wrsprite.c

这是从一款商业嵌入式浏览器中节选出来的代码

                    pix = layers_fb_PACKYUV422( GETJSAMPLE( ptr1[0] ),   /* Y from first pixel   */
                                                GETJSAMPLE( ptr1[1] ),   /* U from first pixel   */
                                                GETJSAMPLE( ptr2[0] ),   /* Y from second pixel  */
                                                GETJSAMPLE( ptr1[2] ) ); /* V from first pixel   */
                    *--bufferptr = pix;
                }

                ASSERT((unsigned char*)bufferptr==(unsigned char *)dest->iobuffer);
                    
            }
            else
            {
                start = ((unsigned int *)dest->iobuffer)+((rows_supplied+2)/2);
                bufferptr = start;

                y = rows_supplied;
                if (cinfo->output_scanline == rows_supplied)
                {
                    /* rhs of image, duplication required */
                    register const JSAMPLE FAR * ptr1 = dest->pub.buffer[rows_supplied-y]+3*x;  /* ptr to 2nd of pair of values to write */
                    unsigned int pix;
            
                    /* pack YUV, ignoring every other thing's UV */
                    pix = layers_fb_PACKYUV422( GETJSAMPLE( ptr1[0] ),   /* Y from first pixel   */
                                                GETJSAMPLE( ptr1[1] ),   /* U from first pixel   */
                                                GETJSAMPLE( ptr1[0] ),   /* Y from first pixel   */
                                                GETJSAMPLE( ptr1[2] ) ); /* V from first pixel   */
                    *--bufferptr = pix;
                    --y;
                }
                else
                {
                    /* rhs of image, duplication required */
                    register const JSAMPLE FAR * ptr1 = dest->pub.buffer[rows_supplied-y]+3*x;  /* ptr to 2nd of pair of values to write */
                    unsigned int pix;
                    unsigned int Y1, Y2, U, V;
            
                    /* for this to work, it needs getdst */
                    ASSERT(dest->getdst);
                    ASSERT(dest->outfile);

                    if (dest->outfile)
                    {
                        /* seek: start at botoom, left and work up in each row. */
                        
                        dest->seekdst(offset, dest->outfile);
                        
                        dest->getdst((unsigned char *)dest->iobuffer, (unsigned char*)start-(unsigned char*)dest->iobuffer, dest->outfile);
                    }
                    
                    /* pack YUV, ignoring every other thing's UV */
                    layers_fb_UNPACKYUV422(*(bufferptr-1),
                                           Y1,
                                           U,
                                           Y2,
                                           V);

                    /* replace Y, U, V with real values */
                    Y1 = GETJSAMPLE(ptr1[0]);
                    U  = GETJSAMPLE(ptr1[1]);
                    V  = GETJSAMPLE(ptr1[2]);

                    pix = layers_fb_PACKYUV422( Y1,   /* Y from first pixel   */
                                                U,    /* U from first pixel   */
                                                Y2,   /* Y from first pixel   */
                                                V );  /* V from first pixel   */
                    *--bufferptr = pix;
                    --y;

                }
                /* now deal with middle rows */
                for (; y>=2; y-=2)
                {
                    register const JSAMPLE FAR * ptr1 = dest->pub.buffer[rows_supplied-y+1]+3*x;    /* ptr to 1st of pair of values to write */
                    register const JSAMPLE FAR * ptr2 = dest->pub.buffer[rows_supplied-y]+3*x;  /* ptr to 2nd of pair of values to write */
                    unsigned int pix;
            
                    /* pack YUV, ignoring every other thing's UV */
                    pix = layers_fb_PACKYUV422( GETJSAMPLE( ptr1[0] ),   /* Y from first pixel   */
                                                GETJSAMPLE( ptr1[1] ),   /* U from first pixel   */
                                                GETJSAMPLE( ptr2[0] ),   /* Y from second pixel  */
                                                GETJSAMPLE( ptr1[2] ) ); /* V from first pixel   */
                    *--bufferptr = pix;
                }

                if (y==1)
                {
                    /* final value which is a duplicate which will be updated later */
                    register const JSAMPLE FAR * ptr1 = dest->pub.buffer[rows_supplied-y]+3*x;    /* ptr to 1st of pair of values to write */
                    unsigned int pix;
                    
                    /* pack YUV, ignoring every other thing's UV */
                    pix = layers_fb_PACKYUV422( GETJSAMPLE( ptr1[0] ),   /* Y from first pixel   */
                                                GETJSAMPLE( ptr1[1] ),   /* U from first pixel   */
                                                GETJSAMPLE( ptr1[0] ),   /* Y from second pixel  */
                                                GETJSAMPLE( ptr1[2] ) ); /* V from first pixel   */
                    *--bufferptr = pix;
                }
                
                /* seek: start at botoom, left and work up in each row. */
                ASSERT((unsigned char*)bufferptr==(unsigned char *)dest->iobuffer);
                    
            }

            if (dest->outfile)
            {
                dest->seekdst(offset, dest->outfile);

                dest->putdst((unsigned char *)dest->iobuffer, (unsigned char *)start-(unsigned char *)dest->iobuffer, dest->outfile);
            }
            else
            {
                ASSERT(0);
                (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
            }

            offset += dest->stride;
        }
    }
}

#endif

/*
 * Write some pixel data.
 * In this module rows_supplied will always be 1.
 *
 * put_pixel4bpp_rows handles the "normal" 4-bit case.
 */

static void
put_pixel4bpp_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
		JDIMENSION rows_supplied)
{
  sprite_dest_ptr dest = (sprite_dest_ptr) dinfo;
  register char *bufferptr;
  register JSAMPROW ptr;
  register JDIMENSION col;

  ptr = dest->pub.buffer[0];
  bufferptr = dest->iobuffer;
  /* fprintf(stderr, "put_pixel4bpp_rows: ptr %x buf %x samples %x bufwidth %x\n", (int) ptr, (int) bufferptr, dest->samples_per_row, dest->buffer_width); */
  for (col = dest->samples_per_row; (col > 0) && (col < JPEG_MAX_DIMENSION); col-=2)
  {
    /* fprintf(stderr, "col %x bufferptr %x ptr %x\n", col, bufferptr, ptr); */
    PUTSPRITESAMPLE4BPP(bufferptr, GETJSAMPLE(ptr[0]), GETJSAMPLE(ptr[1]));
    ptr+=2;
  }

  /* fprintf(stderr, "put_pixel4bpp_rows: out %x io %x len %x\n", (int) dest->pub.output_file, (int) dest->iobuffer, dest->buffer_width); */
  if (dest->outfile)
  {
    dest->putdst((unsigned char *)dest->iobuffer, dest->buffer_width, dest->outfile);
  }
  else
  {
    (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
  }
  NOT_USED(cinfo);
  NOT_USED(rows_supplied);
}

/*
 * Startup: write the file header.
 */

static void
start_output_sprite (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
{
  sprite_dest_ptr dest = (sprite_dest_ptr) dinfo;
  int  spritehdr[sizeof(sprite_header)/sizeof(int)+3+512];
  int  width, mode, size, end_bits, height;
  int  palette = 0;
  int greyscale = 0;

  sprite_header *sph = (sprite_header *)(spritehdr+3);
  ASSERT(sizeof(sprite_header) == 11*sizeof(int));
  
  /* Set unused fields of header to 0 */
  memset((void *) spritehdr, 0, sizeof(spritehdr));

  /* Copy in application description */
  switch (dest->rotate)
  {
  case webimage_rotate_LEFT_90:
  case webimage_rotate_LEFT_270:
      width = (int) cinfo->output_height;
      height = (int) cinfo->output_width;
      break;
  default:
      ASSERT(0);
  case webimage_rotate_LEFT_180:
  case webimage_rotate_NONE:
      width = (int) cinfo->output_width;
      height = (int) cinfo->output_height;
      break;
  }
  end_bits = 0x1f;

  /* If quantising image, then output an old fixed palette 8bpp */
  if (cinfo->quantize_colors)
  {
    if (cinfo->out_color_space == JCS_GRAYSCALE)
    {
      greyscale = 1;
      if (cinfo->actual_number_of_colors == 16)
      {
        /* 4bpp, 16 colour fixed greyscale palette */
        mode = 20;
        if ((width % 8) != 0)
        {
          end_bits = ((width % 8) * 4) - 1;
          width += (8 - (width % 8));
        }
        width = width / 2;
        palette = 128;
      }
      else
      {
        /* 8bpp, 256 colour greyscale palette */
        mode = 21;
        if ((width % 4) != 0)
        {
          end_bits = ((width % 4) * 8) - 1;
          width += (4 - (width % 4));
        }
        palette = 2048;
      }
    }
    else
    {
      /* 8bpp, 256 colour fixed palette */
      mode = 21;
      if ((width % 4) != 0)
      {
        end_bits = ((width % 4) * 8) - 1;
        width += (4 - (width % 4));
      }
#if RISCOS
      palette = 0;
#else
      palette = 2048;
#endif
    }
  }
  else if (!dest->yuv_out)
  {
#if LAYERS_FB_32BITS
    if ( !dest->use_16bpp )
    {
        /* 32bpp, 90x90dpi */
        mode = (6<<27) + (90<<14) + (90<<1) + 1;
        width *= 4;
    }
    else
#endif
    {
        /* 16bpp, 90x90dpi */
        mode = (5<<27) + (90<<14) + (90<<1) + 1;
        if ((width % 2) != 0)
        {
            end_bits = ((width % 2) * 16) - 1;
            width += (2 - (width % 2));
        }
        width *= 2;
    }
  }
  else
  {
      mode = 422;
      if ((width % 2) != 0)
      {
          end_bits = ((width % 2) * 16) - 1;
          width += (2 - (width % 2));
      }
      width *= 2;
  }
  size = 60 + palette + (width * height);

  /* 3 + sizeof(sprite_header) (shoud be 14) word sprite header block */
  spritehdr[0] = ENDIAN_MODIFY(1);		/* # Sprite in area */
  spritehdr[1] = 0x10;                       	/* Byte offset to 1st sprite */
  spritehdr[2] = size;				/* Byte offset to end of block */
						/* No extension words */
  size -= 0x10;
  sph->next = ENDIAN_MODIFY(size);		/* Byte offset to next sprite */

  /* pdh 16-Aug-99: *must* 0-pad name */
  memset( &sph->name, 0, sizeof(sph->name) );
  layers_packedchar_pack_n(sph->name, "i", 12);	/* 12 chars of sprite name (this won't work for lounge) */

  sph->width = ENDIAN_MODIFY((width / 4) - 1);	/* Width in words - 1 */
  dest->stride = width;
  sph->height = ENDIAN_MODIFY(height - 1);	/* Height in scan lines - 1 */
  sph->lbit = 0;				/* First bit used */
  sph->rbit = ENDIAN_MODIFY(end_bits);		/* Last bit used */
  sph->image = ENDIAN_MODIFY(0x2C+palette);	/* Offset to sprite image */
  sph->mask = sph->image;			/* Offset to transparency mask */
  sph->mode = ENDIAN_MODIFY(mode);		/* Mode sprite was defined in */

  /* If grayscale, then write header + palette */
  if (palette)
  {
    int *palhdr = spritehdr+14;
    int maxloop = palette/8;
    int loop;

    if (greyscale)
    {
      if (palette == 128)
      {

	for (loop = 0; loop < maxloop; loop++)
	{
	  palhdr[loop*2] = ENDIAN_MODIFY((loop << 28) + (loop << 24)+ (loop << 20)+ (loop << 16) +
					 (loop << 12) + (loop << 8));
	  palhdr[(loop*2) + 1] = palhdr[loop*2];
	}
      }
      else
      {
	for (loop = 0; loop < maxloop; loop++)
	{
	  palhdr[loop*2] = ENDIAN_MODIFY((loop << 8) + (loop << 16) + (loop << 24));
	  palhdr[(loop*2) + 1] = palhdr[loop*2];
	}
      }
    }
#if !RISCOS
    else
    {
      /* 256 colour palettised colour version */
      unsigned int *pal = win32_palette();
      for (loop = 0; loop < maxloop; loop++)
      {
	palhdr[(loop*2) + 1] = palhdr[loop*2] = ENDIAN_MODIFY(*pal++);
      }
    }
#endif
    if (dest->outfile)
    {
      dest->putdst((unsigned char *) sph, 44+palette, dest->outfile);
      dest->image_offset = 44+palette;
    }
    else
    {
      (void) JFWRITE(dest->pub.output_file, spritehdr, 56+palette);
      dest->image_offset = 56+palette;
    }
  }
  else
  {
    /* Write header */
    if (dest->outfile)
    {
      dest->putdst((unsigned char *) &spritehdr[3], 56-12, dest->outfile);
      dest->image_offset = 56-12;
    }
    else
    {
      (void) JFWRITE(dest->pub.output_file, spritehdr, 56);
      dest->image_offset = 56;
    }
  }

}


/* Build color map for an 8bpp Sprite file.
 * See PRM 3-385 "ColourTrans" for details of 8bpp 'colour numbers'
 * when PALETTE_VIDC is set
 */

static void
read_sprite_map (j_decompress_ptr cinfo)