0cc575488f
This reverts commit d716d4402a.
Bug: skia:8800
Change-Id: Ic16cd4e960be2c3d2462bdf2b54b2e32abbd9f78
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/199081
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
93 lines
2.9 KiB
C
93 lines
2.9 KiB
C
/*
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* Copyright 2018 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkYUVAIndex_DEFINED
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#define SkYUVAIndex_DEFINED
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#include "SkTypes.h"
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/** \enum SkColorChannel
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Describes different color channels one can manipulate
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*/
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enum class SkColorChannel {
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kR, // the red channel
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kG, // the green channel
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kB, // the blue channel
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kA, // the alpha channel
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kLastEnum = kA,
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};
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/** \struct SkYUVAIndex
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Describes from which image source and which channel to read each individual YUVA plane.
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SkYUVAIndex contains a index for which image source to read from and a enum for which channel
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to read from.
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*/
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struct SK_API SkYUVAIndex {
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bool operator==(const SkYUVAIndex& that) const {
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return this->fIndex == that.fIndex && this->fChannel == that.fChannel;
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}
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bool operator!=(const SkYUVAIndex& that) const {
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return !(*this == that);
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}
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// Index in the array of SkYUVAIndex
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// TODO: rename as Component
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enum Index {
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kY_Index = 0,
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kU_Index = 1,
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kV_Index = 2,
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kA_Index = 3,
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kLast_Index = kA_Index
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};
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static constexpr int kIndexCount = kLast_Index + 1;
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/** The index is a number between -1..3 which defines which image source to read from, where -1
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* means the image source doesn't exist. The assumption is we will always have image sources for
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* each of YUV planes, but optionally have image source for A plane. */
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int fIndex;
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/** The channel describes from which channel to read the info from. Currently we only deal with
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* YUV and NV12 and channel info is ignored. */
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SkColorChannel fChannel;
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static bool AreValidIndices(const SkYUVAIndex yuvaIndices[4], int* numPlanes) {
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// Note that 'numPlanes' is always filled in even if the indices are not valid.
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// This means it can always be used to process the backing resources (but be careful
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// of empty intervening slots).
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int maxSlotUsed = -1;
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bool used[4] = { false, false, false, false };
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bool valid = true;
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for (int i = 0; i < 4; ++i) {
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if (yuvaIndices[i].fIndex < 0) {
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if (SkYUVAIndex::kA_Index != i) {
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valid = false; // only the 'A' plane can be omitted
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}
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} else if (yuvaIndices[i].fIndex > 3) {
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valid = false; // A maximum of four input textures is allowed
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} else {
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maxSlotUsed = SkTMax(yuvaIndices[i].fIndex, maxSlotUsed);
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used[i] = true;
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}
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}
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// All the used slots should be packed starting at 0 with no gaps
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for (int i = 0; i <= maxSlotUsed; ++i) {
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if (!used[i]) {
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valid = false;
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}
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}
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*numPlanes = maxSlotUsed + 1;
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return valid;
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}
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};
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#endif
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