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      1 /*
      2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #include <stdlib.h>
     12 
     13 
     14 void vp8_blit_text(const char *msg, unsigned char *address, const int pitch)
     15 {
     16     int letter_bitmap;
     17     unsigned char *output_pos = address;
     18     int colpos;
     19     const int font[] =
     20     {
     21         0x0, 0x5C00, 0x8020, 0xAFABEA, 0xD7EC0, 0x1111111, 0x1855740, 0x18000,
     22         0x45C0, 0x74400, 0x51140, 0x23880, 0xC4000, 0x21080, 0x80000, 0x111110,
     23         0xE9D72E, 0x87E40, 0x12AD732, 0xAAD62A, 0x4F94C4, 0x4D6B7, 0x456AA,
     24         0x3E8423, 0xAAD6AA, 0xAAD6A2, 0x2800, 0x2A00, 0x8A880, 0x52940, 0x22A20,
     25         0x15422, 0x6AD62E, 0x1E4A53E, 0xAAD6BF, 0x8C62E, 0xE8C63F, 0x118D6BF,
     26         0x1094BF, 0xCAC62E, 0x1F2109F, 0x118FE31, 0xF8C628, 0x8A89F, 0x108421F,
     27         0x1F1105F, 0x1F4105F, 0xE8C62E, 0x2294BF, 0x164C62E, 0x12694BF, 0x8AD6A2,
     28         0x10FC21, 0x1F8421F, 0x744107, 0xF8220F, 0x1151151, 0x117041, 0x119D731,
     29         0x47E0, 0x1041041, 0xFC400, 0x10440, 0x1084210, 0x820
     30     };
     31     colpos = 0;
     32 
     33     while (msg[colpos] != 0)
     34     {
     35         char letter = msg[colpos];
     36         int fontcol, fontrow;
     37 
     38         if (letter <= 'Z' && letter >= ' ')
     39             letter_bitmap = font[letter-' '];
     40         else if (letter <= 'z' && letter >= 'a')
     41             letter_bitmap = font[letter-'a'+'A' - ' '];
     42         else
     43             letter_bitmap = font[0];
     44 
     45         for (fontcol = 6; fontcol >= 0 ; fontcol--)
     46             for (fontrow = 0; fontrow < 5; fontrow++)
     47                 output_pos[fontrow *pitch + fontcol] =
     48                     ((letter_bitmap >> (fontcol * 5)) & (1 << fontrow) ? 255 : 0);
     49 
     50         output_pos += 7;
     51         colpos++;
     52     }
     53 }
     54 
     55 static void plot (const int x, const int y, unsigned char *image, const int pitch)
     56 {
     57     image [x+y*pitch] ^= 255;
     58 }
     59 
     60 /* Bresenham line algorithm */
     61 void vp8_blit_line(int x0, int x1, int y0, int y1, unsigned char *image, const int pitch)
     62 {
     63     int steep = abs(y1 - y0) > abs(x1 - x0);
     64     int deltax, deltay;
     65     int error, ystep, y, x;
     66 
     67     if (steep)
     68     {
     69         int t;
     70         t = x0;
     71         x0 = y0;
     72         y0 = t;
     73 
     74         t = x1;
     75         x1 = y1;
     76         y1 = t;
     77     }
     78 
     79     if (x0 > x1)
     80     {
     81         int t;
     82         t = x0;
     83         x0 = x1;
     84         x1 = t;
     85 
     86         t = y0;
     87         y0 = y1;
     88         y1 = t;
     89     }
     90 
     91     deltax = x1 - x0;
     92     deltay = abs(y1 - y0);
     93     error  = deltax / 2;
     94 
     95     y = y0;
     96 
     97     if (y0 < y1)
     98         ystep = 1;
     99     else
    100         ystep = -1;
    101 
    102     if (steep)
    103     {
    104         for (x = x0; x <= x1; x++)
    105         {
    106             plot(y,x, image, pitch);
    107 
    108             error = error - deltay;
    109             if (error < 0)
    110             {
    111                 y = y + ystep;
    112                 error = error + deltax;
    113             }
    114         }
    115     }
    116     else
    117     {
    118         for (x = x0; x <= x1; x++)
    119         {
    120             plot(x,y, image, pitch);
    121 
    122             error = error - deltay;
    123             if (error < 0)
    124             {
    125                 y = y + ystep;
    126                 error = error + deltax;
    127             }
    128         }
    129     }
    130 }
    131