bitblt.c

Mon, 26 Aug 2002 05:43:49 +0000

author
eric
date
Mon, 26 Aug 2002 05:43:49 +0000
changeset 47
bfc6aaa089b0
parent 43
b80cb5a4282a
child 48
3d0be1c1c1b2
permissions
-rw-r--r--

fixed 'middle-endian' output from TIFFReadScanline

     1 #include <assert.h>
     2 #include <stdio.h>
     3 #include <stdlib.h>
     4 #include <string.h>
     6 #include "type.h"
     7 #include "bitblt.h"
    10 #define DIV_ROUND_UP(count,pow2) (((count) - 1) / (pow2) + 1)
    13 static const u8 bit_reverse_byte [0x100] =
    14 {
    15   0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
    16   0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
    17   0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
    18   0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
    19   0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
    20   0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
    21   0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
    22   0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
    23   0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
    24   0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
    25   0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
    26   0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
    27   0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
    28   0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
    29   0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
    30   0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
    31   0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
    32   0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
    33   0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
    34   0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
    35   0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
    36   0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
    37   0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
    38   0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
    39   0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
    40   0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
    41   0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
    42   0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
    43   0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
    44   0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
    45   0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
    46   0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff
    47 };
    50 void reverse_bits (u8 *p, int byte_count)
    51 {
    52   while (byte_count--)
    53     {
    54       (*p) = bit_reverse_byte [*p];
    55       p++;
    56     }
    57 }
    60 static word_type bit_reverse_word (word_type d)
    61 {
    62   return (bit_reverse_byte [d >> 24] |
    63 	  (bit_reverse_byte [(d >> 16) & 0xff] << 8) |
    64 	  (bit_reverse_byte [(d >> 8) & 0xff] << 16) |
    65 	  (bit_reverse_byte [d & 0xff] << 24));
    66 }
    69 static word_type *temp_buffer;
    70 static word_type temp_buffer_size;
    72 static void realloc_temp_buffer (u32 size)
    73 {
    74   if (size <= temp_buffer_size)
    75     return;
    76   temp_buffer = realloc (temp_buffer, size);
    77   if (! temp_buffer)
    78     {
    79       fprintf (stderr, "realloc failed in bitblt library\n");
    80       exit (2);
    81     }
    82   temp_buffer_size = size;
    83 }
    86 static inline word_type pixel_mask (int x)
    87 {
    88 #if defined (MIXED_ENDIAN)  /* disgusting hack for mixed-endian */
    89   word_type m;
    90   m = 0x80 >> (x & 7);
    91   m <<= (x & 24);
    92   return (m);
    93 #elif defined (LSB_RIGHT)
    94   return (1U << ((BITS_PER_WORD - 1) - x));
    95 #else
    96   return (1U << x);
    97 #endif
    98 };
   101 /* mask for range of bits left..right, inclusive */
   102 static inline word_type pixel_range_mask (int left, int right)
   103 {
   104   word_type m1, m2, val;
   106   /* $$$ one of these cases is wrong! */
   107 #if defined (LSB_RIGHT)
   108   m1 = (~ 0U) >> left;
   109   m2 = (~ 0U) << (BITS_PER_WORD - 1 - right);
   110 #else
   111   m1 = (~ 0U) << left;
   112   m2 = (~ 0U) >> (BITS_PER_WORD - 1 - right);
   113 #endif
   114   val = m1 & m2;
   116   printf ("left %d, right %d, mask %08x\n", left, right, val);
   117   return (val);
   118 };
   121 Bitmap *create_bitmap (Rect *rect)
   122 {
   123   Bitmap *bitmap;
   124   u32 width = rect_width (rect);
   125   u32 height = rect_height (rect);
   127   if ((width <= 0) || (height <= 0))
   128     return (NULL);
   130   bitmap = calloc (1, sizeof (Bitmap));
   131   if (! bitmap)
   132     return (NULL);
   133   bitmap->rect = * rect;
   134   bitmap->row_words = DIV_ROUND_UP (width, BITS_PER_WORD);
   135   bitmap->bits = calloc (1, height * bitmap->row_words * sizeof (word_type));
   136   if (! bitmap->bits)
   137     {
   138       free (bitmap);
   139       return (NULL);
   140     }
   141   return (bitmap);
   142 }
   144 void free_bitmap (Bitmap *bitmap)
   145 {
   146   free (bitmap->bits);
   147   free (bitmap);
   148 }
   150 boolean get_pixel (Bitmap *bitmap, Point coord)
   151 {
   152   word_type *p;
   153   int w,b;
   155   if ((coord.x < bitmap->rect.min.x) ||
   156       (coord.x >= bitmap->rect.max.x) ||
   157       (coord.y < bitmap->rect.min.y) ||
   158       (coord.y >= bitmap->rect.max.y))
   159     return (0);
   160   coord.y -= bitmap->rect.min.y;
   161   coord.x -= bitmap->rect.min.x;
   162   w = coord.x / BITS_PER_WORD;
   163   b = coord.x & (BITS_PER_WORD - 1);
   164   p = bitmap->bits + coord.y * bitmap->row_words + w;
   165   return (((*p) & pixel_mask (b)) != 0);
   166 }
   168 void set_pixel (Bitmap *bitmap, Point coord, boolean value)
   169 {
   170   word_type *p;
   171   int w,b;
   173   if ((coord.x < bitmap->rect.min.x) ||
   174       (coord.x >= bitmap->rect.max.x) ||
   175       (coord.y < bitmap->rect.min.y) ||
   176       (coord.y >= bitmap->rect.max.y))
   177     return;
   178   coord.y -= bitmap->rect.min.y;
   179   coord.x -= bitmap->rect.min.x;
   180   w = coord.x / BITS_PER_WORD;
   181   b = coord.x & (BITS_PER_WORD - 1);
   182   p = bitmap->bits + coord.y * bitmap->row_words + w;
   183   if (value)
   184     (*p) |= pixel_mask (b);
   185   else
   186     (*p) &= ~pixel_mask (b);
   187 }
   190 /* modifies rect1 to be the intersection of rect1 and rect2;
   191    returns true if intersection is non-null */
   192 static boolean clip_rect (Rect *rect1, Rect *rect2)
   193 {
   194   if (rect1->min.y > rect2->max.y)
   195     goto empty;
   196   if (rect1->min.y < rect2->min.y)
   197     {
   198       if (rect1->max.y < rect2->max.y)
   199 	goto empty;
   200       rect1->min.y = rect2->min.y;
   201     }
   202   if (rect1->max.y > rect2->max.y)
   203     rect1->max.y = rect2->max.y;
   205   if (rect1->min.x > rect2->max.x)
   206     goto empty;
   207   if (rect1->min.x < rect2->min.x)
   208     {
   209       if (rect1->max.x < rect2->max.x)
   210 	goto empty;
   211       rect1->min.x = rect2->min.x;
   212     }
   213   if (rect1->max.x > rect2->max.x)
   214     rect1->max.x = rect2->max.x;
   216  empty:
   217   rect1->min.x = rect1->min.y =
   218     rect1->max.x = rect1->max.y = 0;
   219   return (0);
   220 }
   223 static void blt_background (Bitmap *dest_bitmap,
   224 			    Rect dest_rect)
   225 {
   226   u32 y;
   227   word_type *rp;
   228   u32 left_bit, left_word;
   229   u32 right_bit, right_word;
   230   word_type left_mask, right_mask;
   231   s32 word_count;
   233   /* This function requires a non-null dest rect */
   234   assert (dest_rect.min.x < dest_rect.max.x);
   235   assert (dest_rect.min.y < dest_rect.max.y);
   237   /* and that the rows of the dest rect lie entirely within the dest bitmap */
   238   assert (dest_rect.min.y >= dest_bitmap->rect.min.y);
   239   assert (dest_rect.max.y <= dest_bitmap->rect.max.y);
   241   /* clip the x axis of the dest_rect to the bounds of the dest bitmap */
   242   if (dest_rect.min.x < dest_bitmap->rect.min.x)
   243     dest_rect.min.x = dest_bitmap->rect.min.x;
   244   if (dest_rect.max.x > dest_bitmap->rect.max.x)
   245     dest_rect.max.x = dest_bitmap->rect.max.x;
   247   rp = dest_bitmap->bits +
   248     (dest_rect.min.y - dest_bitmap->rect.min.y) * dest_bitmap->row_words +
   249     (dest_rect.min.x - dest_bitmap->rect.min.x) / BITS_PER_WORD;
   251   left_bit = dest_rect.min.x % BITS_PER_WORD;
   252   left_word = dest_rect.min.x / BITS_PER_WORD;
   254   right_bit = (dest_rect.max.x - 1) % BITS_PER_WORD;
   255   right_word = (dest_rect.max.x - 1) / BITS_PER_WORD;
   257   word_count = right_word + 1 - left_word;
   259   /* special case if entire horizontal range fits in a single word */
   260   if (word_count == 1)
   261     {
   262       left_mask = 0;
   263       right_mask = ~ pixel_range_mask (left_bit, right_bit);
   264       word_count = 0;
   265     }
   266   else
   267     {
   268       if (left_bit)
   269 	{
   270 	  left_mask = ~ pixel_range_mask (left_bit, BITS_PER_WORD - 1);
   271 	  word_count--;
   272 	}
   274       if (right_bit != (BITS_PER_WORD - 1))
   275 	{
   276 	  right_mask = ~ pixel_range_mask (0, right_bit);
   277 	  word_count--;
   278 	}
   279     }
   281   for (y = 0; y < rect_height (& dest_rect); y++)
   282     {
   283       word_type *wp = rp;
   285       /* partial word at left, if any */
   286       if (left_mask)
   287 	*(wp++) &= left_mask;
   289       /* use Duff's Device for the full words */
   290       if (word_count)
   291 	{
   292 	  s32 i = word_count;
   293 	  switch (i % 8)
   294 	    {
   295 	      while (i > 0)
   296 		{
   297 		  *(wp++) = 0;
   298 		case 7: *(wp++) = 0;
   299 		case 6: *(wp++) = 0;
   300 		case 5: *(wp++) = 0;
   301 		case 4: *(wp++) = 0;
   302 		case 3: *(wp++) = 0;
   303 		case 2: *(wp++) = 0;
   304 		case 1: *(wp++) = 0;
   305 		case 0: i -= 8;
   306 		}
   307 	    }
   308 	}
   310       /* partial word at right, if any */
   311       if (right_mask)
   312 	*wp &= right_mask;
   314       /* advance to next row */
   315       rp += dest_bitmap->row_words;
   316     }
   317 }
   320 #if 0
   321 static void blt (Bitmap *src_bitmap,
   322 		 Rect *src_rect,
   323 		 Bitmap *dest_bitmap,
   324 		 Rect *dest_rect)
   325 {
   326   s32 y;
   327   word_type *rp;
   329   /* This function requires a non-null src rect */
   330   assert (dest_rect->min.x < dest_rect->max.x);
   331   assert (dest_rect->min.y < dest_rect->max.y);
   333   /* and a non-null dest rect */
   334   assert (dest_rect->min.x < dest_rect->max.x);
   335   assert (dest_rect->min.y < dest_rect->max.y);
   337   /* and that the widths and heights of the rects match */
   338   assert (rect_width (src_rect) == rect_width (dest_rect));
   339   assert (rect_height (src_rect) == rect_height (dest_rect));
   341   /* and that the rows of the src rect lie entirely within the src bitmap */
   342   assert (dest_rect->min.y >= dest_bitmap->rect->min.y);
   343   assert (dest_rect->max.y <= dest_bitmap->rect->max.y);
   345   /* and that the rows of the dest rect lie entirely within the dest bitmap */
   346   assert (dest_rect->min.y >= dest_bitmap->rect->min.y);
   347   assert (dest_rect->max.y <= dest_bitmap->rect->max.y);
   349   /* clip the x axis of the dest_rect to the bounds of the dest bitmap,
   350      and adjust the src_rect to match */
   351   if (dest_rect->min.x < dest_bitmap->rect.min.x)
   352     {
   353       src_rect->min.x += ???;
   354       dest_rect->min.x = dest_bitmap->rect.min.x;
   355     }
   356   if (dest_rect->max.x > dest_bitmap->rect.max.x)
   357     {
   358       dest_rect->max.x = dest_bitmap->rect.max.x;
   359     }
   361   rp = ???;
   362   for (y = 0; y < rect_height (dest_rect); y++)
   363     {
   364   ???;
   365       rp += dest_bitmap->row_words;
   366     }
   367 }
   370 /*
   371  * The destination rectangle is first clipped to the dest bitmap, and
   372  * the source rectangle is adjusted in the corresponding manner.
   373  * What's left is divided into five sections, any of which may be
   374  * null.  The portion that actually corresponds to the intersection of
   375  * the source rectangle and the source bitmpa is the "middle".  The
   376  * other four sections will use the background color as the source
   377  * operand.
   378  *
   379  *          
   380  *   y0 ->  -------------------------------------------------
   381  *          |                     top                       |
   382  *          |                                               |
   383  *   y1 ->  -------------------------------------------------
   384  *          |   left        |    middle     |    right      |
   385  *          |               |               |               |
   386  *   y2 ->  -------------------------------------------------
   387  *          |                     bottom                    |
   388  *          |                                               |
   389  *   y3 ->  -------------------------------------------------
   390  *
   391  *          ^               ^               ^               ^
   392  *          |               |               |               |
   393  *         x0              x1              x2              x3
   394  *
   395  * */
   396 Bitmap *bitblt (Bitmap *src_bitmap,
   397 		Rect   *src_rect,
   398 		Bitmap *dest_bitmap,
   399 		Point  *dest_min,
   400 		int tfn,
   401 		int background)
   402 {
   403   Rect sr, dr;     /* src and dest rects, clipped to visible portion of
   404 		      dest rect */
   405   u32 drw, drh;    /* dest rect width, height - gets adjusted */
   406   Point src_point, dest_point;
   408   /* dest coordinates: */
   409   u32 x0, x1, x2, x3;
   410   u32 y0, y1, y2, y3;
   412   {
   413     sr = * src_rect;
   415     u32 srw = rect_width (& sr);
   416     u32 srh = rect_height (& sr);
   418     if ((srw < 0) || (srh < 0))
   419       goto done;  /* the source rect is empty! */
   421     dr.min.x = dest_min->x;
   422     dr.min.y = dest_min->y;
   423     dr.max.x = dr.min.x + srw;
   424     dr.max.y = dr.min.y + srh;
   425   }
   427   if (! dest_bitmap)
   428     {
   429       dest_bitmap = create_bitmap (& dr);
   430       if (! dest_bitmap)
   431 	return (NULL);
   432     }
   434   if ((dr.min.x >= dest_bitmap->rect.max.x) ||
   435       (dr.min.y >= dest_bitmap->rect.max.y))
   436     goto done;  /* the dest rect isn't even in the dest bitmap! */
   438   /* crop dest rect to dest bitmap */
   439   delta = dest_bitmap->rect.min.x - dr.min.x;
   440   if (delta > 0)
   441     {
   442       sr.min.x += delta;
   443       dr.min.x += delta;
   444     }
   446   delta = dest_bitmap->rect.min.y - dr.min.y;
   447   if (delta > 0)
   448     {
   449       sr.min.y += delta;
   450       dr.min.y += delta;
   451     }
   453   delta = dr.max.x - dest_bitmap->rect.max.x;
   454   if (delta > 0)
   455     {
   456       sr.max.x -= delta;
   457       dr.max.x -= delta;
   458     }
   460   delta = dr.max.y - dest_bitmap->rect.max.y;
   461   if (delta > 0)
   462     {
   463       sr.max.x -= delta;
   464       dr.max.x -= delta;
   465     }
   467   drw = rect_width (& dr);
   468   drh = rect_height (& dh);
   470   x0 = dr.min.x;
   471   y0 = dr.min.y;
   472   x3 = dr.max.x;
   473   y3 = dr.max.y;
   475 #if 0
   476   /* if the source rect min y is >= the source bitmap max y,
   477      we transfer background color to the entire dest rect */
   478   if (sr.min.y >= src->rect.max.y)
   479     {
   480       blt_background (dest_bitmap, dr);
   481       goto done;
   482     }
   483 #endif
   485   /* top */
   486   if (y0 != y1)
   487     {
   488       dr2.min.x = x0;
   489       dr2.max.x = x3;
   490       dr2.min.y = y0;
   491       dr2.max.y = y1;
   492       blt_background (dest_bitmap, & dr2);
   493     }
   495   /*
   496    * top:  if the source rect min y is less than the source bitmap min y,
   497    * we need to transfer some backgound color to the top part of the dest
   498    * rect
   499    */
   500   if (sr.min.y < src->rect.min.y)
   501     {
   502       Rect dr2;
   503       uint32 bg_height;
   505       bg_height = src->rect.min.y - sr.min.y;
   506       if (bg_height > sh)
   507 	bg_height = sh;
   509       dr2 = dr;
   510       dr2.max.y = dr2.min.y + bg_height;
   512       blt_background (dest_bitmap, & dr2);
   514       /* now reduce the rect height by the number of lines of background
   515 	 color */
   516       sr.min.y += bg_height;
   517       dr.min.y += bg_height;
   518       sh -= bg_height;
   519       dh -= bg_height;
   521       if (sr.min.y == sr.max.y)
   522 	goto done;
   523     }
   525   if (y1 != y2)
   526     {
   527       /* left */
   528       if (x0 != x1)
   529 	{
   530 	  dr2.min.x = x1;
   531 	  dr2.max.x = x1;
   532 	  dr2.min.y = y1;
   533 	  dr2.max.y = y2
   534 	  blt_background (dest_bitmap, & dr2);
   535 	}
   537       /* middle */
   538       if (x1 != x2)
   539 	{
   540 	  /* ??? */
   541 	}
   543       /* right */
   544       if (x2 != x3)
   545 	{
   546 	  dr2.min.x = x2;
   547 	  dr2.max.x = x3;
   548 	  dr2.min.y = y1;
   549 	  dr2.max.y = y2
   550 	  blt_background (dest_bitmap, & dr2);
   551 	}
   552     }
   554   /* bottom */
   555   if (y2 != y3)
   556     {
   557       dr2.min.x = x0;
   558       dr2.max.x = x3;
   559       dr2.min.y = y2;
   560       dr2.max.y = y3;
   561       blt_background (dest_bitmap, & dr2);
   562     }
   564  done:
   565   return (dest_bitmap);
   566 }
   567 #else
   568 Bitmap *bitblt (Bitmap *src_bitmap,
   569 		Rect   *src_rect,
   570 		Bitmap *dest_bitmap,
   571 		Point  *dest_min,
   572 		int tfn,
   573 		int background)
   574 {
   575   Point src_point, dest_point;
   577   if (! dest_bitmap)
   578     {
   579       Rect dest_rect = {{ 0, 0 }, { dest_min->x + rect_width (src_rect),
   580 				    dest_min->y + rect_height (src_rect) }};
   581       dest_bitmap = create_bitmap (& dest_rect);
   582       if (! dest_bitmap)
   583 	return (NULL);
   584     }
   586   if (tfn == TF_SRC)
   587     {
   588       for (src_point.y = src_rect->min.y;
   589 	   src_point.y < src_rect->max.y;
   590 	   src_point.y++)
   591 	{
   592 	  dest_point.y = dest_min->y + src_point.y - src_rect->min.y;
   594 	  for (src_point.x = src_rect->min.x;
   595 	       src_point.x < src_rect->max.x;
   596 	       src_point.x++)
   597 	    {
   598 	      boolean a;
   600 	      dest_point.x = dest_min->x + src_point.x - src_rect->min.x;
   602 	      a = get_pixel (src_bitmap, src_point);
   603 	      set_pixel (dest_bitmap, dest_point, a);
   604 	    }
   605 	}
   606     }
   607   else
   608     {
   609       for (src_point.y = src_rect->min.y;
   610 	   src_point.y < src_rect->max.y;
   611 	   src_point.y++)
   612 	{
   613 	  dest_point.y = dest_min->y + src_point.y - src_rect->min.y;
   615 	  for (src_point.x = src_rect->min.x;
   616 	       src_point.x < src_rect->max.x;
   617 	       src_point.x++)
   618 	    {
   619 	      boolean a, b, c;
   621 	      dest_point.x = dest_min->x + src_point.x - src_rect->min.x;
   623 	      a = get_pixel (src_bitmap, src_point);
   624 	      b = get_pixel (dest_bitmap, dest_point);
   625 	      c = (tfn & (1 << (a * 2 + b))) != 0;
   627 	      set_pixel (dest_bitmap, dest_point, c);
   628 	    }
   629 	}
   630     }
   631   return (dest_bitmap);
   632 }
   633 #endif
   636 /* in-place transformations */
   637 void flip_h (Bitmap *src)
   638 {
   639   word_type *rp;  /* row pointer */
   640   word_type *p1;  /* work src ptr */
   641   word_type *p2;  /* work dest ptr */
   642   s32 y;
   643   int shift1, shift2;
   645   realloc_temp_buffer ((src->row_words + 1) * sizeof (word_type));
   647   rp = src->bits;
   648   if ((rect_width (& src->rect) & 7) == 0)
   649     {
   650       for (y = src->rect.min.y; y < src->rect.max.y; y++)
   651 	{
   652 	  memcpy (temp_buffer, rp, src->row_words * sizeof (word_type));
   653 	  p1 = temp_buffer + src->row_words;
   654 	  p2 = rp;
   656 	  while (p1 >= temp_buffer)
   657 	    *(p2++) = bit_reverse_word (*(p1--));
   659 	  rp += src->row_words;
   660 	}
   661       return;
   662     }
   664   temp_buffer [0] = 0;
   665   shift1 = rect_width (& src->rect) & (BITS_PER_WORD - 1);
   666   shift2 = BITS_PER_WORD - shift1;
   668   for (y = src->rect.min.y; y < src->rect.max.y; y++)
   669     {
   670       word_type d1, d2;
   672       memcpy (temp_buffer + 1, rp, src->row_words * sizeof (word_type));
   673       p1 = temp_buffer + src->row_words;
   674       p2 = rp;
   676       d2 = *(p1--);
   678       while (p1 >= temp_buffer)
   679 	{
   680 	  d1 = *(p1--);
   681 	  *(p2++) = bit_reverse_word ((d1 << shift1) | (d2 >> shift2));
   682 	  d2 = d1;
   683 	}      
   685       rp += src->row_words;
   686     }
   687 }
   689 void flip_v (Bitmap *src)
   690 {
   691   word_type *p1, *p2;
   693   realloc_temp_buffer (src->row_words * sizeof (word_type));
   695   p1 = src->bits;
   696   p2 = src->bits + src->row_words * (rect_height (& src->rect) - 1);
   697   while (p1 < p2)
   698     {
   699       memcpy (temp_buffer, p1, src->row_words * sizeof (word_type));
   700       memcpy (p1, p2, src->row_words * sizeof (word_type));
   701       memcpy (p2, temp_buffer, src->row_words * sizeof (word_type));
   702       p1 += src->row_words;
   703       p2 -= src->row_words;
   704     }
   705 }
   707 void rot_180 (Bitmap *src)  /* combination of flip_h and flip_v */
   708 {
   709   flip_h (src);
   710   flip_v (src);
   711 }
   713 /* "in-place" transformations - will allocate new memory and free old */
   714 void transpose (Bitmap *src)
   715 {
   716   u32 new_row_words = DIV_ROUND_UP (rect_height (& src->rect), 32);
   717   word_type *new_bits;
   719   new_bits = calloc (1, new_row_words * rect_width (& src->rect) * sizeof (word_type));
   721   /* $$$ more code needed here */
   722 }
   724 void rot_90 (Bitmap *src)   /* transpose + flip_h */
   725 {
   726   transpose (src);
   727   flip_h (src);
   728 }
   730 void rot_270 (Bitmap *src)  /* transpose + flip_v */
   731 {
   732   transpose (src);
   733   flip_v (src);
   734 }