bitblt.c

Wed, 12 Mar 2003 10:59:09 +0000

author
eric
date
Wed, 12 Mar 2003 10:59:09 +0000
changeset 109
663da96ad2bc
parent 96
25c6b1a63f93
child 125
e2ef1c2f9eca
permissions
-rw-r--r--

changed word_type to word_t.

     1 /*
     2  * t2p: Create a PDF file from the contents of one or more TIFF
     3  *      bilevel image files.  The images in the resulting PDF file
     4  *      will be compressed using ITU-T T.6 (G4) fax encoding.
     5  *
     6  * bitblt routines
     7  * $Id: bitblt.c,v 1.15 2003/03/12 02:59:09 eric Exp $
     8  * Copyright 2001, 2002, 2003 Eric Smith <eric@brouhaha.com>
     9  *
    10  * This program is free software; you can redistribute it and/or modify
    11  * it under the terms of the GNU General Public License version 2 as
    12  * published by the Free Software Foundation.  Note that permission is
    13  * not granted to redistribute this program under the terms of any
    14  * other version of the General Public License.
    15  *
    16  * This program is distributed in the hope that it will be useful,
    17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
    18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    19  * GNU General Public License for more details.
    20  *
    21  * You should have received a copy of the GNU General Public License
    22  * along with this program; if not, write to the Free Software
    23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111 USA
    24  */
    27 #include <stdbool.h>
    28 #include <stdint.h>
    29 #include <assert.h>
    30 #include <stdio.h>
    31 #include <stdlib.h>
    32 #include <string.h>
    34 #include "bitblt.h"
    36 #include "bitblt_tables.h"
    39 #define DIV_ROUND_UP(count,pow2) (((count) - 1) / (pow2) + 1)
    42 void reverse_bits (uint8_t *p, int byte_count)
    43 {
    44   while (byte_count--)
    45     {
    46       (*p) = bit_reverse_byte [*p];
    47       p++;
    48     }
    49 }
    52 static word_t bit_reverse_word (word_t d)
    53 {
    54   return (bit_reverse_byte [d >> 24] |
    55 	  (bit_reverse_byte [(d >> 16) & 0xff] << 8) |
    56 	  (bit_reverse_byte [(d >> 8) & 0xff] << 16) |
    57 	  (bit_reverse_byte [d & 0xff] << 24));
    58 }
    61 static word_t *temp_buffer;
    62 static word_t temp_buffer_size;
    64 static void realloc_temp_buffer (uint32_t size)
    65 {
    66   if (size <= temp_buffer_size)
    67     return;
    68   temp_buffer = realloc (temp_buffer, size);
    69   if (! temp_buffer)
    70     {
    71       fprintf (stderr, "realloc failed in bitblt library\n");
    72       exit (2);
    73     }
    74   temp_buffer_size = size;
    75 }
    78 static inline word_t pixel_mask (int x)
    79 {
    80 #if defined (MIXED_ENDIAN)  /* disgusting hack for mixed-endian */
    81   word_t m;
    82   m = 0x80 >> (x & 7);
    83   m <<= (x & 24);
    84   return (m);
    85 #elif defined (LSB_RIGHT)
    86   return (1U << ((BITS_PER_WORD - 1) - x));
    87 #else
    88   return (1U << x);
    89 #endif
    90 };
    93 /* mask for range of bits left..right, inclusive */
    94 static inline word_t pixel_range_mask (int left, int right)
    95 {
    96   word_t m1, m2, val;
    98   /* $$$ one of these cases is wrong! */
    99 #if defined (LSB_RIGHT)
   100   m1 = (~ 0U) >> left;
   101   m2 = (~ 0U) << (BITS_PER_WORD - 1 - right);
   102 #else
   103   m1 = (~ 0U) << left;
   104   m2 = (~ 0U) >> (BITS_PER_WORD - 1 - right);
   105 #endif
   106   val = m1 & m2;
   108   printf ("left %d, right %d, mask %08x\n", left, right, val);
   109   return (val);
   110 };
   113 Bitmap *create_bitmap (Rect *rect)
   114 {
   115   Bitmap *bitmap;
   116   uint32_t width = rect_width (rect);
   117   uint32_t height = rect_height (rect);
   119   if ((width <= 0) || (height <= 0))
   120     return (NULL);
   122   bitmap = calloc (1, sizeof (Bitmap));
   123   if (! bitmap)
   124     return (NULL);
   125   bitmap->rect = * rect;
   126   bitmap->row_words = DIV_ROUND_UP (width, BITS_PER_WORD);
   127   bitmap->bits = calloc (1, height * bitmap->row_words * sizeof (word_t));
   128   if (! bitmap->bits)
   129     {
   130       free (bitmap);
   131       return (NULL);
   132     }
   133   return (bitmap);
   134 }
   136 void free_bitmap (Bitmap *bitmap)
   137 {
   138   free (bitmap->bits);
   139   free (bitmap);
   140 }
   142 bool get_pixel (Bitmap *bitmap, Point coord)
   143 {
   144   word_t *p;
   145   int w,b;
   147   if ((coord.x < bitmap->rect.min.x) ||
   148       (coord.x >= bitmap->rect.max.x) ||
   149       (coord.y < bitmap->rect.min.y) ||
   150       (coord.y >= bitmap->rect.max.y))
   151     return (0);
   152   coord.y -= bitmap->rect.min.y;
   153   coord.x -= bitmap->rect.min.x;
   154   w = coord.x / BITS_PER_WORD;
   155   b = coord.x & (BITS_PER_WORD - 1);
   156   p = bitmap->bits + coord.y * bitmap->row_words + w;
   157   return (((*p) & pixel_mask (b)) != 0);
   158 }
   160 void set_pixel (Bitmap *bitmap, Point coord, bool value)
   161 {
   162   word_t *p;
   163   int w,b;
   165   if ((coord.x < bitmap->rect.min.x) ||
   166       (coord.x >= bitmap->rect.max.x) ||
   167       (coord.y < bitmap->rect.min.y) ||
   168       (coord.y >= bitmap->rect.max.y))
   169     return;
   170   coord.y -= bitmap->rect.min.y;
   171   coord.x -= bitmap->rect.min.x;
   172   w = coord.x / BITS_PER_WORD;
   173   b = coord.x & (BITS_PER_WORD - 1);
   174   p = bitmap->bits + coord.y * bitmap->row_words + w;
   175   if (value)
   176     (*p) |= pixel_mask (b);
   177   else
   178     (*p) &= ~pixel_mask (b);
   179 }
   182 /* modifies rect1 to be the intersection of rect1 and rect2;
   183    returns true if intersection is non-null */
   184 static bool clip_rect (Rect *rect1, Rect *rect2)
   185 {
   186   if (rect1->min.y > rect2->max.y)
   187     goto empty;
   188   if (rect1->min.y < rect2->min.y)
   189     {
   190       if (rect1->max.y < rect2->max.y)
   191 	goto empty;
   192       rect1->min.y = rect2->min.y;
   193     }
   194   if (rect1->max.y > rect2->max.y)
   195     rect1->max.y = rect2->max.y;
   197   if (rect1->min.x > rect2->max.x)
   198     goto empty;
   199   if (rect1->min.x < rect2->min.x)
   200     {
   201       if (rect1->max.x < rect2->max.x)
   202 	goto empty;
   203       rect1->min.x = rect2->min.x;
   204     }
   205   if (rect1->max.x > rect2->max.x)
   206     rect1->max.x = rect2->max.x;
   208  empty:
   209   rect1->min.x = rect1->min.y =
   210     rect1->max.x = rect1->max.y = 0;
   211   return (0);
   212 }
   215 static void blt_background (Bitmap *dest_bitmap,
   216 			    Rect dest_rect)
   217 {
   218   uint32_t y;
   219   word_t *rp;
   220   uint32_t left_bit, left_word;
   221   uint32_t right_bit, right_word;
   222   word_t left_mask, right_mask;
   223   int32_t word_count;
   225   /* This function requires a non-null dest rect */
   226   assert (dest_rect.min.x < dest_rect.max.x);
   227   assert (dest_rect.min.y < dest_rect.max.y);
   229   /* and that the rows of the dest rect lie entirely within the dest bitmap */
   230   assert (dest_rect.min.y >= dest_bitmap->rect.min.y);
   231   assert (dest_rect.max.y <= dest_bitmap->rect.max.y);
   233   /* clip the x axis of the dest_rect to the bounds of the dest bitmap */
   234   if (dest_rect.min.x < dest_bitmap->rect.min.x)
   235     dest_rect.min.x = dest_bitmap->rect.min.x;
   236   if (dest_rect.max.x > dest_bitmap->rect.max.x)
   237     dest_rect.max.x = dest_bitmap->rect.max.x;
   239   rp = dest_bitmap->bits +
   240     (dest_rect.min.y - dest_bitmap->rect.min.y) * dest_bitmap->row_words +
   241     (dest_rect.min.x - dest_bitmap->rect.min.x) / BITS_PER_WORD;
   243   left_bit = dest_rect.min.x % BITS_PER_WORD;
   244   left_word = dest_rect.min.x / BITS_PER_WORD;
   246   right_bit = (dest_rect.max.x - 1) % BITS_PER_WORD;
   247   right_word = (dest_rect.max.x - 1) / BITS_PER_WORD;
   249   word_count = right_word + 1 - left_word;
   251   /* special case if entire horizontal range fits in a single word */
   252   if (word_count == 1)
   253     {
   254       left_mask = 0;
   255       right_mask = ~ pixel_range_mask (left_bit, right_bit);
   256       word_count = 0;
   257     }
   258   else
   259     {
   260       if (left_bit)
   261 	{
   262 	  left_mask = ~ pixel_range_mask (left_bit, BITS_PER_WORD - 1);
   263 	  word_count--;
   264 	}
   266       if (right_bit != (BITS_PER_WORD - 1))
   267 	{
   268 	  right_mask = ~ pixel_range_mask (0, right_bit);
   269 	  word_count--;
   270 	}
   271     }
   273   for (y = 0; y < rect_height (& dest_rect); y++)
   274     {
   275       word_t *wp = rp;
   277       /* partial word at left, if any */
   278       if (left_mask)
   279 	*(wp++) &= left_mask;
   281       /* use Duff's Device for the full words */
   282       if (word_count)
   283 	{
   284 	  int32_t i = word_count;
   285 	  switch (i % 8)
   286 	    {
   287 	      while (i > 0)
   288 		{
   289 		  *(wp++) = 0;
   290 		case 7: *(wp++) = 0;
   291 		case 6: *(wp++) = 0;
   292 		case 5: *(wp++) = 0;
   293 		case 4: *(wp++) = 0;
   294 		case 3: *(wp++) = 0;
   295 		case 2: *(wp++) = 0;
   296 		case 1: *(wp++) = 0;
   297 		case 0: i -= 8;
   298 		}
   299 	    }
   300 	}
   302       /* partial word at right, if any */
   303       if (right_mask)
   304 	*wp &= right_mask;
   306       /* advance to next row */
   307       rp += dest_bitmap->row_words;
   308     }
   309 }
   312 #if 0
   313 static void blt (Bitmap *src_bitmap,
   314 		 Rect *src_rect,
   315 		 Bitmap *dest_bitmap,
   316 		 Rect *dest_rect)
   317 {
   318   int32_t y;
   319   word_t *rp;
   321   /* This function requires a non-null src rect */
   322   assert (dest_rect->min.x < dest_rect->max.x);
   323   assert (dest_rect->min.y < dest_rect->max.y);
   325   /* and a non-null dest rect */
   326   assert (dest_rect->min.x < dest_rect->max.x);
   327   assert (dest_rect->min.y < dest_rect->max.y);
   329   /* and that the widths and heights of the rects match */
   330   assert (rect_width (src_rect) == rect_width (dest_rect));
   331   assert (rect_height (src_rect) == rect_height (dest_rect));
   333   /* and that the rows of the src rect lie entirely within the src bitmap */
   334   assert (dest_rect->min.y >= dest_bitmap->rect->min.y);
   335   assert (dest_rect->max.y <= dest_bitmap->rect->max.y);
   337   /* and that the rows of the dest rect lie entirely within the dest bitmap */
   338   assert (dest_rect->min.y >= dest_bitmap->rect->min.y);
   339   assert (dest_rect->max.y <= dest_bitmap->rect->max.y);
   341   /* clip the x axis of the dest_rect to the bounds of the dest bitmap,
   342      and adjust the src_rect to match */
   343   if (dest_rect->min.x < dest_bitmap->rect.min.x)
   344     {
   345       src_rect->min.x += ???;
   346       dest_rect->min.x = dest_bitmap->rect.min.x;
   347     }
   348   if (dest_rect->max.x > dest_bitmap->rect.max.x)
   349     {
   350       dest_rect->max.x = dest_bitmap->rect.max.x;
   351     }
   353   rp = ???;
   354   for (y = 0; y < rect_height (dest_rect); y++)
   355     {
   356   ???;
   357       rp += dest_bitmap->row_words;
   358     }
   359 }
   362 /*
   363  * The destination rectangle is first clipped to the dest bitmap, and
   364  * the source rectangle is adjusted in the corresponding manner.
   365  * What's left is divided into five sections, any of which may be
   366  * null.  The portion that actually corresponds to the intersection of
   367  * the source rectangle and the source bitmpa is the "middle".  The
   368  * other four sections will use the background color as the source
   369  * operand.
   370  *
   371  *          
   372  *   y0 ->  -------------------------------------------------
   373  *          |                     top                       |
   374  *          |                                               |
   375  *   y1 ->  -------------------------------------------------
   376  *          |   left        |    middle     |    right      |
   377  *          |               |               |               |
   378  *   y2 ->  -------------------------------------------------
   379  *          |                     bottom                    |
   380  *          |                                               |
   381  *   y3 ->  -------------------------------------------------
   382  *
   383  *          ^               ^               ^               ^
   384  *          |               |               |               |
   385  *         x0              x1              x2              x3
   386  *
   387  * */
   388 Bitmap *bitblt (Bitmap *src_bitmap,
   389 		Rect   *src_rect,
   390 		Bitmap *dest_bitmap,
   391 		Point  *dest_min,
   392 		int tfn,
   393 		int background)
   394 {
   395   Rect sr, dr;     /* src and dest rects, clipped to visible portion of
   396 		      dest rect */
   397   uint32_t drw, drh;    /* dest rect width, height - gets adjusted */
   398   Point src_point, dest_point;
   400   /* dest coordinates: */
   401   uint32_t x0, x1, x2, x3;
   402   uint32_t y0, y1, y2, y3;
   404   {
   405     sr = * src_rect;
   407     uint32_t srw = rect_width (& sr);
   408     uint32_t srh = rect_height (& sr);
   410     if ((srw < 0) || (srh < 0))
   411       goto done;  /* the source rect is empty! */
   413     dr.min.x = dest_min->x;
   414     dr.min.y = dest_min->y;
   415     dr.max.x = dr.min.x + srw;
   416     dr.max.y = dr.min.y + srh;
   417   }
   419   if (! dest_bitmap)
   420     {
   421       dest_bitmap = create_bitmap (& dr);
   422       if (! dest_bitmap)
   423 	return (NULL);
   424     }
   426   if ((dr.min.x >= dest_bitmap->rect.max.x) ||
   427       (dr.min.y >= dest_bitmap->rect.max.y))
   428     goto done;  /* the dest rect isn't even in the dest bitmap! */
   430   /* crop dest rect to dest bitmap */
   431   delta = dest_bitmap->rect.min.x - dr.min.x;
   432   if (delta > 0)
   433     {
   434       sr.min.x += delta;
   435       dr.min.x += delta;
   436     }
   438   delta = dest_bitmap->rect.min.y - dr.min.y;
   439   if (delta > 0)
   440     {
   441       sr.min.y += delta;
   442       dr.min.y += delta;
   443     }
   445   delta = dr.max.x - dest_bitmap->rect.max.x;
   446   if (delta > 0)
   447     {
   448       sr.max.x -= delta;
   449       dr.max.x -= delta;
   450     }
   452   delta = dr.max.y - dest_bitmap->rect.max.y;
   453   if (delta > 0)
   454     {
   455       sr.max.x -= delta;
   456       dr.max.x -= delta;
   457     }
   459   drw = rect_width (& dr);
   460   drh = rect_height (& dh);
   462   x0 = dr.min.x;
   463   y0 = dr.min.y;
   464   x3 = dr.max.x;
   465   y3 = dr.max.y;
   467 #if 0
   468   /* if the source rect min y is >= the source bitmap max y,
   469      we transfer background color to the entire dest rect */
   470   if (sr.min.y >= src->rect.max.y)
   471     {
   472       blt_background (dest_bitmap, dr);
   473       goto done;
   474     }
   475 #endif
   477   /* top */
   478   if (y0 != y1)
   479     {
   480       dr2.min.x = x0;
   481       dr2.max.x = x3;
   482       dr2.min.y = y0;
   483       dr2.max.y = y1;
   484       blt_background (dest_bitmap, & dr2);
   485     }
   487   /*
   488    * top:  if the source rect min y is less than the source bitmap min y,
   489    * we need to transfer some backgound color to the top part of the dest
   490    * rect
   491    */
   492   if (sr.min.y < src->rect.min.y)
   493     {
   494       Rect dr2;
   495       uint32 bg_height;
   497       bg_height = src->rect.min.y - sr.min.y;
   498       if (bg_height > sh)
   499 	bg_height = sh;
   501       dr2 = dr;
   502       dr2.max.y = dr2.min.y + bg_height;
   504       blt_background (dest_bitmap, & dr2);
   506       /* now reduce the rect height by the number of lines of background
   507 	 color */
   508       sr.min.y += bg_height;
   509       dr.min.y += bg_height;
   510       sh -= bg_height;
   511       dh -= bg_height;
   513       if (sr.min.y == sr.max.y)
   514 	goto done;
   515     }
   517   if (y1 != y2)
   518     {
   519       /* left */
   520       if (x0 != x1)
   521 	{
   522 	  dr2.min.x = x1;
   523 	  dr2.max.x = x1;
   524 	  dr2.min.y = y1;
   525 	  dr2.max.y = y2
   526 	  blt_background (dest_bitmap, & dr2);
   527 	}
   529       /* middle */
   530       if (x1 != x2)
   531 	{
   532 	  /* ??? */
   533 	}
   535       /* right */
   536       if (x2 != x3)
   537 	{
   538 	  dr2.min.x = x2;
   539 	  dr2.max.x = x3;
   540 	  dr2.min.y = y1;
   541 	  dr2.max.y = y2
   542 	  blt_background (dest_bitmap, & dr2);
   543 	}
   544     }
   546   /* bottom */
   547   if (y2 != y3)
   548     {
   549       dr2.min.x = x0;
   550       dr2.max.x = x3;
   551       dr2.min.y = y2;
   552       dr2.max.y = y3;
   553       blt_background (dest_bitmap, & dr2);
   554     }
   556  done:
   557   return (dest_bitmap);
   558 }
   559 #else
   560 Bitmap *bitblt (Bitmap *src_bitmap,
   561 		Rect   *src_rect,
   562 		Bitmap *dest_bitmap,
   563 		Point  *dest_min,
   564 		int tfn,
   565 		int background)
   566 {
   567   Point src_point, dest_point;
   569   if (! dest_bitmap)
   570     {
   571       Rect dest_rect = {{ 0, 0 }, { dest_min->x + rect_width (src_rect),
   572 				    dest_min->y + rect_height (src_rect) }};
   573       dest_bitmap = create_bitmap (& dest_rect);
   574       if (! dest_bitmap)
   575 	return (NULL);
   576     }
   578   if (tfn == TF_SRC)
   579     {
   580       for (src_point.y = src_rect->min.y;
   581 	   src_point.y < src_rect->max.y;
   582 	   src_point.y++)
   583 	{
   584 	  dest_point.y = dest_min->y + src_point.y - src_rect->min.y;
   586 	  for (src_point.x = src_rect->min.x;
   587 	       src_point.x < src_rect->max.x;
   588 	       src_point.x++)
   589 	    {
   590 	      bool a;
   592 	      dest_point.x = dest_min->x + src_point.x - src_rect->min.x;
   594 	      a = get_pixel (src_bitmap, src_point);
   595 	      set_pixel (dest_bitmap, dest_point, a);
   596 	    }
   597 	}
   598     }
   599   else
   600     {
   601       for (src_point.y = src_rect->min.y;
   602 	   src_point.y < src_rect->max.y;
   603 	   src_point.y++)
   604 	{
   605 	  dest_point.y = dest_min->y + src_point.y - src_rect->min.y;
   607 	  for (src_point.x = src_rect->min.x;
   608 	       src_point.x < src_rect->max.x;
   609 	       src_point.x++)
   610 	    {
   611 	      bool a, b, c;
   613 	      dest_point.x = dest_min->x + src_point.x - src_rect->min.x;
   615 	      a = get_pixel (src_bitmap, src_point);
   616 	      b = get_pixel (dest_bitmap, dest_point);
   617 	      c = (tfn & (1 << (a * 2 + b))) != 0;
   619 	      set_pixel (dest_bitmap, dest_point, c);
   620 	    }
   621 	}
   622     }
   623   return (dest_bitmap);
   624 }
   625 #endif
   628 /* in-place transformations */
   629 void flip_h (Bitmap *src)
   630 {
   631   word_t *rp;  /* row pointer */
   632   word_t *p1;  /* work src ptr */
   633   word_t *p2;  /* work dest ptr */
   634   int32_t y;
   635   int shift1, shift2;
   637   realloc_temp_buffer ((src->row_words + 1) * sizeof (word_t));
   639   rp = src->bits;
   640   if ((rect_width (& src->rect) & 7) == 0)
   641     {
   642       for (y = src->rect.min.y; y < src->rect.max.y; y++)
   643 	{
   644 	  memcpy (temp_buffer, rp, src->row_words * sizeof (word_t));
   645 	  p1 = temp_buffer + src->row_words;
   646 	  p2 = rp;
   648 	  while (p1 >= temp_buffer)
   649 	    *(p2++) = bit_reverse_word (*(p1--));
   651 	  rp += src->row_words;
   652 	}
   653       return;
   654     }
   656   temp_buffer [0] = 0;
   657   shift1 = rect_width (& src->rect) & (BITS_PER_WORD - 1);
   658   shift2 = BITS_PER_WORD - shift1;
   660   for (y = src->rect.min.y; y < src->rect.max.y; y++)
   661     {
   662       word_t d1, d2;
   664       memcpy (temp_buffer + 1, rp, src->row_words * sizeof (word_t));
   665       p1 = temp_buffer + src->row_words;
   666       p2 = rp;
   668       d2 = *(p1--);
   670       while (p1 >= temp_buffer)
   671 	{
   672 	  d1 = *(p1--);
   673 	  *(p2++) = bit_reverse_word ((d1 << shift1) | (d2 >> shift2));
   674 	  d2 = d1;
   675 	}      
   677       rp += src->row_words;
   678     }
   679 }
   681 void flip_v (Bitmap *src)
   682 {
   683   word_t *p1, *p2;
   685   realloc_temp_buffer (src->row_words * sizeof (word_t));
   687   p1 = src->bits;
   688   p2 = src->bits + src->row_words * (rect_height (& src->rect) - 1);
   689   while (p1 < p2)
   690     {
   691       memcpy (temp_buffer, p1, src->row_words * sizeof (word_t));
   692       memcpy (p1, p2, src->row_words * sizeof (word_t));
   693       memcpy (p2, temp_buffer, src->row_words * sizeof (word_t));
   694       p1 += src->row_words;
   695       p2 -= src->row_words;
   696     }
   697 }
   699 void rot_180 (Bitmap *src)  /* combination of flip_h and flip_v */
   700 {
   701   flip_h (src);
   702   flip_v (src);
   703 }
   705 /* "in-place" transformations - will allocate new memory and free old */
   706 void transpose (Bitmap *src)
   707 {
   708   uint32_t new_row_words = DIV_ROUND_UP (rect_height (& src->rect), 32);
   709   word_t *new_bits;
   711   new_bits = calloc (1, new_row_words * rect_width (& src->rect) * sizeof (word_t));
   713   /* $$$ more code needed here */
   714 }
   716 void rot_90 (Bitmap *src)   /* transpose + flip_h */
   717 {
   718   transpose (src);
   719   flip_h (src);
   720 }
   722 void rot_270 (Bitmap *src)  /* transpose + flip_v */
   723 {
   724   transpose (src);
   725   flip_v (src);
   726 }