DistanceFieldAdjustTable.h

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/*
 * Copyright 2015 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
#ifndef sktext_gpu_DistanceFieldAdjustTable_DEFINED
#define sktext_gpu_DistanceFieldAdjustTable_DEFINED
 
#include "include/core/SkScalar.h"
 
template <typename T> class SkNoDestructor;
 
namespace sktext::gpu {
 
// Distance field text needs this table to compute a value for use in the fragment shader.
class DistanceFieldAdjustTable {
public:
    static const DistanceFieldAdjustTable* Get();
 
    ~DistanceFieldAdjustTable() {
        delete[] fTable;
        delete[] fGammaCorrectTable;
    }
 
    SkScalar getAdjustment(int lum, bool useGammaCorrectTable) const {
        lum >>= kDistanceAdjustLumShift;
        return useGammaCorrectTable ? fGammaCorrectTable[lum] : fTable[lum];
    }
 
private:
    DistanceFieldAdjustTable();
 
    static constexpr int kDistanceAdjustLumShift = 5;
 
    SkScalar* fTable;
    SkScalar* fGammaCorrectTable;
 
    friend class SkNoDestructor<DistanceFieldAdjustTable>;
};
 
}  // namespace sktext::gpu
 
#endif