bitblt.c

Mon, 14 Dec 2009 16:18:21 +0000

author
Philip Pemberton <philpem@philpem.me.uk>
date
Mon, 14 Dec 2009 16:18:21 +0000
changeset 172
2fae6df568f6
parent 135
5d3d2dccb3ff
permissions
-rw-r--r--

remove erroneous 0.33-philpem1 tag

     1 /*
     2  * tumble: build a PDF file from image files
     3  *
     4  * bitblt routines
     5  * $Id: bitblt.c,v 1.17 2003/03/16 07:27:06 eric Exp $
     6  * Copyright 2001, 2002, 2003 Eric Smith <eric@brouhaha.com>
     7  *
     8  * This program is free software; you can redistribute it and/or modify
     9  * it under the terms of the GNU General Public License version 2 as
    10  * published by the Free Software Foundation.  Note that permission is
    11  * not granted to redistribute this program under the terms of any
    12  * other version of the General Public License.
    13  *
    14  * This program is distributed in the hope that it will be useful,
    15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
    16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    17  * GNU General Public License for more details.
    18  *
    19  * You should have received a copy of the GNU General Public License
    20  * along with this program; if not, write to the Free Software
    21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111 USA
    22  */
    25 #include <stdbool.h>
    26 #include <stdint.h>
    27 #include <assert.h>
    28 #include <stdio.h>
    29 #include <stdlib.h>
    30 #include <string.h>
    32 #include "bitblt.h"
    34 #include "bitblt_tables.h"
    37 #define DIV_ROUND_UP(count,pow2) (((count) - 1) / (pow2) + 1)
    40 void reverse_bits (uint8_t *p, int byte_count)
    41 {
    42   while (byte_count--)
    43     {
    44       (*p) = bit_reverse_byte [*p];
    45       p++;
    46     }
    47 }
    50 static word_t bit_reverse_word (word_t d)
    51 {
    52   return (bit_reverse_byte [d >> 24] |
    53 	  (bit_reverse_byte [(d >> 16) & 0xff] << 8) |
    54 	  (bit_reverse_byte [(d >> 8) & 0xff] << 16) |
    55 	  (bit_reverse_byte [d & 0xff] << 24));
    56 }
    59 static void reverse_range_of_bytes (uint8_t *b, uint32_t count)
    60 {
    61   uint8_t *b2 = b + count - 1;
    63   while (b < b2)
    64     {
    65       uint8_t t = bit_reverse_byte [*b];
    66       *b = bit_reverse_byte [*b2];
    67       *b2 = t;
    68       b++;
    69       b2--;
    70     }
    72   if (b == b2)
    73     *b = bit_reverse_byte [*b];
    74 }
    77 static word_t *temp_buffer;
    78 static word_t temp_buffer_size;
    80 static void realloc_temp_buffer (uint32_t size)
    81 {
    82   if (size <= temp_buffer_size)
    83     return;
    84   temp_buffer = realloc (temp_buffer, size);
    85   if (! temp_buffer)
    86     {
    87       fprintf (stderr, "realloc failed in bitblt library\n");
    88       exit (2);
    89     }
    90   temp_buffer_size = size;
    91 }
    94 static inline word_t pixel_mask (int x)
    95 {
    96 #if defined (MIXED_ENDIAN)  /* disgusting hack for mixed-endian */
    97   word_t m;
    98   m = 0x80 >> (x & 7);
    99   m <<= (x & 24);
   100   return (m);
   101 #elif defined (LSB_RIGHT)
   102   return (1U << ((BITS_PER_WORD - 1) - x));
   103 #else
   104   return (1U << x);
   105 #endif
   106 };
   109 /* mask for range of bits left..right, inclusive */
   110 static inline word_t pixel_range_mask (int left, int right)
   111 {
   112   word_t m1, m2, val;
   114   /* $$$ one of these cases is wrong! */
   115 #if defined (LSB_RIGHT)
   116   m1 = (~ 0U) >> left;
   117   m2 = (~ 0U) << (BITS_PER_WORD - 1 - right);
   118 #else
   119   m1 = (~ 0U) << left;
   120   m2 = (~ 0U) >> (BITS_PER_WORD - 1 - right);
   121 #endif
   122   val = m1 & m2;
   124   printf ("left %d, right %d, mask %08x\n", left, right, val);
   125   return (val);
   126 };
   129 Bitmap *create_bitmap (Rect *rect)
   130 {
   131   Bitmap *bitmap;
   132   uint32_t width = rect_width (rect);
   133   uint32_t height = rect_height (rect);
   135   if ((width <= 0) || (height <= 0))
   136     return (NULL);
   138   bitmap = calloc (1, sizeof (Bitmap));
   139   if (! bitmap)
   140     return (NULL);
   141   bitmap->rect = * rect;
   142   bitmap->row_words = DIV_ROUND_UP (width, BITS_PER_WORD);
   143   bitmap->bits = calloc (1, height * bitmap->row_words * sizeof (word_t));
   144   if (! bitmap->bits)
   145     {
   146       free (bitmap);
   147       return (NULL);
   148     }
   149   return (bitmap);
   150 }
   152 void free_bitmap (Bitmap *bitmap)
   153 {
   154   free (bitmap->bits);
   155   free (bitmap);
   156 }
   158 bool get_pixel (Bitmap *bitmap, Point coord)
   159 {
   160   word_t *p;
   161   int w,b;
   163   if ((coord.x < bitmap->rect.min.x) ||
   164       (coord.x >= bitmap->rect.max.x) ||
   165       (coord.y < bitmap->rect.min.y) ||
   166       (coord.y >= bitmap->rect.max.y))
   167     return (0);
   168   coord.y -= bitmap->rect.min.y;
   169   coord.x -= bitmap->rect.min.x;
   170   w = coord.x / BITS_PER_WORD;
   171   b = coord.x & (BITS_PER_WORD - 1);
   172   p = bitmap->bits + coord.y * bitmap->row_words + w;
   173   return (((*p) & pixel_mask (b)) != 0);
   174 }
   176 void set_pixel (Bitmap *bitmap, Point coord, bool value)
   177 {
   178   word_t *p;
   179   int w,b;
   181   if ((coord.x < bitmap->rect.min.x) ||
   182       (coord.x >= bitmap->rect.max.x) ||
   183       (coord.y < bitmap->rect.min.y) ||
   184       (coord.y >= bitmap->rect.max.y))
   185     return;
   186   coord.y -= bitmap->rect.min.y;
   187   coord.x -= bitmap->rect.min.x;
   188   w = coord.x / BITS_PER_WORD;
   189   b = coord.x & (BITS_PER_WORD - 1);
   190   p = bitmap->bits + coord.y * bitmap->row_words + w;
   191   if (value)
   192     (*p) |= pixel_mask (b);
   193   else
   194     (*p) &= ~pixel_mask (b);
   195 }
   198 /* modifies rect1 to be the intersection of rect1 and rect2;
   199    returns true if intersection is non-null */
   200 static bool clip_rect (Rect *rect1, Rect *rect2)
   201 {
   202   if (rect1->min.y > rect2->max.y)
   203     goto empty;
   204   if (rect1->min.y < rect2->min.y)
   205     {
   206       if (rect1->max.y < rect2->max.y)
   207 	goto empty;
   208       rect1->min.y = rect2->min.y;
   209     }
   210   if (rect1->max.y > rect2->max.y)
   211     rect1->max.y = rect2->max.y;
   213   if (rect1->min.x > rect2->max.x)
   214     goto empty;
   215   if (rect1->min.x < rect2->min.x)
   216     {
   217       if (rect1->max.x < rect2->max.x)
   218 	goto empty;
   219       rect1->min.x = rect2->min.x;
   220     }
   221   if (rect1->max.x > rect2->max.x)
   222     rect1->max.x = rect2->max.x;
   224  empty:
   225   rect1->min.x = rect1->min.y =
   226     rect1->max.x = rect1->max.y = 0;
   227   return (0);
   228 }
   231 static void blt_background (Bitmap *dest_bitmap,
   232 			    Rect dest_rect)
   233 {
   234   uint32_t y;
   235   word_t *rp;
   236   uint32_t left_bit, left_word;
   237   uint32_t right_bit, right_word;
   238   word_t left_mask, right_mask;
   239   int32_t word_count;
   241   /* This function requires a non-null dest rect */
   242   assert (dest_rect.min.x < dest_rect.max.x);
   243   assert (dest_rect.min.y < dest_rect.max.y);
   245   /* and that the rows of the dest rect lie entirely within the dest bitmap */
   246   assert (dest_rect.min.y >= dest_bitmap->rect.min.y);
   247   assert (dest_rect.max.y <= dest_bitmap->rect.max.y);
   249   /* clip the x axis of the dest_rect to the bounds of the dest bitmap */
   250   if (dest_rect.min.x < dest_bitmap->rect.min.x)
   251     dest_rect.min.x = dest_bitmap->rect.min.x;
   252   if (dest_rect.max.x > dest_bitmap->rect.max.x)
   253     dest_rect.max.x = dest_bitmap->rect.max.x;
   255   rp = dest_bitmap->bits +
   256     (dest_rect.min.y - dest_bitmap->rect.min.y) * dest_bitmap->row_words +
   257     (dest_rect.min.x - dest_bitmap->rect.min.x) / BITS_PER_WORD;
   259   left_bit = dest_rect.min.x % BITS_PER_WORD;
   260   left_word = dest_rect.min.x / BITS_PER_WORD;
   262   right_bit = (dest_rect.max.x - 1) % BITS_PER_WORD;
   263   right_word = (dest_rect.max.x - 1) / BITS_PER_WORD;
   265   word_count = right_word + 1 - left_word;
   267   /* special case if entire horizontal range fits in a single word */
   268   if (word_count == 1)
   269     {
   270       left_mask = 0;
   271       right_mask = ~ pixel_range_mask (left_bit, right_bit);
   272       word_count = 0;
   273     }
   274   else
   275     {
   276       if (left_bit)
   277 	{
   278 	  left_mask = ~ pixel_range_mask (left_bit, BITS_PER_WORD - 1);
   279 	  word_count--;
   280 	}
   282       if (right_bit != (BITS_PER_WORD - 1))
   283 	{
   284 	  right_mask = ~ pixel_range_mask (0, right_bit);
   285 	  word_count--;
   286 	}
   287     }
   289   for (y = 0; y < rect_height (& dest_rect); y++)
   290     {
   291       word_t *wp = rp;
   293       /* partial word at left, if any */
   294       if (left_mask)
   295 	*(wp++) &= left_mask;
   297       /* use Duff's Device for the full words */
   298       if (word_count)
   299 	{
   300 	  int32_t i = word_count;
   301 	  switch (i % 8)
   302 	    {
   303 	      while (i > 0)
   304 		{
   305 		  *(wp++) = 0;
   306 		case 7: *(wp++) = 0;
   307 		case 6: *(wp++) = 0;
   308 		case 5: *(wp++) = 0;
   309 		case 4: *(wp++) = 0;
   310 		case 3: *(wp++) = 0;
   311 		case 2: *(wp++) = 0;
   312 		case 1: *(wp++) = 0;
   313 		case 0: i -= 8;
   314 		}
   315 	    }
   316 	}
   318       /* partial word at right, if any */
   319       if (right_mask)
   320 	*wp &= right_mask;
   322       /* advance to next row */
   323       rp += dest_bitmap->row_words;
   324     }
   325 }
   328 #if 0
   329 static void blt (Bitmap *src_bitmap,
   330 		 Rect *src_rect,
   331 		 Bitmap *dest_bitmap,
   332 		 Rect *dest_rect)
   333 {
   334   int32_t y;
   335   word_t *rp;
   337   /* This function requires a non-null src rect */
   338   assert (dest_rect->min.x < dest_rect->max.x);
   339   assert (dest_rect->min.y < dest_rect->max.y);
   341   /* and a non-null dest rect */
   342   assert (dest_rect->min.x < dest_rect->max.x);
   343   assert (dest_rect->min.y < dest_rect->max.y);
   345   /* and that the widths and heights of the rects match */
   346   assert (rect_width (src_rect) == rect_width (dest_rect));
   347   assert (rect_height (src_rect) == rect_height (dest_rect));
   349   /* and that the rows of the src rect lie entirely within the src bitmap */
   350   assert (dest_rect->min.y >= dest_bitmap->rect->min.y);
   351   assert (dest_rect->max.y <= dest_bitmap->rect->max.y);
   353   /* and that the rows of the dest rect lie entirely within the dest bitmap */
   354   assert (dest_rect->min.y >= dest_bitmap->rect->min.y);
   355   assert (dest_rect->max.y <= dest_bitmap->rect->max.y);
   357   /* clip the x axis of the dest_rect to the bounds of the dest bitmap,
   358      and adjust the src_rect to match */
   359   if (dest_rect->min.x < dest_bitmap->rect.min.x)
   360     {
   361       src_rect->min.x += ???;
   362       dest_rect->min.x = dest_bitmap->rect.min.x;
   363     }
   364   if (dest_rect->max.x > dest_bitmap->rect.max.x)
   365     {
   366       dest_rect->max.x = dest_bitmap->rect.max.x;
   367     }
   369   rp = ???;
   370   for (y = 0; y < rect_height (dest_rect); y++)
   371     {
   372   ???;
   373       rp += dest_bitmap->row_words;
   374     }
   375 }
   378 /*
   379  * The destination rectangle is first clipped to the dest bitmap, and
   380  * the source rectangle is adjusted in the corresponding manner.
   381  * What's left is divided into five sections, any of which may be
   382  * null.  The portion that actually corresponds to the intersection of
   383  * the source rectangle and the source bitmpa is the "middle".  The
   384  * other four sections will use the background color as the source
   385  * operand.
   386  *
   387  *          
   388  *   y0 ->  -------------------------------------------------
   389  *          |                     top                       |
   390  *          |                                               |
   391  *   y1 ->  -------------------------------------------------
   392  *          |   left        |    middle     |    right      |
   393  *          |               |               |               |
   394  *   y2 ->  -------------------------------------------------
   395  *          |                     bottom                    |
   396  *          |                                               |
   397  *   y3 ->  -------------------------------------------------
   398  *
   399  *          ^               ^               ^               ^
   400  *          |               |               |               |
   401  *         x0              x1              x2              x3
   402  *
   403  * */
   404 Bitmap *bitblt (Bitmap *src_bitmap,
   405 		Rect   *src_rect,
   406 		Bitmap *dest_bitmap,
   407 		Point  *dest_min,
   408 		int tfn,
   409 		int background)
   410 {
   411   Rect sr, dr;     /* src and dest rects, clipped to visible portion of
   412 		      dest rect */
   413   uint32_t drw, drh;    /* dest rect width, height - gets adjusted */
   414   Point src_point, dest_point;
   416   /* dest coordinates: */
   417   uint32_t x0, x1, x2, x3;
   418   uint32_t y0, y1, y2, y3;
   420   {
   421     sr = * src_rect;
   423     uint32_t srw = rect_width (& sr);
   424     uint32_t srh = rect_height (& sr);
   426     if ((srw < 0) || (srh < 0))
   427       goto done;  /* the source rect is empty! */
   429     dr.min.x = dest_min->x;
   430     dr.min.y = dest_min->y;
   431     dr.max.x = dr.min.x + srw;
   432     dr.max.y = dr.min.y + srh;
   433   }
   435   if (! dest_bitmap)
   436     {
   437       dest_bitmap = create_bitmap (& dr);
   438       if (! dest_bitmap)
   439 	return (NULL);
   440     }
   442   if ((dr.min.x >= dest_bitmap->rect.max.x) ||
   443       (dr.min.y >= dest_bitmap->rect.max.y))
   444     goto done;  /* the dest rect isn't even in the dest bitmap! */
   446   /* crop dest rect to dest bitmap */
   447   delta = dest_bitmap->rect.min.x - dr.min.x;
   448   if (delta > 0)
   449     {
   450       sr.min.x += delta;
   451       dr.min.x += delta;
   452     }
   454   delta = dest_bitmap->rect.min.y - dr.min.y;
   455   if (delta > 0)
   456     {
   457       sr.min.y += delta;
   458       dr.min.y += delta;
   459     }
   461   delta = dr.max.x - dest_bitmap->rect.max.x;
   462   if (delta > 0)
   463     {
   464       sr.max.x -= delta;
   465       dr.max.x -= delta;
   466     }
   468   delta = dr.max.y - dest_bitmap->rect.max.y;
   469   if (delta > 0)
   470     {
   471       sr.max.x -= delta;
   472       dr.max.x -= delta;
   473     }
   475   drw = rect_width (& dr);
   476   drh = rect_height (& dh);
   478   x0 = dr.min.x;
   479   y0 = dr.min.y;
   480   x3 = dr.max.x;
   481   y3 = dr.max.y;
   483 #if 0
   484   /* if the source rect min y is >= the source bitmap max y,
   485      we transfer background color to the entire dest rect */
   486   if (sr.min.y >= src->rect.max.y)
   487     {
   488       blt_background (dest_bitmap, dr);
   489       goto done;
   490     }
   491 #endif
   493   /* top */
   494   if (y0 != y1)
   495     {
   496       dr2.min.x = x0;
   497       dr2.max.x = x3;
   498       dr2.min.y = y0;
   499       dr2.max.y = y1;
   500       blt_background (dest_bitmap, & dr2);
   501     }
   503   /*
   504    * top:  if the source rect min y is less than the source bitmap min y,
   505    * we need to transfer some backgound color to the top part of the dest
   506    * rect
   507    */
   508   if (sr.min.y < src->rect.min.y)
   509     {
   510       Rect dr2;
   511       uint32 bg_height;
   513       bg_height = src->rect.min.y - sr.min.y;
   514       if (bg_height > sh)
   515 	bg_height = sh;
   517       dr2 = dr;
   518       dr2.max.y = dr2.min.y + bg_height;
   520       blt_background (dest_bitmap, & dr2);
   522       /* now reduce the rect height by the number of lines of background
   523 	 color */
   524       sr.min.y += bg_height;
   525       dr.min.y += bg_height;
   526       sh -= bg_height;
   527       dh -= bg_height;
   529       if (sr.min.y == sr.max.y)
   530 	goto done;
   531     }
   533   if (y1 != y2)
   534     {
   535       /* left */
   536       if (x0 != x1)
   537 	{
   538 	  dr2.min.x = x1;
   539 	  dr2.max.x = x1;
   540 	  dr2.min.y = y1;
   541 	  dr2.max.y = y2
   542 	  blt_background (dest_bitmap, & dr2);
   543 	}
   545       /* middle */
   546       if (x1 != x2)
   547 	{
   548 	  /* ??? */
   549 	}
   551       /* right */
   552       if (x2 != x3)
   553 	{
   554 	  dr2.min.x = x2;
   555 	  dr2.max.x = x3;
   556 	  dr2.min.y = y1;
   557 	  dr2.max.y = y2
   558 	  blt_background (dest_bitmap, & dr2);
   559 	}
   560     }
   562   /* bottom */
   563   if (y2 != y3)
   564     {
   565       dr2.min.x = x0;
   566       dr2.max.x = x3;
   567       dr2.min.y = y2;
   568       dr2.max.y = y3;
   569       blt_background (dest_bitmap, & dr2);
   570     }
   572  done:
   573   return (dest_bitmap);
   574 }
   575 #else
   576 Bitmap *bitblt (Bitmap *src_bitmap,
   577 		Rect   *src_rect,
   578 		Bitmap *dest_bitmap,
   579 		Point  *dest_min,
   580 		int tfn,
   581 		int background)
   582 {
   583   Point src_point, dest_point;
   585   if (! dest_bitmap)
   586     {
   587       Rect dest_rect = {{ 0, 0 }, { dest_min->x + rect_width (src_rect),
   588 				    dest_min->y + rect_height (src_rect) }};
   589       dest_bitmap = create_bitmap (& dest_rect);
   590       if (! dest_bitmap)
   591 	return (NULL);
   592     }
   594   if (tfn == TF_SRC)
   595     {
   596       for (src_point.y = src_rect->min.y;
   597 	   src_point.y < src_rect->max.y;
   598 	   src_point.y++)
   599 	{
   600 	  dest_point.y = dest_min->y + src_point.y - src_rect->min.y;
   602 	  for (src_point.x = src_rect->min.x;
   603 	       src_point.x < src_rect->max.x;
   604 	       src_point.x++)
   605 	    {
   606 	      bool a;
   608 	      dest_point.x = dest_min->x + src_point.x - src_rect->min.x;
   610 	      a = get_pixel (src_bitmap, src_point);
   611 	      set_pixel (dest_bitmap, dest_point, a);
   612 	    }
   613 	}
   614     }
   615   else
   616     {
   617       for (src_point.y = src_rect->min.y;
   618 	   src_point.y < src_rect->max.y;
   619 	   src_point.y++)
   620 	{
   621 	  dest_point.y = dest_min->y + src_point.y - src_rect->min.y;
   623 	  for (src_point.x = src_rect->min.x;
   624 	       src_point.x < src_rect->max.x;
   625 	       src_point.x++)
   626 	    {
   627 	      bool a, b, c;
   629 	      dest_point.x = dest_min->x + src_point.x - src_rect->min.x;
   631 	      a = get_pixel (src_bitmap, src_point);
   632 	      b = get_pixel (dest_bitmap, dest_point);
   633 	      c = (tfn & (1 << (a * 2 + b))) != 0;
   635 	      set_pixel (dest_bitmap, dest_point, c);
   636 	    }
   637 	}
   638     }
   639   return (dest_bitmap);
   640 }
   641 #endif
   644 /* in-place transformations */
   645 void flip_h (Bitmap *src)
   646 {
   647   word_t *rp;  /* row pointer */
   648   int32_t y;
   649   int shift1, shift2;
   651   rp = src->bits;
   652   if ((rect_width (& src->rect) & 7) == 0)
   653     {
   654       for (y = src->rect.min.y; y < src->rect.max.y; y++)
   655 	{
   656           reverse_range_of_bytes ((uint8_t *) rp, rect_width (& src->rect) / 8);
   657 	  rp += src->row_words;
   658 	}
   659       return;
   660     }
   662   realloc_temp_buffer ((src->row_words + 1) * sizeof (word_t));
   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_t d1, d2;
   671       word_t *p1;  /* work src ptr */
   672       word_t *p2;  /* work dest ptr */
   674       memcpy (temp_buffer + 1, rp, src->row_words * sizeof (word_t));
   675       p1 = temp_buffer + src->row_words;
   676       p2 = rp;
   678       d2 = *(p1--);
   680       while (p1 >= temp_buffer)
   681 	{
   682 	  word_t t;
   683 	  d1 = *(p1--);
   684 	  t = (d1 >> shift1) | (d2 << shift2);
   685 	  *(p2++) = bit_reverse_word (t);
   686 	  d2 = d1;
   687 	}      
   689       rp += src->row_words;
   690     }
   691 }
   694 void flip_v (Bitmap *src)
   695 {
   696   word_t *p1, *p2;
   698   realloc_temp_buffer (src->row_words * sizeof (word_t));
   700   p1 = src->bits;
   701   p2 = src->bits + src->row_words * (rect_height (& src->rect) - 1);
   702   while (p1 < p2)
   703     {
   704       memcpy (temp_buffer, p1, src->row_words * sizeof (word_t));
   705       memcpy (p1, p2, src->row_words * sizeof (word_t));
   706       memcpy (p2, temp_buffer, src->row_words * sizeof (word_t));
   707       p1 += src->row_words;
   708       p2 -= src->row_words;
   709     }
   710 }
   712 void rot_180 (Bitmap *src)  /* combination of flip_h and flip_v */
   713 {
   714   flip_h (src);
   715   flip_v (src);
   716 }
   718 /* "in-place" transformations - will allocate new memory and free old */
   719 void transpose (Bitmap *src)
   720 {
   721   uint32_t new_row_words = DIV_ROUND_UP (rect_height (& src->rect), 32);
   722   word_t *new_bits;
   724   new_bits = calloc (1, new_row_words * rect_width (& src->rect) * sizeof (word_t));
   726   /* $$$ more code needed here */
   727 }
   729 void rot_90 (Bitmap *src)   /* transpose + flip_h */
   730 {
   731   transpose (src);
   732   flip_h (src);
   733 }
   735 void rot_270 (Bitmap *src)  /* transpose + flip_v */
   736 {
   737   transpose (src);
   738   flip_v (src);
   739 }