C++ SkScalerContext类代码示例

uint16_t SkScalerContext::charToGlyphID(SkUnichar uni) {
    unsigned glyphID = this->generateCharToGlyph(uni);

    if (0 == glyphID) {   // try auxcontext
        SkScalerContext* ctx = this->loadAuxContext();
        if (NULL != ctx) {
            glyphID = ctx->generateCharToGlyph(uni);
            if (0 != glyphID) {   // only fiddle with it if its not missing
                glyphID += this->getGlyphCount();
                if (glyphID > 0xFFFF) {
                    glyphID = 0;
                }
            }
        }
    }
#ifdef TRACK_MISSING_CHARS
    if (0 == glyphID) {
        bool announce = false;
        if (uni > 0xFFFF) {   // we don't record these
            announce = true;
        } else {
            unsigned index = uni >> 3;
            unsigned mask = 1 << (uni & 7);
            SkASSERT(index < SK_ARRAY_COUNT(gMissingChars));
            if ((gMissingChars[index] & mask) == 0) {
                gMissingChars[index] |= mask;
                announce = true;
            }
        }
        if (announce) {
            printf(">>> MISSING CHAR <<< 0x%04X\n", uni);
        }
    }

SkScalerContext* SkScalerContext::getContextFromChar(SkUnichar uni, unsigned& glyphID) {
    SkScalerContext* ctx = this;
    for (;;) {
        glyphID = ctx->generateCharToGlyph(uni);
        if (glyphID) {
            break;  // found it
        }
        ctx = ctx->getNextContext();
        if (NULL == ctx) {
            return NULL;
        }
    }
    return ctx;
}

SkUnichar SkScalerContext::glyphIDToChar(uint16_t glyphID) {
    SkScalerContext* ctx = this;
    unsigned rangeEnd = 0;
    do {
        unsigned rangeStart = rangeEnd;

        rangeEnd += ctx->getGlyphCount();
        if (rangeStart <= glyphID && glyphID < rangeEnd) {
            return ctx->generateGlyphToChar(glyphID - rangeStart);
        }
        ctx = ctx->getNextContext();
    } while (NULL != ctx);
    return 0;
}

/*  Return the next context, creating it if its not already created, but return
    NULL if the fonthost says there are no more fonts to fallback to.
 */
SkScalerContext* SkScalerContext::getNextContext() {
    SkScalerContext* next = fNextContext;
    // if next is null, then either it isn't cached yet, or we're at the
    // end of our possible chain
    if (NULL == next) {
        next = allocNextContext(fRec);
        if (NULL == next) {
            return NULL;
        }
        // next's base is our base + our local count
        next->setBaseGlyphCount(fBaseGlyphCount + this->getGlyphCount());
        // cache the answer
        fNextContext = next;
    }
    return next;
}

/*  This loops through all available fallback contexts (if needed) until it
    finds some context that can handle the unichar and return it.

    As this is somewhat expensive operation, it should only be done on the first
    char of a run.
 */
unsigned SkScalerContext::getBaseGlyphCount(SkUnichar uni) {
    SkScalerContext* ctx = this;
    unsigned glyphID;
    for (;;) {
        glyphID = ctx->generateCharToGlyph(uni);
        if (glyphID) {
            break;  // found it
        }
        ctx = ctx->getNextContext();
        if (NULL == ctx) {
            SkDebugf("--- no context for char %x\n", uni);
            // just return the original context (this)
            return this->fBaseGlyphCount;
        }
    }
    return ctx->fBaseGlyphCount;
}

SkScalerContext* SkScalerContext::getGlyphContext(const SkGlyph& glyph) {
    unsigned glyphID = glyph.getGlyphID();
    SkScalerContext* ctx = this;
    for (;;) {
        unsigned count = ctx->getGlyphCount();
        if (glyphID < count) {
            break;
        }
        glyphID -= count;
        ctx = ctx->getNextContext();
        if (NULL == ctx) {
            SkDebugf("--- no context for glyph %x\n", glyph.getGlyphID());
            // just return the original context (this)
            return this;
        }
    }
    return ctx;
}

SkScalerContext* SkScalerContext::getContextFromChar(SkUnichar uni,
                                                     uint16_t* glyphID) {
    SkScalerContext* ctx = this;
    for (;;) {
        const uint16_t glyph = ctx->generateCharToGlyph(uni);
        if (glyph) {
            if (NULL != glyphID) {
                *glyphID = glyph;
            }
            break;  // found it
        }
        ctx = ctx->getNextContext();
        if (NULL == ctx) {
            return NULL;
        }
    }
    return ctx;
}

/*  This loops through all available fallback contexts (if needed) until it
    finds some context that can handle the unichar. If all fail, returns 0
 */
uint16_t SkScalerContext::charToGlyphID(SkUnichar uni) {
    SkScalerContext* ctx = this;
    unsigned glyphID;
    for (;;) {
        glyphID = ctx->generateCharToGlyph(uni);
        if (glyphID) {
            break;  // found it
        }
        ctx = ctx->getNextContext();
        if (NULL == ctx) {
            return 0;   // no more contexts, return missing glyph
        }
    }
    // add the ctx's base, making glyphID unique for chain of contexts
    glyphID += ctx->fBaseGlyphCount;
    // check for overflow of 16bits, since our glyphID cannot exceed that
    if (glyphID > 0xFFFF) {
        glyphID = 0;
    }
    return SkToU16(glyphID);
}

void SkGScalerContext::generateMetrics(SkGlyph* glyph) {
    fProxy->getMetrics(glyph);

    SkVector advance;
    fMatrix.mapXY(SkFloatToScalar(glyph->fAdvanceX),
                  SkFloatToScalar(glyph->fAdvanceY), &advance);
    glyph->fAdvanceX = SkScalarToFloat(advance.fX);
    glyph->fAdvanceY = SkScalarToFloat(advance.fY);

    SkPath path;
    fProxy->getPath(*glyph, &path);
    path.transform(fMatrix);

    SkRect storage;
    const SkPaint& paint = fFace->paint();
    const SkRect& newBounds = paint.doComputeFastBounds(path.getBounds(),
                                                        &storage,
                                                        SkPaint::kFill_Style);
    SkIRect ibounds;
    newBounds.roundOut(&ibounds);
    glyph->fLeft = ibounds.fLeft;
    glyph->fTop = ibounds.fTop;
    glyph->fWidth = ibounds.width();
    glyph->fHeight = ibounds.height();
    glyph->fMaskFormat = SkMask::kARGB32_Format;
}

void SkRandomScalerContext::generateMetrics(SkGlyph* glyph) {
    fProxy->getAdvance(glyph);

    SkVector advance;
    fMatrix.mapXY(SkFixedToScalar(glyph->fAdvanceX),
                  SkFixedToScalar(glyph->fAdvanceY), &advance);
    glyph->fAdvanceX = SkScalarToFixed(advance.fX);
    glyph->fAdvanceY = SkScalarToFixed(advance.fY);

    SkPath path;
    fProxy->getPath(*glyph, &path);
    path.transform(fMatrix);

    SkRect storage;
    const SkPaint& paint = fFace->paint();
    const SkRect& newBounds = paint.doComputeFastBounds(path.getBounds(),
                                                        &storage,
                                                        SkPaint::kFill_Style);
    SkIRect ibounds;
    newBounds.roundOut(&ibounds);
    glyph->fLeft = ibounds.fLeft;
    glyph->fTop = ibounds.fTop;
    glyph->fWidth = ibounds.width();
    glyph->fHeight = ibounds.height();

    // Here we will change the mask format of the glyph
    // NOTE this is being overridden by the base class
    SkMask::Format format;
    switch (glyph->getGlyphID() % 6) {
        case 0:
            format = SkMask::kLCD16_Format;
            break;
        case 1:
            format = SkMask::kA8_Format;
            break;
        case 2:
            format = SkMask::kARGB32_Format;
            break;
        default:
            // we will fiddle with these in generate image
            format = (SkMask::Format)MASK_FORMAT_UNKNOWN;
    }

    glyph->fMaskFormat = format;
}

void SkGScalerContext::generateAdvance(SkGlyph* glyph) {
    fProxy->getAdvance(glyph);

    SkVector advance;
    fMatrix.mapXY(SkFloatToScalar(glyph->fAdvanceX),
                  SkFloatToScalar(glyph->fAdvanceY), &advance);
    glyph->fAdvanceX = SkScalarToFloat(advance.fX);
    glyph->fAdvanceY = SkScalarToFloat(advance.fY);
}

void SkGScalerContext::generateImage(const SkGlyph& glyph) {
    if (SkMask::kARGB32_Format == glyph.fMaskFormat) {
        SkPath path;
        fProxy->getPath(glyph, &path);

        SkBitmap bm;
        bm.installPixels(SkImageInfo::MakeN32Premul(glyph.fWidth, glyph.fHeight),
                         glyph.fImage, glyph.rowBytes());
        bm.eraseColor(0);

        SkCanvas canvas(bm);
        canvas.translate(-SkIntToScalar(glyph.fLeft),
                         -SkIntToScalar(glyph.fTop));
        canvas.concat(fMatrix);
        canvas.drawPath(path, fFace->paint());
    } else {
        fProxy->getImage(glyph);
    }
}

void SkRandomScalerContext::generateImage(const SkGlyph& glyph) {
    SkMask::Format format = (SkMask::Format)glyph.fMaskFormat;
    switch (glyph.getGlyphID() % 4) {
        case 0:
            format = SkMask::kLCD16_Format;
            break;
        case 1:
            format = SkMask::kA8_Format;
            break;
        case 2:
            format = SkMask::kARGB32_Format;
            break;
        case 3:
            format = SkMask::kBW_Format;
            break;
    }
    const_cast<SkGlyph&>(glyph).fMaskFormat = format;

    // if the format is ARGB, we just draw the glyph from path ourselves.  Otherwise, we force
    // our proxy context to generate the image from paths.
    if (!fFakeIt) {
        if (SkMask::kARGB32_Format == glyph.fMaskFormat) {
            SkPath path;
            fProxy->getPath(glyph, &path);

            SkBitmap bm;
            bm.installPixels(SkImageInfo::MakeN32Premul(glyph.fWidth, glyph.fHeight),
                             glyph.fImage, glyph.rowBytes());
            bm.eraseColor(0);

            SkCanvas canvas(bm);
            canvas.translate(-SkIntToScalar(glyph.fLeft),
                             -SkIntToScalar(glyph.fTop));
            canvas.drawPath(path, fFace->paint());
        } else {
            fProxy->forceGenerateImageFromPath();
            fProxy->getImage(glyph);
            fProxy->forceOffGenerateImageFromPath();
        }
    } else {
        sk_bzero(glyph.fImage, glyph.computeImageSize());
    }
}

void SkGScalerContext::generateFontMetrics(SkPaint::FontMetrics* metrics) {
    fProxy->getFontMetrics(metrics);
    if (metrics) {
        SkScalar scale = fMatrix.getScaleY();
        metrics->fTop = SkScalarMul(metrics->fTop, scale);
        metrics->fAscent = SkScalarMul(metrics->fAscent, scale);
        metrics->fDescent = SkScalarMul(metrics->fDescent, scale);
        metrics->fBottom = SkScalarMul(metrics->fBottom, scale);
        metrics->fLeading = SkScalarMul(metrics->fLeading, scale);
        metrics->fAvgCharWidth = SkScalarMul(metrics->fAvgCharWidth, scale);
        metrics->fXMin = SkScalarMul(metrics->fXMin, scale);
        metrics->fXMax = SkScalarMul(metrics->fXMax, scale);
        metrics->fXHeight = SkScalarMul(metrics->fXHeight, scale);
    }
}

void SkRandomScalerContext::generateFontMetrics(SkPaint::FontMetrics* metrics) {
    fProxy->getFontMetrics(metrics);
}