/* * Copyright 2018 Google Inc. * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ #ifndef SkYUVAIndex_DEFINED #define SkYUVAIndex_DEFINED #include "include/core/SkTypes.h" /** \enum SkColorChannel Describes different color channels one can manipulate */ enum class SkColorChannel { kR, // the red channel kG, // the green channel kB, // the blue channel kA, // the alpha channel kLastEnum = kA, }; /** \struct SkYUVAIndex Describes from which image source and which channel to read each individual YUVA plane. SkYUVAIndex contains a index for which image source to read from and a enum for which channel to read from. */ struct SK_API SkYUVAIndex { bool operator==(const SkYUVAIndex& that) const { return this->fIndex == that.fIndex && this->fChannel == that.fChannel; } bool operator!=(const SkYUVAIndex& that) const { return !(*this == that); } // Index in the array of SkYUVAIndex // TODO: rename as Component enum Index { kY_Index = 0, kU_Index = 1, kV_Index = 2, kA_Index = 3, kLast_Index = kA_Index }; static constexpr int kIndexCount = kLast_Index + 1; /** The index is a number between -1..3 which defines which image source to read from, where -1 * means the image source doesn't exist. The assumption is we will always have image sources for * each of YUV planes, but optionally have image source for A plane. */ int fIndex; /** The channel describes from which channel to read the info from. Currently we only deal with * YUV and NV12 and channel info is ignored. */ SkColorChannel fChannel; static bool AreValidIndices(const SkYUVAIndex yuvaIndices[4], int* numPlanes) { // Note that 'numPlanes' is always filled in even if the indices are not valid. // This means it can always be used to process the backing resources (but be careful // of empty intervening slots). int maxSlotUsed = -1; bool used[4] = { false, false, false, false }; bool valid = true; for (int i = 0; i < 4; ++i) { if (yuvaIndices[i].fIndex < 0) { if (SkYUVAIndex::kA_Index != i) { valid = false; // only the 'A' plane can be omitted } } else if (yuvaIndices[i].fIndex > 3) { valid = false; // A maximum of four input textures is allowed } else { maxSlotUsed = SkTMax(yuvaIndices[i].fIndex, maxSlotUsed); used[i] = true; } } // All the used slots should be packed starting at 0 with no gaps for (int i = 0; i <= maxSlotUsed; ++i) { if (!used[i]) { valid = false; } } *numPlanes = maxSlotUsed + 1; return valid; } }; #endif