text: /*
   * Copyright 2015 Google Inc.
   *
   * Use of this source code is governed by a BSD-style license that can be
   * found in the LICENSE file.
   */
  
  #include "GrYUVProvider.h"
  #include "GrClip.h"
  #include "GrContext.h"
  #include "GrContextPriv.h"
  #include "GrRenderTargetContext.h"
  #include "GrTextureProxy.h"
  #include "SkAutoMalloc.h"
  #include "SkCachedData.h"
  #include "SkRefCnt.h"
  #include "SkResourceCache.h"
  #include "SkYUVPlanesCache.h"
  #include "effects/GrNonlinearColorSpaceXformEffect.h"
  #include "effects/GrSRGBEffect.h"
  #include "effects/GrYUVEffect.h"
  
  namespace {
  /**
   *  Helper class to manage the resources used for storing the YUV planar data. Depending on the
   *  useCache option, we may find (and lock) the data in our ResourceCache, or we may have allocated
   *  it in scratch storage.
   */
  class YUVScoper {
  public:
      bool init(GrYUVProvider*, SkYUVPlanesCache::Info*, void* planes[3], bool useCache);
  
  private:
      // we only use one or the other of these
      sk_sp<SkCachedData>  fCachedData;
      SkAutoMalloc         fStorage;
  };
  }
  
  bool YUVScoper::init(GrYUVProvider* provider, SkYUVPlanesCache::Info* yuvInfo, void* planes[3],
                       bool useCache) {
      if (useCache) {
          fCachedData.reset(SkYUVPlanesCache::FindAndRef(provider->onGetID(), yuvInfo));
      }
  
      if (fCachedData.get()) {
          planes[0] = (void*)fCachedData->data();
          planes[1] = (uint8_t*)planes[0] + (yuvInfo->fSizeInfo.fWidthBytes[SkYUVSizeInfo::kY] *
                                             yuvInfo->fSizeInfo.fSizes[SkYUVSizeInfo::kY].fHeight);
          planes[2] = (uint8_t*)planes[1] + (yuvInfo->fSizeInfo.fWidthBytes[SkYUVSizeInfo::kU] *
                                             yuvInfo->fSizeInfo.fSizes[SkYUVSizeInfo::kU].fHeight);
      } else {
          // Fetch yuv plane sizes for memory allocation.
          if (!provider->onQueryYUV8(&yuvInfo->fSizeInfo, &yuvInfo->fColorSpace)) {
              return false;
          }
  
          // Allocate the memory for YUV
          size_t totalSize(0);
          for (int i = 0; i < 3; i++) {
              totalSize += yuvInfo->fSizeInfo.fWidthBytes[i] * yuvInfo->fSizeInfo.fSizes[i].fHeight;
          }
          if (useCache) {
              fCachedData.reset(SkResourceCache::NewCachedData(totalSize));
              planes[0] = fCachedData->writable_data();
          } else {
              fStorage.reset(totalSize);
              planes[0] = fStorage.get();
          }
          planes[1] = (uint8_t*)planes[0] + (yuvInfo->fSizeInfo.fWidthBytes[SkYUVSizeInfo::kY] *
                                             yuvInfo->fSizeInfo.fSizes[SkYUVSizeInfo::kY].fHeight);
          planes[2] = (uint8_t*)planes[1] + (yuvInfo->fSizeInfo.fWidthBytes[SkYUVSizeInfo::kU] *
                                             yuvInfo->fSizeInfo.fSizes[SkYUVSizeInfo::kU].fHeight);
  
          // Get the YUV planes.
          if (!provider->onGetYUV8Planes(yuvInfo->fSizeInfo, planes)) {
              return false;
          }
  
          if (useCache) {
              // Decoding is done, cache the resulting YUV planes
              SkYUVPlanesCache::Add(provider->onGetID(), fCachedData.get(), yuvInfo);
          }
      }
      return true;
  }
  
  sk_sp<GrTextureProxy> GrYUVProvider::refAsTextureProxy(GrContext* ctx, const GrSurfaceDesc& desc,
                                                         bool useCache,
                                                         const SkColorSpace* srcColorSpace,
                                                         const SkColorSpace* dstColorSpace) {
      SkYUVPlanesCache::Info yuvInfo;
      void* planes[3];
      YUVScoper scoper;
      if (!scoper.init(this, &yuvInfo, planes, useCache)) {
          return nullptr;
      }
  
      GrSurfaceDesc yuvDesc;
      yuvDesc.fOrigin = kTopLeft_GrSurfaceOrigin;
      yuvDesc.fConfig = kAlpha_8_GrPixelConfig;
      sk_sp<GrSurfaceContext> yuvTextureContexts[3];
      for (int i = 0; i < 3; i++) {
          yuvDesc.fWidth  = yuvInfo.fSizeInfo.fSizes[i].fWidth;
          yuvDesc.fHeight = yuvInfo.fSizeInfo.fSizes[i].fHeight;
          // TODO: why do we need this check?
          SkBackingFit fit =
                  (yuvDesc.fWidth  != yuvInfo.fSizeInfo.fSizes[SkYUVSizeInfo::kY].fWidth) ||
                  (yuvDesc.fHeight != yuvInfo.fSizeInfo.fSizes[SkYUVSizeInfo::kY].fHeight)
                      ? SkBackingFit::kExact : SkBackingFit::kApprox;
  
          yuvTextureContexts[i] = ctx->contextPriv().makeDeferredSurfaceContext(yuvDesc,
                                                                                GrMipMapped::kNo,
                                                                                fit,
                                                                                SkBudgeted::kYes);
          if (!yuvTextureContexts[i]) {
              return nullptr;
          }
  
          const SkImageInfo ii = SkImageInfo::MakeA8(yuvDesc.fWidth, yuvDesc.fHeight);
          if (!yuvTextureContexts[i]->writePixels(ii, planes[i],
                                                  yuvInfo.fSizeInfo.fWidthBytes[i], 0, 0)) {
              return nullptr;
          }
      }
  
      // We never want to perform color-space conversion during the decode
      // TODO: investigate preallocating mip maps here
      sk_sp<GrRenderTargetContext> renderTargetContext(ctx->makeDeferredRenderTargetContext(
                                                                      SkBackingFit::kExact,
                                                                      desc.fWidth, desc.fHeight,
                                                                      desc.fConfig, nullptr,
                                                                      desc.fSampleCnt,
                                                                      GrMipMapped::kNo,
                                                                      kTopLeft_GrSurfaceOrigin));
      if (!renderTargetContext) {
          return nullptr;
      }
  
      GrPaint paint;
      auto yuvToRgbProcessor =
              GrYUVEffect::MakeYUVToRGB(yuvTextureContexts[0]->asTextureProxyRef(),
                                        yuvTextureContexts[1]->asTextureProxyRef(),
                                        yuvTextureContexts[2]->asTextureProxyRef(),
                                        yuvInfo.fSizeInfo.fSizes, yuvInfo.fColorSpace, false);
      paint.addColorFragmentProcessor(std::move(yuvToRgbProcessor));
  
      // If we're decoding an sRGB image, the result of our linear math on the YUV planes is already
      // in sRGB. (The encoding is just math on bytes, with no concept of color spaces.) So, we need
      // to output the results of that math directly to the buffer that we will then consider sRGB.
      // If we have sRGB write control, we can just tell the HW not to do the Linear -> sRGB step.
      // Otherwise, we do our shader math to go from YUV -> sRGB, manually convert sRGB -> Linear,
      // then let the HW convert Linear -> sRGB.
      if (GrPixelConfigIsSRGB(desc.fConfig)) {
          if (ctx->caps()->srgbWriteControl()) {
              paint.setDisableOutputConversionToSRGB(true);
          } else {
              paint.addColorFragmentProcessor(GrSRGBEffect::Make(GrSRGBEffect::Mode::kSRGBToLinear,
                                                                 GrSRGBEffect::Alpha::kOpaque));
          }
      }
  
      // If the caller expects the pixels in a different color space than the one from the image,
      // apply a color conversion to do this.
      std::unique_ptr<GrFragmentProcessor> colorConversionProcessor =
              GrNonlinearColorSpaceXformEffect::Make(srcColorSpace, dstColorSpace);
      if (colorConversionProcessor) {
          paint.addColorFragmentProcessor(std::move(colorConversionProcessor));
      }
  
      paint.setPorterDuffXPFactory(SkBlendMode::kSrc);
      const SkRect r = SkRect::MakeIWH(yuvInfo.fSizeInfo.fSizes[SkYUVSizeInfo::kY].fWidth,
                                       yuvInfo.fSizeInfo.fSizes[SkYUVSizeInfo::kY].fHeight);
  
      renderTargetContext->drawRect(GrNoClip(), std::move(paint), GrAA::kNo, SkMatrix::I(), r);
  
      return renderTargetContext->asTextureProxyRef();
  }
  