bitblt.c

Tue, 21 Jan 2003 18:30:49 +0000

author
eric
date
Tue, 21 Jan 2003 18:30:49 +0000
changeset 49
be20d7e8466f
parent 48
3d0be1c1c1b2
child 53
bb180150e603
permissions
-rw-r--r--

added command-line mode

     1 #include <stdbool.h>
     2 #include <stdint.h>
     3 #include <assert.h>
     4 #include <stdio.h>
     5 #include <stdlib.h>
     6 #include <string.h>
     8 #include "bitblt.h"
    11 #define DIV_ROUND_UP(count,pow2) (((count) - 1) / (pow2) + 1)
    14 static const uint8_t bit_reverse_byte [0x100] =
    15 {
    16   0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
    17   0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
    18   0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
    19   0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
    20   0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
    21   0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
    22   0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
    23   0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
    24   0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
    25   0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
    26   0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
    27   0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
    28   0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
    29   0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
    30   0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
    31   0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
    32   0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
    33   0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
    34   0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
    35   0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
    36   0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
    37   0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
    38   0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
    39   0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
    40   0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
    41   0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
    42   0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
    43   0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
    44   0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
    45   0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
    46   0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
    47   0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff
    48 };
    51 void reverse_bits (uint8_t *p, int byte_count)
    52 {
    53   while (byte_count--)
    54     {
    55       (*p) = bit_reverse_byte [*p];
    56       p++;
    57     }
    58 }
    61 static word_type bit_reverse_word (word_type d)
    62 {
    63   return (bit_reverse_byte [d >> 24] |
    64 	  (bit_reverse_byte [(d >> 16) & 0xff] << 8) |
    65 	  (bit_reverse_byte [(d >> 8) & 0xff] << 16) |
    66 	  (bit_reverse_byte [d & 0xff] << 24));
    67 }
    70 static word_type *temp_buffer;
    71 static word_type temp_buffer_size;
    73 static void realloc_temp_buffer (uint32_t size)
    74 {
    75   if (size <= temp_buffer_size)
    76     return;
    77   temp_buffer = realloc (temp_buffer, size);
    78   if (! temp_buffer)
    79     {
    80       fprintf (stderr, "realloc failed in bitblt library\n");
    81       exit (2);
    82     }
    83   temp_buffer_size = size;
    84 }
    87 static inline word_type pixel_mask (int x)
    88 {
    89 #if defined (MIXED_ENDIAN)  /* disgusting hack for mixed-endian */
    90   word_type m;
    91   m = 0x80 >> (x & 7);
    92   m <<= (x & 24);
    93   return (m);
    94 #elif defined (LSB_RIGHT)
    95   return (1U << ((BITS_PER_WORD - 1) - x));
    96 #else
    97   return (1U << x);
    98 #endif
    99 };
   102 /* mask for range of bits left..right, inclusive */
   103 static inline word_type pixel_range_mask (int left, int right)
   104 {
   105   word_type m1, m2, val;
   107   /* $$$ one of these cases is wrong! */
   108 #if defined (LSB_RIGHT)
   109   m1 = (~ 0U) >> left;
   110   m2 = (~ 0U) << (BITS_PER_WORD - 1 - right);
   111 #else
   112   m1 = (~ 0U) << left;
   113   m2 = (~ 0U) >> (BITS_PER_WORD - 1 - right);
   114 #endif
   115   val = m1 & m2;
   117   printf ("left %d, right %d, mask %08x\n", left, right, val);
   118   return (val);
   119 };
   122 Bitmap *create_bitmap (Rect *rect)
   123 {
   124   Bitmap *bitmap;
   125   uint32_t width = rect_width (rect);
   126   uint32_t height = rect_height (rect);
   128   if ((width <= 0) || (height <= 0))
   129     return (NULL);
   131   bitmap = calloc (1, sizeof (Bitmap));
   132   if (! bitmap)
   133     return (NULL);
   134   bitmap->rect = * rect;
   135   bitmap->row_words = DIV_ROUND_UP (width, BITS_PER_WORD);
   136   bitmap->bits = calloc (1, height * bitmap->row_words * sizeof (word_type));
   137   if (! bitmap->bits)
   138     {
   139       free (bitmap);
   140       return (NULL);
   141     }
   142   return (bitmap);
   143 }
   145 void free_bitmap (Bitmap *bitmap)
   146 {
   147   free (bitmap->bits);
   148   free (bitmap);
   149 }
   151 bool get_pixel (Bitmap *bitmap, Point coord)
   152 {
   153   word_type *p;
   154   int w,b;
   156   if ((coord.x < bitmap->rect.min.x) ||
   157       (coord.x >= bitmap->rect.max.x) ||
   158       (coord.y < bitmap->rect.min.y) ||
   159       (coord.y >= bitmap->rect.max.y))
   160     return (0);
   161   coord.y -= bitmap->rect.min.y;
   162   coord.x -= bitmap->rect.min.x;
   163   w = coord.x / BITS_PER_WORD;
   164   b = coord.x & (BITS_PER_WORD - 1);
   165   p = bitmap->bits + coord.y * bitmap->row_words + w;
   166   return (((*p) & pixel_mask (b)) != 0);
   167 }
   169 void set_pixel (Bitmap *bitmap, Point coord, bool value)
   170 {
   171   word_type *p;
   172   int w,b;
   174   if ((coord.x < bitmap->rect.min.x) ||
   175       (coord.x >= bitmap->rect.max.x) ||
   176       (coord.y < bitmap->rect.min.y) ||
   177       (coord.y >= bitmap->rect.max.y))
   178     return;
   179   coord.y -= bitmap->rect.min.y;
   180   coord.x -= bitmap->rect.min.x;
   181   w = coord.x / BITS_PER_WORD;
   182   b = coord.x & (BITS_PER_WORD - 1);
   183   p = bitmap->bits + coord.y * bitmap->row_words + w;
   184   if (value)
   185     (*p) |= pixel_mask (b);
   186   else
   187     (*p) &= ~pixel_mask (b);
   188 }
   191 /* modifies rect1 to be the intersection of rect1 and rect2;
   192    returns true if intersection is non-null */
   193 static bool clip_rect (Rect *rect1, Rect *rect2)
   194 {
   195   if (rect1->min.y > rect2->max.y)
   196     goto empty;
   197   if (rect1->min.y < rect2->min.y)
   198     {
   199       if (rect1->max.y < rect2->max.y)
   200 	goto empty;
   201       rect1->min.y = rect2->min.y;
   202     }
   203   if (rect1->max.y > rect2->max.y)
   204     rect1->max.y = rect2->max.y;
   206   if (rect1->min.x > rect2->max.x)
   207     goto empty;
   208   if (rect1->min.x < rect2->min.x)
   209     {
   210       if (rect1->max.x < rect2->max.x)
   211 	goto empty;
   212       rect1->min.x = rect2->min.x;
   213     }
   214   if (rect1->max.x > rect2->max.x)
   215     rect1->max.x = rect2->max.x;
   217  empty:
   218   rect1->min.x = rect1->min.y =
   219     rect1->max.x = rect1->max.y = 0;
   220   return (0);
   221 }
   224 static void blt_background (Bitmap *dest_bitmap,
   225 			    Rect dest_rect)
   226 {
   227   uint32_t y;
   228   word_type *rp;
   229   uint32_t left_bit, left_word;
   230   uint32_t right_bit, right_word;
   231   word_type left_mask, right_mask;
   232   int32_t word_count;
   234   /* This function requires a non-null dest rect */
   235   assert (dest_rect.min.x < dest_rect.max.x);
   236   assert (dest_rect.min.y < dest_rect.max.y);
   238   /* and that the rows of the dest rect lie entirely within the dest bitmap */
   239   assert (dest_rect.min.y >= dest_bitmap->rect.min.y);
   240   assert (dest_rect.max.y <= dest_bitmap->rect.max.y);
   242   /* clip the x axis of the dest_rect to the bounds of the dest bitmap */
   243   if (dest_rect.min.x < dest_bitmap->rect.min.x)
   244     dest_rect.min.x = dest_bitmap->rect.min.x;
   245   if (dest_rect.max.x > dest_bitmap->rect.max.x)
   246     dest_rect.max.x = dest_bitmap->rect.max.x;
   248   rp = dest_bitmap->bits +
   249     (dest_rect.min.y - dest_bitmap->rect.min.y) * dest_bitmap->row_words +
   250     (dest_rect.min.x - dest_bitmap->rect.min.x) / BITS_PER_WORD;
   252   left_bit = dest_rect.min.x % BITS_PER_WORD;
   253   left_word = dest_rect.min.x / BITS_PER_WORD;
   255   right_bit = (dest_rect.max.x - 1) % BITS_PER_WORD;
   256   right_word = (dest_rect.max.x - 1) / BITS_PER_WORD;
   258   word_count = right_word + 1 - left_word;
   260   /* special case if entire horizontal range fits in a single word */
   261   if (word_count == 1)
   262     {
   263       left_mask = 0;
   264       right_mask = ~ pixel_range_mask (left_bit, right_bit);
   265       word_count = 0;
   266     }
   267   else
   268     {
   269       if (left_bit)
   270 	{
   271 	  left_mask = ~ pixel_range_mask (left_bit, BITS_PER_WORD - 1);
   272 	  word_count--;
   273 	}
   275       if (right_bit != (BITS_PER_WORD - 1))
   276 	{
   277 	  right_mask = ~ pixel_range_mask (0, right_bit);
   278 	  word_count--;
   279 	}
   280     }
   282   for (y = 0; y < rect_height (& dest_rect); y++)
   283     {
   284       word_type *wp = rp;
   286       /* partial word at left, if any */
   287       if (left_mask)
   288 	*(wp++) &= left_mask;
   290       /* use Duff's Device for the full words */
   291       if (word_count)
   292 	{
   293 	  int32_t i = word_count;
   294 	  switch (i % 8)
   295 	    {
   296 	      while (i > 0)
   297 		{
   298 		  *(wp++) = 0;
   299 		case 7: *(wp++) = 0;
   300 		case 6: *(wp++) = 0;
   301 		case 5: *(wp++) = 0;
   302 		case 4: *(wp++) = 0;
   303 		case 3: *(wp++) = 0;
   304 		case 2: *(wp++) = 0;
   305 		case 1: *(wp++) = 0;
   306 		case 0: i -= 8;
   307 		}
   308 	    }
   309 	}
   311       /* partial word at right, if any */
   312       if (right_mask)
   313 	*wp &= right_mask;
   315       /* advance to next row */
   316       rp += dest_bitmap->row_words;
   317     }
   318 }
   321 #if 0
   322 static void blt (Bitmap *src_bitmap,
   323 		 Rect *src_rect,
   324 		 Bitmap *dest_bitmap,
   325 		 Rect *dest_rect)
   326 {
   327   int32_t y;
   328   word_type *rp;
   330   /* This function requires a non-null src rect */
   331   assert (dest_rect->min.x < dest_rect->max.x);
   332   assert (dest_rect->min.y < dest_rect->max.y);
   334   /* and a non-null dest rect */
   335   assert (dest_rect->min.x < dest_rect->max.x);
   336   assert (dest_rect->min.y < dest_rect->max.y);
   338   /* and that the widths and heights of the rects match */
   339   assert (rect_width (src_rect) == rect_width (dest_rect));
   340   assert (rect_height (src_rect) == rect_height (dest_rect));
   342   /* and that the rows of the src rect lie entirely within the src bitmap */
   343   assert (dest_rect->min.y >= dest_bitmap->rect->min.y);
   344   assert (dest_rect->max.y <= dest_bitmap->rect->max.y);
   346   /* and that the rows of the dest rect lie entirely within the dest bitmap */
   347   assert (dest_rect->min.y >= dest_bitmap->rect->min.y);
   348   assert (dest_rect->max.y <= dest_bitmap->rect->max.y);
   350   /* clip the x axis of the dest_rect to the bounds of the dest bitmap,
   351      and adjust the src_rect to match */
   352   if (dest_rect->min.x < dest_bitmap->rect.min.x)
   353     {
   354       src_rect->min.x += ???;
   355       dest_rect->min.x = dest_bitmap->rect.min.x;
   356     }
   357   if (dest_rect->max.x > dest_bitmap->rect.max.x)
   358     {
   359       dest_rect->max.x = dest_bitmap->rect.max.x;
   360     }
   362   rp = ???;
   363   for (y = 0; y < rect_height (dest_rect); y++)
   364     {
   365   ???;
   366       rp += dest_bitmap->row_words;
   367     }
   368 }
   371 /*
   372  * The destination rectangle is first clipped to the dest bitmap, and
   373  * the source rectangle is adjusted in the corresponding manner.
   374  * What's left is divided into five sections, any of which may be
   375  * null.  The portion that actually corresponds to the intersection of
   376  * the source rectangle and the source bitmpa is the "middle".  The
   377  * other four sections will use the background color as the source
   378  * operand.
   379  *
   380  *          
   381  *   y0 ->  -------------------------------------------------
   382  *          |                     top                       |
   383  *          |                                               |
   384  *   y1 ->  -------------------------------------------------
   385  *          |   left        |    middle     |    right      |
   386  *          |               |               |               |
   387  *   y2 ->  -------------------------------------------------
   388  *          |                     bottom                    |
   389  *          |                                               |
   390  *   y3 ->  -------------------------------------------------
   391  *
   392  *          ^               ^               ^               ^
   393  *          |               |               |               |
   394  *         x0              x1              x2              x3
   395  *
   396  * */
   397 Bitmap *bitblt (Bitmap *src_bitmap,
   398 		Rect   *src_rect,
   399 		Bitmap *dest_bitmap,
   400 		Point  *dest_min,
   401 		int tfn,
   402 		int background)
   403 {
   404   Rect sr, dr;     /* src and dest rects, clipped to visible portion of
   405 		      dest rect */
   406   uint32_t drw, drh;    /* dest rect width, height - gets adjusted */
   407   Point src_point, dest_point;
   409   /* dest coordinates: */
   410   uint32_t x0, x1, x2, x3;
   411   uint32_t y0, y1, y2, y3;
   413   {
   414     sr = * src_rect;
   416     uint32_t srw = rect_width (& sr);
   417     uint32_t srh = rect_height (& sr);
   419     if ((srw < 0) || (srh < 0))
   420       goto done;  /* the source rect is empty! */
   422     dr.min.x = dest_min->x;
   423     dr.min.y = dest_min->y;
   424     dr.max.x = dr.min.x + srw;
   425     dr.max.y = dr.min.y + srh;
   426   }
   428   if (! dest_bitmap)
   429     {
   430       dest_bitmap = create_bitmap (& dr);
   431       if (! dest_bitmap)
   432 	return (NULL);
   433     }
   435   if ((dr.min.x >= dest_bitmap->rect.max.x) ||
   436       (dr.min.y >= dest_bitmap->rect.max.y))
   437     goto done;  /* the dest rect isn't even in the dest bitmap! */
   439   /* crop dest rect to dest bitmap */
   440   delta = dest_bitmap->rect.min.x - dr.min.x;
   441   if (delta > 0)
   442     {
   443       sr.min.x += delta;
   444       dr.min.x += delta;
   445     }
   447   delta = dest_bitmap->rect.min.y - dr.min.y;
   448   if (delta > 0)
   449     {
   450       sr.min.y += delta;
   451       dr.min.y += delta;
   452     }
   454   delta = dr.max.x - dest_bitmap->rect.max.x;
   455   if (delta > 0)
   456     {
   457       sr.max.x -= delta;
   458       dr.max.x -= delta;
   459     }
   461   delta = dr.max.y - dest_bitmap->rect.max.y;
   462   if (delta > 0)
   463     {
   464       sr.max.x -= delta;
   465       dr.max.x -= delta;
   466     }
   468   drw = rect_width (& dr);
   469   drh = rect_height (& dh);
   471   x0 = dr.min.x;
   472   y0 = dr.min.y;
   473   x3 = dr.max.x;
   474   y3 = dr.max.y;
   476 #if 0
   477   /* if the source rect min y is >= the source bitmap max y,
   478      we transfer background color to the entire dest rect */
   479   if (sr.min.y >= src->rect.max.y)
   480     {
   481       blt_background (dest_bitmap, dr);
   482       goto done;
   483     }
   484 #endif
   486   /* top */
   487   if (y0 != y1)
   488     {
   489       dr2.min.x = x0;
   490       dr2.max.x = x3;
   491       dr2.min.y = y0;
   492       dr2.max.y = y1;
   493       blt_background (dest_bitmap, & dr2);
   494     }
   496   /*
   497    * top:  if the source rect min y is less than the source bitmap min y,
   498    * we need to transfer some backgound color to the top part of the dest
   499    * rect
   500    */
   501   if (sr.min.y < src->rect.min.y)
   502     {
   503       Rect dr2;
   504       uint32 bg_height;
   506       bg_height = src->rect.min.y - sr.min.y;
   507       if (bg_height > sh)
   508 	bg_height = sh;
   510       dr2 = dr;
   511       dr2.max.y = dr2.min.y + bg_height;
   513       blt_background (dest_bitmap, & dr2);
   515       /* now reduce the rect height by the number of lines of background
   516 	 color */
   517       sr.min.y += bg_height;
   518       dr.min.y += bg_height;
   519       sh -= bg_height;
   520       dh -= bg_height;
   522       if (sr.min.y == sr.max.y)
   523 	goto done;
   524     }
   526   if (y1 != y2)
   527     {
   528       /* left */
   529       if (x0 != x1)
   530 	{
   531 	  dr2.min.x = x1;
   532 	  dr2.max.x = x1;
   533 	  dr2.min.y = y1;
   534 	  dr2.max.y = y2
   535 	  blt_background (dest_bitmap, & dr2);
   536 	}
   538       /* middle */
   539       if (x1 != x2)
   540 	{
   541 	  /* ??? */
   542 	}
   544       /* right */
   545       if (x2 != x3)
   546 	{
   547 	  dr2.min.x = x2;
   548 	  dr2.max.x = x3;
   549 	  dr2.min.y = y1;
   550 	  dr2.max.y = y2
   551 	  blt_background (dest_bitmap, & dr2);
   552 	}
   553     }
   555   /* bottom */
   556   if (y2 != y3)
   557     {
   558       dr2.min.x = x0;
   559       dr2.max.x = x3;
   560       dr2.min.y = y2;
   561       dr2.max.y = y3;
   562       blt_background (dest_bitmap, & dr2);
   563     }
   565  done:
   566   return (dest_bitmap);
   567 }
   568 #else
   569 Bitmap *bitblt (Bitmap *src_bitmap,
   570 		Rect   *src_rect,
   571 		Bitmap *dest_bitmap,
   572 		Point  *dest_min,
   573 		int tfn,
   574 		int background)
   575 {
   576   Point src_point, dest_point;
   578   if (! dest_bitmap)
   579     {
   580       Rect dest_rect = {{ 0, 0 }, { dest_min->x + rect_width (src_rect),
   581 				    dest_min->y + rect_height (src_rect) }};
   582       dest_bitmap = create_bitmap (& dest_rect);
   583       if (! dest_bitmap)
   584 	return (NULL);
   585     }
   587   if (tfn == TF_SRC)
   588     {
   589       for (src_point.y = src_rect->min.y;
   590 	   src_point.y < src_rect->max.y;
   591 	   src_point.y++)
   592 	{
   593 	  dest_point.y = dest_min->y + src_point.y - src_rect->min.y;
   595 	  for (src_point.x = src_rect->min.x;
   596 	       src_point.x < src_rect->max.x;
   597 	       src_point.x++)
   598 	    {
   599 	      bool a;
   601 	      dest_point.x = dest_min->x + src_point.x - src_rect->min.x;
   603 	      a = get_pixel (src_bitmap, src_point);
   604 	      set_pixel (dest_bitmap, dest_point, a);
   605 	    }
   606 	}
   607     }
   608   else
   609     {
   610       for (src_point.y = src_rect->min.y;
   611 	   src_point.y < src_rect->max.y;
   612 	   src_point.y++)
   613 	{
   614 	  dest_point.y = dest_min->y + src_point.y - src_rect->min.y;
   616 	  for (src_point.x = src_rect->min.x;
   617 	       src_point.x < src_rect->max.x;
   618 	       src_point.x++)
   619 	    {
   620 	      bool a, b, c;
   622 	      dest_point.x = dest_min->x + src_point.x - src_rect->min.x;
   624 	      a = get_pixel (src_bitmap, src_point);
   625 	      b = get_pixel (dest_bitmap, dest_point);
   626 	      c = (tfn & (1 << (a * 2 + b))) != 0;
   628 	      set_pixel (dest_bitmap, dest_point, c);
   629 	    }
   630 	}
   631     }
   632   return (dest_bitmap);
   633 }
   634 #endif
   637 /* in-place transformations */
   638 void flip_h (Bitmap *src)
   639 {
   640   word_type *rp;  /* row pointer */
   641   word_type *p1;  /* work src ptr */
   642   word_type *p2;  /* work dest ptr */
   643   int32_t y;
   644   int shift1, shift2;
   646   realloc_temp_buffer ((src->row_words + 1) * sizeof (word_type));
   648   rp = src->bits;
   649   if ((rect_width (& src->rect) & 7) == 0)
   650     {
   651       for (y = src->rect.min.y; y < src->rect.max.y; y++)
   652 	{
   653 	  memcpy (temp_buffer, rp, src->row_words * sizeof (word_type));
   654 	  p1 = temp_buffer + src->row_words;
   655 	  p2 = rp;
   657 	  while (p1 >= temp_buffer)
   658 	    *(p2++) = bit_reverse_word (*(p1--));
   660 	  rp += src->row_words;
   661 	}
   662       return;
   663     }
   665   temp_buffer [0] = 0;
   666   shift1 = rect_width (& src->rect) & (BITS_PER_WORD - 1);
   667   shift2 = BITS_PER_WORD - shift1;
   669   for (y = src->rect.min.y; y < src->rect.max.y; y++)
   670     {
   671       word_type d1, d2;
   673       memcpy (temp_buffer + 1, rp, src->row_words * sizeof (word_type));
   674       p1 = temp_buffer + src->row_words;
   675       p2 = rp;
   677       d2 = *(p1--);
   679       while (p1 >= temp_buffer)
   680 	{
   681 	  d1 = *(p1--);
   682 	  *(p2++) = bit_reverse_word ((d1 << shift1) | (d2 >> shift2));
   683 	  d2 = d1;
   684 	}      
   686       rp += src->row_words;
   687     }
   688 }
   690 void flip_v (Bitmap *src)
   691 {
   692   word_type *p1, *p2;
   694   realloc_temp_buffer (src->row_words * sizeof (word_type));
   696   p1 = src->bits;
   697   p2 = src->bits + src->row_words * (rect_height (& src->rect) - 1);
   698   while (p1 < p2)
   699     {
   700       memcpy (temp_buffer, p1, src->row_words * sizeof (word_type));
   701       memcpy (p1, p2, src->row_words * sizeof (word_type));
   702       memcpy (p2, temp_buffer, src->row_words * sizeof (word_type));
   703       p1 += src->row_words;
   704       p2 -= src->row_words;
   705     }
   706 }
   708 void rot_180 (Bitmap *src)  /* combination of flip_h and flip_v */
   709 {
   710   flip_h (src);
   711   flip_v (src);
   712 }
   714 /* "in-place" transformations - will allocate new memory and free old */
   715 void transpose (Bitmap *src)
   716 {
   717   uint32_t new_row_words = DIV_ROUND_UP (rect_height (& src->rect), 32);
   718   word_type *new_bits;
   720   new_bits = calloc (1, new_row_words * rect_width (& src->rect) * sizeof (word_type));
   722   /* $$$ more code needed here */
   723 }
   725 void rot_90 (Bitmap *src)   /* transpose + flip_h */
   726 {
   727   transpose (src);
   728   flip_h (src);
   729 }
   731 void rot_270 (Bitmap *src)  /* transpose + flip_v */
   732 {
   733   transpose (src);
   734   flip_v (src);
   735 }