C++ SkFont类代码示例

static void drawKernText(SkCanvas* canvas, const void* text, size_t len,
                         SkScalar x, SkScalar y, const SkFont& font, const SkPaint& paint) {
    SkTypeface* face = font.getTypefaceOrDefault();
    if (!face) {
        canvas->drawSimpleText(text, len, SkTextEncoding::kUTF8, x, y, font, paint);
        return;
    }

    SkAutoSTMalloc<128, uint16_t> glyphStorage(len);
    uint16_t* glyphs = glyphStorage.get();
    int glyphCount = font.textToGlyphs(text, len, SkTextEncoding::kUTF8, glyphs, len);
    if (glyphCount < 1) {
        return;
    }

    SkAutoSTMalloc<128, int32_t> adjustmentStorage(glyphCount - 1);
    int32_t* adjustments = adjustmentStorage.get();
    if (!face->getKerningPairAdjustments(glyphs, glyphCount, adjustments)) {
        canvas->drawSimpleText(text, len, SkTextEncoding::kUTF8, x, y, font, paint);
        return;
    }


    SkTextBlobBuilder builder;
    auto rec = builder.allocRunPos(font, glyphCount);
    memcpy(rec.glyphs, glyphs, glyphCount * sizeof(SkGlyphID));
    getGlyphPositions(font, glyphs, glyphCount, x, y, rec.points());
    applyKerning(rec.points(), adjustments, glyphCount, font);

    canvas->drawTextBlob(builder.make(), 0, 0, paint);
}

DEF_TEST(TextBlob_extended, reporter) {
    SkTextBlobBuilder textBlobBuilder;
    SkFont font;
    const char text1[] = "Foo";
    const char text2[] = "Bar";

    int glyphCount = font.countText(text1, strlen(text1), SkTextEncoding::kUTF8);
    SkAutoTMalloc<uint16_t> glyphs(glyphCount);
    (void)font.textToGlyphs(text1, strlen(text1), SkTextEncoding::kUTF8, glyphs.get(), glyphCount);

    auto run = SkTextBlobBuilderPriv::AllocRunText(&textBlobBuilder,
            font, glyphCount, 0, 0, SkToInt(strlen(text2)), SkString(), nullptr);
    memcpy(run.glyphs, glyphs.get(), sizeof(uint16_t) * glyphCount);
    memcpy(run.utf8text, text2, strlen(text2));
    for (int i = 0; i < glyphCount; ++i) {
        run.clusters[i] = SkTMin(SkToU32(i), SkToU32(strlen(text2)));
    }
    sk_sp<SkTextBlob> blob(textBlobBuilder.make());
    REPORTER_ASSERT(reporter, blob);

    for (SkTextBlobRunIterator it(blob.get()); !it.done(); it.next()) {
        REPORTER_ASSERT(reporter, it.glyphCount() == (uint32_t)glyphCount);
        for (uint32_t i = 0; i < it.glyphCount(); ++i) {
            REPORTER_ASSERT(reporter, it.glyphs()[i] == glyphs[i]);
        }
        REPORTER_ASSERT(reporter, SkTextBlobRunIterator::kDefault_Positioning == it.positioning());
        REPORTER_ASSERT(reporter, (SkPoint{0.0f, 0.0f}) == it.offset());
        REPORTER_ASSERT(reporter, it.textSize() > 0);
        REPORTER_ASSERT(reporter, it.clusters());
        for (uint32_t i = 0; i < it.glyphCount(); ++i) {
            REPORTER_ASSERT(reporter, i == it.clusters()[i]);
        }
        REPORTER_ASSERT(reporter, 0 == strncmp(text2, it.text(), it.textSize()));
    }
}

void draw(SkCanvas* canvas) {
    SkFont font;
    font.setSize(24);
    SkPaint canvasPaint;
    canvasPaint.setColor(SK_ColorBLUE); // respected
    canvasPaint.setTextSize(2); // ignored
    sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromString("Hello World", font);
    canvas->drawTextBlob(blob, 20, 20, canvasPaint);
}

static void applyKerning(SkPoint pos[], const int32_t adjustments[], int count,
                         const SkFont& font) {
    SkScalar scale = font.getSize() / font.getTypefaceOrDefault()->getUnitsPerEm();

    SkScalar globalAdj = 0;
    for (int i = 0; i < count - 1; ++i) {
        globalAdj += adjustments[i] * scale;
        pos[i + 1].fX += globalAdj;
    }
}

void draw(SkCanvas* canvas) {
    SkFont blobFont;
    blobFont.setSize(24);
    sk_sp<SkTextBlob> blob = SkTextBlob::MakeFromText("Hello World", 11, blobFont);
    char storage[2048];
    size_t used = blob->serialize(SkSerialProcs(), storage, sizeof(storage));
    sk_sp<SkTextBlob> copy = SkTextBlob::Deserialize(storage, used, SkDeserialProcs());
    canvas->drawTextBlob(copy, 20, 20, SkPaint());
    std::string usage = "size=" + std::to_string(sizeof(storage)) + " used=" + std::to_string(used);
    canvas->drawString(usage.c_str(), 20, 40, SkPaint());
}

static sk_sp<SkPicture> make_picture(sk_sp<SkTypeface> tf0, sk_sp<SkTypeface> tf1) {
    SkPictureRecorder rec;
    SkCanvas* canvas = rec.beginRecording(100, 100);
    SkPaint paint;
    SkFont font;
    font.setTypeface(tf0); canvas->drawString("hello", 0, 0, font, paint);
    font.setTypeface(tf1); canvas->drawString("hello", 0, 0, font, paint);
    font.setTypeface(tf0); canvas->drawString("hello", 0, 0, font, paint);
    font.setTypeface(tf1); canvas->drawString("hello", 0, 0, font, paint);
    return rec.finishRecordingAsPicture();
}

void draw(SkCanvas* canvas) {
    SkTextBlobBuilder textBlobBuilder;
    SkFont font;
    font.setSize(50);
    const SkTextBlobBuilder::RunBuffer& run =
            textBlobBuilder.allocRun(font, 1, 20, 100);
    run.glyphs[0] = 20;
    sk_sp<const SkTextBlob> blob = textBlobBuilder.make();
    SkPaint paint;
    paint.setColor(SK_ColorBLUE);
    canvas->drawTextBlob(blob.get(), 0, 0, paint);
}

    void onDraw(int loops, SkCanvas* canvas) override {
        SkFont font;
        font.setEdging(SkFont::Edging::kAntiAlias);

        const uint16_t* array = gUniqueGlyphIDs;
        while (*array != gUniqueGlyphIDs_Sentinel) {
            int count = count_glyphs(array);
            for (int i = 0; i < loops; ++i) {
                (void)font.measureText(array, count * sizeof(uint16_t), SkTextEncoding::kGlyphID);
            }
            array += count + 1;    // skip the sentinel
        }
    }

SkFont GrTextContext::InitDistanceFieldFont(const SkFont& font,
                                            const SkMatrix& viewMatrix,
                                            const Options& options,
                                            SkScalar* textRatio) {
    SkScalar textSize = font.getSize();
    SkScalar scaledTextSize = scaled_text_size(textSize, viewMatrix);

    SkFont dfFont{font};

    if (scaledTextSize <= kSmallDFFontLimit) {
        *textRatio = textSize / kSmallDFFontSize;
        dfFont.setSize(SkIntToScalar(kSmallDFFontSize));
    } else if (scaledTextSize <= kMediumDFFontLimit) {
        *textRatio = textSize / kMediumDFFontSize;
        dfFont.setSize(SkIntToScalar(kMediumDFFontSize));
    } else {
        *textRatio = textSize / kLargeDFFontSize;
        dfFont.setSize(SkIntToScalar(kLargeDFFontSize));
    }

    dfFont.setEdging(SkFont::Edging::kAntiAlias);
    dfFont.setForceAutoHinting(false);
    dfFont.setHinting(SkFontHinting::kNormal);

    // The sub-pixel position will always happen when transforming to the screen.
    dfFont.setSubpixel(false);
    return dfFont;
}

    void drawText(SkCanvas* canvas) {
        static const int kSizes[] = {8, 9, 10, 11, 12, 13, 18, 20, 25};

        static const SkString kTexts[] = {SkString("ABCDEFGHIJKLMNOPQRSTUVWXYZ"),
                                          SkString("abcdefghijklmnopqrstuvwxyz"),
                                          SkString("0123456789"),
                                          SkString("[email protected]#$%^&*()<>[]{}")};
        SkFont font;
        font.setEdging(SkFont::Edging::kAntiAlias);
        font.setSubpixel(true);

        static const SkScalar kSubPixelInc = 1 / 2.f;
        SkScalar x = 0;
        SkScalar y = 10;
        SkScalar subpixelX = 0;
        SkScalar subpixelY = 0;
        bool offsetX = true;

        if (GrContextOptions::Enable::kYes == fAllowMultipleTextures) {
            canvas->scale(10, 10);
        }

        do {
            for (auto s : kSizes) {
                auto size = 2 * s;
                font.setSize(size);
                for (const auto& typeface : fTypefaces) {
                    font.setTypeface(typeface);
                    for (const auto& text : kTexts) {
                        x = size + draw_string(canvas, text, x + subpixelX, y + subpixelY, font);
                        x = SkScalarCeilToScalar(x);
                        if (x + 100 > kSize) {
                            x = 0;
                            y += SkScalarCeilToScalar(size + 3);
                            if (y > kSize) {
                                return;
                            }
                        }
                    }
                }
                (offsetX ? subpixelX : subpixelY) += kSubPixelInc;
                offsetX = !offsetX;
            }
        } while (true);
    }

static void draw_scene(SkCanvas* canvas, const SkHighContrastConfig& config) {
    SkRect bounds = SkRect::MakeLTRB(0.0f, 0.0f, 1.0f, 1.0f);
    SkPaint xferPaint;
    xferPaint.setColorFilter(SkHighContrastFilter::Make(config));
    canvas->saveLayer(&bounds, &xferPaint);

    SkPaint paint;
    bounds = SkRect::MakeLTRB(0.1f, 0.2f, 0.9f, 0.4f);
    paint.setARGB(0xff, 0x66, 0x11, 0x11);
    canvas->drawRect(bounds, paint);

    SkFont font;
    font.setSize(0.15f);
    font.setEdging(SkFont::Edging::kAlias);

    paint.setARGB(0xff, 0xbb, 0x77, 0x77);
    canvas->drawString("A", 0.15f, 0.35f, font, paint);

    bounds = SkRect::MakeLTRB(0.1f, 0.8f, 0.9f, 1.0f);
    paint.setARGB(0xff, 0xcc, 0xcc, 0xff);
    canvas->drawRect(bounds, paint);

    paint.setARGB(0xff, 0x88, 0x88, 0xbb);
    canvas->drawString("Z", 0.75f, 0.95f, font, paint);

    bounds = SkRect::MakeLTRB(0.1f, 0.4f, 0.9f, 0.6f);
    SkPoint     pts[] = { { 0, 0 }, { 1, 0 } };
    SkColor     colors[] = { SK_ColorWHITE, SK_ColorBLACK };
    SkScalar    pos[] = { 0.2f, 0.8f };
    paint.setShader(SkGradientShader::MakeLinear(
        pts, colors, pos,
        SK_ARRAY_COUNT(colors), SkTileMode::kClamp));
    canvas->drawRect(bounds, paint);

    bounds = SkRect::MakeLTRB(0.1f, 0.6f, 0.9f, 0.8f);
    SkColor colors2[] = { SK_ColorGREEN, SK_ColorWHITE };
    paint.setShader(SkGradientShader::MakeLinear(
        pts, colors2, pos,
        SK_ARRAY_COUNT(colors2), SkTileMode::kClamp));
    canvas->drawRect(bounds, paint);

    canvas->restore();
}

static void getGlyphPositions(const SkFont& font, const uint16_t glyphs[],
                             int count, SkScalar x, SkScalar y, SkPoint pos[]) {
    SkAutoSTMalloc<128, SkScalar> widthStorage(count);
    SkScalar* widths = widthStorage.get();
    font.getWidths(glyphs, count, widths);

    for (int i = 0; i < count; ++i) {
        pos[i].set(x, y);
        x += widths[i];
    }
}

    void onDraw(SkCanvas* canvas) override {
        SkFont font;
        font.setSize(30);

        const char* text = fApplyKerning ? "Type AWAY" : "Hamburgefons";
        const size_t textLen = strlen(text);

        SkScalar x = SkIntToScalar(10);
        SkScalar dy = font.getMetrics(nullptr);
        SkScalar y = dy;

        if (fApplyKerning) {
            font.setSubpixel(true);
        } else {
            font.setLinearMetrics(true);
        }

        SkPaint paint;
        for (int i = 0; i < gStylesCount; i++) {
            font.setTypeface(fFaces[i]);
            canvas->drawSimpleText(text, textLen, SkTextEncoding::kUTF8, x, y, font, paint);
            if (fApplyKerning) {
                drawKernText(canvas, text, textLen, x + 240, y, font, paint);
            }
            y += dy;
        }
    }

static void make_big_bitmap(SkBitmap* bm) {
    static const char gText[] =
        "We the people, in order to form a more perfect union, establish justice,"
        " ensure domestic tranquility, provide for the common defense, promote the"
        " general welfare and ensure the blessings of liberty to ourselves and our"
        " posterity, do ordain and establish this constitution for the United"
        " States of America.";

    const int BIG_H = 120;

    SkFont font;
    font.setSize(SkIntToScalar(BIG_H));

    const int BIG_W = SkScalarRoundToInt(font.measureText(gText, strlen(gText), SkTextEncoding::kUTF8));

    bm->allocN32Pixels(BIG_W, BIG_H);
    bm->eraseColor(SK_ColorWHITE);

    SkCanvas canvas(*bm);

    canvas.drawSimpleText(gText, strlen(gText), SkTextEncoding::kUTF8, 0, font.getSize()*4/5, font, SkPaint());
}

void SkTextUtils::GetPath(const void* text, size_t length, SkTextEncoding encoding,
                          SkScalar x, SkScalar y, const SkFont& font, SkPath* path) {
    SkAutoToGlyphs ag(font, text, length, encoding);
    SkAutoTArray<SkPoint> pos(ag.count());
    font.getPos(ag.glyphs(), ag.count(), pos.get(), {x, y});

    struct Rec {
        SkPath* fDst;
        const SkPoint* fPos;
    } rec = { path, pos.get() };

    path->reset();
    font.getPaths(ag.glyphs(), ag.count(), [](const SkPath* src, const SkMatrix& mx, void* ctx) {
        Rec* rec = (Rec*)ctx;
        if (src) {
            SkMatrix m(mx);
            m.postTranslate(rec->fPos->fX, rec->fPos->fY);
            rec->fDst->addPath(*src, m);
        }
        rec->fPos += 1;
    }, &rec);
}