setAbsoluteTransform(const AffineTransform& absoluteTransform)
50    {
51        // Filters can only accept scaling and translating transformations, as coordinates
52        // in most primitives are given in horizontal and vertical directions.
53        ASSERT(!absoluteTransform.b() && !absoluteTransform.c());
54        m_absoluteTransform = absoluteTransform;
55        m_inverseTransform = absoluteTransform.inverse();
56        m_absoluteFilterRegion = m_absoluteTransform.mapRect(m_filterRegion);
57    }
58    FloatPoint mapAbsolutePointToLocalPoint(const FloatPoint& point) const { return m_inverseTransform.mapPoint(point); }
59    FloatRect mapLocalRectToAbsoluteRect(const FloatRect& rect) const { return m_absoluteTransform.mapRect(rect); }
60    FloatRect mapAbsoluteRectToLocalRect(const FloatRect& rect) const { return m_inverseTransform.mapRect(rect); }
61
62    virtual float applyHorizontalScale(float value) const
63    {
64        return value * m_absoluteTransform.a();
65    }
66    virtual float applyVerticalScale(float value) const
67    {
68        return value * m_absoluteTransform.d();
69    }
70    virtual FloatPoint3D resolve3dPoint(const FloatPoint3D& point) const { return point; }
71
72    virtual IntRect sourceImageRect() const = 0;
73
74    FloatRect absoluteFilterRegion() const { return m_absoluteFilterRegion; }
75
76    FloatRect filterRegion() const { return m_filterRegion; }
77    void setFilterRegion(const FloatRect& rect)
78    {
79        m_filterRegion = rect;
80        m_absoluteFilterRegion = m_absoluteTransform.mapRect(m_filterRegion);
81    }
82
83private:
84    OwnPtr<ImageBuffer> m_sourceImage;
85    AffineTransform m_absoluteTransform;
86    AffineTransform m_inverseTransform;
87    FloatRect m_absoluteFilterRegion;
88    FloatRect m_filterRegion;
89};
90
91} // namespace blink
92
93#endif // Filter_h
94