samplecode/SampleArc.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 "SkAnimTimer.h"
#include "SkCanvas.h"
#include "SkColorFilter.h"
#include "SkColorPriv.h"
#include "SkCornerPathEffect.h"
#include "SkDrawable.h"
#include "SkGradientShader.h"
#include "SkPath.h"
#include "SkPathMeasure.h"
#include "SkPictureRecorder.h"
#include "SkRandom.h"
#include "SkRegion.h"
#include "SkShader.h"
#include "SkString.h"
#include "SkUTF.h"
#include "Sk1DPathEffect.h"

#include "SkParsePath.h"
static void testparse() {
    SkRect r;
    r.set(0, 0, 10, 10.5f);
    SkPath p, p2;
    SkString str, str2;

    p.addRect(r);
    SkParsePath::ToSVGString(p, &str);
    SkParsePath::FromSVGString(str.c_str(), &p2);
    SkParsePath::ToSVGString(p2, &str2);
}

class ArcsView : public Sample {
    class MyDrawable : public SkDrawable {
        SkRect   fR;
        SkScalar fSweep;
    public:
        MyDrawable(const SkRect& r) : fR(r), fSweep(0) {}

        void setSweep(SkScalar sweep) {
            if (fSweep != sweep) {
                fSweep = sweep;
                this->notifyDrawingChanged();
            }
        }

        void onDraw(SkCanvas* canvas) override {
            SkPaint paint;
            paint.setAntiAlias(true);
            paint.setStrokeWidth(SkIntToScalar(2));

            paint.setStyle(SkPaint::kFill_Style);
            paint.setColor(0x800000FF);
            canvas->drawArc(fR, 0, fSweep, true, paint);

            paint.setColor(0x800FF000);
            canvas->drawArc(fR, 0, fSweep, false, paint);

            paint.setStyle(SkPaint::kStroke_Style);
            paint.setColor(SK_ColorRED);
            canvas->drawArc(fR, 0, fSweep, true, paint);

            paint.setStrokeWidth(0);
            paint.setColor(SK_ColorBLUE);
            canvas->drawArc(fR, 0, fSweep, false, paint);
        }

        SkRect onGetBounds() override {
            SkRect r(fR);
            r.outset(2, 2);
            return r;
        }
    };

public:
    SkRect fRect;
    sk_sp<MyDrawable> fAnimatingDrawable;
    sk_sp<SkDrawable> fRootDrawable;

    ArcsView() {
        testparse();
        fSweep = SkIntToScalar(100);
        this->setBGColor(0xFFDDDDDD);

        fRect.set(0, 0, SkIntToScalar(200), SkIntToScalar(200));
        fRect.offset(SkIntToScalar(20), SkIntToScalar(20));
        fAnimatingDrawable = sk_make_sp<MyDrawable>(fRect);

        SkPictureRecorder recorder;
        this->drawRoot(recorder.beginRecording(SkRect::MakeWH(800, 500)));
        fRootDrawable = recorder.finishRecordingAsDrawable();
    }

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

    static void DrawRectWithLines(SkCanvas* canvas, const SkRect& r, const SkPaint& p) {
        canvas->drawRect(r, p);
        canvas->drawLine(r.fLeft, r.fTop, r.fRight, r.fBottom, p);
        canvas->drawLine(r.fLeft, r.fBottom, r.fRight, r.fTop, p);
        canvas->drawLine(r.fLeft, r.centerY(), r.fRight, r.centerY(), p);
        canvas->drawLine(r.centerX(), r.fTop, r.centerX(), r.fBottom, p);
    }

    static void DrawLabel(SkCanvas* canvas, const SkRect& rect, SkScalar start, SkScalar sweep) {
        SkPaint paint;

        paint.setAntiAlias(true);
        paint.setTextAlign(SkPaint::kCenter_Align);

        SkString    str;

        str.appendScalar(start);
        str.append(", ");
        str.appendScalar(sweep);
        canvas->drawString(str, rect.centerX(),
                         rect.fBottom + paint.getTextSize() * 5/4, paint);
    }

    static void DrawArcs(SkCanvas* canvas) {
        SkPaint paint;
        SkRect  r;
        SkScalar w = 75;
        SkScalar h = 50;

        r.set(0, 0, w, h);
        paint.setAntiAlias(true);
        paint.setStyle(SkPaint::kStroke_Style);

        canvas->save();
        canvas->translate(SkIntToScalar(10), SkIntToScalar(300));

        paint.setStrokeWidth(SkIntToScalar(1));

        static const SkScalar gAngles[] = {
            0, 360,
            0, 45,
            0, -45,
            720, 135,
            -90, 269,
            -90, 270,
            -90, 271,
            -180, -270,
            225, 90
        };

        for (size_t i = 0; i < SK_ARRAY_COUNT(gAngles); i += 2) {
            paint.setColor(SK_ColorBLACK);
            DrawRectWithLines(canvas, r, paint);

            paint.setColor(SK_ColorRED);
            canvas->drawArc(r, gAngles[i], gAngles[i+1], false, paint);

            DrawLabel(canvas, r, gAngles[i], gAngles[i+1]);

            canvas->translate(w * 8 / 7, 0);
        }

        canvas->restore();
    }

    void drawRoot(SkCanvas* canvas) {
        SkPaint paint;
        paint.setAntiAlias(true);
        paint.setStrokeWidth(SkIntToScalar(2));
        paint.setStyle(SkPaint::kStroke_Style);

        DrawRectWithLines(canvas, fRect, paint);

        canvas->drawDrawable(fAnimatingDrawable.get());

        DrawArcs(canvas);
    }

    void onDrawContent(SkCanvas* canvas) override {
        canvas->drawDrawable(fRootDrawable.get());
    }

    bool onAnimate(const SkAnimTimer& timer) override {
        SkScalar angle = SkDoubleToScalar(fmod(timer.secs() * 360 / 24, 360));
        fAnimatingDrawable->setSweep(angle);
        return true;
    }

private:
    SkScalar fSweep;

    typedef Sample INHERITED;
};

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

DEF_SAMPLE( return new ArcsView(); )