tor-browser

enc_squeeze.cc (5283B)

---

// 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.

#include "lib/jxl/modular/transform/enc_squeeze.h"

#include <jxl/memory_manager.h>

#include <cstdlib>

#include "lib/jxl/base/data_parallel.h"
#include "lib/jxl/modular/modular_image.h"
#include "lib/jxl/modular/transform/squeeze.h"
#include "lib/jxl/modular/transform/transform.h"

namespace jxl {

#define AVERAGE(X, Y) (((X) + (Y) + (((X) > (Y)) ? 1 : 0)) >> 1)

Status FwdHSqueeze(Image &input, int c, int rc) {
 const Channel &chin = input.channel[c];
 JxlMemoryManager *memory_manager = input.memory_manager();

 JXL_DEBUG_V(4, "Doing horizontal squeeze of channel %i to new channel %i", c,
             rc);

 JXL_ASSIGN_OR_RETURN(Channel chout,
                      Channel::Create(memory_manager, (chin.w + 1) / 2, chin.h,
                                      chin.hshift + 1, chin.vshift));
 JXL_ASSIGN_OR_RETURN(Channel chout_residual,
                      Channel::Create(memory_manager, chin.w - chout.w,
                                      chout.h, chin.hshift + 1, chin.vshift));

 for (size_t y = 0; y < chout.h; y++) {
   const pixel_type *JXL_RESTRICT p_in = chin.Row(y);
   pixel_type *JXL_RESTRICT p_out = chout.Row(y);
   pixel_type *JXL_RESTRICT p_res = chout_residual.Row(y);
   for (size_t x = 0; x < chout_residual.w; x++) {
     pixel_type A = p_in[x * 2];
     pixel_type B = p_in[x * 2 + 1];
     pixel_type avg = AVERAGE(A, B);
     p_out[x] = avg;

     pixel_type diff = A - B;

     pixel_type next_avg = avg;
     if (x + 1 < chout_residual.w) {
       pixel_type C = p_in[x * 2 + 2];
       pixel_type D = p_in[x * 2 + 3];
       next_avg = AVERAGE(C, D);  // which will be chout.value(y,x+1)
     } else if (chin.w & 1) {
       next_avg = p_in[x * 2 + 2];
     }
     pixel_type left = (x > 0 ? p_in[x * 2 - 1] : avg);
     pixel_type tendency = SmoothTendency(left, avg, next_avg);

     p_res[x] = diff - tendency;
   }
   if (chin.w & 1) {
     int x = chout.w - 1;
     p_out[x] = p_in[x * 2];
   }
 }
 input.channel[c] = std::move(chout);
 input.channel.insert(input.channel.begin() + rc, std::move(chout_residual));
 return true;
}

Status FwdVSqueeze(Image &input, int c, int rc) {
 const Channel &chin = input.channel[c];
 JxlMemoryManager *memory_manager = input.memory_manager();

 JXL_DEBUG_V(4, "Doing vertical squeeze of channel %i to new channel %i", c,
             rc);

 JXL_ASSIGN_OR_RETURN(Channel chout,
                      Channel::Create(memory_manager, chin.w, (chin.h + 1) / 2,
                                      chin.hshift, chin.vshift + 1));
 JXL_ASSIGN_OR_RETURN(Channel chout_residual,
                      Channel::Create(memory_manager, chin.w, chin.h - chout.h,
                                      chin.hshift, chin.vshift + 1));
 intptr_t onerow_in = chin.plane.PixelsPerRow();
 for (size_t y = 0; y < chout_residual.h; y++) {
   const pixel_type *JXL_RESTRICT p_in = chin.Row(y * 2);
   pixel_type *JXL_RESTRICT p_out = chout.Row(y);
   pixel_type *JXL_RESTRICT p_res = chout_residual.Row(y);
   for (size_t x = 0; x < chout.w; x++) {
     pixel_type A = p_in[x];
     pixel_type B = p_in[x + onerow_in];
     pixel_type avg = AVERAGE(A, B);
     p_out[x] = avg;

     pixel_type diff = A - B;

     pixel_type next_avg = avg;
     if (y + 1 < chout_residual.h) {
       pixel_type C = p_in[x + 2 * onerow_in];
       pixel_type D = p_in[x + 3 * onerow_in];
       next_avg = AVERAGE(C, D);  // which will be chout.value(y+1,x)
     } else if (chin.h & 1) {
       next_avg = p_in[x + 2 * onerow_in];
     }
     pixel_type top =
         (y > 0 ? p_in[static_cast<ssize_t>(x) - onerow_in] : avg);
     pixel_type tendency = SmoothTendency(top, avg, next_avg);

     p_res[x] = diff - tendency;
   }
 }
 if (chin.h & 1) {
   size_t y = chout.h - 1;
   const pixel_type *p_in = chin.Row(y * 2);
   pixel_type *p_out = chout.Row(y);
   for (size_t x = 0; x < chout.w; x++) {
     p_out[x] = p_in[x];
   }
 }
 input.channel[c] = std::move(chout);
 input.channel.insert(input.channel.begin() + rc, std::move(chout_residual));
 return true;
}

Status FwdSqueeze(Image &input, std::vector<SqueezeParams> parameters,
                 ThreadPool *pool) {
 if (parameters.empty()) {
   DefaultSqueezeParameters(&parameters, input);
 }
 // if nothing to do, don't do squeeze
 if (parameters.empty()) return false;
 for (auto &parameter : parameters) {
   JXL_RETURN_IF_ERROR(
       CheckMetaSqueezeParams(parameter, input.channel.size()));
   bool horizontal = parameter.horizontal;
   bool in_place = parameter.in_place;
   uint32_t beginc = parameter.begin_c;
   uint32_t endc = parameter.begin_c + parameter.num_c - 1;
   uint32_t offset;
   if (in_place) {
     offset = endc + 1;
   } else {
     offset = input.channel.size();
   }
   for (uint32_t c = beginc; c <= endc; c++) {
     if (horizontal) {
       JXL_RETURN_IF_ERROR(FwdHSqueeze(input, c, offset + c - beginc));
     } else {
       JXL_RETURN_IF_ERROR(FwdVSqueeze(input, c, offset + c - beginc));
     }
   }
 }
 return true;
}

}  // namespace jxl