# dlib C++ Library - wrbmp.c

    /*
     * wrbmp.c
     *
     * Copyright (C) 1994-1996, Thomas G. Lane.
     * This file is part of the Independent JPEG Group's software.
     * For conditions of distribution and use, see the accompanying README file.
     *
     * This file contains routines to write output images in Microsoft "BMP"
     * format (MS Windows 3.x and OS/2 1.x flavors).
     * Either 8-bit colormapped or 24-bit full-color format can be written.
     * No compression is supported.
     *
     * These routines may need modification for non-Unix environments or
     * specialized applications.  As they stand, they assume output to
     * an ordinary stdio stream.
     *
     * This code contributed by James Arthur Boucher.
     */

    #include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */

    #ifdef BMP_SUPPORTED

    /*
     * To support 12-bit JPEG data, we'd have to scale output down to 8 bits.
     * This is not yet implemented.
     */

    #if BITS_IN_JSAMPLE != 8
      Sorry, this code only copes with 8-bit JSAMPLEs. /* deliberate syntax err */
    #endif

    /*
     * Since BMP stores scanlines bottom-to-top, we have to invert the image
     * from JPEG's top-to-bottom order.  To do this, we save the outgoing data
     * in a virtual array during put_pixel_row calls, then actually emit the
     * BMP file during finish_output.  The virtual array contains one JSAMPLE per
     * pixel if the output is grayscale or colormapped, three if it is full color.
     */

    /* Private version of data destination object */

    typedef struct {
      struct djpeg_dest_struct pub;	/* public fields */

      boolean is_os2;		/* saves the OS2 format request flag */

      jvirt_sarray_ptr whole_image;	/* needed to reverse row order */
      JDIMENSION data_width;	/* JSAMPLEs per row */
      JDIMENSION row_width;		/* physical width of one row in the BMP file */
      int pad_bytes;		/* number of padding bytes needed per row */
      JDIMENSION cur_output_row;	/* next row# to write to virtual array */
    } bmp_dest_struct;

    typedef bmp_dest_struct * bmp_dest_ptr;

    /* Forward declarations */
    LOCAL(void) write_colormap
    	JPP((j_decompress_ptr cinfo, bmp_dest_ptr dest,
    	     int map_colors, int map_entry_size));

    /*
     * Write some pixel data.
     * In this module rows_supplied will always be 1.
     */

    METHODDEF(void)
    put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
    		JDIMENSION rows_supplied)
    /* This version is for writing 24-bit pixels */
    {
      bmp_dest_ptr dest = (bmp_dest_ptr) dinfo;
      JSAMPARRAY image_ptr;
      register JSAMPROW inptr, outptr;
      register JDIMENSION col;
      int pad;

      /* Access next row in virtual array */
      image_ptr = (*cinfo->mem->access_virt_sarray)
        ((j_common_ptr) cinfo, dest->whole_image,
         dest->cur_output_row, (JDIMENSION) 1, TRUE);
      dest->cur_output_row++;

      /* Transfer data.  Note destination values must be in BGR order
       * (even though Microsoft's own documents say the opposite).
       */
      inptr = dest->pub.buffer[0];
      outptr = image_ptr[0];
      for (col = cinfo->output_width; col > 0; col--) {
        outptr[2] = *inptr++;	/* can omit GETJSAMPLE() safely */
        outptr[1] = *inptr++;
        outptr[0] = *inptr++;
        outptr += 3;
      }

      /* Zero out the pad bytes. */
      pad = dest->pad_bytes;
      while (--pad >= 0)
        *outptr++ = 0;
    }

    METHODDEF(void)
    put_gray_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
    	       JDIMENSION rows_supplied)
    /* This version is for grayscale OR quantized color output */
    {
      bmp_dest_ptr dest = (bmp_dest_ptr) dinfo;
      JSAMPARRAY image_ptr;
      register JSAMPROW inptr, outptr;
      register JDIMENSION col;
      int pad;

      /* Access next row in virtual array */
      image_ptr = (*cinfo->mem->access_virt_sarray)
        ((j_common_ptr) cinfo, dest->whole_image,
         dest->cur_output_row, (JDIMENSION) 1, TRUE);
      dest->cur_output_row++;

      /* Transfer data. */
      inptr = dest->pub.buffer[0];
      outptr = image_ptr[0];
      for (col = cinfo->output_width; col > 0; col--) {
        *outptr++ = *inptr++;	/* can omit GETJSAMPLE() safely */
      }

      /* Zero out the pad bytes. */
      pad = dest->pad_bytes;
      while (--pad >= 0)
        *outptr++ = 0;
    }

    /*
     * Startup: normally writes the file header.
     * In this module we may as well postpone everything until finish_output.
     */

    METHODDEF(void)
    start_output_bmp (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
    {
      /* no work here */
    }

    /*
     * Finish up at the end of the file.
     *
     * Here is where we really output the BMP file.
     *
     * First, routines to write the Windows and OS/2 variants of the file header.
     */

    LOCAL(void)
    write_bmp_header (j_decompress_ptr cinfo, bmp_dest_ptr dest)
    /* Write a Windows-style BMP file header, including colormap if needed */
    {
      char bmpfileheader[14];
      char bmpinfoheader[40];
    #define PUT_2B(array,offset,value)  \
    	(array[offset] = (char) ((value) & 0xFF), \
    	 array[offset+1] = (char) (((value) >> 8) & 0xFF))
    #define PUT_4B(array,offset,value)  \
    	(array[offset] = (char) ((value) & 0xFF), \
    	 array[offset+1] = (char) (((value) >> 8) & 0xFF), \
    	 array[offset+2] = (char) (((value) >> 16) & 0xFF), \
    	 array[offset+3] = (char) (((value) >> 24) & 0xFF))
      INT32 headersize, bfSize;
      int bits_per_pixel, cmap_entries;

      /* Compute colormap size and total file size */
      if (cinfo->out_color_space == JCS_RGB) {
        if (cinfo->quantize_colors) {
          /* Colormapped RGB */
          bits_per_pixel = 8;
          cmap_entries = 256;
        } else {
          /* Unquantized, full color RGB */
          bits_per_pixel = 24;
          cmap_entries = 0;
        }
      } else {
        /* Grayscale output.  We need to fake a 256-entry colormap. */
        bits_per_pixel = 8;
        cmap_entries = 256;
      }
      /* File size */
      headersize = 14 + 40 + cmap_entries * 4; /* Header and colormap */
      bfSize = headersize + (INT32) dest->row_width * (INT32) cinfo->output_height;

      /* Set unused fields of header to 0 */
      MEMZERO(bmpfileheader, SIZEOF(bmpfileheader));
      MEMZERO(bmpinfoheader, SIZEOF(bmpinfoheader));

      /* Fill the file header */
      bmpfileheader[0] = 0x42;	/* first 2 bytes are ASCII 'B', 'M' */
      bmpfileheader[1] = 0x4D;
      PUT_4B(bmpfileheader, 2, bfSize); /* bfSize */
      /* we leave bfReserved1 & bfReserved2 = 0 */
      PUT_4B(bmpfileheader, 10, headersize); /* bfOffBits */

      /* Fill the info header (Microsoft calls this a BITMAPINFOHEADER) */
      PUT_2B(bmpinfoheader, 0, 40);	/* biSize */
      PUT_4B(bmpinfoheader, 4, cinfo->output_width); /* biWidth */
      PUT_4B(bmpinfoheader, 8, cinfo->output_height); /* biHeight */
      PUT_2B(bmpinfoheader, 12, 1);	/* biPlanes - must be 1 */
      PUT_2B(bmpinfoheader, 14, bits_per_pixel); /* biBitCount */
      /* we leave biCompression = 0, for none */
      /* we leave biSizeImage = 0; this is correct for uncompressed data */
      if (cinfo->density_unit == 2) { /* if have density in dots/cm, then */
        PUT_4B(bmpinfoheader, 24, (INT32) (cinfo->X_density*100)); /* XPels/M */
        PUT_4B(bmpinfoheader, 28, (INT32) (cinfo->Y_density*100)); /* XPels/M */
      }
      PUT_2B(bmpinfoheader, 32, cmap_entries); /* biClrUsed */
      /* we leave biClrImportant = 0 */

      if (JFWRITE(dest->pub.output_file, bmpfileheader, 14) != (size_t) 14)
        ERREXIT(cinfo, JERR_FILE_WRITE);
      if (JFWRITE(dest->pub.output_file, bmpinfoheader, 40) != (size_t) 40)
        ERREXIT(cinfo, JERR_FILE_WRITE);

      if (cmap_entries > 0)
        write_colormap(cinfo, dest, cmap_entries, 4);
    }

    LOCAL(void)
    write_os2_header (j_decompress_ptr cinfo, bmp_dest_ptr dest)
    /* Write an OS2-style BMP file header, including colormap if needed */
    {
      char bmpfileheader[14];
      char bmpcoreheader[12];
      INT32 headersize, bfSize;
      int bits_per_pixel, cmap_entries;

      /* Compute colormap size and total file size */
      if (cinfo->out_color_space == JCS_RGB) {
        if (cinfo->quantize_colors) {
          /* Colormapped RGB */
          bits_per_pixel = 8;
          cmap_entries = 256;
        } else {
          /* Unquantized, full color RGB */
          bits_per_pixel = 24;
          cmap_entries = 0;
        }
      } else {
        /* Grayscale output.  We need to fake a 256-entry colormap. */
        bits_per_pixel = 8;
        cmap_entries = 256;
      }
      /* File size */
      headersize = 14 + 12 + cmap_entries * 3; /* Header and colormap */
      bfSize = headersize + (INT32) dest->row_width * (INT32) cinfo->output_height;

      /* Set unused fields of header to 0 */
      MEMZERO(bmpfileheader, SIZEOF(bmpfileheader));
      MEMZERO(bmpcoreheader, SIZEOF(bmpcoreheader));

      /* Fill the file header */
      bmpfileheader[0] = 0x42;	/* first 2 bytes are ASCII 'B', 'M' */
      bmpfileheader[1] = 0x4D;
      PUT_4B(bmpfileheader, 2, bfSize); /* bfSize */
      /* we leave bfReserved1 & bfReserved2 = 0 */
      PUT_4B(bmpfileheader, 10, headersize); /* bfOffBits */

      /* Fill the info header (Microsoft calls this a BITMAPCOREHEADER) */
      PUT_2B(bmpcoreheader, 0, 12);	/* bcSize */
      PUT_2B(bmpcoreheader, 4, cinfo->output_width); /* bcWidth */
      PUT_2B(bmpcoreheader, 6, cinfo->output_height); /* bcHeight */
      PUT_2B(bmpcoreheader, 8, 1);	/* bcPlanes - must be 1 */
      PUT_2B(bmpcoreheader, 10, bits_per_pixel); /* bcBitCount */

      if (JFWRITE(dest->pub.output_file, bmpfileheader, 14) != (size_t) 14)
        ERREXIT(cinfo, JERR_FILE_WRITE);
      if (JFWRITE(dest->pub.output_file, bmpcoreheader, 12) != (size_t) 12)
        ERREXIT(cinfo, JERR_FILE_WRITE);

      if (cmap_entries > 0)
        write_colormap(cinfo, dest, cmap_entries, 3);
    }

    /*
     * Write the colormap.
     * Windows uses BGR0 map entries; OS/2 uses BGR entries.
     */

    LOCAL(void)
    write_colormap (j_decompress_ptr cinfo, bmp_dest_ptr dest,
    		int map_colors, int map_entry_size)
    {
      JSAMPARRAY colormap = cinfo->colormap;
      int num_colors = cinfo->actual_number_of_colors;
      FILE * outfile = dest->pub.output_file;
      int i;

      if (colormap != NULL) {
        if (cinfo->out_color_components == 3) {
          /* Normal case with RGB colormap */
          for (i = 0; i < num_colors; i++) {
    	putc(GETJSAMPLE(colormap[2][i]), outfile);
    	putc(GETJSAMPLE(colormap[1][i]), outfile);
    	putc(GETJSAMPLE(colormap[0][i]), outfile);
    	if (map_entry_size == 4)
    	  putc(0, outfile);
          }
        } else {
          /* Grayscale colormap (only happens with grayscale quantization) */
          for (i = 0; i < num_colors; i++) {
    	putc(GETJSAMPLE(colormap[0][i]), outfile);
    	putc(GETJSAMPLE(colormap[0][i]), outfile);
    	putc(GETJSAMPLE(colormap[0][i]), outfile);
    	if (map_entry_size == 4)
    	  putc(0, outfile);
          }
        }
      } else {
        /* If no colormap, must be grayscale data.  Generate a linear "map". */
        for (i = 0; i < 256; i++) {
          putc(i, outfile);
          putc(i, outfile);
          putc(i, outfile);
          if (map_entry_size == 4)
    	putc(0, outfile);
        }
      }
      /* Pad colormap with zeros to ensure specified number of colormap entries */
      if (i > map_colors)
        ERREXIT1(cinfo, JERR_TOO_MANY_COLORS, i);
      for (; i < map_colors; i++) {
        putc(0, outfile);
        putc(0, outfile);
        putc(0, outfile);
        if (map_entry_size == 4)
          putc(0, outfile);
      }
    }

    METHODDEF(void)
    finish_output_bmp (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
    {
      bmp_dest_ptr dest = (bmp_dest_ptr) dinfo;
      register FILE * outfile = dest->pub.output_file;
      JSAMPARRAY image_ptr;
      register JSAMPROW data_ptr;
      JDIMENSION row;
      register JDIMENSION col;
      cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;

      /* Write the header and colormap */
      if (dest->is_os2)
        write_os2_header(cinfo, dest);
      else
        write_bmp_header(cinfo, dest);

      /* Write the file body from our virtual array */
      for (row = cinfo->output_height; row > 0; row--) {
        if (progress != NULL) {
          progress->pub.pass_counter = (long) (cinfo->output_height - row);
          progress->pub.pass_limit = (long) cinfo->output_height;
          (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
        }
        image_ptr = (*cinfo->mem->access_virt_sarray)
          ((j_common_ptr) cinfo, dest->whole_image, row-1, (JDIMENSION) 1, FALSE);
        data_ptr = image_ptr[0];
        for (col = dest->row_width; col > 0; col--) {
          putc(GETJSAMPLE(*data_ptr), outfile);
          data_ptr++;
        }
      }
      if (progress != NULL)
        progress->completed_extra_passes++;

      /* Make sure we wrote the output file OK */
      fflush(outfile);
      if (ferror(outfile))
        ERREXIT(cinfo, JERR_FILE_WRITE);
    }

    /*
     * The module selection routine for BMP format output.
     */

    GLOBAL(djpeg_dest_ptr)
    jinit_write_bmp (j_decompress_ptr cinfo, boolean is_os2)
    {
      bmp_dest_ptr dest;
      JDIMENSION row_width;

      /* Create module interface object, fill in method pointers */
      dest = (bmp_dest_ptr)
          (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
    				  SIZEOF(bmp_dest_struct));
      dest->pub.start_output = start_output_bmp;
      dest->pub.finish_output = finish_output_bmp;
      dest->is_os2 = is_os2;

      if (cinfo->out_color_space == JCS_GRAYSCALE) {
        dest->pub.put_pixel_rows = put_gray_rows;
      } else if (cinfo->out_color_space == JCS_RGB) {
        if (cinfo->quantize_colors)
          dest->pub.put_pixel_rows = put_gray_rows;
        else
          dest->pub.put_pixel_rows = put_pixel_rows;
      } else {
        ERREXIT(cinfo, JERR_BMP_COLORSPACE);
      }

      /* Calculate output image dimensions so we can allocate space */
      jpeg_calc_output_dimensions(cinfo);

      /* Determine width of rows in the BMP file (padded to 4-byte boundary). */
      row_width = cinfo->output_width * cinfo->output_components;
      dest->data_width = row_width;
      while ((row_width & 3) != 0) row_width++;
      dest->row_width = row_width;
      dest->pad_bytes = (int) (row_width - dest->data_width);

      /* Allocate space for inversion array, prepare for write pass */
      dest->whole_image = (*cinfo->mem->request_virt_sarray)
        ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
         row_width, cinfo->output_height, (JDIMENSION) 1);
      dest->cur_output_row = 0;
      if (cinfo->progress != NULL) {
        cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
        progress->total_extra_passes++; /* count file input as separate pass */
      }

      /* Create decompressor output buffer. */
      dest->pub.buffer = (*cinfo->mem->alloc_sarray)
        ((j_common_ptr) cinfo, JPOOL_IMAGE, row_width, (JDIMENSION) 1);
      dest->pub.buffer_height = 1;

      return (djpeg_dest_ptr) dest;
    }

    #endif /* BMP_SUPPORTED */