tumble: bitblt.c@2fae6df568f6 (annotated)

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bitblt.c@2fae6df568f6 (annotated)

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

 /*
  * tumble: build a PDF file from image files
  *
  * bitblt routines
  * $Id: bitblt.c,v 1.17 2003/03/16 07:27:06 eric Exp $
  * Copyright 2001, 2002, 2003 Eric Smith <eric@brouhaha.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.  Note that permission is
  * not granted to redistribute this program under the terms of any
  * other version of the General Public License.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111 USA
  */
 #include <stdbool.h>
 #include <stdint.h>
 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include "bitblt.h"
 #include "bitblt_tables.h"
 #define DIV_ROUND_UP(count,pow2) (((count) - 1) / (pow2) + 1)
 void reverse_bits (uint8_t *p, int byte_count)
 {
   while (byte_count--)
     {
       (*p) = bit_reverse_byte [*p];
       p++;
     }
 }
 static word_t bit_reverse_word (word_t d)
 {
   return (bit_reverse_byte [d >> 24] |
 	  (bit_reverse_byte [(d >> 16) & 0xff] << 8) |
 	  (bit_reverse_byte [(d >> 8) & 0xff] << 16) |
 	  (bit_reverse_byte [d & 0xff] << 24));
 }
 static void reverse_range_of_bytes (uint8_t *b, uint32_t count)
 {
   uint8_t *b2 = b + count - 1;
   while (b < b2)
     {
       uint8_t t = bit_reverse_byte [*b];
       *b = bit_reverse_byte [*b2];
       *b2 = t;
       b++;
       b2--;
     }
   if (b == b2)
     *b = bit_reverse_byte [*b];
 }
 static word_t *temp_buffer;
 static word_t temp_buffer_size;
 static void realloc_temp_buffer (uint32_t size)
 {
   if (size <= temp_buffer_size)
     return;
   temp_buffer = realloc (temp_buffer, size);
   if (! temp_buffer)
     {
       fprintf (stderr, "realloc failed in bitblt library\n");
       exit (2);
     }
   temp_buffer_size = size;
 }
 static inline word_t pixel_mask (int x)
 {
 #if defined (MIXED_ENDIAN)  /* disgusting hack for mixed-endian */
   word_t m;
   m = 0x80 >> (x & 7);
   m <<= (x & 24);
   return (m);
 #elif defined (LSB_RIGHT)
   return (1U << ((BITS_PER_WORD - 1) - x));
 #else
   return (1U << x);
 #endif
 };
 /* mask for range of bits left..right, inclusive */
 static inline word_t pixel_range_mask (int left, int right)
 {
   word_t m1, m2, val;
   /* $$$ one of these cases is wrong! */
 #if defined (LSB_RIGHT)
   m1 = (~ 0U) >> left;
   m2 = (~ 0U) << (BITS_PER_WORD - 1 - right);
 #else
   m1 = (~ 0U) << left;
   m2 = (~ 0U) >> (BITS_PER_WORD - 1 - right);
 #endif
   val = m1 & m2;
   printf ("left %d, right %d, mask %08x\n", left, right, val);
   return (val);
 };
 Bitmap *create_bitmap (Rect *rect)
 {
   Bitmap *bitmap;
   uint32_t width = rect_width (rect);
   uint32_t height = rect_height (rect);
   if ((width <= 0) || (height <= 0))
     return (NULL);
   bitmap = calloc (1, sizeof (Bitmap));
   if (! bitmap)
     return (NULL);
   bitmap->rect = * rect;
   bitmap->row_words = DIV_ROUND_UP (width, BITS_PER_WORD);
   bitmap->bits = calloc (1, height * bitmap->row_words * sizeof (word_t));
   if (! bitmap->bits)
     {
       free (bitmap);
       return (NULL);
     }
   return (bitmap);
 }
 void free_bitmap (Bitmap *bitmap)
 {
   free (bitmap->bits);
   free (bitmap);
 }
 bool get_pixel (Bitmap *bitmap, Point coord)
 {
   word_t *p;
   int w,b;
   if ((coord.x < bitmap->rect.min.x) ||
       (coord.x >= bitmap->rect.max.x) ||
       (coord.y < bitmap->rect.min.y) ||
       (coord.y >= bitmap->rect.max.y))
     return (0);
   coord.y -= bitmap->rect.min.y;
   coord.x -= bitmap->rect.min.x;
   w = coord.x / BITS_PER_WORD;
   b = coord.x & (BITS_PER_WORD - 1);
   p = bitmap->bits + coord.y * bitmap->row_words + w;
   return (((*p) & pixel_mask (b)) != 0);
 }
 void set_pixel (Bitmap *bitmap, Point coord, bool value)
 {
   word_t *p;
   int w,b;
   if ((coord.x < bitmap->rect.min.x) ||
       (coord.x >= bitmap->rect.max.x) ||
       (coord.y < bitmap->rect.min.y) ||
       (coord.y >= bitmap->rect.max.y))
     return;
   coord.y -= bitmap->rect.min.y;
   coord.x -= bitmap->rect.min.x;
   w = coord.x / BITS_PER_WORD;
   b = coord.x & (BITS_PER_WORD - 1);
   p = bitmap->bits + coord.y * bitmap->row_words + w;
   if (value)
     (*p) |= pixel_mask (b);
   else
     (*p) &= ~pixel_mask (b);
 }
 /* modifies rect1 to be the intersection of rect1 and rect2;
    returns true if intersection is non-null */
 static bool clip_rect (Rect *rect1, Rect *rect2)
 {
   if (rect1->min.y > rect2->max.y)
     goto empty;
   if (rect1->min.y < rect2->min.y)
     {
       if (rect1->max.y < rect2->max.y)
 	goto empty;
       rect1->min.y = rect2->min.y;
     }
   if (rect1->max.y > rect2->max.y)
     rect1->max.y = rect2->max.y;
   if (rect1->min.x > rect2->max.x)
     goto empty;
   if (rect1->min.x < rect2->min.x)
     {
       if (rect1->max.x < rect2->max.x)
 	goto empty;
       rect1->min.x = rect2->min.x;
     }
   if (rect1->max.x > rect2->max.x)
     rect1->max.x = rect2->max.x;
  empty:
   rect1->min.x = rect1->min.y =
     rect1->max.x = rect1->max.y = 0;
   return (0);
 }
 static void blt_background (Bitmap *dest_bitmap,
 			    Rect dest_rect)
 {
   uint32_t y;
   word_t *rp;
   uint32_t left_bit, left_word;
   uint32_t right_bit, right_word;
   word_t left_mask, right_mask;
   int32_t word_count;
   /* This function requires a non-null dest rect */
   assert (dest_rect.min.x < dest_rect.max.x);
   assert (dest_rect.min.y < dest_rect.max.y);
   /* and that the rows of the dest rect lie entirely within the dest bitmap */
   assert (dest_rect.min.y >= dest_bitmap->rect.min.y);
   assert (dest_rect.max.y <= dest_bitmap->rect.max.y);
   /* clip the x axis of the dest_rect to the bounds of the dest bitmap */
   if (dest_rect.min.x < dest_bitmap->rect.min.x)
     dest_rect.min.x = dest_bitmap->rect.min.x;
   if (dest_rect.max.x > dest_bitmap->rect.max.x)
     dest_rect.max.x = dest_bitmap->rect.max.x;
   rp = dest_bitmap->bits +
     (dest_rect.min.y - dest_bitmap->rect.min.y) * dest_bitmap->row_words +
     (dest_rect.min.x - dest_bitmap->rect.min.x) / BITS_PER_WORD;
   left_bit = dest_rect.min.x % BITS_PER_WORD;
   left_word = dest_rect.min.x / BITS_PER_WORD;
   right_bit = (dest_rect.max.x - 1) % BITS_PER_WORD;
   right_word = (dest_rect.max.x - 1) / BITS_PER_WORD;
   word_count = right_word + 1 - left_word;
   /* special case if entire horizontal range fits in a single word */
   if (word_count == 1)
     {
       left_mask = 0;
       right_mask = ~ pixel_range_mask (left_bit, right_bit);
       word_count = 0;
     }
   else
     {
       if (left_bit)
 	{
 	  left_mask = ~ pixel_range_mask (left_bit, BITS_PER_WORD - 1);
 	  word_count--;
 	}
       if (right_bit != (BITS_PER_WORD - 1))
 	{
 	  right_mask = ~ pixel_range_mask (0, right_bit);
 	  word_count--;
 	}
     }
   for (y = 0; y < rect_height (& dest_rect); y++)
     {
       word_t *wp = rp;
       /* partial word at left, if any */
       if (left_mask)
 	*(wp++) &= left_mask;
       /* use Duff's Device for the full words */
       if (word_count)
 	{
 	  int32_t i = word_count;
 	  switch (i % 8)
 	    {
 	      while (i > 0)
 		{
 		  *(wp++) = 0;
 		case 7: *(wp++) = 0;
 		case 6: *(wp++) = 0;
 		case 5: *(wp++) = 0;
 		case 4: *(wp++) = 0;
 		case 3: *(wp++) = 0;
 		case 2: *(wp++) = 0;
 		case 1: *(wp++) = 0;
 		case 0: i -= 8;
 		}
 	    }
 	}
       /* partial word at right, if any */
       if (right_mask)
 	*wp &= right_mask;
       /* advance to next row */
       rp += dest_bitmap->row_words;
     }
 }
 #if 0
 static void blt (Bitmap *src_bitmap,
 		 Rect *src_rect,
 		 Bitmap *dest_bitmap,
 		 Rect *dest_rect)
 {
   int32_t y;
   word_t *rp;
   /* This function requires a non-null src rect */
   assert (dest_rect->min.x < dest_rect->max.x);
   assert (dest_rect->min.y < dest_rect->max.y);
   /* and a non-null dest rect */
   assert (dest_rect->min.x < dest_rect->max.x);
   assert (dest_rect->min.y < dest_rect->max.y);
   /* and that the widths and heights of the rects match */
   assert (rect_width (src_rect) == rect_width (dest_rect));
   assert (rect_height (src_rect) == rect_height (dest_rect));
   /* and that the rows of the src rect lie entirely within the src bitmap */
   assert (dest_rect->min.y >= dest_bitmap->rect->min.y);
   assert (dest_rect->max.y <= dest_bitmap->rect->max.y);
   /* and that the rows of the dest rect lie entirely within the dest bitmap */
   assert (dest_rect->min.y >= dest_bitmap->rect->min.y);
   assert (dest_rect->max.y <= dest_bitmap->rect->max.y);
   /* clip the x axis of the dest_rect to the bounds of the dest bitmap,
      and adjust the src_rect to match */
   if (dest_rect->min.x < dest_bitmap->rect.min.x)
     {
       src_rect->min.x += ???;
       dest_rect->min.x = dest_bitmap->rect.min.x;
     }
   if (dest_rect->max.x > dest_bitmap->rect.max.x)
     {
       dest_rect->max.x = dest_bitmap->rect.max.x;
     }
   rp = ???;
   for (y = 0; y < rect_height (dest_rect); y++)
     {
   ???;
       rp += dest_bitmap->row_words;
     }
 }
 /*
  * The destination rectangle is first clipped to the dest bitmap, and
  * the source rectangle is adjusted in the corresponding manner.
  * What's left is divided into five sections, any of which may be
  * null.  The portion that actually corresponds to the intersection of
  * the source rectangle and the source bitmpa is the "middle".  The
  * other four sections will use the background color as the source
  * operand.
  *
  *
  *   y0 ->  -------------------------------------------------
  *          |                     top                       |
  *          |                                               |
  *   y1 ->  -------------------------------------------------
  *          |   left        |    middle     |    right      |
  *          |               |               |               |
  *   y2 ->  -------------------------------------------------
  *          |                     bottom                    |
  *          |                                               |
  *   y3 ->  -------------------------------------------------
  *
  *          ^               ^               ^               ^
  *          |               |               |               |
  *         x0              x1              x2              x3
  *
  * */
 Bitmap *bitblt (Bitmap *src_bitmap,
 		Rect   *src_rect,
 		Bitmap *dest_bitmap,
 		Point  *dest_min,
 		int tfn,
 		int background)
 {
   Rect sr, dr;     /* src and dest rects, clipped to visible portion of
 		      dest rect */
   uint32_t drw, drh;    /* dest rect width, height - gets adjusted */
   Point src_point, dest_point;
   /* dest coordinates: */
   uint32_t x0, x1, x2, x3;
   uint32_t y0, y1, y2, y3;
   {
     sr = * src_rect;
     uint32_t srw = rect_width (& sr);
     uint32_t srh = rect_height (& sr);
     if ((srw < 0) || (srh < 0))
       goto done;  /* the source rect is empty! */
     dr.min.x = dest_min->x;
     dr.min.y = dest_min->y;
     dr.max.x = dr.min.x + srw;
     dr.max.y = dr.min.y + srh;
   }
   if (! dest_bitmap)
     {
       dest_bitmap = create_bitmap (& dr);
       if (! dest_bitmap)
 	return (NULL);
     }
   if ((dr.min.x >= dest_bitmap->rect.max.x) ||
       (dr.min.y >= dest_bitmap->rect.max.y))
     goto done;  /* the dest rect isn't even in the dest bitmap! */
   /* crop dest rect to dest bitmap */
   delta = dest_bitmap->rect.min.x - dr.min.x;
   if (delta > 0)
     {
       sr.min.x += delta;
       dr.min.x += delta;
     }
   delta = dest_bitmap->rect.min.y - dr.min.y;
   if (delta > 0)
     {
       sr.min.y += delta;
       dr.min.y += delta;
     }
   delta = dr.max.x - dest_bitmap->rect.max.x;
   if (delta > 0)
     {
       sr.max.x -= delta;
       dr.max.x -= delta;
     }
   delta = dr.max.y - dest_bitmap->rect.max.y;
   if (delta > 0)
     {
       sr.max.x -= delta;
       dr.max.x -= delta;
     }
   drw = rect_width (& dr);
   drh = rect_height (& dh);
   x0 = dr.min.x;
   y0 = dr.min.y;
   x3 = dr.max.x;
   y3 = dr.max.y;
 #if 0
   /* if the source rect min y is >= the source bitmap max y,
      we transfer background color to the entire dest rect */
   if (sr.min.y >= src->rect.max.y)
     {
       blt_background (dest_bitmap, dr);
       goto done;
     }
 #endif
   /* top */
   if (y0 != y1)
     {
       dr2.min.x = x0;
       dr2.max.x = x3;
       dr2.min.y = y0;
       dr2.max.y = y1;
       blt_background (dest_bitmap, & dr2);
     }
   /*
    * top:  if the source rect min y is less than the source bitmap min y,
    * we need to transfer some backgound color to the top part of the dest
    * rect
    */
   if (sr.min.y < src->rect.min.y)
     {
       Rect dr2;
       uint32 bg_height;
       bg_height = src->rect.min.y - sr.min.y;
       if (bg_height > sh)
 	bg_height = sh;
       dr2 = dr;
       dr2.max.y = dr2.min.y + bg_height;
       blt_background (dest_bitmap, & dr2);
       /* now reduce the rect height by the number of lines of background
 	 color */
       sr.min.y += bg_height;
       dr.min.y += bg_height;
       sh -= bg_height;
       dh -= bg_height;
       if (sr.min.y == sr.max.y)
 	goto done;
     }
   if (y1 != y2)
     {
       /* left */
       if (x0 != x1)
 	{
 	  dr2.min.x = x1;
 	  dr2.max.x = x1;
 	  dr2.min.y = y1;
 	  dr2.max.y = y2
 	  blt_background (dest_bitmap, & dr2);
 	}
       /* middle */
       if (x1 != x2)
 	{
 	  /* ??? */
 	}
       /* right */
       if (x2 != x3)
 	{
 	  dr2.min.x = x2;
 	  dr2.max.x = x3;
 	  dr2.min.y = y1;
 	  dr2.max.y = y2
 	  blt_background (dest_bitmap, & dr2);
 	}
     }
   /* bottom */
   if (y2 != y3)
     {
       dr2.min.x = x0;
       dr2.max.x = x3;
       dr2.min.y = y2;
       dr2.max.y = y3;
       blt_background (dest_bitmap, & dr2);
     }
  done:
   return (dest_bitmap);
 }
 #else
 Bitmap *bitblt (Bitmap *src_bitmap,
 		Rect   *src_rect,
 		Bitmap *dest_bitmap,
 		Point  *dest_min,
 		int tfn,
 		int background)
 {
   Point src_point, dest_point;
   if (! dest_bitmap)
     {
       Rect dest_rect = {{ 0, 0 }, { dest_min->x + rect_width (src_rect),
 				    dest_min->y + rect_height (src_rect) }};
       dest_bitmap = create_bitmap (& dest_rect);
       if (! dest_bitmap)
 	return (NULL);
     }
   if (tfn == TF_SRC)
     {
       for (src_point.y = src_rect->min.y;
 	   src_point.y < src_rect->max.y;
 	   src_point.y++)
 	{
 	  dest_point.y = dest_min->y + src_point.y - src_rect->min.y;
 	  for (src_point.x = src_rect->min.x;
 	       src_point.x < src_rect->max.x;
 	       src_point.x++)
 	    {
 	      bool a;
 	      dest_point.x = dest_min->x + src_point.x - src_rect->min.x;
 	      a = get_pixel (src_bitmap, src_point);
 	      set_pixel (dest_bitmap, dest_point, a);
 	    }
 	}
     }
   else
     {
       for (src_point.y = src_rect->min.y;
 	   src_point.y < src_rect->max.y;
 	   src_point.y++)
 	{
 	  dest_point.y = dest_min->y + src_point.y - src_rect->min.y;
 	  for (src_point.x = src_rect->min.x;
 	       src_point.x < src_rect->max.x;
 	       src_point.x++)
 	    {
 	      bool a, b, c;
 	      dest_point.x = dest_min->x + src_point.x - src_rect->min.x;
 	      a = get_pixel (src_bitmap, src_point);
 	      b = get_pixel (dest_bitmap, dest_point);
 	      c = (tfn & (1 << (a * 2 + b))) != 0;
 	      set_pixel (dest_bitmap, dest_point, c);
 	    }
 	}
     }
   return (dest_bitmap);
 }
 #endif
 /* in-place transformations */
 void flip_h (Bitmap *src)
 {
   word_t *rp;  /* row pointer */
   int32_t y;
   int shift1, shift2;
   rp = src->bits;
   if ((rect_width (& src->rect) & 7) == 0)
     {
       for (y = src->rect.min.y; y < src->rect.max.y; y++)
 	{
           reverse_range_of_bytes ((uint8_t *) rp, rect_width (& src->rect) / 8);
 	  rp += src->row_words;
 	}
       return;
     }
   realloc_temp_buffer ((src->row_words + 1) * sizeof (word_t));
   temp_buffer [0] = 0;
   shift1 = rect_width (& src->rect) & (BITS_PER_WORD - 1);
   shift2 = BITS_PER_WORD - shift1;
   for (y = src->rect.min.y; y < src->rect.max.y; y++)
     {
       word_t d1, d2;
       word_t *p1;  /* work src ptr */
       word_t *p2;  /* work dest ptr */
       memcpy (temp_buffer + 1, rp, src->row_words * sizeof (word_t));
       p1 = temp_buffer + src->row_words;
       p2 = rp;
       d2 = *(p1--);
       while (p1 >= temp_buffer)
 	{
 	  word_t t;
 	  d1 = *(p1--);
 	  t = (d1 >> shift1) | (d2 << shift2);
 	  *(p2++) = bit_reverse_word (t);
 	  d2 = d1;
 	}
       rp += src->row_words;
     }
 }
 void flip_v (Bitmap *src)
 {
   word_t *p1, *p2;
   realloc_temp_buffer (src->row_words * sizeof (word_t));
   p1 = src->bits;
   p2 = src->bits + src->row_words * (rect_height (& src->rect) - 1);
   while (p1 < p2)
     {
       memcpy (temp_buffer, p1, src->row_words * sizeof (word_t));
       memcpy (p1, p2, src->row_words * sizeof (word_t));
       memcpy (p2, temp_buffer, src->row_words * sizeof (word_t));
       p1 += src->row_words;
       p2 -= src->row_words;
     }
 }
 void rot_180 (Bitmap *src)  /* combination of flip_h and flip_v */
 {
   flip_h (src);
   flip_v (src);
 }
 /* "in-place" transformations - will allocate new memory and free old */
 void transpose (Bitmap *src)
 {
   uint32_t new_row_words = DIV_ROUND_UP (rect_height (& src->rect), 32);
   word_t *new_bits;
   new_bits = calloc (1, new_row_words * rect_width (& src->rect) * sizeof (word_t));
   /* $$$ more code needed here */
 }
 void rot_90 (Bitmap *src)   /* transpose + flip_h */
 {
   transpose (src);
   flip_h (src);
 }
 void rot_270 (Bitmap *src)  /* transpose + flip_v */
 {
   transpose (src);
   flip_v (src);
 }

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bitblt.c@2fae6df568f6 (annotated)

bitblt.c