jpeg_optimizer.h

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/*
 * Copyright 2009 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http:///www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


#ifndef PAGESPEED_KERNEL_IMAGE_JPEG_OPTIMIZER_H_
#define PAGESPEED_KERNEL_IMAGE_JPEG_OPTIMIZER_H_

#include <setjmp.h>
#include <cstddef>
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/image/image_util.h"
#include "pagespeed/kernel/image/scanline_interface.h"
#include "pagespeed/kernel/image/scanline_status.h"


namespace net_instaweb {
class MessageHandler;
}

namespace pagespeed {

namespace image_compression {

using net_instaweb::MessageHandler;

enum ColorSampling {
  RETAIN,
  YUV420,
  YUV422,
  YUV444
};

struct JpegLossyOptions {
  JpegLossyOptions() : quality(85), num_scans(-1), color_sampling(YUV420) {}
  int quality;

  int num_scans;

  ColorSampling color_sampling;
};

struct JpegCompressionOptions : public ScanlineWriterConfig {
  JpegCompressionOptions()
    : progressive(false), retain_color_profile(false),
      retain_exif_data(false), lossy(false) {}

  ~JpegCompressionOptions() override;

  bool progressive;

  bool retain_color_profile;

  bool retain_exif_data;

  bool lossy;

  JpegLossyOptions lossy_options;
};

bool OptimizeJpeg(const GoogleString &original,
                  GoogleString *compressed,
                  MessageHandler* handler);

bool OptimizeJpegWithOptions(const GoogleString &original,
                             GoogleString *compressed,
                             const JpegCompressionOptions &options,
                             MessageHandler* handler);

class JpegScanlineWriter : public ScanlineWriterInterface {
 public:
  explicit JpegScanlineWriter(MessageHandler* handler);
  virtual ~JpegScanlineWriter();

  void SetJmpBufEnv(jmp_buf* env);

  void AbortWrite();

  virtual ScanlineStatus InitWithStatus(const size_t width, const size_t height,
                                        PixelFormat pixel_format);
  virtual ScanlineStatus InitializeWriteWithStatus(const void* params,
                                                   GoogleString *compressed);
  virtual ScanlineStatus WriteNextScanlineWithStatus(
      const void *scanline_bytes);
  virtual ScanlineStatus FinalizeWriteWithStatus();

 private:
  void SetJpegCompressParams(const JpegCompressionOptions& options);

  struct Data;
  Data* const data_;
  MessageHandler* message_handler_;

  
};

}  

}  

#endif