// Copyright (c) the JPEG XL Project Authors. All rights reserved.

//

// Use of this source code is governed by a BSD-style

// license that can be found in the LICENSE file.

#ifndef LIB_JXL_ENC_COMPARATOR_H_

#define LIB_JXL_ENC_COMPARATOR_H_

#include <jxl/cms_interface.h>

#include "lib/jxl/base/data_parallel.h"

#include "lib/jxl/base/status.h"

#include "lib/jxl/image.h"

#include "lib/jxl/image_bundle.h"

namespace jxl {

class Comparator {

 public:

  virtual ~Comparator() = default;

  // Sets the reference image, the first to compare

  // Image must be in linear sRGB (gamma expanded) in range 0.0f-1.0f as

  // the range from standard black point to standard white point, but values

  // outside permitted.

  virtual Status SetReferenceImage(const ImageBundle& ref) = 0;

  // Sets the actual image (with loss), the second to compare

  // Image must be in linear sRGB (gamma expanded) in range 0.0f-1.0f as

  // the range from standard black point to standard white point, but values

  // outside permitted.

  // In diffmap it outputs the local score per pixel, while in score it outputs

  // a single score. Any one may be set to nullptr to not compute it.

  virtual Status CompareWith(const ImageBundle& actual, ImageF* diffmap,

                             float* score) = 0;

  // Quality thresholds for diffmap and score values.

  // The good score must represent a value where the images are considered to

  // be perceptually indistinguishable (but not identical)

  // The bad value must be larger than good to indicate "lower means better"

  // and smaller than good to indicate "higher means better"

  virtual float GoodQualityScore() const = 0;

  virtual float BadQualityScore() const = 0;

};

// Computes the score given images in any RGB color model, optionally with

// alpha channel.

Status ComputeScore(const ImageBundle& rgb0, const ImageBundle& rgb1,

                    Comparator* comparator, const JxlCmsInterface& cms,

                    float* score, ImageF* diffmap = nullptr,

                    ThreadPool* pool = nullptr, bool ignore_alpha = false);

}  // namespace jxl

#endif  // LIB_JXL_ENC_COMPARATOR_H_