C++ SkRect::centerY方法代码示例

static void doDraw(SkCanvas* canvas, const SkPaint& paint, const char text[]) {
    canvas->drawColor(SK_ColorWHITE);
    SkPaint red;
    red.setColor(SK_ColorRED);
    canvas->drawCircle(150.0, 150.0, 100.0, red);
    SkRect bounds;
    canvas->getClipBounds(&bounds);
    canvas->drawText(text, strlen(text),
                     bounds.centerX(), bounds.centerY(),
                     paint);
}

static void draw_center_letter(char c,
                               SkPaint* p,
                               SkColor color,
                               SkScalar x,
                               SkScalar y,
                               SkCanvas* canvas) {
    SkRect bounds;
    p->setColor(color);
    p->measureText(&c, 1, &bounds);
    canvas->drawText(&c, 1, x - bounds.centerX(), y - bounds.centerY(), *p);
}

static void draw_text(SkCanvas* canvas, const SkRect& r, SkImageFilter* imf) {
    SkPaint paint;
    paint.setImageFilter(imf);
    paint.setColor(SK_ColorGREEN);
    paint.setAntiAlias(true);
    paint.setTextSize(r.height()/2);
    paint.setTextAlign(SkPaint::kCenter_Align);
    canvas->save();
    canvas->clipRect(r);
    canvas->drawText("Text", 4, r.centerX(), r.centerY(), paint);
    canvas->restore();
}

static void draw_text(SkCanvas* canvas, const SkRect& r, sk_sp<SkImageFilter> imf) {
    SkPaint paint;
    paint.setImageFilter(std::move(imf));
    paint.setColor(SK_ColorGREEN);
    paint.setAntiAlias(true);
    sk_tool_utils::set_portable_typeface(&paint);
    paint.setTextSize(r.height()/2);
    paint.setTextAlign(SkPaint::kCenter_Align);
    canvas->save();
    canvas->clipRect(r);
    canvas->drawText("Text", 4, r.centerX(), r.centerY(), paint);
    canvas->restore();
}

static void compute_rects(SkRect* devOutside, SkRect* devOutsideAssist, SkRect* devInside,
                          bool* isDegenerate, const SkMatrix& viewMatrix, const SkRect& rect,
                          SkScalar strokeWidth, bool miterStroke) {
    SkRect devRect;
    viewMatrix.mapRect(&devRect, rect);

    SkVector devStrokeSize;
    if (strokeWidth > 0) {
        devStrokeSize.set(strokeWidth, strokeWidth);
        viewMatrix.mapVectors(&devStrokeSize, 1);
        devStrokeSize.setAbs(devStrokeSize);
    } else {
        devStrokeSize.set(SK_Scalar1, SK_Scalar1);
    }

    const SkScalar dx = devStrokeSize.fX;
    const SkScalar dy = devStrokeSize.fY;
    const SkScalar rx = SkScalarMul(dx, SK_ScalarHalf);
    const SkScalar ry = SkScalarMul(dy, SK_ScalarHalf);

    *devOutside = devRect;
    *devOutsideAssist = devRect;
    *devInside = devRect;

    devOutside->outset(rx, ry);
    devInside->inset(rx, ry);

    // If we have a degenerate stroking rect(ie the stroke is larger than inner rect) then we
    // make a degenerate inside rect to avoid double hitting.  We will also jam all of the points
    // together when we render these rects.
    SkScalar spare;
    {
        SkScalar w = devRect.width() - dx;
        SkScalar h = devRect.height() - dy;
        spare = SkTMin(w, h);
    }

    *isDegenerate = spare <= 0;
    if (*isDegenerate) {
        devInside->fLeft = devInside->fRight = devRect.centerX();
        devInside->fTop = devInside->fBottom = devRect.centerY();
    }

    // For bevel-stroke, use 2 SkRect instances(devOutside and devOutsideAssist)
    // to draw the outside of the octagon. Because there are 8 vertices on the outer
    // edge, while vertex number of inner edge is 4, the same as miter-stroke.
    if (!miterStroke) {
        devOutside->inset(0, ry);
        devOutsideAssist->outset(0, ry);
    }
}

void drawTestBox(SkCanvas* cv, SkRect* r, float rot, SkPaint* paintIcon, std::string text, SkPaint* paintText)
{
	cv->save();
	cv->translate(r->centerX(),r->centerY());
	cv->rotate(rot * 180 / M_PI);
	SkRect rs = SkRect::MakeLTRB(-r->width()/2, -r->height()/2,
			r->width()/2, r->height()/2);
	cv->drawRect(rs, *paintIcon);
	if (paintText != NULL) {
		cv->drawText(text.data(), text.length(), rs.centerX(), rs.centerY(),
				*paintText);
	}
	cv->restore();
}

static void draw_clipped_filter(SkCanvas* canvas, sk_sp<SkImageFilter> filter, size_t i,
                                const SkRect& primBounds, const SkRect& clipBounds) {
    SkPaint paint;
    paint.setColor(SK_ColorWHITE);
    paint.setImageFilter(std::move(filter));
    paint.setAntiAlias(true);
    canvas->save();
    canvas->clipRect(clipBounds);
    if (5 == i) {
        canvas->translate(SkIntToScalar(16), SkIntToScalar(-32));
    } else if (6 == i) {
        canvas->scale(SkScalarInvert(RESIZE_FACTOR_X), SkScalarInvert(RESIZE_FACTOR_Y));
    }
    canvas->drawCircle(primBounds.centerX(), primBounds.centerY(),
                       primBounds.width() * 2 / 5, paint);
    canvas->restore();
}

    void onDraw(SkCanvas* canvas) override {
        SkPaint paint;
        paint.setAntiAlias(true);
        sk_tool_utils::set_portable_typeface(&paint);
        paint.setTextSize(1500);

        SkRect r;
        (void)paint.measureText("/", 1, &r);
        SkPoint pos = {
            this->width()/2 - r.centerX(),
            this->height()/2 - r.centerY()
        };

        paint.setColor(SK_ColorRED);
        canvas->drawString("/", pos.fX, pos.fY, paint);

        paint.setColor(SK_ColorBLUE);
        canvas->drawPosText("\\", 1, &pos, paint);
    }

    void onDrawContent(SkCanvas* canvas) override {
        const SkRect oval = fOval.makeOffset(fCenter.fX - fOval.centerX(),
                                             fCenter.fY - fOval.centerY());

        SkPaint p;
        p.setAntiAlias(true);

        p.setStyle(SkPaint::kStroke_Style);
        canvas->drawOval(oval, p);

        const SkRect r = SkRect::MakeLTRB(200, 200, 300, 300);
        canvas->clipRect(r);

        p.setStyle(SkPaint::kFill_Style);
        p.setColor(SK_ColorRED);
        canvas->drawRect(r, p);

        p.setColor(0x800000FF);
        canvas->drawOval(oval, p);
    }

PathTexture* ArcShapeCache::getArc(float width, float height,
        float startAngle, float sweepAngle, bool useCenter, SkPaint* paint) {
    ArcShapeCacheEntry entry(width, height, startAngle, sweepAngle, useCenter, paint);
    PathTexture* texture = get(entry);

    if (!texture) {
        SkPath path;
        SkRect r;
        r.set(0.0f, 0.0f, width, height);
        if (useCenter) {
            path.moveTo(r.centerX(), r.centerY());
        }
        path.arcTo(r, startAngle, sweepAngle, !useCenter);
        if (useCenter) {
            path.close();
        }

        texture = addTexture(entry, &path, paint);
    }

    return texture;
}

    void onDrawContent(SkCanvas* canvas) override {
        SkRect oval = fOval;
        oval.offset(fCenter.fX - oval.centerX(), fCenter.fY - oval.centerY());

        SkPaint p;
        p.setAntiAlias(true);

        p.setStyle(SkPaint::kStroke_Style);
        canvas->drawOval(oval, p);

        SkRect r;
        r.set(SkIntToScalar(200), SkIntToScalar(200),
              SkIntToScalar(300), SkIntToScalar(300));
        canvas->clipRect(r);

        p.setStyle(SkPaint::kFill_Style);
        p.setColor(SK_ColorRED);
        canvas->drawRect(r, p);

        p.setColor(0x800000FF);
        r.set(SkIntToScalar(150), SkIntToScalar(10),
              SkIntToScalar(250), SkIntToScalar(400));
        canvas->drawOval(oval, p);
    }

static void draw_oval(SkCanvas* canvas, bool showGL, int flags) {
    SkPaint paint;
    paint.setAntiAlias(true);

    SkRect r = SkRect::MakeLTRB(50, 70, 250, 370);

    setFade(&paint, showGL);
    canvas->drawOval(r, paint);
    if (showGL) {
        switch (flags) {
            case 0: {
                SkPath path;
                path.addOval(r);
                show_glframe(canvas, path);
            } break;
            case 1:
            case 3: {
                SkPath src, dst;
                src.addOval(r);
                tesselate(src, &dst);
                show_fan(canvas, dst, r.centerX(), r.centerY());
            } break;
            case 2: {
                SkPaint p(paint);
                show_mesh(canvas, r);
                setGLFrame(&p);
                paint.setStyle(SkPaint::kFill_Style);
                canvas->drawCircle(r.centerX(), r.centerY(), 3, p);
            } break;
        }
    }

    canvas->translate(320, 0);

    paint.setStyle(SkPaint::kStroke_Style);
    paint.setStrokeWidth(25);
    canvas->drawOval(r, paint);
    if (showGL) {
        switch (flags) {
            case 0: {
                SkPath path;
                SkScalar rad = paint.getStrokeWidth() / 2;
                r.outset(rad, rad);
                path.addOval(r);
                r.inset(rad*2, rad*2);
                path.addOval(r);
                show_glframe(canvas, path);
            } break;
            case 1: {
                SkPath path0, path1;
                SkScalar rad = paint.getStrokeWidth() / 2;
                r.outset(rad, rad);
                path0.addOval(r);
                r.inset(rad*2, rad*2);
                path1.addOval(r);
                show_mesh_between(canvas, path0, path1);
            } break;
            case 2: {
                SkPath path;
                path.addOval(r);
                show_glframe(canvas, path);
                SkScalar rad = paint.getStrokeWidth() / 2;
                r.outset(rad, rad);
                show_mesh(canvas, r);
            } break;
            case 3: {
                SkScalar rad = paint.getStrokeWidth() / 2;
                r.outset(rad, rad);
                SkPaint paint;
                paint.setAlpha(0x33);
                canvas->drawRect(r, paint);
                show_mesh(canvas, r);
            } break;
        }
    }
}

    virtual void onDraw(SkCanvas* canvas) {
        if (!fInitialized) {
            this->make_checkerboard();
            this->make_gradient_circle(64, 64);
            fInitialized = true;
        }
        canvas->clear(0x00000000);

        SkAutoTUnref<SkImageFilter> gradient(SkBitmapSource::Create(fGradientCircle));
        SkAutoTUnref<SkImageFilter> checkerboard(SkBitmapSource::Create(fCheckerboard));
        SkAutoTUnref<SkShader> noise(SkPerlinNoiseShader::CreateFractalNoise(
            SkDoubleToScalar(0.1), SkDoubleToScalar(0.05), 1, 0));
        SkMatrix resizeMatrix;
        resizeMatrix.setScale(RESIZE_FACTOR_X, RESIZE_FACTOR_Y);

        SkImageFilter* filters[] = {
            SkBlurImageFilter::Create(SkIntToScalar(12), SkIntToScalar(12)),
            SkDropShadowImageFilter::Create(SkIntToScalar(10), SkIntToScalar(10), SkIntToScalar(3),
                                            SK_ColorGREEN),
            SkDisplacementMapEffect::Create(SkDisplacementMapEffect::kR_ChannelSelectorType,
                                            SkDisplacementMapEffect::kR_ChannelSelectorType,
                                            SkIntToScalar(12),
                                            gradient.get(),
                                            checkerboard.get()),
            SkDilateImageFilter::Create(2, 2, checkerboard.get()),
            SkErodeImageFilter::Create(2, 2, checkerboard.get()),
            SkOffsetImageFilter::Create(SkIntToScalar(-16), SkIntToScalar(32)),
            SkMatrixImageFilter::Create(resizeMatrix, SkPaint::kNone_FilterLevel),
            SkRectShaderImageFilter::Create(noise),
        };

        SkRect r = SkRect::MakeWH(SkIntToScalar(64), SkIntToScalar(64));
        SkScalar margin = SkIntToScalar(16);
        SkRect bounds = r;
        bounds.outset(margin, margin);

        for (int xOffset = 0; xOffset < 80; xOffset += 16) {
            canvas->save();
            bounds.fLeft = SkIntToScalar(xOffset);
            for (size_t i = 0; i < SK_ARRAY_COUNT(filters); ++i) {
                SkPaint paint;
                paint.setColor(SK_ColorWHITE);
                paint.setImageFilter(filters[i]);
                paint.setAntiAlias(true);
                canvas->save();
                canvas->clipRect(bounds);
                if (5 == i) {
                    canvas->translate(SkIntToScalar(16), SkIntToScalar(-32));
                } else if (6 == i) {
                    canvas->scale(SkScalarInvert(RESIZE_FACTOR_X),
                                  SkScalarInvert(RESIZE_FACTOR_Y));
                }
                canvas->drawCircle(r.centerX(), r.centerY(),
                                   SkScalarDiv(r.width()*2, SkIntToScalar(5)), paint);
                canvas->restore();
                canvas->translate(r.width() + margin, 0);
            }
            canvas->restore();
            canvas->translate(0, r.height() + margin);
        }

        for (size_t i = 0; i < SK_ARRAY_COUNT(filters); ++i) {
            SkSafeUnref(filters[i]);
        }
    }

bool GetSpotShadowTransform(const SkPoint3& lightPos, SkScalar lightRadius,
                            const SkMatrix& ctm, const SkPoint3& zPlaneParams,
                            const SkRect& pathBounds, SkMatrix* shadowTransform, SkScalar* radius) {
    auto heightFunc = [zPlaneParams] (SkScalar x, SkScalar y) {
        return zPlaneParams.fX*x + zPlaneParams.fY*y + zPlaneParams.fZ;
    };
    SkScalar occluderHeight = heightFunc(pathBounds.centerX(), pathBounds.centerY());

    if (!ctm.hasPerspective()) {
        SkScalar scale;
        SkVector translate;
        SkDrawShadowMetrics::GetSpotParams(occluderHeight, lightPos.fX, lightPos.fY, lightPos.fZ,
                                           lightRadius, radius, &scale, &translate);
        shadowTransform->setScaleTranslate(scale, scale, translate.fX, translate.fY);
        shadowTransform->preConcat(ctm);
    } else {
        if (SkScalarNearlyZero(pathBounds.width()) || SkScalarNearlyZero(pathBounds.height())) {
            return false;
        }

        // get rotated quad in 3D
        SkPoint pts[4];
        ctm.mapRectToQuad(pts, pathBounds);
        // No shadows for bowties or other degenerate cases
        if (!SkIsConvexPolygon(pts, 4)) {
            return false;
        }
        SkPoint3 pts3D[4];
        SkScalar z = heightFunc(pathBounds.fLeft, pathBounds.fTop);
        pts3D[0].set(pts[0].fX, pts[0].fY, z);
        z = heightFunc(pathBounds.fRight, pathBounds.fTop);
        pts3D[1].set(pts[1].fX, pts[1].fY, z);
        z = heightFunc(pathBounds.fRight, pathBounds.fBottom);
        pts3D[2].set(pts[2].fX, pts[2].fY, z);
        z = heightFunc(pathBounds.fLeft, pathBounds.fBottom);
        pts3D[3].set(pts[3].fX, pts[3].fY, z);

        // project from light through corners to z=0 plane
        for (int i = 0; i < 4; ++i) {
            SkScalar dz = lightPos.fZ - pts3D[i].fZ;
            // light shouldn't be below or at a corner's z-location
            if (dz <= SK_ScalarNearlyZero) {
                return false;
            }
            SkScalar zRatio = pts3D[i].fZ / dz;
            pts3D[i].fX -= (lightPos.fX - pts3D[i].fX)*zRatio;
            pts3D[i].fY -= (lightPos.fY - pts3D[i].fY)*zRatio;
            pts3D[i].fZ = SK_Scalar1;
        }

        // Generate matrix that projects from [-1,1]x[-1,1] square to projected quad
        SkPoint3 h0, h1, h2;
        // Compute homogenous crossing point between top and bottom edges (gives new x-axis).
        h0 = (pts3D[1].cross(pts3D[0])).cross(pts3D[2].cross(pts3D[3]));
        // Compute homogenous crossing point between left and right edges (gives new y-axis).
        h1 = (pts3D[0].cross(pts3D[3])).cross(pts3D[1].cross(pts3D[2]));
        // Compute homogenous crossing point between diagonals (gives new origin).
        h2 = (pts3D[0].cross(pts3D[2])).cross(pts3D[1].cross(pts3D[3]));
        // If h2 is a vector (z=0 in 2D homogeneous space), that means that at least
        // two of the quad corners are coincident and we don't have a realistic projection
        if (SkScalarNearlyZero(h2.fZ)) {
            return false;
        }
        // In some cases the crossing points are in the wrong direction
        // to map (-1,-1) to pts3D[0], so we need to correct for that.
        // Want h0 to be to the right of the left edge.
        SkVector3 v = pts3D[3] - pts3D[0];
        SkVector3 w = h0 - pts3D[0];
        SkScalar perpDot = v.fX*w.fY - v.fY*w.fX;
        if (perpDot > 0) {
            h0 = -h0;
        }
        // Want h1 to be above the bottom edge.
        v = pts3D[1] - pts3D[0];
        perpDot = v.fX*w.fY - v.fY*w.fX;
        if (perpDot < 0) {
            h1 = -h1;
        }
        shadowTransform->setAll(h0.fX / h2.fZ, h1.fX / h2.fZ, h2.fX / h2.fZ,
                               h0.fY / h2.fZ, h1.fY / h2.fZ, h2.fY / h2.fZ,
                               h0.fZ / h2.fZ, h1.fZ / h2.fZ, 1);
        // generate matrix that transforms from bounds to [-1,1]x[-1,1] square
        SkMatrix toHomogeneous;
        SkScalar xScale = 2/(pathBounds.fRight - pathBounds.fLeft);
        SkScalar yScale = 2/(pathBounds.fBottom - pathBounds.fTop);
        toHomogeneous.setAll(xScale, 0, -xScale*pathBounds.fLeft - 1,
                             0, yScale, -yScale*pathBounds.fTop - 1,
                             0, 0, 1);
        shadowTransform->preConcat(toHomogeneous);

        *radius = SkDrawShadowMetrics::SpotBlurRadius(occluderHeight, lightPos.fZ, lightRadius);
    }

    return true;
}

    void onOnceBeforeDraw() override {
        const SkRect fieldBounds = kBounds.makeOutset(kBallSize / 2, kBallSize / 2);
        const SkRRect ball = SkRRect::MakeOval(SkRect::MakeWH(kBallSize, kBallSize));
        const SkRRect paddle = SkRRect::MakeRectXY(SkRect::MakeWH(kPaddleSize.width(),
                                                                  kPaddleSize.height()),
                                                   kPaddleSize.width() / 2,
                                                   kPaddleSize.width() / 2);
        fBall.initialize(ball,
                         SkPoint::Make(kBounds.centerX(), kBounds.centerY()),
                         SkVector::Make(fRand.nextRangeScalar(kBallSpeedMin, kBallSpeedMax),
                                        fRand.nextRangeScalar(kBallSpeedMin, kBallSpeedMax)));
        fPaddle0.initialize(paddle,
                            SkPoint::Make(fieldBounds.left() - kPaddleSize.width() / 2,
                                          fieldBounds.centerY()),
                            SkVector::Make(0, 0));
        fPaddle1.initialize(paddle,
                            SkPoint::Make(fieldBounds.right() + kPaddleSize.width() / 2,
                                          fieldBounds.centerY()),
                            SkVector::Make(0, 0));

        // Background decoration.
        SkPath bgPath;
        bgPath.moveTo(kBounds.left() , fieldBounds.top());
        bgPath.lineTo(kBounds.right(), fieldBounds.top());
        bgPath.moveTo(kBounds.left() , fieldBounds.bottom());
        bgPath.lineTo(kBounds.right(), fieldBounds.bottom());
        // TODO: stroke-dash support would come in handy right about now.
        for (uint32_t i = 0; i < kBackgroundDashCount; ++i) {
            bgPath.moveTo(kBounds.centerX(),
                          kBounds.top() + (i + 0.25f) * kBounds.height() / kBackgroundDashCount);
            bgPath.lineTo(kBounds.centerX(),
                          kBounds.top() + (i + 0.75f) * kBounds.height() / kBackgroundDashCount);
        }

        auto bg_path  = sksg::Path::Make(bgPath);
        auto bg_paint = sksg::Color::Make(SK_ColorBLACK);
        bg_paint->setStyle(SkPaint::kStroke_Style);
        bg_paint->setStrokeWidth(kBackgroundStroke);

        auto ball_paint    = sksg::Color::Make(SK_ColorGREEN),
             paddle0_paint = sksg::Color::Make(SK_ColorBLUE),
             paddle1_paint = sksg::Color::Make(SK_ColorRED),
             shadow_paint  = sksg::Color::Make(SK_ColorBLACK);
        ball_paint->setAntiAlias(true);
        paddle0_paint->setAntiAlias(true);
        paddle1_paint->setAntiAlias(true);
        shadow_paint->setAntiAlias(true);
        shadow_paint->setOpacity(kShadowOpacity);

        // Build the scene graph.
        auto group = sksg::Group::Make();
        group->addChild(sksg::Draw::Make(std::move(bg_path), std::move(bg_paint)));
        group->addChild(sksg::Draw::Make(fPaddle0.shadowNode, shadow_paint));
        group->addChild(sksg::Draw::Make(fPaddle1.shadowNode, shadow_paint));
        group->addChild(sksg::Draw::Make(fBall.shadowNode, shadow_paint));
        group->addChild(sksg::Draw::Make(fPaddle0.objectNode, paddle0_paint));
        group->addChild(sksg::Draw::Make(fPaddle1.objectNode, paddle1_paint));
        group->addChild(sksg::Draw::Make(fBall.objectNode, ball_paint));

        // Handle everything in a normalized 1x1 space.
        fContentMatrix = sksg::Matrix<SkMatrix>::Make(
            SkMatrix::MakeRectToRect(SkRect::MakeWH(1, 1),
                                     SkRect::MakeIWH(this->width(), this->height()),
                                     SkMatrix::kFill_ScaleToFit));
        auto root = sksg::TransformEffect::Make(std::move(group), fContentMatrix);
        fScene = sksg::Scene::Make(std::move(root), sksg::AnimatorList());

        // Off we go.
        this->updatePaddleStrategy();
    }