C++ SkPaint::setDither方法代码示例

    virtual void onDraw(SkCanvas* canvas) {
        this->drawBG(canvas);

      //  canvas->scale(1.5f, 1.5f);
        
        canvas->drawBitmap(fBM, 0, 0);
        
        SkIRect margins;
        SkRect  dst;
        int d = 25;
        
        margins.set(d, d, d, d);
        margins.fLeft   = fBM.width()/2 - 1;
        margins.fTop    = fBM.height()/2 - 1;
        margins.fRight  = fBM.width() - margins.fLeft - 1;
        margins.fBottom = fBM.height() - margins.fTop - 1;

   //     canvas->translate(fX/5, fY/5);
        canvas->translate(0, 76);

        dst.set(0, 0, SkIntToScalar(200), SkIntToScalar(200));
        
        SkPaint paint;
        paint.setAntiAlias(false);
        paint.setDither(true);
        paint.setFilterBitmap(false);
    //    SkNinePatch::DrawNine(canvas, dst, fBM, margins, &paint);
        test_rects(canvas, fBM, &paint);
    }

    virtual void onDrawContent(SkCanvas* canvas) {
        SkPaint paint;
        paint.setDither(true);
        paint.setFilterBitmap(true);

        for (size_t i = 0; i < SK_ARRAY_COUNT(fRecs); i++) {
            canvas->save();

            paint.setShader(NULL);
            canvas->drawVertices(fRecs[i].fMode, fRecs[i].fCount,
                                 fRecs[i].fVerts, fRecs[i].fTexs,
                                 NULL, NULL, NULL, 0, paint);

            canvas->translate(SkIntToScalar(250), 0);

            paint.setShader(fShader0);
            canvas->drawVertices(fRecs[i].fMode, fRecs[i].fCount,
                                 fRecs[i].fVerts, fRecs[i].fTexs,
                                 NULL, NULL, NULL, 0, paint);

            canvas->translate(SkIntToScalar(250), 0);

            paint.setShader(fShader1);
            canvas->drawVertices(fRecs[i].fMode, fRecs[i].fCount,
                                 fRecs[i].fVerts, fRecs[i].fTexs,
                                 NULL, NULL, NULL, 0, paint);
            canvas->restore();

            canvas->translate(0, SkIntToScalar(250));
        }
    }

    void onDrawContent(SkCanvas* canvas) override {
        SkPaint paint;
        paint.setDither(true);
        paint.setFilterQuality(kLow_SkFilterQuality);

        for (size_t i = 0; i < SK_ARRAY_COUNT(fRecs); i++) {
            auto verts = SkVertices::MakeCopy(fRecs[i].fMode, fRecs[i].fCount,
                                              fRecs[i].fVerts, fRecs[i].fTexs,
                                              nullptr);
            canvas->save();

            paint.setShader(nullptr);
            canvas->drawVertices(verts, SkBlendMode::kModulate, paint);

            canvas->translate(SkIntToScalar(250), 0);

            paint.setShader(fShader0);
            canvas->drawVertices(verts, SkBlendMode::kModulate, paint);

            canvas->translate(SkIntToScalar(250), 0);

            paint.setShader(fShader1);
            canvas->drawVertices(verts, SkBlendMode::kModulate, paint);
            canvas->restore();

            canvas->translate(0, SkIntToScalar(250));
        }
    }

static void gradient_slide(SkCanvas* canvas) {
    SkPoint pts[2] = {
        { 0, 0 },
        { SkIntToScalar(100), SkIntToScalar(100) }
    };
    SkShader::TileMode tm = SkShader::kClamp_TileMode;
    SkRect r = { 0, 0, SkIntToScalar(100), SkIntToScalar(100) };
    SkPaint paint;
    paint.setAntiAlias(true);
    paint.setDither(true);

    canvas->translate(SkIntToScalar(20), SkIntToScalar(10));
    for (size_t i = 0; i < SK_ARRAY_COUNT(gGradData); i++) {
        canvas->save();
        for (size_t j = 0; j < SK_ARRAY_COUNT(gGradMakers); j++) {
            SkShader* shader = gGradMakers[j](pts, gGradData[i], tm);
            paint.setShader(shader);
            canvas->drawRect(r, paint);
            shader->unref();
            canvas->translate(0, SkIntToScalar(120));
        }
        canvas->restore();
        canvas->translate(SkIntToScalar(120), 0);
    }
}

    virtual void onDraw(SkCanvas* canvas) {

        SkPoint pts[2] = {
            { 0, 0 },
            { SkIntToScalar(100), SkIntToScalar(100) }
        };
        SkShader::TileMode tm = SkShader::kClamp_TileMode;
        SkRect r = { 0, 0, SkIntToScalar(100), SkIntToScalar(100) };
        SkPaint paint;
        paint.setAntiAlias(true);
        paint.setDither(fDither);

        canvas->translate(SkIntToScalar(20), SkIntToScalar(20));
        for (size_t i = 0; i < SK_ARRAY_COUNT(gGradData); i++) {
            canvas->save();
            for (size_t j = 0; j < SK_ARRAY_COUNT(gGradMakers); j++) {
                SkMatrix scale = SkMatrix::I();

                if (i == 5) { // if the clamp case
                    scale.setScale(0.5f, 0.5f);
                    scale.postTranslate(25.f, 25.f);
                }

                paint.setShader(gGradMakers[j](pts, gGradData[i], tm, scale));
                canvas->drawRect(r, paint);
                canvas->translate(0, SkIntToScalar(120));
            }
            canvas->restore();
            canvas->translate(SkIntToScalar(120), 0);
        }
    }

    static void draw2(SkCanvas* canvas, const SkBitmap& bm) {
        SkPaint paint;
        SkBitmap bitmap(bm);

        setBitmapOpaque(&bitmap, false);
        paint.setDither(false);
        canvas->drawBitmap(bitmap, 0, 0, &paint);
        paint.setDither(true);
        canvas->drawBitmap(bitmap, 0, SkIntToScalar(bm.height() + 10), &paint);

        setBitmapOpaque(&bitmap, true);
        SkScalar x = SkIntToScalar(bm.width() + 10);
        paint.setDither(false);
        canvas->drawBitmap(bitmap, x, 0, &paint);
        paint.setDither(true);
        canvas->drawBitmap(bitmap, x, SkIntToScalar(bm.height() + 10), &paint);
    }

// Make sure our blits always map src==0 to a noop, and src==FF to full opaque
static void test_00_FF(skiatest::Reporter* reporter) {
    static const int W = 256;

    static const SkBitmap::Config gDstConfig[] = {
        SkBitmap::kARGB_8888_Config,
        SkBitmap::kRGB_565_Config,
//        SkBitmap::kARGB_4444_Config,
//        SkBitmap::kA8_Config,
    };

    static const struct {
        SkColor     fSrc;
        SkColor     fDst;
        SkPMColor   fResult32;
        uint16_t    fResult16;
        uint8_t     fResult8;
    } gSrcRec[] = {
        { 0,            0,          0,                                    0,      0 },
        { 0,            0xFFFFFFFF, SkPackARGB32(0xFF, 0xFF, 0xFF, 0xFF), 0xFFFF, 0xFF },
        { 0xFFFFFFFF,   0,          SkPackARGB32(0xFF, 0xFF, 0xFF, 0xFF), 0xFFFF, 0xFF },
        { 0xFFFFFFFF,   0xFFFFFFFF, SkPackARGB32(0xFF, 0xFF, 0xFF, 0xFF), 0xFFFF, 0xFF },
    };

    SkPaint paint;

    SkBitmap srcBM;
    srcBM.setConfig(SkBitmap::kARGB_8888_Config, W, 1);
    srcBM.allocPixels();

    for (size_t i = 0; i < SK_ARRAY_COUNT(gDstConfig); i++) {
        SkBitmap dstBM;
        dstBM.setConfig(gDstConfig[i], W, 1);
        dstBM.allocPixels();
        
        SkCanvas canvas(dstBM);
        for (size_t j = 0; j < SK_ARRAY_COUNT(gSrcRec); j++) {
            srcBM.eraseColor(gSrcRec[j].fSrc);
            dstBM.eraseColor(gSrcRec[j].fDst);

            for (int k = 0; k < 4; k++) {
                bool dither = (k & 1) != 0;
                bool blend = (k & 2) != 0;
                if (gSrcRec[j].fSrc != 0 && blend) {
                    // can't make a numerical promise about blending anything
                    // but 0
                 //   continue;
                }
                paint.setDither(dither);
                paint.setAlpha(blend ? 0x80 : 0xFF);
                canvas.drawBitmap(srcBM, 0, 0, &paint);
                if (!check_color(dstBM, gSrcRec[j].fResult32, gSrcRec[j].fResult16,
                                 gSrcRec[j].fResult8, reporter)) {
                    SkDebugf("--- src index %d dither %d blend %d\n", j, dither, blend);
                }
            }
        }
    }
}

void Gradient::applyToPaint(SkPaint& paint, const SkMatrix& localMatrix) {
  if (!m_cachedShader || localMatrix != m_cachedShader->getLocalMatrix())
    m_cachedShader = createShader(localMatrix);

  paint.setShader(m_cachedShader);

  // Legacy behavior: gradients are always dithered.
  paint.setDither(true);
}

void Gradient::applyToPaint(SkPaint& paint)
{
    if (!m_gradient)
        m_gradient = createShader();

    paint.setShader(m_gradient);

    // Legacy behavior: gradients are always dithered.
    paint.setDither(true);
}

static void show_ramp(SkCanvas* canvas, const SkRect& r) {
    SkPoint pts[] = { r.fLeft, 0, r.fRight, 0 };
    SkColor colors[] = { SK_ColorRED, SK_ColorBLUE };
    SkShader* s = SkGradientShader::CreateLinear(pts, colors, NULL, 2,
                                                 SkShader::kRepeat_TileMode);
    SkPaint p;
    p.setShader(s)->unref();
    canvas->drawRect(r, p);
    canvas->translate(r.width() + SkIntToScalar(8), 0);
    p.setDither(true);
    canvas->drawRect(r, p);
}

static void draw_gradient(SkCanvas* canvas) {
    SkRect r = { 0, 0, SkIntToScalar(256), SkIntToScalar(32) };
    SkPoint pts[] = { { r.fLeft, r.fTop }, { r.fRight, r.fTop } };
    SkColor colors[] = { 0xFF000000, 0xFFFF0000 };
    SkPaint p;
    p.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, 2, SkShader::kClamp_TileMode));
    draw_rect(canvas, r, p);

    canvas->translate(0, SkIntToScalar(40));
    p.setDither(true);
    draw_rect(canvas, r, p);
}

static SkPaint make_paint() {
    SkPaint paint;
    if (fuzz->exhausted()) {
        return paint;
    }
    paint.setHinting(make_paint_hinting());
    paint.setAntiAlias(make_bool());
    paint.setDither(make_bool());
    paint.setLinearText(make_bool());
    paint.setSubpixelText(make_bool());
    paint.setLCDRenderText(make_bool());
    paint.setEmbeddedBitmapText(make_bool());
    paint.setAutohinted(make_bool());
    paint.setVerticalText(make_bool());
    paint.setFakeBoldText(make_bool());
    paint.setDevKernText(make_bool());
    paint.setFilterQuality(make_filter_quality());
    paint.setStyle(make_paint_style());
    paint.setColor(make_color());
    paint.setStrokeWidth(make_number(false));
    paint.setStrokeMiter(make_number(false));
    paint.setStrokeCap(make_paint_cap());
    paint.setStrokeJoin(make_paint_join());
    paint.setColorFilter(make_color_filter());
    paint.setBlendMode(make_blendmode());
    paint.setPathEffect(make_path_effect());
    paint.setMaskFilter(make_mask_filter());

    if (false) {
        // our validating buffer does not support typefaces yet, so skip this for now
        paint.setTypeface(SkTypeface::MakeFromName(make_font_name().c_str(),make_typeface_style()));
    }

    SkLayerRasterizer::Builder rasterizerBuilder;
    SkPaint paintForRasterizer;
    if (make_bool()) {
        paintForRasterizer = make_paint();
    }
    rasterizerBuilder.addLayer(paintForRasterizer);
    paint.setRasterizer(rasterizerBuilder.detach());
    paint.setImageFilter(make_image_filter());
    bool a, b, c;
    fuzz->next(&a, &b, &c);
    sk_sp<SkData> data(make_3Dlut(nullptr, a, b, c));
    paint.setTextAlign(make_paint_align());
    SkScalar d, e, f;
    fuzz->next(&d, &e, &f);
    paint.setTextSize(d);
    paint.setTextScaleX(e);
    paint.setTextSkewX(f);
    paint.setTextEncoding(make_paint_text_encoding());
    return paint;
}

        virtual void onDrawContent(SkCanvas* canvas)
            {
            canvas->translate(SkIntToScalar(10), SkIntToScalar(50));

            const SkScalar W = SkIntToScalar(fBitmaps[0].width() + 1);
            const SkScalar H = SkIntToScalar(fBitmaps[0].height() + 1);
            SkPaint paint;

            const SkScalar scale = SkFloatToScalar(0.897917f);
            canvas->scale(SK_Scalar1, scale);

            for (int k = 0; k < 2; k++)
                {
                paint.setFilterBitmap(k == 1);
                for (int j = 0; j < 2; j++)
                    {
                    paint.setDither(j == 1);
                    for (int i = 0; i < fBitmapCount; i++)
                        {
                        SkScalar x = (k * fBitmapCount + j) * W;
                        SkScalar y = i * H;
                        x = SkIntToScalar(SkScalarRound(x));
                        y = SkIntToScalar(SkScalarRound(y));
                        canvas->drawBitmap(fBitmaps[i], x, y, &paint);
                        if (i == 0)
                            {
                            SkPaint p;
                            p.setAntiAlias(true);
                            p.setTextAlign(SkPaint::kCenter_Align);
                            p.setTextSize(SkIntToScalar(18));
                            SkString s("dither=");
                            s.appendS32(paint.isDither());
                            s.append(" filter=");
                            s.appendS32(paint.isFilterBitmap());
                            canvas->drawText(s.c_str(), s.size(), x + W/2,
                                             y - p.getTextSize(), p);
                            }
                        if (k+j == 2)
                            {
                            SkPaint p;
                            p.setAntiAlias(true);
                            p.setTextSize(SkIntToScalar(18));
                            SkString s;
                            s.append(" depth=");
                            s.appendS32(fBitmaps[i].config() == SkBitmap::kRGB_565_Config ? 16 : 32);
                            canvas->drawText(s.c_str(), s.size(), x + W + SkIntToScalar(4),
                                             y + H/2, p);
                            }
                        }
                    }
                }
            }

    void onDraw(SkCanvas* canvas) override {
        const SkColor colors[] = { sk_tool_utils::color_to_565(0xFF555555), 
                sk_tool_utils::color_to_565(0xFF444444) };
        const int colorCount = SK_ARRAY_COUNT(colors);

        SkRect r = { 0, 0, this->width(), this->height() };
        SkSize size = SkSize::Make(r.width(), r.height());

        SkPaint paint;
        paint.setShader(fProc(colors, colorCount, size))->unref();
        paint.setDither(fDither);
        canvas->drawRect(r, paint);
    }

    virtual void onDrawContent(SkCanvas* canvas) {
        SkPaint paint;

        paint.setAntiAlias(true);
        paint.setStyle(SkPaint::kStroke_Style);
        paint.setStrokeWidth(SkIntToScalar(10));
        paint.setMaskFilter(new SkEmbossMaskFilter(fLight, SkIntToScalar(4)))->unref();
        paint.setShader(new SkColorShader(SK_ColorBLUE))->unref();
        paint.setDither(true);

        canvas->drawCircle(SkIntToScalar(50), SkIntToScalar(50),
                           SkIntToScalar(30), paint);
    }