#if defined(_MSC_VER) && (_MSC_VER >= 1400)

#define _CRT_SECURE_NO_DEPRECATE 1

#endif

#include <memory></memory>

#include "tmachine.h"

#include "texception.h"

#include "tfilepath.h"

#include "tiio_png.h"

#include "tiio.h"

#include "../compatibility/tfile_io.h"

#include "png.h"

#include "tpixel.h"

#include "tpixelutils.h"

using namespace std;

//------------------------------------------------------------

extern "C" {

static void tnz_abort(jmp_buf, int) {}

static void tnz_error_fun(png_structp pngPtr, png_const_charp error_message) {

  *(int *)png_get_error_ptr(pngPtr) = 0;

}

}

#if !defined(TNZ_LITTLE_ENDIAN)

#error "TNZ_LITTLE_ENDIAN undefined !!"

#endif

//=========================================================

/* Check for the older version of libpng */

#if defined(PNG_LIBPNG_VER)

#if (PNG_LIBPNG_VER < 10527)

extern "C" {

static png_uint_32 png_get_current_row_number(const png_structp png_ptr) {

  /* See the comments in png.h - this is the sub-image row when reading and

   * interlaced image.

   */

  if (png_ptr != NULL) return png_ptr->row_number;

  return PNG_UINT_32_MAX; /* help the app not to fail silently */

}

static png_byte png_get_current_pass_number(const png_structp png_ptr) {

  if (png_ptr != NULL) return png_ptr->pass;

  return 8; /* invalid */

}

}

#endif

#else

#error "PNG_LIBPNG_VER undefined, libpng too old?"

#endif

//=========================================================

inline USHORT mySwap(USHORT val) {

#if TNZ_LITTLE_ENDIAN

  return ((val) |

          ((val & 0xff) << 8));  //((val>>8)|((val&0xff)<<8)); (vecchio codice)

#else

  return val;

#endif

}

//=========================================================

class PngReader final : public Tiio::Reader {

  FILE *m_chan;

  png_structp m_png_ptr;

  png_infop m_info_ptr, m_end_info_ptr;

  int m_bit_depth, m_color_type, m_interlace_type;

  int m_compression_type, m_filter_type;

  unsigned int m_sig_read;

  int m_y;

  bool m_is16bitEnabled;

  std::unique_ptr<unsigned char[]=""> m_rowBuffer;</unsigned>

  std::unique_ptr<unsigned char[]=""> m_tempBuffer;  // Buffer temporaneo</unsigned>

  int m_canDelete;

public:

  PngReader()

      : m_chan(0)

      , m_png_ptr(0)

      , m_info_ptr(0)

      , m_end_info_ptr(0)

      , m_bit_depth(0)

      , m_color_type(0)

      , m_interlace_type(0)

      , m_compression_type(0)

      , m_filter_type(0)

      , m_sig_read(0)

      , m_y(0)

      , m_is16bitEnabled(true)

      , m_canDelete(0) {}

  ~PngReader() {

    if (m_canDelete == 1) {

      png_destroy_read_struct(&m_png_ptr, &m_info_ptr, &m_end_info_ptr);

    }

  }

  bool read16BitIsEnabled() const override { return m_is16bitEnabled; }

  void enable16BitRead(bool enabled) override { m_is16bitEnabled = enabled; }

  void readLineInterlace(char *buffer) {

    readLineInterlace(buffer, 0, m_info.m_lx - 1, 1);

  }

  void readLineInterlace(short *buffer) {

    readLineInterlace(buffer, 0, m_info.m_lx - 1, 1);

  }

  void open(FILE *file) override {

    try {

      m_chan = file;

    } catch (...) {

      perror("uffa");

      return;

    }

    unsigned char signature[8];  // da 1 a 8 bytes

    fread(signature, 1, sizeof signature, m_chan);

    bool isPng = !png_sig_cmp(signature, 0, sizeof signature);

    if (!isPng) return;

    m_png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, &m_canDelete,

                                       tnz_error_fun, 0);

    if (!m_png_ptr) return;

#if defined(PNG_LIBPNG_VER)

#if (PNG_LIBPNG_VER >= 10527)

    png_set_longjmp_fn(m_png_ptr, tnz_abort,

                       sizeof(jmp_buf)); /* ignore all fatal errors */

#endif                                   // (PNG_LIBPNG_VER >= 10527)

#endif                                   // defined(PNG_LIBPNG_VER)

    m_canDelete = 1;

    m_info_ptr  = png_create_info_struct(m_png_ptr);

    if (!m_info_ptr) {

      png_destroy_read_struct(&m_png_ptr, (png_infopp)0, (png_infopp)0);

      return;

    }

    m_end_info_ptr = png_create_info_struct(m_png_ptr);

    if (!m_end_info_ptr) {

      png_destroy_read_struct(&m_png_ptr, &m_info_ptr, (png_infopp)0);

      return;

    }

    png_init_io(m_png_ptr, m_chan);

    png_set_sig_bytes(m_png_ptr, sizeof signature);

#if defined(TNZ_MACHINE_CHANNEL_ORDER_MBGR)

    png_set_bgr(m_png_ptr);

    png_set_swap_alpha(m_png_ptr);

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_BGRM)

    png_set_bgr(m_png_ptr);

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_MRGB)

    png_set_swap_alpha(m_png_ptr);

#elif !defined(TNZ_MACHINE_CHANNEL_ORDER_RGBM)

#error "unknown channel order"

#endif

    png_read_info(m_png_ptr, m_info_ptr);

    if (png_get_valid(m_png_ptr, m_info_ptr, PNG_INFO_pHYs)) {

      png_uint_32 xdpi = png_get_x_pixels_per_meter(m_png_ptr, m_info_ptr);

      png_uint_32 ydpi = png_get_y_pixels_per_meter(m_png_ptr, m_info_ptr);

      m_info.m_dpix    = tround(xdpi * 0.0254);

      m_info.m_dpiy    = tround(ydpi * 0.0254);

    }

    int rowBytes = png_get_rowbytes(m_png_ptr, m_info_ptr);

    png_uint_32 lx = 0, ly = 0;

    png_get_IHDR(m_png_ptr, m_info_ptr, &lx, &ly, &m_bit_depth, &m_color_type,

                 &m_interlace_type, &m_compression_type, &m_filter_type);

    m_info.m_lx = lx;

    m_info.m_ly = ly;

    m_info.m_bitsPerSample = m_bit_depth;

    int channels            = png_get_channels(m_png_ptr, m_info_ptr);

    m_info.m_samplePerPixel = channels;

    if (channels == 1 || channels == 2) {

      if (m_bit_depth <

          8)  // (m_bit_depth == 1 || m_bit_depth == 2 || m_bit_depth == 4)

        m_rowBuffer.reset(new unsigned char[lx * 3]);

      else

        m_rowBuffer.reset(new unsigned char[rowBytes * 4]);

    } else {

      m_rowBuffer.reset(new unsigned char[rowBytes]);

    }

    if (m_color_type == PNG_COLOR_TYPE_PALETTE) {

      m_info.m_valid = true;

      png_set_palette_to_rgb(m_png_ptr);

      // treat the image as RGBA from now on

      m_info.m_samplePerPixel =

          4;  // there are 4 channels per pixel (R, G, B, and A)

      // if there is no alpha channel, then fill it with "255" (full opacity)

      png_set_filler(m_png_ptr, 0xFF, PNG_FILLER_AFTER);

    }

    if (m_color_type == PNG_COLOR_TYPE_GRAY && m_bit_depth < 8) {

      png_set_expand_gray_1_2_4_to_8(m_png_ptr);

    }

    if (png_get_valid(m_png_ptr, m_info_ptr, PNG_INFO_tRNS)) {

      png_set_tRNS_to_alpha(m_png_ptr);

    }

    if (m_bit_depth == 16 && !m_is16bitEnabled) {

      png_set_strip_16(m_png_ptr);

    }

#if defined(TNZ_MACHINE_CHANNEL_ORDER_BGRM)

    if (m_color_type == PNG_COLOR_TYPE_RGB ||

        m_color_type == PNG_COLOR_TYPE_RGB_ALPHA) {

      png_set_bgr(m_png_ptr);

    }

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_MBGR)

    if (m_color_type == PNG_COLOR_TYPE_RGB_ALPHA) {

      png_set_swap_alpha(m_png_ptr);

    }

#elif !defined(TNZ_MACHINE_CHANNEL_ORDER_RGBM) &&                              \

    !defined(TNZ_MACHINE_CHANNEL_ORDER_MRGB)

#error "unknown channel order"

#endif

    if (m_color_type == PNG_COLOR_TYPE_GRAY ||

        m_color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {

      png_set_gray_to_rgb(m_png_ptr);

    }

  }

  void readLine(char *buffer, int x0, int x1, int shrink) override {

    int ly = m_info.m_ly;

    if (!m_tempBuffer) {

      int lx       = m_info.m_lx;

      int channels = png_get_channels(m_png_ptr, m_info_ptr);

      int rowBytes = png_get_rowbytes(m_png_ptr, m_info_ptr);

      if (m_interlace_type == 1) {

        if (channels == 1 || channels == 2) {

          if (m_bit_depth < 8)

            m_tempBuffer.reset(new unsigned char[ly * lx * 3]);

          else

            m_tempBuffer.reset(new unsigned char[ly * rowBytes * 4]);

        } else {

          m_tempBuffer.reset(new unsigned char[ly * rowBytes]);

        }

      }

    }

    int lx = m_info.m_lx;

    if (m_interlace_type == 1 && lx > 4) {

      readLineInterlace(&buffer[0], x0, x1, shrink);

      m_y++;

      if (m_tempBuffer && m_y == ly) {

        m_tempBuffer.reset();

      }

      return;

    }

    int y = m_info.m_ly - 1 - m_y;

    if (y < 0) return;

    m_y++;

    png_bytep row_pointer = m_rowBuffer.get();

    png_read_row(m_png_ptr, row_pointer, NULL);

    writeRow(buffer);

    if (m_tempBuffer && m_y == ly) {

      m_tempBuffer.reset();

    }

  }

  void readLine(short *buffer, int x0, int x1, int shrink) override {

    int ly = m_info.m_ly;

    if (!m_tempBuffer) {

      int lx       = m_info.m_lx;

      int channels = png_get_channels(m_png_ptr, m_info_ptr);

      int rowBytes = png_get_rowbytes(m_png_ptr, m_info_ptr);

      if (m_interlace_type == 1) {

        if (channels == 1 || channels == 2) {

          if (m_bit_depth <

              8)  // (m_bit_depth == 1 || m_bit_depth == 2 || m_bit_depth == 4)

            m_tempBuffer.reset(new unsigned char[ly * lx * 3]);

          else

            m_tempBuffer.reset(new unsigned char[ly * rowBytes * 4]);

        } else {

          m_tempBuffer.reset(new unsigned char[ly * rowBytes]);

        }

      }

    }

    if (png_get_interlace_type(m_png_ptr, m_info_ptr) == PNG_INTERLACE_ADAM7) {

      readLineInterlace(&buffer[0], x0, x1, shrink);

      m_y++;

      if (m_tempBuffer && m_y == ly) {

        m_tempBuffer.reset();

      }

      return;

    }

    int y = m_info.m_ly - 1 - m_y;

    if (y < 0) return;

    m_y++;

    png_bytep row_pointer = m_rowBuffer.get();

    png_read_row(m_png_ptr, row_pointer, NULL);

    writeRow(buffer);

    if (m_tempBuffer && m_y == ly) {

      m_tempBuffer.reset();

    }

  }

  int skipLines(int lineCount) override {

    for (int i = 0; i < lineCount; i++) {

      if (m_interlace_type == 1 &&

          m_info.m_lx > 4)  // pezza. Studiare il codice

      {

        int channels     = png_get_channels(m_png_ptr, m_info_ptr);

        char *lineBuffer = (char *)malloc(4 * m_info.m_lx * sizeof(char));

        readLine(lineBuffer, 0, m_info.m_lx - 1, 1);

        free(lineBuffer);

      } else {

        m_y++;

        png_bytep row_pointer = m_rowBuffer.get();

        png_read_row(m_png_ptr, row_pointer, NULL);

      }

    }

    return lineCount;

  }

  Tiio::RowOrder getRowOrder() const override { return Tiio::TOP2BOTTOM; }

  void writeRow(char *buffer) {

    if (m_color_type == PNG_COLOR_TYPE_RGB_ALPHA ||

        m_color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||

        m_color_type == PNG_COLOR_TYPE_PALETTE) {  // PNG_COLOR_TYPE_PALETTE is

                                                   // expanded to RGBA

      if (m_bit_depth == 16) {

        TPixel32 *pix = (TPixel32 *)buffer;

        int i         = -2;

        for (int j = 0; j < m_info.m_lx; j++) {

#if defined(TNZ_MACHINE_CHANNEL_ORDER_MRGB)

          pix[j].m = m_rowBuffer[i = i + 2];

          pix[j].r = m_rowBuffer[i = i + 2];

          pix[j].g = m_rowBuffer[i = i + 2];

          pix[j].b = m_rowBuffer[i = i + 2];

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_RGBM)

          pix[j].r = m_rowBuffer[i = i + 2];

          pix[j].g = m_rowBuffer[i = i + 2];

          pix[j].b = m_rowBuffer[i = i + 2];

          pix[j].m = m_rowBuffer[i = i + 2];

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_BGRM)

          pix[j].b = m_rowBuffer[i = i + 2];

          pix[j].g = m_rowBuffer[i = i + 2];

          pix[j].r = m_rowBuffer[i = i + 2];

          pix[j].m = m_rowBuffer[i = i + 2];

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_MBGR)

          pix[j].m = m_rowBuffer[i = i + 2];

          pix[j].b = m_rowBuffer[i = i + 2];

          pix[j].g = m_rowBuffer[i = i + 2];

          pix[j].r = m_rowBuffer[i = i + 2];

#else

#error "unknown channel order"

#endif

          // premultiply here

          premult(pix[j]);

        }

      } else {

        TPixel32 *pix = (TPixel32 *)buffer;

        int i         = 0;

        for (int j = 0; j < m_info.m_lx; j++) {

#if defined(TNZ_MACHINE_CHANNEL_ORDER_MRGB)

          pix[j].m = m_rowBuffer[i++];

          pix[j].r = m_rowBuffer[i++];

          pix[j].g = m_rowBuffer[i++];

          pix[j].b = m_rowBuffer[i++];

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_RGBM)

          pix[j].r = m_rowBuffer[i++];

          pix[j].g = m_rowBuffer[i++];

          pix[j].b = m_rowBuffer[i++];

          pix[j].m = m_rowBuffer[i++];

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_BGRM)

          pix[j].b = m_rowBuffer[i++];

          pix[j].g = m_rowBuffer[i++];

          pix[j].r = m_rowBuffer[i++];

          pix[j].m = m_rowBuffer[i++];

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_MBGR)

          pix[j].m = m_rowBuffer[i++];

          pix[j].b = m_rowBuffer[i++];

          pix[j].g = m_rowBuffer[i++];

          pix[j].r = m_rowBuffer[i++];

#else

#error "unknown channel order"

#endif

          // premultiply here

          premult(pix[j]);

        }

      }

    } else  // qui gestisce RGB senza alpha.

    {       // grayscale e' gestito come RGB perche' si usa png_set_gray_to_rgb

      if (m_bit_depth == 16) {

        TPixel32 *pix = (TPixel32 *)buffer;

        int i         = -2;

        for (int j = 0; j < m_info.m_lx; j++) {

#if defined(TNZ_MACHINE_CHANNEL_ORDER_MRGB) ||                                 \

    defined(TNZ_MACHINE_CHANNEL_ORDER_RGBM)

          pix[j].r = m_rowBuffer[i = i + 2];

          pix[j].g = m_rowBuffer[i = i + 2];

          pix[j].b = m_rowBuffer[i = i + 2];

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_MBGR) ||                               \

    defined(TNZ_MACHINE_CHANNEL_ORDER_BGRM)

          pix[j].b = m_rowBuffer[i = i + 2];

          pix[j].g = m_rowBuffer[i = i + 2];

          pix[j].r = m_rowBuffer[i = i + 2];

#else

#error "unknown channel order"

#endif

          pix[j].m = 255;

        }

      } else {

        TPixel32 *pix = (TPixel32 *)buffer;

        int i         = 0;

        for (int j = 0; j < m_info.m_lx; j++) {

#if defined(TNZ_MACHINE_CHANNEL_ORDER_MRGB) ||                                 \

    defined(TNZ_MACHINE_CHANNEL_ORDER_RGBM)

          pix[j].r = m_rowBuffer[i++];

          pix[j].g = m_rowBuffer[i++];

          pix[j].b = m_rowBuffer[i++];

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_MBGR) ||                               \

    defined(TNZ_MACHINE_CHANNEL_ORDER_BGRM)

          pix[j].b = m_rowBuffer[i++];

          pix[j].g = m_rowBuffer[i++];

          pix[j].r = m_rowBuffer[i++];

#else

#error "unknown channel order"

#endif

          pix[j].m = 255;

        }

      }

    }

  }

  void writeRow(short *buffer) {

    if (m_color_type == PNG_COLOR_TYPE_RGB_ALPHA ||

        m_color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||

        m_color_type == PNG_COLOR_TYPE_PALETTE) {  // PNG_COLOR_TYPE_PALETTE is

                                                   // expanded to RGBA

      TPixel64 *pix = (TPixel64 *)buffer;

      int i         = -2;  // 0;

      for (int j = 0; j < m_info.m_lx; j++) {

#if defined(TNZ_MACHINE_CHANNEL_ORDER_MRGB) ||                                 \

    defined(TNZ_MACHINE_CHANNEL_ORDER_RGBM)

        pix[j].r = mySwap(m_rowBuffer[i = i + 2]);  // i++

        pix[j].g = mySwap(m_rowBuffer[i = i + 2]);

        pix[j].b = mySwap(m_rowBuffer[i = i + 2]);

        pix[j].m = mySwap(m_rowBuffer[i = i + 2]);

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_MBGR) ||                               \

    defined(TNZ_MACHINE_CHANNEL_ORDER_BGRM)

        pix[j].b = mySwap(m_rowBuffer[i = i + 2]);  // i++

        pix[j].g = mySwap(m_rowBuffer[i = i + 2]);

        pix[j].r = mySwap(m_rowBuffer[i = i + 2]);

        pix[j].m = mySwap(m_rowBuffer[i = i + 2]);

#else

#error "unknown channel order"

#endif

        // pix[j].m = 255;

        // premultiply here

        premult(pix[j]);

      }

    } else  // qui gestisce RGB senza alpha.

    {       // grayscale e' gestito come RGB perche' si usa png_set_gray_to_rgb

      TPixel64 *pix = (TPixel64 *)buffer;

      int i         = -2;

      for (int j = 0; j < m_info.m_lx; j++) {

#if defined(TNZ_MACHINE_CHANNEL_ORDER_MRGB) ||                                 \

    defined(TNZ_MACHINE_CHANNEL_ORDER_RGBM)

        pix[j].r = mySwap(m_rowBuffer[i = i + 2]);

        pix[j].g = mySwap(m_rowBuffer[i = i + 2]);

        pix[j].b = mySwap(m_rowBuffer[i = i + 2]);

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_MBGR) ||                               \

    defined(TNZ_MACHINE_CHANNEL_ORDER_BGRM)

        pix[j].b = mySwap(m_rowBuffer[i = i + 2]);

        pix[j].g = mySwap(m_rowBuffer[i = i + 2]);

        pix[j].r = mySwap(m_rowBuffer[i = i + 2]);

#else

#error "unknown channel order"

#endif

        pix[j].m = mySwap(255);

      }

    }

  }

  void copyPixel(int count, int dstX, int dstDx, int dstY) {

    int channels = png_get_channels(m_png_ptr, m_info_ptr);

    int rowBytes = png_get_rowbytes(m_png_ptr, m_info_ptr);

    int lx       = m_info.m_lx;

    if ((channels == 4 || channels == 3) && m_bit_depth == 16) {

      for (int i = 0; i < count; i += 2) {

        for (int j = 0; j < channels * 2; j++) {

          (m_tempBuffer.get() +

           (dstY * rowBytes))[(i * dstDx + dstX) * channels + j] =

              m_rowBuffer[i * channels + j];

        }

      }

    } else if (channels == 2 && m_bit_depth == 16) {

      for (int i = 0; i < count; i += 2) {

        for (int j = 0; j < 4 * 2; j++) {

          (m_tempBuffer.get() +

           (dstY * rowBytes * 4))[(i * dstDx + dstX) * 4 + j] =

              m_rowBuffer[i * 4 + j];

        }

      }

    } else if (channels == 1 && m_bit_depth == 16) {

      for (int i = 0; i < count; i += 2) {

        for (int j = 0; j < 3 * 2; j++) {

          (m_tempBuffer.get() +

           (dstY * rowBytes * 4))[(i * dstDx + dstX) * 3 + j] =

              m_rowBuffer[i * 3 + j];

        }

      }

    } else if (channels == 1 && m_bit_depth == 8) {

      for (int i = 0; i < count; i++) {

        for (int j = 0; j < 3; j++) {

          (m_tempBuffer.get() +

           (dstY * rowBytes * 4))[(i * dstDx + dstX) * 3 + j] =

              m_rowBuffer[i * 3 + j];

        }

      }

    } else if (channels == 2 && m_bit_depth == 8) {

      for (int i = 0; i < count; i++) {

        for (int j = 0; j < 4; j++) {

          (m_tempBuffer.get() +

           (dstY * rowBytes * 4))[(i * dstDx + dstX) * 4 + j] =

              m_rowBuffer[i * 4 + j];

        }

      }

    } else if ((channels == 1 || channels == 2) && m_bit_depth < 8) {

      for (int i = 0; i < count; i++) {

        for (int j = 0; j < 3; j++) {

          (m_tempBuffer.get() + (dstY * lx * 3))[(i * dstDx + dstX) * 3 + j] =

              m_rowBuffer[i * 3 + j];

        }

      }

    } else {

      for (int i = 0; i < count; i++) {

        for (int j = 0; j < channels; j++) {

          (m_tempBuffer.get() +

           (dstY * rowBytes))[(i * dstDx + dstX) * channels + j] =

              m_rowBuffer[i * channels + j];

        }

      }

    }

  }

  void readLineInterlace(char *buffer, int x0, int x1, int shrink) {

    // m_png_ptr->row_number è l'indice di riga che scorre quando chiamo la

    // png_read_row

    int rowNumber = png_get_current_row_number(m_png_ptr);

    // numRows è il numero di righe processate in ogni passo

    int numRows = (int)png_get_image_height(m_png_ptr, m_info_ptr) / 8;

    int passPng = png_get_current_pass_number(m_png_ptr);

    int passRow = 5 + (m_y & 1);  // passo desiderato per la riga corrente

    int channels = png_get_channels(m_png_ptr, m_info_ptr);

    int rowBytes          = png_get_rowbytes(m_png_ptr, m_info_ptr);

    png_bytep row_pointer = m_rowBuffer.get();

    int lx = m_info.m_lx;

    while (passPng <= passRow &&

           rowNumber <=

               numRows)  // finchè il passo d'interlacciamento è minore o uguale

    // <             //del passo desiderato effettua tante volte le lettura

    // della riga

    // quant'è il passo desiderato per quella riga

    {

      rowNumber = png_get_current_row_number(m_png_ptr);

      png_read_row(m_png_ptr, row_pointer, NULL);

      numRows = png_get_image_height(m_png_ptr, m_info_ptr);

      // devo memorizzare la riga letta nel buffer di appoggio in base al passo

      // di riga

      // e al blocchetto di appartenenza della riga

      // copio i pixel che desidero nel buffer temporaneo

      // il membro di PngReader copyPixel deve tener conto della riga processata

      // e del passo che si è effettuato ( e in base a quello so quanti pixel

      // copiare!)

      if (m_bit_depth == 16) {

        if (passPng == 0)

          copyPixel(lx / 4, 0, 8, rowNumber * 8);

        else if (passPng == 1)

          copyPixel(lx / 4, 8, 8, rowNumber * 8);

        else if (passPng == 2)

          copyPixel(lx / 2, 0, 4, rowNumber * 8 + 4);

        else if (passPng == 3)

          copyPixel(lx / 2, 4, 4, rowNumber * 4);

        else if (passPng == 4)

          copyPixel(lx, 0, 2, rowNumber * 4 + 2);

        else if (passPng == 5)

          copyPixel(lx, 2, 2, rowNumber * 2);

        else if (passPng == 6)

          copyPixel(2 * lx, 0, 1, rowNumber * 2 + 1);

      } else {

        if (passPng == 0)

          copyPixel((lx + 7) / 8, 0, 8, rowNumber * 8);

        else if (passPng == 1)

          copyPixel((lx + 3) / 8, 4, 8, rowNumber * 8);

        else if (passPng == 2)

          copyPixel((lx + 3) / 4, 0, 4, rowNumber * 8 + 4);

        else if (passPng == 3)

          copyPixel((lx + 1) / 4, 2, 4, rowNumber * 4);

        else if (passPng == 4)

          copyPixel((lx + 1) / 2, 0, 2, rowNumber * 4 + 2);

        else if (passPng == 5)

          copyPixel(lx / 2, 1, 2, rowNumber * 2);

        else if (passPng == 6)

          copyPixel(lx, 0, 1, rowNumber * 2 + 1);

      }

      passPng = png_get_current_pass_number(m_png_ptr);

    }

    // fase di copia

    if (channels == 1 || channels == 2) {

      if (m_bit_depth < 8)

        memcpy(m_rowBuffer.get(), m_tempBuffer.get() + ((m_y)*lx * 3), lx * 3);

      else

        memcpy(m_rowBuffer.get(), m_tempBuffer.get() + ((m_y)*rowBytes * 4),

               rowBytes * 4);

    } else {

      memcpy(m_rowBuffer.get(), m_tempBuffer.get() + ((m_y)*rowBytes),

             rowBytes);

    }

    // fase di copia vecchia

    // memcpy(m_rowBuffer, m_tempBuffer+((m_y)*rowBytes), rowBytes);

    // tutto quello che segue lo metto in una funzione in cui scrivo il buffer

    // di restituzione della readLine

    //è una funzione comune alle ReadLine

    writeRow(buffer);

  }

  void readLineInterlace(short *buffer, int x0, int x1, int shrink) {

    // m_png_ptr->row_number è l'indice di riga che scorre quando chiamo la

    // png_read_row

    int rowNumber = png_get_current_row_number(m_png_ptr);

    // numRows è il numero di righe processate in ogni passo

    int numRows = png_get_image_height(m_png_ptr, m_info_ptr) / 8;

    int passPng = png_get_current_pass_number(

        m_png_ptr);  // conosco il passo d'interlacciamento

    int passRow = 5 + (m_y & 1);  // passo desiderato per la riga corrente

    int channels = png_get_channels(m_png_ptr, m_info_ptr);

    int lx       = m_info.m_lx;

    int rowBytes          = png_get_rowbytes(m_png_ptr, m_info_ptr);

    png_bytep row_pointer = m_rowBuffer.get();

    while (passPng <= passRow &&

           rowNumber <

               numRows)  // finchè il passo d'interlacciamento è minore o uguale

    // del passo desiderato effettua tante volte le lettura della riga

    // quant'è il passo desiderato per quella riga

    {

      rowNumber = png_get_current_row_number(m_png_ptr);

      png_read_row(m_png_ptr, row_pointer, NULL);

      numRows = png_get_image_height(m_png_ptr, m_info_ptr);

      int lx  = m_info.m_lx;

      // devo memorizzare la riga letta nel buffer di appoggio in base al passo

      // di riga

      // e al blocchetto di appartenenza della riga

      // copio i pixel che desidero nel buffer temporaneo

      // il membro di PngReader copyPixel deve tener conto della riga processata

      // e del passo che si è effettuato ( e in base a quello so quanti pixel

      // copiare!)

      int channels = png_get_channels(m_png_ptr, m_info_ptr);

      if (passPng == 0)

        copyPixel(lx / 4, 0, 8, rowNumber * 8);

      else if (passPng == 1)

        copyPixel(lx / 4, 8, 8, rowNumber * 8);

      else if (passPng == 2)

        copyPixel(lx / 2, 0, 4, rowNumber * 8 + 4);

      else if (passPng == 3)

        copyPixel(lx / 2, 4, 4, rowNumber * 4);

      else if (passPng == 4)

        copyPixel(lx, 0, 2, rowNumber * 4 + 2);

      else if (passPng == 5)

        copyPixel(lx, 2, 2, rowNumber * 2);

      else if (passPng == 6)

        copyPixel(2 * lx, 0, 1, rowNumber * 2 + 1);

      passPng = png_get_current_pass_number(m_png_ptr);

    }

    // fase di copia

    if (channels == 1 || channels == 2) {

      memcpy(m_rowBuffer.get(), m_tempBuffer.get() + ((m_y)*rowBytes * 4),

             rowBytes * 4);

    } else {

      memcpy(m_rowBuffer.get(), m_tempBuffer.get() + ((m_y)*rowBytes),

             rowBytes);

    }

    // fase di copia

    // memcpy(m_rowBuffer, m_tempBuffer+((m_y)*rowBytes), rowBytes);

    // tutto quello che segue lo metto in una funzione in cui scrivo il buffer

    // di restituzione della readLine

    //è una funzione comune alle ReadLine

    writeRow(buffer);

  }

};

//=========================================================

Tiio::PngWriterProperties::PngWriterProperties()

    : m_matte("Alpha Channel", true)

{

  bind(m_matte);

}

void Tiio::PngWriterProperties::updateTranslation() {

  m_matte.setQStringName(tr("Alpha Channel"));

}

//=========================================================

class PngWriter final : public Tiio::Writer {

  png_structp m_png_ptr;

  png_infop m_info_ptr;

  FILE *m_chan;

  bool m_matte;

  std::vector<tpixel> *m_colormap;</tpixel>

public:

  PngWriter();

  ~PngWriter();

  void open(FILE *file, const TImageInfo &info) override;

  void writeLine(char *buffer) override;

  void writeLine(short *buffer) override;

  Tiio::RowOrder getRowOrder() const override { return Tiio::TOP2BOTTOM; }

  void flush() override;

  bool write64bitSupported() const override { return true; }

  // m_matte is set to "Alpha Channel" property value in the function open()

  bool writeAlphaSupported() const override { return m_matte; };

};

//---------------------------------------------------------

PngWriter::PngWriter()

    : m_png_ptr(0), m_info_ptr(0), m_matte(true), m_colormap(0) {}

//---------------------------------------------------------

PngWriter::~PngWriter() {

  if (m_png_ptr) {

    png_destroy_write_struct(&m_png_ptr, &m_info_ptr);

  }

  if (m_chan) {

    fflush(m_chan);

    m_chan = 0;

  }

}

//---------------------------------------------------------

png_color palette[256];

png_byte alpha[1];

void PngWriter::open(FILE *file, const TImageInfo &info) {

  m_info    = info;

  m_png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,

                                      (png_voidp)0,  // user_error_ptr,

                                      0,             // user_error_fn,

                                      0);            // user_warning_fn);

  if (!m_png_ptr) return;

  m_info_ptr = png_create_info_struct(m_png_ptr);

  if (!m_info_ptr) {

    png_destroy_write_struct(&m_png_ptr, (png_infopp)0);

    return;

  }

  m_chan = file;

  png_init_io(m_png_ptr, m_chan);

  if (!m_properties) m_properties = new Tiio::PngWriterProperties();

  TBoolProperty *alphaProp =

      (TBoolProperty *)(m_properties->getProperty("Alpha Channel"));

  TPointerProperty *colormap =

      (TPointerProperty *)(m_properties->getProperty("Colormap"));

  m_matte = (alphaProp && alphaProp->getValue()) ? true : false;

  if (colormap) m_colormap = (vector<tpixel> *)colormap->getValue();</tpixel>

  TUINT32 x_pixels_per_meter = tround(m_info.m_dpix / 0.0254);

  TUINT32 y_pixels_per_meter = tround(m_info.m_dpiy / 0.0254);

  if (!m_colormap)

    png_set_IHDR(m_png_ptr, m_info_ptr, m_info.m_lx, m_info.m_ly,

                 info.m_bitsPerSample,

                 m_matte ? PNG_COLOR_TYPE_RGB_ALPHA : PNG_COLOR_TYPE_RGB,

                 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT,

                 PNG_FILTER_TYPE_DEFAULT);

  else {

    png_set_IHDR(m_png_ptr, m_info_ptr, m_info.m_lx, m_info.m_ly, 8,

                 PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE,

                 PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);

    for (unsigned int i = 0; i < m_colormap->size(); i++) {

      /*unsigned char red = (i>>5)&0x7;

      unsigned char green = (i>>2)&0x7;

      unsigned char blue = i&0x3;

      palette[i].red = (red>>1) | (red<<2) | (red<<5);

      palette[i].green = (green>>1) | (green<<2) | (green<<5);

      palette[i].blue = blue | (blue<<2) | (blue<<4) | (blue<<6);

      if (red==0 && green==0) alpha[i] = 0; else if (blue==0 && green==0)

      alpha[i] = 128; else alpha[i] = 255;*/

      palette[i].red   = (*m_colormap)[i].r;

      palette[i].green = (*m_colormap)[i].g;

      palette[i].blue  = (*m_colormap)[i].b;

    }

    png_set_PLTE(m_png_ptr, m_info_ptr, palette, m_colormap->size());

  }

  // png_set_dither(m_png_ptr, palette, 256, 256, 0, 1);

#if defined(TNZ_MACHINE_CHANNEL_ORDER_MBGR)

  png_set_bgr(m_png_ptr);

  png_set_swap_alpha(m_png_ptr);

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_BGRM)

  png_set_bgr(m_png_ptr);

#elif defined(TNZ_MACHINE_CHANNEL_ORDER_MRGB)

  png_set_swap_alpha(m_png_ptr);

#elif !defined(TNZ_MACHINE_CHANNEL_ORDER_RGBM)

#error "unknownchannel order"

#endif

  png_set_pHYs(m_png_ptr, m_info_ptr, x_pixels_per_meter, y_pixels_per_meter,

               1);