src/core/SkPathEffect.cpp

/*
 * 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.
 */


#include "SkPathEffect.h"
#include "SkPath.h"
#include "SkFlattenableBuffers.h"
#include "SkPaintDefaults.h"

// must be < 0, since ==0 means hairline, and >0 means normal stroke
#define kStrokeRec_FillStyleWidth     (-SK_Scalar1)

SkStrokeRec::SkStrokeRec(InitStyle s) {
    fWidth          = (kFill_InitStyle == s) ? kStrokeRec_FillStyleWidth : 0;
    fMiterLimit     = SkPaintDefaults_MiterLimit;
    fCap            = SkPaint::kDefault_Cap;
    fJoin           = SkPaint::kDefault_Join;
    fStrokeAndFill  = false;
}

SkStrokeRec::SkStrokeRec(const SkStrokeRec& src) {
    memcpy(this, &src, sizeof(src));
}

SkStrokeRec::SkStrokeRec(const SkPaint& paint) {
    switch (paint.getStyle()) {
        case SkPaint::kFill_Style:
            fWidth = kStrokeRec_FillStyleWidth;
            fStrokeAndFill = false;
            break;
        case SkPaint::kStroke_Style:
            fWidth = paint.getStrokeWidth();
            fStrokeAndFill = false;
            break;
        case SkPaint::kStrokeAndFill_Style:
            if (0 == paint.getStrokeWidth()) {
                // hairline+fill == fill
                fWidth = kStrokeRec_FillStyleWidth;
                fStrokeAndFill = false;
            } else {
                fWidth = paint.getStrokeWidth();
                fStrokeAndFill = true;
            }
            break;
        default:
            SkASSERT(!"unknown paint style");
            // fall back on just fill
            fWidth = kStrokeRec_FillStyleWidth;
            fStrokeAndFill = false;
            break;
    }

    // copy these from the paint, regardless of our "style"
    fMiterLimit = paint.getStrokeMiter();
    fCap        = paint.getStrokeCap();
    fJoin       = paint.getStrokeJoin();
}

SkStrokeRec::Style SkStrokeRec::getStyle() const {
    if (fWidth < 0) {
        return kFill_Style;
    } else if (0 == fWidth) {
        return kHairline_Style;
    } else {
        return fStrokeAndFill ? kStrokeAndFill_Style : kStroke_Style;
    }
}

void SkStrokeRec::setFillStyle() {
    fWidth = kStrokeRec_FillStyleWidth;
    fStrokeAndFill = false;
}

void SkStrokeRec::setHairlineStyle() {
    fWidth = 0;
    fStrokeAndFill = false;
}

void SkStrokeRec::setStrokeStyle(SkScalar width, bool strokeAndFill) {
    if (strokeAndFill && (0 == width)) {
        // hairline+fill == fill
        this->setFillStyle();
    } else {
        fWidth = width;
        fStrokeAndFill = strokeAndFill;
    }
}

#include "SkStroke.h"

bool SkStrokeRec::applyToPath(SkPath* dst, const SkPath& src) const {
    if (fWidth <= 0) {  // hairline or fill
        return false;
    }

    SkStroke stroker;
    stroker.setCap(fCap);
    stroker.setJoin(fJoin);
    stroker.setMiterLimit(fMiterLimit);
    stroker.setWidth(fWidth);
    stroker.setDoFill(fStrokeAndFill);
    stroker.strokePath(src, dst);
    return true;
}

///////////////////////////////////////////////////////////////////////////////

SK_DEFINE_INST_COUNT(SkPathEffect)

void SkPathEffect::computeFastBounds(SkRect* dst, const SkRect& src) {
    *dst = src;
}

bool SkPathEffect::asPoints(PointData* results, const SkPath& src,
                            const SkStrokeRec&, const SkMatrix&) const {
    return false;
}

///////////////////////////////////////////////////////////////////////////////

SkPairPathEffect::SkPairPathEffect(SkPathEffect* pe0, SkPathEffect* pe1)
        : fPE0(pe0), fPE1(pe1) {
    SkASSERT(pe0);
    SkASSERT(pe1);
    fPE0->ref();
    fPE1->ref();
}

SkPairPathEffect::~SkPairPathEffect() {
    SkSafeUnref(fPE0);
    SkSafeUnref(fPE1);
}

/*
    Format: [oe0-factory][pe1-factory][pe0-size][pe0-data][pe1-data]
*/
void SkPairPathEffect::flatten(SkFlattenableWriteBuffer& buffer) const {
    this->INHERITED::flatten(buffer);
    buffer.writeFlattenable(fPE0);
    buffer.writeFlattenable(fPE1);
}

SkPairPathEffect::SkPairPathEffect(SkFlattenableReadBuffer& buffer) {
    fPE0 = buffer.readFlattenableT<SkPathEffect>();
    fPE1 = buffer.readFlattenableT<SkPathEffect>();
    // either of these may fail, so we have to check for nulls later on
}

///////////////////////////////////////////////////////////////////////////////

bool SkComposePathEffect::filterPath(SkPath* dst, const SkPath& src,
                                     SkStrokeRec* rec) {
    // we may have failed to unflatten these, so we have to check
    if (!fPE0 || !fPE1) {
        return false;
    }

    SkPath          tmp;
    const SkPath*   ptr = &src;

    if (fPE1->filterPath(&tmp, src, rec)) {
        ptr = &tmp;
    }
    return fPE0->filterPath(dst, *ptr, rec);
}

///////////////////////////////////////////////////////////////////////////////

bool SkSumPathEffect::filterPath(SkPath* dst, const SkPath& src,
                                 SkStrokeRec* rec) {
    // use bit-or so that we always call both, even if the first one succeeds
    return fPE0->filterPath(dst, src, rec) | fPE1->filterPath(dst, src, rec);
}