samplecode/SampleTextEffects.cpp

/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
#include "Sample.h"
#include "SkCanvas.h"
#include "SkReadBuffer.h"
#include "SkWriteBuffer.h"
#include "SkGradientShader.h"
#include "SkPath.h"
#include "SkRegion.h"
#include "SkShader.h"
#include "SkUTF.h"
#include "SkColorPriv.h"
#include "SkColorFilter.h"
#include "SkStrokeRec.h"
#include "SkTextUtils.h"
#include "SkTypeface.h"

#include "SkGradientShader.h"
#include "SkBlurMaskFilter.h"

#include "Sk2DPathEffect.h"

class Dot2DPathEffect : public Sk2DPathEffect {
public:
    Dot2DPathEffect(SkScalar radius, const SkMatrix& matrix,
                    SkTDArray<SkPoint>* pts)
    : Sk2DPathEffect(matrix), fRadius(radius), fPts(pts) {}

    SK_FLATTENABLE_HOOKS(Dot2DPathEffect)
protected:
    void begin(const SkIRect& uvBounds, SkPath* dst) const override {
        if (fPts) {
            fPts->reset();
        }
        this->INHERITED::begin(uvBounds, dst);
    }

    virtual void next(const SkPoint& loc, int u, int v,
                      SkPath* dst) const override {
        if (fPts) {
            *fPts->append() = loc;
        }
        dst->addCircle(loc.fX, loc.fY, fRadius);
    }

    void flatten(SkWriteBuffer& buffer) const override {
        buffer.writeMatrix(this->getMatrix());
        buffer.writeScalar(fRadius);
    }

private:

    SkScalar fRadius;
    SkTDArray<SkPoint>* fPts;

    typedef Sk2DPathEffect INHERITED;
};

// Register this path effect as deserializable before main().
namespace {
    static struct Initializer {
        Initializer() {
            SK_REGISTER_FLATTENABLE(Dot2DPathEffect);
        }
    } initializer;
}


sk_sp<SkFlattenable> Dot2DPathEffect::CreateProc(SkReadBuffer& buffer) {
    SkMatrix matrix;
    buffer.readMatrix(&matrix);
    return sk_make_sp<Dot2DPathEffect>(buffer.readScalar(), matrix, nullptr);
}

class InverseFillPE : public SkPathEffect {
public:
    InverseFillPE() {}
    virtual bool onFilterPath(SkPath* dst, const SkPath& src,
                              SkStrokeRec*, const SkRect*) const override {
        *dst = src;
        dst->setFillType(SkPath::kInverseWinding_FillType);
        return true;
    }

private:
    SK_FLATTENABLE_HOOKS(InverseFillPE)

    typedef SkPathEffect INHERITED;
};

sk_sp<SkFlattenable> InverseFillPE::CreateProc(SkReadBuffer& buffer) {
    return sk_make_sp<InverseFillPE>();
}

static sk_sp<SkPathEffect> makepe(float interp, SkTDArray<SkPoint>* pts) {
    SkMatrix    lattice;
    SkScalar    rad = 3 + SkIntToScalar(4) * (1 - interp);
    lattice.setScale(rad*2, rad*2, 0, 0);
    lattice.postSkew(SK_Scalar1/3, 0, 0, 0);
    return sk_make_sp<Dot2DPathEffect>(rad, lattice, pts);
}

class TextEffectsView : public Sample {
    sk_sp<SkTypeface> fFace;
    SkScalar fInterp;
    SkScalar fDx;

public:
    TextEffectsView() {
        fFace = SkTypeface::MakeFromFile("/Users/reed/Downloads/p052024l.pfb");
        fInterp = 0;
        fDx = SK_Scalar1/64;
    }

protected:
    bool onQuery(Sample::Event* evt) override {
        if (Sample::TitleQ(*evt)) {
            Sample::TitleR(evt, "Text Effects");
            return true;
        }
        return this->INHERITED::onQuery(evt);
    }

    void drawBG(SkCanvas* canvas) {
        canvas->drawColor(SK_ColorWHITE);
    }

    void drawdots(SkCanvas* canvas, SkString s, SkScalar x, SkScalar y, const SkFont& font) {
        SkTDArray<SkPoint> pts;
        auto pe = makepe(fInterp, &pts);

        SkStrokeRec rec(SkStrokeRec::kFill_InitStyle);
        SkPath path, dstPath;
        SkTextUtils::GetPath(s.c_str(), s.size(), kUTF8_SkTextEncoding, x, y, font, &path);
        pe->filterPath(&dstPath, path, &rec, nullptr);

        SkPaint paint;
        paint.setAntiAlias(true);
        paint.setStrokeWidth(10);
        paint.setColor(SK_ColorRED);
        canvas->drawPoints(SkCanvas::kPoints_PointMode, pts.count(), pts.begin(), paint);
    }

    void onDrawContent(SkCanvas* canvas) override {
        this->drawBG(canvas);

        SkScalar x = SkIntToScalar(20);
        SkScalar y = SkIntToScalar(300);

        SkFont font(SkTypeface::MakeFromName("sans-serif", SkFontStyle::Bold()), 240);

        SkString str("9");

        canvas->drawString(str, x, y, font, SkPaint());
        drawdots(canvas, str, x, y, font);

        if (false) {
            fInterp += fDx;
            if (fInterp > 1) {
                fInterp = 1;
                fDx = -fDx;
            } else if (fInterp < 0) {
                fInterp = 0;
                fDx = -fDx;
            }
        }
    }

private:
    typedef Sample INHERITED;
};

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

DEF_SAMPLE( return new TextEffectsView(); )