C++ SkSize类代码示例

static SkVector map_sigma(const SkSize& localSigma, const SkMatrix& ctm) {
    SkVector sigma = SkVector::Make(localSigma.width(), localSigma.height());
    ctm.mapVectors(&sigma, 1);
    sigma.fX = SkMinScalar(SkScalarAbs(sigma.fX), MAX_SIGMA);
    sigma.fY = SkMinScalar(SkScalarAbs(sigma.fY), MAX_SIGMA);
    return sigma;
}

bool SkBitmapController::State::processHighRequest(const SkBitmapProvider& provider) {
    if (fQuality != kHigh_SkFilterQuality) {
        return false;
    }

    fQuality = kMedium_SkFilterQuality;

    SkScalar invScaleX = fInvMatrix.getScaleX();
    SkScalar invScaleY = fInvMatrix.getScaleY();
    if (fInvMatrix.getType() & SkMatrix::kAffine_Mask) {
        SkSize scale;
        if (!fInvMatrix.decomposeScale(&scale)) {
            return false;
        }
        invScaleX = scale.width();
        invScaleY = scale.height();
    }
    invScaleX = SkScalarAbs(invScaleX);
    invScaleY = SkScalarAbs(invScaleY);

    if (invScaleX >= 1 - SK_ScalarNearlyZero || invScaleY >= 1 - SK_ScalarNearlyZero) {
        // we're down-scaling so abort HQ
        return false;
    }

    // Confirmed that we can use HQ (w/ rasterpipeline)
    fQuality = kHigh_SkFilterQuality;
    (void)provider.asBitmap(&fResultBitmap);
    return true;
}

 void draw(SkCanvas* canvas,
           const SkRect& rect,
           const SkSize& deviceSize,
           SkPaint::FilterLevel filterLevel,
           SkImageFilter* input = NULL) {
     SkRect dstRect;
     canvas->getTotalMatrix().mapRect(&dstRect, rect);
     canvas->save();
     SkScalar deviceScaleX = SkScalarDiv(deviceSize.width(), dstRect.width());
     SkScalar deviceScaleY = SkScalarDiv(deviceSize.height(), dstRect.height());
     canvas->translate(rect.x(), rect.y());
     canvas->scale(deviceScaleX, deviceScaleY);
     canvas->translate(-rect.x(), -rect.y());
     SkMatrix matrix;
     matrix.setScale(SkScalarInvert(deviceScaleX),
                     SkScalarInvert(deviceScaleY));
     SkAutoTUnref<SkImageFilter> imageFilter(
         SkMatrixImageFilter::Create(matrix, filterLevel, input));
     SkPaint filteredPaint;
     filteredPaint.setImageFilter(imageFilter.get());
     canvas->saveLayer(&rect, &filteredPaint);
     SkPaint paint;
     paint.setColor(0xFF00FF00);
     SkRect ovalRect = rect;
     ovalRect.inset(SkIntToScalar(4), SkIntToScalar(4));
     canvas->drawOval(ovalRect, paint);
     canvas->restore(); // for saveLayer
     canvas->restore();
 }

/*
 *  High quality is implemented by performing up-right scale-only filtering and then
 *  using bilerp for any remaining transformations.
 */
bool SkDefaultBitmapControllerState::processHQRequest(const SkBitmap& origBitmap) {
    if (fQuality != kHigh_SkFilterQuality) {
        return false;
    }
    
    // Our default return state is to downgrade the request to Medium, w/ or w/o setting fBitmap
    // to a valid bitmap. If we succeed, we will set this to Low instead.
    fQuality = kMedium_SkFilterQuality;
    
    if (kN32_SkColorType != origBitmap.colorType() || !cache_size_okay(origBitmap, fInvMatrix) ||
        fInvMatrix.hasPerspective())
    {
        return false; // can't handle the reqeust
    }
    
    SkScalar invScaleX = fInvMatrix.getScaleX();
    SkScalar invScaleY = fInvMatrix.getScaleY();
    if (fInvMatrix.getType() & SkMatrix::kAffine_Mask) {
        SkSize scale;
        if (!fInvMatrix.decomposeScale(&scale)) {
            return false;
        }
        invScaleX = scale.width();
        invScaleY = scale.height();
    }
    if (SkScalarNearlyEqual(invScaleX, 1) && SkScalarNearlyEqual(invScaleY, 1)) {
        return false; // no need for HQ
    }
    
    SkScalar trueDestWidth  = origBitmap.width() / invScaleX;
    SkScalar trueDestHeight = origBitmap.height() / invScaleY;
    SkScalar roundedDestWidth = SkScalarRoundToScalar(trueDestWidth);
    SkScalar roundedDestHeight = SkScalarRoundToScalar(trueDestHeight);
    
    if (!SkBitmapCache::Find(origBitmap, roundedDestWidth, roundedDestHeight, &fResultBitmap)) {
        SkAutoPixmapUnlock src;
        if (!origBitmap.requestLock(&src)) {
            return false;
        }
        if (!SkBitmapScaler::Resize(&fResultBitmap, src.pixmap(), SkBitmapScaler::RESIZE_BEST,
                                    roundedDestWidth, roundedDestHeight,
                                    SkResourceCache::GetAllocator())) {
            return false; // we failed to create fScaledBitmap
        }
        
        SkASSERT(fResultBitmap.getPixels());
        fResultBitmap.setImmutable();
        SkBitmapCache::Add(origBitmap, roundedDestWidth, roundedDestHeight, fResultBitmap);
    }
    
    SkASSERT(fResultBitmap.getPixels());
    
    fInvMatrix.postScale(roundedDestWidth / origBitmap.width(),
                         roundedDestHeight / origBitmap.height());
    fQuality = kLow_SkFilterQuality;
    return true;
}

/*
 *  Modulo internal errors, this should always succeed *if* the matrix is downscaling
 *  (in this case, we have the inverse, so it succeeds if fInvMatrix is upscaling)
 */
bool SkDefaultBitmapControllerState::processMediumRequest(const SkBitmapProvider& provider) {
    SkASSERT(fQuality <= kMedium_SkFilterQuality);
    if (fQuality != kMedium_SkFilterQuality) {
        return false;
    }

    // Our default return state is to downgrade the request to Low, w/ or w/o setting fBitmap
    // to a valid bitmap.
    fQuality = kLow_SkFilterQuality;

    SkSize invScaleSize;
    if (!fInvMatrix.decomposeScale(&invScaleSize, nullptr)) {
        return false;
    }

    // Use the largest (non-inverse) scale, to ensure anisotropic consistency.
    SkASSERT(invScaleSize.width() >= 0 && invScaleSize.height() >= 0);
    const SkScalar invScale = SkTMin(invScaleSize.width(), invScaleSize.height());

    if (invScale > SK_Scalar1) {
        fCurrMip.reset(SkMipMapCache::FindAndRef(provider.makeCacheDesc()));
        if (nullptr == fCurrMip.get()) {
            SkBitmap orig;
            if (!provider.asBitmap(&orig)) {
                return false;
            }
            fCurrMip.reset(SkMipMapCache::AddAndRef(orig));
            if (nullptr == fCurrMip.get()) {
                return false;
            }
        }
        // diagnostic for a crasher...
        if (nullptr == fCurrMip->data()) {
            sk_throw();
        }

        SkScalar levelScale = SkScalarInvert(invScale);
        SkMipMap::Level level;
        if (fCurrMip->extractLevel(levelScale, &level)) {
            const SkSize& invScaleFixup = level.fScale;
            fInvMatrix.postScale(invScaleFixup.width(), invScaleFixup.height());

            // todo: if we could wrap the fCurrMip in a pixelref, then we could just install
            //       that here, and not need to explicitly track it ourselves.
            return fResultBitmap.installPixels(level.fPixmap);
        } else {
            // failed to extract, so release the mipmap
            fCurrMip.reset(nullptr);
        }
    }
    return false;
}

static bool check_decompScale(const SkMatrix& matrix) {
    SkSize scale;
    SkMatrix remaining;

    if (!matrix.decomposeScale(&scale, &remaining)) {
        return false;
    }
    if (scale.width() <= 0 || scale.height() <= 0) {
        return false;
    }
    remaining.preScale(scale.width(), scale.height());
    return nearly_equal(matrix, remaining);
}

/*
 *  Modulo internal errors, this should always succeed *if* the matrix is downscaling
 *  (in this case, we have the inverse, so it succeeds if fInvMatrix is upscaling)
 */
bool SkDefaultBitmapControllerState::processMediumRequest(const SkBitmapProvider& provider) {
    SkASSERT(fQuality <= kMedium_SkFilterQuality);
    if (fQuality != kMedium_SkFilterQuality) {
        return false;
    }

    // Our default return state is to downgrade the request to Low, w/ or w/o setting fBitmap
    // to a valid bitmap.
    fQuality = kLow_SkFilterQuality;

    SkSize invScaleSize;
    if (!fInvMatrix.decomposeScale(&invScaleSize, nullptr)) {
        return false;
    }

    SkDestinationSurfaceColorMode colorMode = provider.dstColorSpace()
        ? SkDestinationSurfaceColorMode::kGammaAndColorSpaceAware
        : SkDestinationSurfaceColorMode::kLegacy;
    if (invScaleSize.width() > SK_Scalar1 || invScaleSize.height() > SK_Scalar1) {
        fCurrMip.reset(SkMipMapCache::FindAndRef(provider.makeCacheDesc(), colorMode));
        if (nullptr == fCurrMip.get()) {
            SkBitmap orig;
            if (!provider.asBitmap(&orig)) {
                return false;
            }
            fCurrMip.reset(SkMipMapCache::AddAndRef(orig, colorMode));
            if (nullptr == fCurrMip.get()) {
                return false;
            }
        }
        // diagnostic for a crasher...
        SkASSERT_RELEASE(fCurrMip->data());

        const SkSize scale = SkSize::Make(SkScalarInvert(invScaleSize.width()),
                                          SkScalarInvert(invScaleSize.height()));
        SkMipMap::Level level;
        if (fCurrMip->extractLevel(scale, &level)) {
            const SkSize& invScaleFixup = level.fScale;
            fInvMatrix.postScale(invScaleFixup.width(), invScaleFixup.height());

            // todo: if we could wrap the fCurrMip in a pixelref, then we could just install
            //       that here, and not need to explicitly track it ourselves.
            return fResultBitmap.installPixels(level.fPixmap);
        } else {
            // failed to extract, so release the mipmap
            fCurrMip.reset(nullptr);
        }
    }
    return false;
}

/*
 *  Modulo internal errors, this should always succeed *if* the matrix is downscaling
 *  (in this case, we have the inverse, so it succeeds if fInvMatrix is upscaling)
 */
bool SkDefaultBitmapControllerState::processMediumRequest(const SkBitmap& origBitmap) {
    SkASSERT(fQuality <= kMedium_SkFilterQuality);
    if (fQuality != kMedium_SkFilterQuality) {
        return false;
    }
    
    // Our default return state is to downgrade the request to Low, w/ or w/o setting fBitmap
    // to a valid bitmap.
    fQuality = kLow_SkFilterQuality;
    
    SkSize invScaleSize;
    if (!fInvMatrix.decomposeScale(&invScaleSize, NULL)) {
        return false;
    }
    SkScalar invScale = SkScalarSqrt(invScaleSize.width() * invScaleSize.height());
    
    if (invScale > SK_Scalar1) {
        fCurrMip.reset(SkMipMapCache::FindAndRef(origBitmap));
        if (NULL == fCurrMip.get()) {
            fCurrMip.reset(SkMipMapCache::AddAndRef(origBitmap));
            if (NULL == fCurrMip.get()) {
                return false;
            }
        }
        // diagnostic for a crasher...
        if (NULL == fCurrMip->data()) {
            sk_throw();
        }
        
        SkScalar levelScale = SkScalarInvert(invScale);
        SkMipMap::Level level;
        if (fCurrMip->extractLevel(levelScale, &level)) {
            SkScalar invScaleFixup = level.fScale;
            fInvMatrix.postScale(invScaleFixup, invScaleFixup);
            
            const SkImageInfo info = origBitmap.info().makeWH(level.fWidth, level.fHeight);
            // todo: if we could wrap the fCurrMip in a pixelref, then we could just install
            //       that here, and not need to explicitly track it ourselves.
            return fResultBitmap.installPixels(info, level.fPixels, level.fRowBytes);
        } else {
            // failed to extract, so release the mipmap
            fCurrMip.reset(NULL);
        }
    }
    return false;
}

// Here is an example of using Skia’s PDF backend (SkPDF) via the SkDocument
// and SkCanvas APIs.
void WritePDF(SkWStream* outputStream,
              const char* documentTitle,
              void (*writePage)(SkCanvas*, int page),
              int numberOfPages,
              SkSize pageSize) {
    SkPDF::Metadata metadata;
    metadata.fTitle = documentTitle;
    metadata.fCreator = "Example WritePDF() Function";
    metadata.fCreation = {0, 2019, 1, 4, 31, 12, 34, 56};
    metadata.fModified = {0, 2019, 1, 4, 31, 12, 34, 56};
    auto pdfDocument = SkPDF::MakeDocument(outputStream, metadata);
    SkASSERT(pdfDocument);
    for (int page = 0; page < numberOfPages; ++page) {
        SkCanvas* pageCanvas = pdfDocument->beginPage(pageSize.width(),
                                                      pageSize.height());
        writePage(pageCanvas, page);
        pdfDocument->endPage();
    }
    pdfDocument->close();
}

SkShader* SkPictureShader::refBitmapShader(const SkMatrix& matrix, const SkMatrix* localM) const {
    SkASSERT(fPicture && fPicture->width() > 0 && fPicture->height() > 0);

    SkMatrix m;
    m.setConcat(matrix, this->getLocalMatrix());
    if (localM) {
        m.preConcat(*localM);
    }

    // Use a rotation-invariant scale
    SkPoint scale;
    if (!SkDecomposeUpper2x2(m, NULL, &scale, NULL)) {
        // Decomposition failed, use an approximation.
        scale.set(SkScalarSqrt(m.getScaleX() * m.getScaleX() + m.getSkewX() * m.getSkewX()),
                  SkScalarSqrt(m.getScaleY() * m.getScaleY() + m.getSkewY() * m.getSkewY()));
    }
    SkSize scaledSize = SkSize::Make(scale.x() * fPicture->width(), scale.y() * fPicture->height());

    SkISize tileSize = scaledSize.toRound();
    if (tileSize.isEmpty()) {
        return NULL;
    }

    // The actual scale, compensating for rounding.
    SkSize tileScale = SkSize::Make(SkIntToScalar(tileSize.width()) / fPicture->width(),
                                    SkIntToScalar(tileSize.height()) / fPicture->height());

    SkAutoMutexAcquire ama(fCachedBitmapShaderMutex);

    if (!fCachedBitmapShader || tileScale != fCachedTileScale) {
        SkBitmap bm;
        if (!bm.allocN32Pixels(tileSize.width(), tileSize.height())) {
            return NULL;
        }
        bm.eraseColor(SK_ColorTRANSPARENT);

        SkCanvas canvas(bm);
        canvas.scale(tileScale.width(), tileScale.height());
        canvas.drawPicture(fPicture);

        fCachedTileScale = tileScale;

        SkMatrix shaderMatrix = this->getLocalMatrix();
        shaderMatrix.preScale(1 / tileScale.width(), 1 / tileScale.height());
        fCachedBitmapShader.reset(CreateBitmapShader(bm, fTmx, fTmy, &shaderMatrix));
    }

    // Increment the ref counter inside the mutex to ensure the returned pointer is still valid.
    // Otherwise, the pointer may have been overwritten on a different thread before the object's
    // ref count was incremented.
    fCachedBitmapShader.get()->ref();
    return fCachedBitmapShader;
}

bool SkMultiPictureDocumentRead(SkStreamSeekable* stream,
                                SkDocumentPage* dstArray,
                                int dstArrayCount,
                                const SkDeserialProcs* procs) {
    if (!SkMultiPictureDocumentReadPageSizes(stream, dstArray, dstArrayCount)) {
        return false;
    }
    SkSize joined = {0.0f, 0.0f};
    for (int i = 0; i < dstArrayCount; ++i) {
        joined = SkSize{SkTMax(joined.width(), dstArray[i].fSize.width()),
                        SkTMax(joined.height(), dstArray[i].fSize.height())};
    }

    auto picture = SkPicture::MakeFromStream(stream, procs);

    PagerCanvas canvas(joined.toCeil(), dstArray, dstArrayCount);
    // Must call playback(), not drawPicture() to reach
    // PagerCanvas::onDrawAnnotation().
    picture->playback(&canvas);
    if (canvas.fIndex != dstArrayCount) {
        SkDEBUGF("Malformed SkMultiPictureDocument\n");
    }
    return true;
}

bool SkMipMap::extractLevel(const SkSize& scaleSize, Level* levelPtr) const {
    if (nullptr == fLevels) {
        return false;
    }

    SkASSERT(scaleSize.width() >= 0 && scaleSize.height() >= 0);

#ifndef SK_SUPPORT_LEGACY_ANISOTROPIC_MIPMAP_SCALE
    // Use the smallest scale to match the GPU impl.
    const SkScalar scale = SkTMin(scaleSize.width(), scaleSize.height());
#else
    // Ideally we'd pick the smaller scale, to match Ganesh.  But ignoring one of the
    // scales can produce some atrocious results, so for now we use the geometric mean.
    // (https://bugs.chromium.org/p/skia/issues/detail?id=4863)
    const SkScalar scale = SkScalarSqrt(scaleSize.width() * scaleSize.height());
#endif

    if (scale >= SK_Scalar1 || scale <= 0 || !SkScalarIsFinite(scale)) {
        return false;
    }

    SkScalar L = -SkScalarLog2(scale);
    if (!SkScalarIsFinite(L)) {
        return false;
    }
    SkASSERT(L >= 0);
    int level = SkScalarFloorToInt(L);

    SkASSERT(level >= 0);
    if (level <= 0) {
        return false;
    }

    if (level > fCount) {
        level = fCount;
    }
    if (levelPtr) {
        *levelPtr = fLevels[level - 1];
        // need to augment with our colorspace
        levelPtr->fPixmap.setColorSpace(fCS);
    }
    return true;
}

int main() {
    const DrawOptions options = GetDrawOptions();
    if (options.source) {
        sk_sp<SkData> data(SkData::NewFromFileName(options.source));
        if (!data) {
            perror(options.source);
            return 1;
        } else {
            image = SkImage::MakeFromEncoded(std::move(data));
            if (!image) {
                perror("Unable to decode the source image.");
                return 1;
            }
            SkAssertResult(image->asLegacyBitmap(
                                   &source, SkImage::kRO_LegacyBitmapMode));
        }
    }
    sk_sp<SkData> rasterData, gpuData, pdfData, skpData;
    if (options.raster) {
        auto rasterSurface =
                SkSurface::MakeRaster(SkImageInfo::MakeN32Premul(options.size));
        srand(0);
        draw(rasterSurface->getCanvas());
        rasterData.reset(encode_snapshot(rasterSurface));
    }
    if (options.gpu) {
        auto grContext = create_grcontext();
        if (!grContext) {
            fputs("Unable to get GrContext.\n", stderr);
        } else {
            auto surface = SkSurface::MakeRenderTarget(
                    grContext.get(),
                    SkBudgeted::kNo,
                    SkImageInfo::MakeN32Premul(options.size));
            if (!surface) {
                fputs("Unable to get render surface.\n", stderr);
                exit(1);
            }
            srand(0);
            draw(surface->getCanvas());
            gpuData.reset(encode_snapshot(surface));
        }
    }
    if (options.pdf) {
        SkDynamicMemoryWStream pdfStream;
        sk_sp<SkDocument> document(SkDocument::MakePDF(&pdfStream));
        srand(0);
        draw(document->beginPage(options.size.width(), options.size.height()));
        document->close();
        pdfData.reset(pdfStream.copyToData());
    }
    if (options.skp) {
        SkSize size;
        size = options.size;
        SkPictureRecorder recorder;
        srand(0);
        draw(recorder.beginRecording(size.width(), size.height()));
        auto picture = recorder.finishRecordingAsPicture();
        SkDynamicMemoryWStream skpStream;
        picture->serialize(&skpStream);
        skpData.reset(skpStream.copyToData());
    }

    printf("{\n");
    dump_output(rasterData, "Raster", !gpuData && !pdfData && !skpData);
    dump_output(gpuData, "Gpu", !pdfData && !skpData);
    dump_output(pdfData, "Pdf", !skpData);
    dump_output(skpData, "Skp");
    printf("}\n");

    return 0;
}

SkPDFShader::State::State(const SkShader& shader, const SkMatrix& canvasTransform,
                          const SkIRect& bbox, SkScalar rasterScale)
        : fCanvasTransform(canvasTransform),
          fBBox(bbox),
          fPixelGeneration(0) {
    fInfo.fColorCount = 0;
    fInfo.fColors = NULL;
    fInfo.fColorOffsets = NULL;
    fShaderTransform = shader.getLocalMatrix();
    fImageTileModes[0] = fImageTileModes[1] = SkShader::kClamp_TileMode;

    fType = shader.asAGradient(&fInfo);

    if (fType == SkShader::kNone_GradientType) {
        SkShader::BitmapType bitmapType;
        SkMatrix matrix;
        bitmapType = shader.asABitmap(&fImage, &matrix, fImageTileModes);
        if (bitmapType != SkShader::kDefault_BitmapType) {
            // Generic fallback for unsupported shaders:
            //  * allocate a bbox-sized bitmap
            //  * shade the whole area
            //  * use the result as a bitmap shader

            // bbox is in device space. While that's exactly what we want for sizing our bitmap,
            // we need to map it into shader space for adjustments (to match
            // SkPDFImageShader::Create's behavior).
            SkRect shaderRect = SkRect::Make(bbox);
            if (!inverse_transform_bbox(canvasTransform, &shaderRect)) {
                fImage.reset();
                return;
            }

            // Clamp the bitmap size to about 1M pixels
            static const SkScalar kMaxBitmapArea = 1024 * 1024;
            SkScalar bitmapArea = rasterScale * bbox.width() * rasterScale * bbox.height();
            if (bitmapArea > kMaxBitmapArea) {
                rasterScale *= SkScalarSqrt(SkScalarDiv(kMaxBitmapArea, bitmapArea));
            }

            SkISize size = SkISize::Make(SkScalarRoundToInt(rasterScale * bbox.width()),
                                         SkScalarRoundToInt(rasterScale * bbox.height()));
            SkSize scale = SkSize::Make(SkIntToScalar(size.width()) / shaderRect.width(),
                                        SkIntToScalar(size.height()) / shaderRect.height());

            fImage.allocN32Pixels(size.width(), size.height());
            fImage.eraseColor(SK_ColorTRANSPARENT);

            SkPaint p;
            p.setShader(const_cast<SkShader*>(&shader));

            SkCanvas canvas(fImage);
            canvas.scale(scale.width(), scale.height());
            canvas.translate(-shaderRect.x(), -shaderRect.y());
            canvas.drawPaint(p);

            fShaderTransform.setTranslate(shaderRect.x(), shaderRect.y());
            fShaderTransform.preScale(1 / scale.width(), 1 / scale.height());
        } else {
            SkASSERT(matrix.isIdentity());
        }
        fPixelGeneration = fImage.getGenerationID();
    } else {
        AllocateGradientInfoStorage();
        shader.asAGradient(&fInfo);
    }
}

    int checkOval(int* flatCount, int* buldgeCount) {
        int flatc = 0;
        int buldgec = 0;
        const SkScalar rad = SkScalarHalf(fSize.width());
        SkScalar cx = SkScalarHalf(fSize.width());
        SkScalar cy = SkScalarHalf(fSize.height());
        for (int y = 0; y < kILimit; y++) {
            for (int x = 0; x < kILimit; x++) {
                // measure from pixel centers
                SkScalar px = SkIntToScalar(x) + SK_ScalarHalf;
                SkScalar py = SkIntToScalar(y) + SK_ScalarHalf;

                SkPMColor* ptr = fBitmap.getAddr32(x, y);
                SkScalar dist = SkPoint::Length(px - cx, py - cy);
                if (dist <= rad && !*ptr) {
                    flatc++;
                    *ptr = fInsideColor;
                } else if (dist > rad && *ptr) {
                    buldgec++;
                    *ptr = fOutsideColor;
                }
            }
        }
        if (flatCount) *flatCount = flatc;
        if (buldgeCount) *buldgeCount = buldgec;
        return flatc + buldgec;
    }