skia2/include/effects/Sk1DPathEffect.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 Sk1DPathEffect_DEFINED
#define Sk1DPathEffect_DEFINED

#include "SkPathEffect.h"
#include "SkPath.h"

class SkPathMeasure;

//  This class is not exported to java.
class Sk1DPathEffect : public SkPathEffect {
public:
    //  override from SkPathEffect
    virtual bool filterPath(SkPath* dst, const SkPath& src, SkScalar* width);

protected:
    /** Called at the start of each contour, returns the initial offset
        into that contour.
    */
    virtual SkScalar begin(SkScalar contourLength) = 0;
    /** Called with the current distance along the path, with the current matrix
        for the point/tangent at the specified distance.
        Return the distance to travel for the next call. If return <= 0, then that
        contour is done.
    */
    virtual SkScalar next(SkPath* dst, SkScalar distance, SkPathMeasure&) = 0;

private:
    typedef SkPathEffect INHERITED;
};

class SkPath1DPathEffect : public Sk1DPathEffect {
public:
    enum Style {
        kTranslate_Style,   // translate the shape to each position
        kRotate_Style,      // rotate the shape about its center
        kMorph_Style,       // transform each point, and turn lines into curves
        
        kStyleCount
    };
    
    /** Dash by replicating the specified path.
        @param path The path to replicate (dash)
        @param advance The space between instances of path
        @param phase distance (mod advance) along path for its initial position
        @param style how to transform path at each point (based on the current
                     position and tangent)
    */
    SkPath1DPathEffect(const SkPath& path, SkScalar advance, SkScalar phase, Style);

    // override from SkPathEffect
    virtual bool filterPath(SkPath* dst, const SkPath& src, SkScalar* width);

    static SkFlattenable* CreateProc(SkFlattenableReadBuffer& buffer) {
        return SkNEW_ARGS(SkPath1DPathEffect, (buffer));
    }

protected:
    SkPath1DPathEffect(SkFlattenableReadBuffer& buffer);

    // overrides from Sk1DPathEffect
    virtual SkScalar begin(SkScalar contourLength);
    virtual SkScalar next(SkPath* dst, SkScalar distance, SkPathMeasure&);
    // overrides from SkFlattenable
    virtual void flatten(SkFlattenableWriteBuffer& );
    virtual Factory getFactory() { return CreateProc; }
    
private:
    SkPath      fPath;          // copied from constructor
    SkScalar    fAdvance;       // copied from constructor
    SkScalar    fInitialOffset; // computed from phase
    Style       fStyle;         // copied from constructor

    typedef Sk1DPathEffect INHERITED;
};


#endif