ResSimple.h

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/*
 *    Copyright (C) 2016-2026 Grok Image Compression Inc.
 *
 *    This source code is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    as published by the Free Software Foundation.
 *
 *    This source code is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Affero General Public License for more details.
 *
 *    You should have received a copy of the GNU Affero General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
 
#pragma once
 
#include "t1_common.h"
 
namespace grk
{
 
struct ResSimple : public Rect32
{
  ResSimple(void) : numTileBandWindows(0) {}
  ResSimple(Rect32* res, uint8_t numTileBandWindows, Rect32 (&tileBand)[t1::BAND_NUM_INDICES])
  {
    setRect(res);
    this->numTileBandWindows = numTileBandWindows;
    for(uint8_t i = 0; i < numTileBandWindows; i++)
      this->tileBand[i] = tileBand[i];
  }
  ResSimple(Rect32 currentRes, bool finalResolution)
  {
    setRect(currentRes);
    if(finalResolution)
    {
      numTileBandWindows = 1;
      tileBand[0] = currentRes;
    }
    else
    {
      numTileBandWindows = 3;
      for(uint8_t j = 0; j < numTileBandWindows; ++j)
        tileBand[j] = getBandWindow(1, j + 1, currentRes);
    }
  }

  static Rect32 getBandWindow(uint8_t numDecomps, uint8_t orientation,
                              Rect32 tileCompWindowUnreduced)
  {
    assert(orientation < t1::BAND_NUM_ORIENTATIONS);
    if(numDecomps == 0)
      return tileCompWindowUnreduced;
 
    /* project window onto sub-band generated by `numDecomps` decompositions */
    /* See equation B-15 of the standard. */
    uint32_t bx0 = orientation & 1;
    uint32_t by0 = (uint32_t)(orientation >> 1U);
 
    uint32_t bx0Offset = (1U << (numDecomps - 1)) * bx0;
    uint32_t by0Offset = (1U << (numDecomps - 1)) * by0;
 
    uint32_t tc_originx0 = tileCompWindowUnreduced.origin_x0;
    uint32_t tc_originy0 = tileCompWindowUnreduced.origin_y0;
    uint32_t tcx0 = tileCompWindowUnreduced.x0;
    uint32_t tcy0 = tileCompWindowUnreduced.y0;
    uint32_t tcx1 = tileCompWindowUnreduced.x1;
    uint32_t tcy1 = tileCompWindowUnreduced.y1;
 
    return Rect32(
        (tc_originx0 <= bx0Offset) ? 0 : ceildivpow2<uint32_t>(tc_originx0 - bx0Offset, numDecomps),
        (tc_originy0 <= by0Offset) ? 0 : ceildivpow2<uint32_t>(tc_originy0 - by0Offset, numDecomps),
        (tcx0 <= bx0Offset) ? 0 : ceildivpow2<uint32_t>(tcx0 - bx0Offset, numDecomps),
        (tcy0 <= by0Offset) ? 0 : ceildivpow2<uint32_t>(tcy0 - by0Offset, numDecomps),
        (tcx1 <= bx0Offset) ? 0 : ceildivpow2<uint32_t>(tcx1 - bx0Offset, numDecomps),
        (tcy1 <= by0Offset) ? 0 : ceildivpow2<uint32_t>(tcy1 - by0Offset, numDecomps));
  }
 
  Rect32 tileBand[t1::BAND_NUM_INDICES]; // unreduced tile component bands in canvas coordinates
  uint8_t numTileBandWindows; // 1 or 3
};
 
} // namespace grk