SkPDFGraphicState.h revision bf799cd228282431e6311900dd383083f8af7164 
1
2/*
3 * Copyright 2010 The Android Open Source Project
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10#ifndef SkPDFGraphicState_DEFINED
11#define SkPDFGraphicState_DEFINED
12
13#include "SkPaint.h"
14#include "SkPDFTypes.h"
15#include "SkTemplates.h"
16#include "SkThread.h"
17
18class SkPDFFormXObject;
19
20/** \class SkPDFGraphicState
21    SkPaint objects roughly correspond to graphic state dictionaries that can
22    be installed. So that a given dictionary is only output to the pdf file
23    once, we want to canonicalize them. Static methods in this class manage
24    a weakly referenced set of SkPDFGraphicState objects: when the last
25    reference to a SkPDFGraphicState is removed, it removes itself from the
26    static set of objects.
27
28*/
29class SkPDFGraphicState : public SkPDFDict {
30    SK_DECLARE_INST_COUNT(SkPDFGraphicState)
31public:
32    enum SkPDFSMaskMode {
33        kAlpha_SMaskMode,
34        kLuminosity_SMaskMode
35    };
36
37    virtual ~SkPDFGraphicState();
38
39    // Override emitObject so that we can populate the dictionary on
40    // demand.
41    virtual void emitObject(SkWStream* stream, SkPDFCatalog* catalog);
42
43    /** Get the graphic state for the passed SkPaint. The reference count of
44     *  the object is incremented and it is the caller's responsibility to
45     *  unreference it when done. This is needed to accommodate the weak
46     *  reference pattern used when the returned object is new and has no
47     *  other references.
48     *  @param paint  The SkPaint to emulate.
49     */
50    static SkPDFGraphicState* GetGraphicStateForPaint(const SkPaint& paint);
51
52    /** Make a graphic state that only sets the passed soft mask. The
53     *  reference count of the object is incremented and it is the caller's
54     *  responsibility to unreference it when done.
55     *  @param sMask     The form xobject to use as a soft mask.
56     *  @param invert    Indicates if the alpha of the sMask should be inverted.
57     *  @param sMaskMode Whether to use alpha or luminosity for the sMask.
58     */
59    static SkPDFGraphicState* GetSMaskGraphicState(SkPDFFormXObject* sMask,
60                                                   bool invert,
61                                                   SkPDFSMaskMode sMaskMode);
62
63    /** Get a graphic state that only unsets the soft mask. The reference
64     *  count of the object is incremented and it is the caller's responsibility
65     *  to unreference it when done. This is needed to accommodate the weak
66     *  reference pattern used when the returned object is new and has no
67     *  other references.
68     */
69    static SkPDFGraphicState* GetNoSMaskGraphicState();
70
71    bool equals(const SkPaint&) const;
72
73    // Only public for SK_DECLARE_STATIC_LAZY_PTR
74    static SkPDFGraphicState* CreateNoSMaskGraphicState();
75
76private:
77    const SkPaint fPaint;
78    bool fPopulated;
79    bool fSMask;
80
81    SkPDFGraphicState();
82    explicit SkPDFGraphicState(const SkPaint& paint);
83
84    void populateDict();
85
86    typedef SkPDFDict INHERITED;
87};
88
89#endif
90