update sampleapp for stroking experiment

samplecode/SampleQuadStroker.cpp

Index: samplecode/SampleQuadStroker.cpp
diff --git a/samplecode/SampleQuadStroker.cpp b/samplecode/SampleQuadStroker.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..4fd6e7434b691ae55083c69a4fb0ac8afd3dc5f3
--- /dev/null
+++ b/samplecode/SampleQuadStroker.cpp
@@ -0,0 +1,536 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "sk_tool_utils.h"
+#include "SampleCode.h"
+#include "SkView.h"
+#include "SkCanvas.h"
+#include "SkPathMeasure.h"
+#include "SkRandom.h"
+#include "SkRRect.h"
+#include "SkColorPriv.h"
+#include "SkStrokerPriv.h"
+#include "SkSurface.h"
+
+static bool hittest(const SkPoint& target, SkScalar x, SkScalar y) {
+    const SkScalar TOL = 7;
+    return SkPoint::Distance(target, SkPoint::Make(x, y)) <= TOL;
+}
+
+static int getOnCurvePoints(const SkPath& path, SkPoint storage[]) {
+    SkPath::RawIter iter(path);
+    SkPoint pts[4];
+    SkPath::Verb verb;
+
+    int count = 0;
+    while ((verb = iter.next(pts)) != SkPath::kDone_Verb) {
+        switch (verb) {
+            case SkPath::kMove_Verb:
+            case SkPath::kLine_Verb:
+            case SkPath::kQuad_Verb:
+            case SkPath::kConic_Verb:
+            case SkPath::kCubic_Verb:
+                storage[count++] = pts[0];
+                break;
+            default:
+                break;
+        }
+    }
+    return count;
+}
+
+static void getContourCounts(const SkPath& path, SkTArray<int>* contourCounts) {
+    SkPath::RawIter iter(path);
+    SkPoint pts[4];
+    SkPath::Verb verb;
+
+    int count = 0;
+    while ((verb = iter.next(pts)) != SkPath::kDone_Verb) {
+        switch (verb) {
+            case SkPath::kMove_Verb:
+            case SkPath::kLine_Verb:
+                count += 1;
+                break;
+            case SkPath::kQuad_Verb:
+            case SkPath::kConic_Verb:
+                count += 2;
+                break;
+            case SkPath::kCubic_Verb:
+                count += 3;
+                break;
+            case SkPath::kClose_Verb:
+                contourCounts->push_back(count);
+                count = 0;
+                break;
+            default:
+                break;
+        }
+    }
+    if (count > 0) {
+        contourCounts->push_back(count);
+    }
+}
+
+static void erase(SkSurface* surface) {
+    surface->getCanvas()->clear(SK_ColorTRANSPARENT);
+}
+
+struct StrokeTypeButton {
+    SkRect fBounds;
+    char fLabel;
+    bool fEnabled;
+};
+
+class QuadStrokerView : public SampleView {
+    enum {
+        SKELETON_COLOR = 0xFF0000FF,
+        WIREFRAME_COLOR = 0x80FF0000
+    };
+
+    enum {
+        kCount = 10
+    };
+    SkPoint fPts[kCount];
+    SkRect fErrorControl;
+    SkRect fWidthControl;
+    SkRect fBounds;
+    SkMatrix fMatrix, fInverse;
+    SkAutoTUnref<SkShader> fShader;
+    SkAutoTUnref<SkSurface> fMinSurface;
+    SkAutoTUnref<SkSurface> fMaxSurface;
+    StrokeTypeButton fCubicButton;
+    StrokeTypeButton fQuadButton;
+    StrokeTypeButton fRRectButton;
+    StrokeTypeButton fTextButton;
+    SkString fText;
+    SkScalar fTextSize;
+    SkScalar fWidth, fDWidth;
+    SkScalar fWidthScale;
+    int fW, fH, fZoom;
+    bool fAnimate;
+    bool fDrawRibs;
+    bool fDrawTangents;
+#if QUAD_STROKE_APPROXIMATION && defined(SK_DEBUG)
+    #define kStrokerErrorMin 0.001f
+    #define kStrokerErrorMax 5
+#endif
+    #define kWidthMin 1
+    #define kWidthMax 100
+public:
+    QuadStrokerView() {
+        this->setBGColor(SK_ColorLTGRAY);
+
+        fPts[0].set(50, 200);
+        fPts[1].set(50, 100);
+        fPts[2].set(150, 50);
+        fPts[3].set(300, 50);
+
+        fPts[4].set(350, 200);
+        fPts[5].set(350, 100);
+        fPts[6].set(450, 50);
+
+        fPts[7].set(200, 200);
+        fPts[8].set(400, 400);
+
+        fPts[9].set(250, 800);
+        fText = "a";
+        fTextSize = 12;
+        fWidth = 50;
+        fDWidth = 0.25f;
+
+        fCubicButton.fLabel = 'C';
+        fCubicButton.fEnabled = false;
+        fQuadButton.fLabel = 'Q';
+        fQuadButton.fEnabled = false;
+        fRRectButton.fLabel = 'R';
+        fRRectButton.fEnabled = false;
+        fTextButton.fLabel = 'T';
+        fTextButton.fEnabled = true;
+        fAnimate = true;
+        setAsNeeded();
+    }
+
+protected:
+    bool onQuery(SkEvent* evt) SK_OVERRIDE {
+        if (SampleCode::TitleQ(*evt)) {
+            SampleCode::TitleR(evt, "QuadStroker");
+            return true;
+        }
+        SkUnichar uni;
+        if (fTextButton.fEnabled && SampleCode::CharQ(*evt, &uni)) {
+            switch (uni) {
+                case ' ':
+                    fText = "";
+                    break;
+                case '-':
+                    fTextSize = SkTMax(1.0f, fTextSize - 1);
+                    break;
+                case '+':
+                case '=':
+                    fTextSize += 1;
+                    break;
+                default:
+                    fText.appendUnichar(uni);
+            }
+            this->inval(NULL);
+            return true;
+        }
+        return this->INHERITED::onQuery(evt);
+    }
+
+    void onSizeChange() SK_OVERRIDE {
+        fErrorControl.setXYWH(this->width() - 100, 30, 30, 400);
+        fWidthControl.setXYWH(this->width() -  50, 30, 30, 400);
+        fCubicButton.fBounds.setXYWH(this->width() - 50, 450, 30, 30);
+        fQuadButton.fBounds.setXYWH(this->width() - 50, 500, 30, 30);
+        fRRectButton.fBounds.setXYWH(this->width() - 50, 550, 30, 30);
+        fTextButton.fBounds.setXYWH(this->width() - 50, 600, 30, 30);
+        this->INHERITED::onSizeChange();
+    }
+
+     void copyMinToMax() {
+        erase(fMaxSurface);
+        SkCanvas* canvas = fMaxSurface->getCanvas();
+        canvas->save();
+        canvas->concat(fMatrix);
+        fMinSurface->draw(canvas, 0, 0, NULL);
+        canvas->restore();
+
+        SkPaint paint;
+        paint.setXfermodeMode(SkXfermode::kClear_Mode);
+        for (int iy = 1; iy < fH; ++iy) {
+            SkScalar y = SkIntToScalar(iy * fZoom);
+            canvas->drawLine(0, y - SK_ScalarHalf, 999, y - SK_ScalarHalf, paint);
+        }
+        for (int ix = 1; ix < fW; ++ix) {
+            SkScalar x = SkIntToScalar(ix * fZoom);
+            canvas->drawLine(x - SK_ScalarHalf, 0, x - SK_ScalarHalf, 999, paint);
+        }
+    }
+
+   void setWHZ(int width, int height, int zoom) {
+        fZoom = zoom;
+        fBounds.set(0, 0, SkIntToScalar(width * zoom), SkIntToScalar(height * zoom));
+        fMatrix.setScale(SkIntToScalar(zoom), SkIntToScalar(zoom));
+        fInverse.setScale(SK_Scalar1 / zoom, SK_Scalar1 / zoom);
+        fShader.reset(sk_tool_utils::create_checkerboard_shader(
+                              0xFFCCCCCC, 0xFFFFFFFF, zoom));
+
+        SkImageInfo info = SkImageInfo::MakeN32Premul(width, height);
+        fMinSurface.reset(SkSurface::NewRaster(info));
+        info = info.makeWH(width * zoom, height * zoom);
+        fMaxSurface.reset(SkSurface::NewRaster(info));
+    }
+
+    void draw_points(SkCanvas* canvas, const SkPath& path, SkColor color,
+                     bool show_lines) {
+        SkPaint paint;
+        paint.setColor(color);
+        paint.setAlpha(0x80);
+        paint.setAntiAlias(true);
+        int n = path.countPoints();
+        SkAutoSTArray<32, SkPoint> pts(n);
+        if (show_lines && fDrawTangents) {
+            SkTArray<int> contourCounts;
+            getContourCounts(path, &contourCounts);
+            SkPoint* ptPtr = pts.get();
+            for (int i = 0; i < contourCounts.count(); ++i) {
+                int count = contourCounts[i];
+                path.getPoints(ptPtr, count);
+                canvas->drawPoints(SkCanvas::kPolygon_PointMode, count, ptPtr, paint);
+                ptPtr += count;
+            }
+        } else {
+            n = getOnCurvePoints(path, pts.get());
+        }
+        paint.setStrokeWidth(5);
+        canvas->drawPoints(SkCanvas::kPoints_PointMode, n, pts.get(), paint);
+    }
+
+    void draw_ribs(SkCanvas* canvas, const SkPath& path, SkScalar width,
+                   SkColor color) {
+        const SkScalar radius = width / 2;
+
+        SkPathMeasure meas(path, false);
+        SkScalar total = meas.getLength();
+
+        SkScalar delta = 8;
+        SkPaint paint;
+        paint.setColor(color);
+
+        SkPoint pos, tan;
+        for (SkScalar dist = 0; dist <= total; dist += delta) {
+            if (meas.getPosTan(dist, &pos, &tan)) {
+                tan.scale(radius);
+                tan.rotateCCW();
+                canvas->drawLine(pos.x() + tan.x(), pos.y() + tan.y(),
+                                 pos.x() - tan.x(), pos.y() - tan.y(), paint);
+            }
+        }
+    }
+
+    void draw_stroke(SkCanvas* canvas, const SkPath& path, SkScalar width, bool drawText) {
+        SkRect bounds = path.getBounds();
+        if (bounds.isEmpty()) {
+            return;
+        }
+        this->setWHZ(SkScalarCeilToInt(bounds.right()), SkScalarRoundToInt(fTextSize * 3 / 2),
+            SkScalarRoundToInt(950.0f / fTextSize));
+        erase(fMinSurface);
+        SkPaint paint;
+        paint.setColor(0x1f1f0f0f);
+        fMinSurface->getCanvas()->drawPath(path, paint);
+        paint.setStyle(SkPaint::kStroke_Style);
+        paint.setStrokeWidth(width * fTextSize * fTextSize);
+        paint.setColor(0x3f0f1f3f);
+        fMinSurface->getCanvas()->drawPath(path, paint);
+
+        this->copyMinToMax();
+        fMaxSurface->draw(canvas, 0, 0, NULL);
+
+        paint.setAntiAlias(true);
+        paint.setStyle(SkPaint::kStroke_Style);
+        paint.setStrokeWidth(1);
+
+        paint.setColor(SKELETON_COLOR);
+        SkPath scaled;
+        SkMatrix matrix;
+        matrix.reset();
+        matrix.setScale(950 / fTextSize, 950 / fTextSize);
+        if (drawText) {
+            path.transform(matrix, &scaled);
+        } else {
+            scaled = path;
+        }
+        canvas->drawPath(scaled, paint);
+        draw_points(canvas, scaled, SKELETON_COLOR, true);
+
+        if (fDrawRibs) {
+            draw_ribs(canvas, scaled, width, 0xFF00FF00);
+        }
+
+        SkPath fill;
+
+        SkPaint p;
+        p.setStyle(SkPaint::kStroke_Style);
+        p.setStrokeWidth(width * fTextSize * fTextSize);
+
+        p.getFillPath(path, &fill);
+        SkPath scaledFill;
+        if (drawText) {
+            fill.transform(matrix, &scaledFill);
+        } else {
+            scaledFill = fill;
+        }
+        paint.setColor(WIREFRAME_COLOR);
+        canvas->drawPath(scaledFill, paint);
+        draw_points(canvas, scaledFill, WIREFRAME_COLOR, false);
+    }
+
+    void draw_button(SkCanvas* canvas, const StrokeTypeButton& button) {
+        SkPaint paint;
+        paint.setAntiAlias(true);
+        paint.setStyle(SkPaint::kStroke_Style);
+        paint.setColor(button.fEnabled ? 0xFF3F0000 : 0x6F3F0000);
+        canvas->drawRect(button.fBounds, paint);
+        paint.setTextSize(25.0f);
+        paint.setColor(button.fEnabled ? 0xFF3F0000 : 0x6F3F0000);
+        paint.setTextAlign(SkPaint::kCenter_Align);
+        paint.setStyle(SkPaint::kFill_Style);
+        canvas->drawText(&button.fLabel, 1, button.fBounds.centerX(), button.fBounds.fBottom - 5,
+                paint);
+    }
+
+    void draw_control(SkCanvas* canvas, const SkRect& bounds, SkScalar value,
+            SkScalar min, SkScalar max, const char* name) {
+        SkPaint paint;
+        paint.setAntiAlias(true);
+        paint.setStyle(SkPaint::kStroke_Style);
+        canvas->drawRect(bounds, paint);
+        SkScalar scale = max - min;
+        SkScalar yPos = bounds.fTop + (value - min) * bounds.height() / scale;
+        paint.setColor(0xFFFF0000);
+        canvas->drawLine(bounds.fLeft - 5, yPos, bounds.fRight + 5, yPos, paint);
+        SkString label;
+        label.printf("%0.3g", value);
+        paint.setColor(0xFF000000);
+        paint.setTextSize(11.0f);
+        paint.setStyle(SkPaint::kFill_Style);
+        canvas->drawText(label.c_str(), label.size(), bounds.fLeft + 5, yPos - 5, paint);
+        paint.setTextSize(13.0f);
+        canvas->drawText(name, strlen(name), bounds.fLeft, bounds.bottom() + 11, paint);
+    }
+
+    void setForGeometry() {
+        fDrawRibs = true;
+        fDrawTangents = true;
+        fWidthScale = 1;
+    }
+
+    void setForText() {
+        fDrawRibs = fDrawTangents = false;
+        fWidthScale = 0.002f;
+    }
+
+    void setAsNeeded() {
+        if (fCubicButton.fEnabled || fQuadButton.fEnabled || fRRectButton.fEnabled) {
+            setForGeometry();
+        } else {
+            setForText();
+        }
+    }
+
+    void onDrawContent(SkCanvas* canvas) SK_OVERRIDE {
+        SkPath path;
+        SkScalar width = fWidth;
+
+        if (fCubicButton.fEnabled) {
+            path.moveTo(fPts[0]);
+            path.cubicTo(fPts[1], fPts[2], fPts[3]);
+            setForGeometry();
+            draw_stroke(canvas, path, width, false);
+        }
+
+        if (fQuadButton.fEnabled) {
+            path.reset();
+            path.moveTo(fPts[4]);
+            path.quadTo(fPts[5], fPts[6]);
+            setForGeometry();
+            draw_stroke(canvas, path, width, false);
+        }
+
+        if (fRRectButton.fEnabled) {
+            SkScalar rad = 32;
+            SkRect r;
+            r.set(&fPts[7], 2);
+            path.reset();
+            SkRRect rr;
+            rr.setRectXY(r, rad, rad);
+            path.addRRect(rr);
+            setForGeometry();
+            draw_stroke(canvas, path, width, false);
+
+            path.reset();
+            SkRRect rr2;
+            rr.inset(width/2, width/2, &rr2);
+            path.addRRect(rr2, SkPath::kCCW_Direction);
+            rr.inset(-width/2, -width/2, &rr2);
+            path.addRRect(rr2, SkPath::kCW_Direction);
+            SkPaint paint;
+            paint.setAntiAlias(true);
+            paint.setColor(0x40FF8844);
+            canvas->drawPath(path, paint);
+        }
+
+        if (fTextButton.fEnabled) {
+            path.reset();
+            SkPaint paint;
+            paint.setAntiAlias(true);
+            paint.setTextSize(fTextSize);
+            paint.getTextPath(fText.c_str(), fText.size(), 0, fTextSize, &path);
+            setForText();
+            draw_stroke(canvas, path, width * fWidthScale / fTextSize, true);
+        }
+
+        if (fAnimate) {
+            fWidth += fDWidth;
+            if (fDWidth > 0 && fWidth > kWidthMax) {
+                fDWidth = -fDWidth;
+            } else if (fDWidth < 0 && fWidth < kWidthMin) {
+                fDWidth = -fDWidth;
+            }
+        }
+        setAsNeeded();
+#if QUAD_STROKE_APPROXIMATION && defined(SK_DEBUG)
+        draw_control(canvas, fErrorControl, gDebugStrokerError, kStrokerErrorMin, kStrokerErrorMax,
+                "error");
+#endif
+        draw_control(canvas, fWidthControl, fWidth * fWidthScale, kWidthMin * fWidthScale,
+                kWidthMax * fWidthScale, "width");
+        draw_button(canvas, fQuadButton);
+        draw_button(canvas, fCubicButton);
+        draw_button(canvas, fRRectButton);
+        draw_button(canvas, fTextButton);
+        this->inval(NULL);
+    }
+
+    class MyClick : public Click {
+    public:
+        int fIndex;
+        MyClick(SkView* target, int index) : Click(target), fIndex(index) {}
+    };
+
+    virtual SkView::Click* onFindClickHandler(SkScalar x, SkScalar y,
+                                              unsigned modi) SK_OVERRIDE {
+        for (size_t i = 0; i < SK_ARRAY_COUNT(fPts); ++i) {
+            if (hittest(fPts[i], x, y)) {
+                return new MyClick(this, (int)i);
+            }
+        }
+        const SkRect& rectPt = SkRect::MakeXYWH(x, y, 1, 1);
+#if QUAD_STROKE_APPROXIMATION && defined(SK_DEBUG)
+        if (fErrorControl.contains(rectPt)) {
+            return new MyClick(this, (int) SK_ARRAY_COUNT(fPts) + 1);
+        }
+#endif
+        if (fWidthControl.contains(rectPt)) {
+            return new MyClick(this, (int) SK_ARRAY_COUNT(fPts) + 3);
+        }
+        if (fCubicButton.fBounds.contains(rectPt)) {
+            fCubicButton.fEnabled ^= true;
+            return new MyClick(this, (int) SK_ARRAY_COUNT(fPts) + 4);
+        }
+        if (fQuadButton.fBounds.contains(rectPt)) {
+            fQuadButton.fEnabled ^= true;
+            return new MyClick(this, (int) SK_ARRAY_COUNT(fPts) + 5);
+        }
+        if (fRRectButton.fBounds.contains(rectPt)) {
+            fRRectButton.fEnabled ^= true;
+            return new MyClick(this, (int) SK_ARRAY_COUNT(fPts) + 6);
+        }
+        if (fTextButton.fBounds.contains(rectPt)) {
+            fTextButton.fEnabled ^= true;
+            return new MyClick(this, (int) SK_ARRAY_COUNT(fPts) + 7);
+        }
+        return this->INHERITED::onFindClickHandler(x, y, modi);
+    }
+
+    static SkScalar MapScreenYtoValue(int y, const SkRect& control, SkScalar min,
+            SkScalar max) {
+        return (SkIntToScalar(y) - control.fTop) / control.height() * (max - min) + min;
+    }
+
+    bool onClick(Click* click) SK_OVERRIDE {
+        int index = ((MyClick*)click)->fIndex;
+        if (index < (int) SK_ARRAY_COUNT(fPts)) {
+            fPts[index].offset(SkIntToScalar(click->fICurr.fX - click->fIPrev.fX),
+                               SkIntToScalar(click->fICurr.fY - click->fIPrev.fY));
+            this->inval(NULL);
+        }
+#if QUAD_STROKE_APPROXIMATION && defined(SK_DEBUG)
+        else if (index == (int) SK_ARRAY_COUNT(fPts) + 1) {
+            gDebugStrokerError = SkTMax(FLT_EPSILON, MapScreenYtoValue(click->fICurr.fY,
+                    fErrorControl, kStrokerErrorMin, kStrokerErrorMax));
+            gDebugStrokerErrorSet = true;
+        }
+#endif
+        else if (index == (int) SK_ARRAY_COUNT(fPts) + 3) {
+            fWidth = SkTMax(FLT_EPSILON, MapScreenYtoValue(click->fICurr.fY, fWidthControl,
+                    kWidthMin, kWidthMax));
+            fAnimate = fWidth <= kWidthMin;
+        }
+        return true;
+    }
+
+private:
+    typedef SkView INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+static SkView* F2() { return new QuadStrokerView; }
+static SkViewRegister gR2(F2);