SkPathEffect.h

/*
 * Copyright 2006 The Android Open Source Project
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */


#ifndef SkPathEffect_DEFINED
#define SkPathEffect_DEFINED

#include "SkFlattenable.h"
#include "SkPath.h"
#include "SkPoint.h"
#include "SkRect.h"

class SkPath;
class SkStrokeRec;

class SK_API SkPathEffect : public SkFlattenable {
public:
    virtual bool filterPath(SkPath* dst, const SkPath& src,
                            SkStrokeRec*, const SkRect* cullR) const = 0;

    virtual void computeFastBounds(SkRect* dst, const SkRect& src) const;

    class PointData {
    public:
        PointData()
            : fFlags(0)
            , fPoints(NULL)
            , fNumPoints(0) {
            fSize.set(SK_Scalar1, SK_Scalar1);
            // 'asPoints' needs to initialize/fill-in 'fClipRect' if it sets
            // the kUseClip flag
        };
        ~PointData() {
            delete [] fPoints;
        }

        // TODO: consider using passed-in flags to limit the work asPoints does.
        // For example, a kNoPath flag could indicate don't bother generating
        // stamped solutions.

        // Currently none of these flags are supported.
        enum PointFlags {
            kCircles_PointFlag            = 0x01,   // draw points as circles (instead of rects)
            kUsePath_PointFlag            = 0x02,   // draw points as stamps of the returned path
            kUseClip_PointFlag            = 0x04,   // apply 'fClipRect' before drawing the points
        };

        uint32_t           fFlags;      // flags that impact the drawing of the points
        SkPoint*           fPoints;     // the center point of each generated point
        int                fNumPoints;  // number of points in fPoints
        SkVector           fSize;       // the size to draw the points
        SkRect             fClipRect;   // clip required to draw the points (if kUseClip is set)
        SkPath             fPath;       // 'stamp' to be used at each point (if kUsePath is set)

        SkPath             fFirst;      // If not empty, contains geometry for first point
        SkPath             fLast;       // If not empty, contains geometry for last point
    };

    virtual bool asPoints(PointData* results, const SkPath& src,
                          const SkStrokeRec&, const SkMatrix&,
                          const SkRect* cullR) const;

    enum DashType {
        kNone_DashType, 
        kDash_DashType, 
    };

    struct DashInfo {
        DashInfo() : fIntervals(NULL), fCount(0), fPhase(0) {}
        DashInfo(SkScalar* intervals, int32_t count, SkScalar phase)
            : fIntervals(intervals), fCount(count), fPhase(phase) {}

        SkScalar*   fIntervals;         
                                        //   Even values represent ons, and odds offs
        int32_t     fCount;             
        SkScalar    fPhase;             
                                        //   mod the sum of all intervals
    };

    virtual DashType asADash(DashInfo* info) const;

    SK_TO_STRING_PUREVIRT()
    SK_DEFINE_FLATTENABLE_TYPE(SkPathEffect)

#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
    virtual bool exposedInAndroidJavaAPI() const { return false; }
#endif

protected:
    SkPathEffect() {}

private:
    // illegal
    SkPathEffect(const SkPathEffect&);
    SkPathEffect& operator=(const SkPathEffect&);

    typedef SkFlattenable INHERITED;
};

class SK_API SkPairPathEffect : public SkPathEffect {
protected:
    SkPairPathEffect(sk_sp<SkPathEffect> pe0, sk_sp<SkPathEffect> pe1);

    void flatten(SkWriteBuffer&) const override;

    // these are visible to our subclasses
    sk_sp<SkPathEffect> fPE0;
    sk_sp<SkPathEffect> fPE1;

    SK_TO_STRING_OVERRIDE()

private:
    typedef SkPathEffect INHERITED;
};

class SK_API SkComposePathEffect : public SkPairPathEffect {
public:
    static sk_sp<SkPathEffect> Make(sk_sp<SkPathEffect> outer, sk_sp<SkPathEffect> inner) {
        if (!outer) {
            return inner;
        }
        if (!inner) {
            return outer;
        }
        return sk_sp<SkPathEffect>(new SkComposePathEffect(outer, inner));
    }

#ifdef SK_SUPPORT_LEGACY_PATHEFFECT_PTR
    static SkPathEffect* Create(SkPathEffect* outer, SkPathEffect* inner) {
        return Make(sk_ref_sp(outer), sk_ref_sp(inner)).release();
    }
#endif

    virtual bool filterPath(SkPath* dst, const SkPath& src,
                            SkStrokeRec*, const SkRect*) const override;

    SK_TO_STRING_OVERRIDE()
    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkComposePathEffect)

#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
    bool exposedInAndroidJavaAPI() const override { return true; }
#endif

protected:
    SkComposePathEffect(sk_sp<SkPathEffect> outer, sk_sp<SkPathEffect> inner)
        : INHERITED(outer, inner) {}

private:
    // illegal
    SkComposePathEffect(const SkComposePathEffect&);
    SkComposePathEffect& operator=(const SkComposePathEffect&);

    typedef SkPairPathEffect INHERITED;
};

class SK_API SkSumPathEffect : public SkPairPathEffect {
public:
    static sk_sp<SkPathEffect> Make(sk_sp<SkPathEffect> first, sk_sp<SkPathEffect> second) {
        if (!first) {
            return second;
        }
        if (!second) {
            return first;
        }
        return sk_sp<SkPathEffect>(new SkSumPathEffect(first, second));
    }

#ifdef SK_SUPPORT_LEGACY_PATHEFFECT_PTR
    static SkPathEffect* Create(SkPathEffect* first, SkPathEffect* second) {
        return Make(sk_ref_sp(first), sk_ref_sp(second)).release();
    }
#endif
    virtual bool filterPath(SkPath* dst, const SkPath& src,
                            SkStrokeRec*, const SkRect*) const override;

    SK_TO_STRING_OVERRIDE()
    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkSumPathEffect)

#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
    bool exposedInAndroidJavaAPI() const override { return true; }
#endif

protected:
    SkSumPathEffect(sk_sp<SkPathEffect> first, sk_sp<SkPathEffect> second)
        : INHERITED(first, second) {}

private:
    // illegal
    SkSumPathEffect(const SkSumPathEffect&);
    SkSumPathEffect& operator=(const SkSumPathEffect&);

    typedef SkPairPathEffect INHERITED;
};

#endif