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bitblt.c@bfc6aaa089b0 (annotated)

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

 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include "type.h"
 #include "bitblt.h"
 #define DIV_ROUND_UP(count,pow2) (((count) - 1) / (pow2) + 1)
 static const u8 bit_reverse_byte [0x100] =
 {
 x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
 x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
 x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
 x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
 x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
 x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
 x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
 x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
 x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
 x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
 x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
 x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
 x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
 x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
 x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
 x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
 x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
 x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
 x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
 x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
 x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
 x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
 x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
 x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
 x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
 x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
 x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
 x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
 x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
 x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
 x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
 x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff
 };
 void reverse_bits (u8 *p, int byte_count)
 {
   while (byte_count--)
     {
       (*p) = bit_reverse_byte [*p];
       p++;
     }
 }
 static word_type bit_reverse_word (word_type 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 word_type *temp_buffer;
 static word_type temp_buffer_size;
 static void realloc_temp_buffer (u32 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_type pixel_mask (int x)
 {
 #if defined (MIXED_ENDIAN)  /* disgusting hack for mixed-endian */
   word_type 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_type pixel_range_mask (int left, int right)
 {
   word_type 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;
   u32 width = rect_width (rect);
   u32 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_type));
   if (! bitmap->bits)
     {
       free (bitmap);
       return (NULL);
     }
   return (bitmap);
 }
 void free_bitmap (Bitmap *bitmap)
 {
   free (bitmap->bits);
   free (bitmap);
 }
 boolean get_pixel (Bitmap *bitmap, Point coord)
 {
   word_type *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, boolean value)
 {
   word_type *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 boolean 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)
 {
   u32 y;
   word_type *rp;
   u32 left_bit, left_word;
   u32 right_bit, right_word;
   word_type left_mask, right_mask;
   s32 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_type *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)
 	{
 	  s32 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)
 {
   s32 y;
   word_type *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 */
   u32 drw, drh;    /* dest rect width, height - gets adjusted */
   Point src_point, dest_point;
   /* dest coordinates: */
   u32 x0, x1, x2, x3;
   u32 y0, y1, y2, y3;
   {
     sr = * src_rect;
     u32 srw = rect_width (& sr);
     u32 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++)
 	    {
 	      boolean 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++)
 	    {
 	      boolean 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_type *rp;  /* row pointer */
   word_type *p1;  /* work src ptr */
   word_type *p2;  /* work dest ptr */
   s32 y;
   int shift1, shift2;
   realloc_temp_buffer ((src->row_words + 1) * sizeof (word_type));
   rp = src->bits;
   if ((rect_width (& src->rect) & 7) == 0)
     {
       for (y = src->rect.min.y; y < src->rect.max.y; y++)
 	{
 	  memcpy (temp_buffer, rp, src->row_words * sizeof (word_type));
 	  p1 = temp_buffer + src->row_words;
 	  p2 = rp;
 	  while (p1 >= temp_buffer)
 	    *(p2++) = bit_reverse_word (*(p1--));
 	  rp += src->row_words;
 	}
       return;
     }
   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_type d1, d2;
       memcpy (temp_buffer + 1, rp, src->row_words * sizeof (word_type));
       p1 = temp_buffer + src->row_words;
       p2 = rp;
       d2 = *(p1--);
       while (p1 >= temp_buffer)
 	{
 	  d1 = *(p1--);
 	  *(p2++) = bit_reverse_word ((d1 << shift1) | (d2 >> shift2));
 	  d2 = d1;
 	}
       rp += src->row_words;
     }
 }
 void flip_v (Bitmap *src)
 {
   word_type *p1, *p2;
   realloc_temp_buffer (src->row_words * sizeof (word_type));
   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_type));
       memcpy (p1, p2, src->row_words * sizeof (word_type));
       memcpy (p2, temp_buffer, src->row_words * sizeof (word_type));
       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)
 {
   u32 new_row_words = DIV_ROUND_UP (rect_height (& src->rect), 32);
   word_type *new_bits;
   new_bits = calloc (1, new_row_words * rect_width (& src->rect) * sizeof (word_type));
   /* $$$ 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);
 }

tumble / annotate

bitblt.c@bfc6aaa089b0 (annotated)

bitblt.c