/* Main function */
char *decode_authimage(struct image *img)
{
static struct font *font = NULL;
char *result;
struct image *tmp;
int x, y, r, g, b, i;
if(!font)
{
font = font_load_fixed(DECODER, "font.png",
"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ");
if(!font)
exit(-1);
}
/* authimage captchas have 6 characters */
result = malloc(7 * sizeof(char));
memset(result, '\0', 7);
/* double the captcha size for better accuracy in the rotation */
tmp = image_dup(img);
filter_scale(tmp, 2.0);
getpixel(tmp, 0, 0, &r, &g, &b);
filter_threshold(tmp, r * 3 / 4);
filter_smooth(tmp);
filter_threshold(tmp, 220);
for(i = 0; i < 6; i++)
{
int mindiff = INT_MAX, minch = -1, ch;
for(ch = 0; ch < font->size; ch++)
{
int diff = 0;
for(y = 0; y < 7; y++)
{
for(x = 0; x < 5; x++)
{
int newx, newy, r2;
newx = 35.0 + (x + 6 * i) * 218.0 / 34.0 + y * 5.0 / 6.0 + 0.5;
newy = 33.0 - (x + 6 * i) * 18.0 / 34.0 + y * 42.0 / 6.0 + 0.5;
getpixel(tmp, newx, newy, &r, &g, &b);
getpixel(font->img, x + 6 * ch, y, &r2, &g, &b);
diff += (r - r2) * (r - r2);
}
}
if(diff < mindiff)
{
mindiff = diff;
minch = ch;
}
}
result[i] = font->glyphs[minch].c;
}
image_free(tmp);
return result;
}
/* Main function */
char *decode_vbulletin(struct image *img)
{
static struct font *font = NULL;
char *result;
struct image *tmp;
int limits[6] = { 26, 53, 80, 107, 134, 160 };
int x, y, r, g, b, i, j;
if(!font)
{
font = font_load_fixed(DECODER, "font.png",
"2346789ABCDEFGHJKLMNPRTWXYZ");
if(!font)
exit(-1);
}
/* vBulletin captchas have 6 characters */
result = malloc(7 * sizeof(char));
strcpy(result, " ");
/* half the captchas are inverse video; we set them back to normal */
tmp = image_dup(img);
getpixel(tmp, 0, 0, &r, &g, &b);
if(r < 50)
filter_threshold(tmp, 128);
else
filter_threshold(tmp, -128);
/* Remove garbage around the cells */
for(x = 0; x < tmp->width; x++)
{
for(y = 0; y < 15; y++)
setpixel(tmp, x, y, 255, 255, 255);
for(y = 45; y < tmp->height; y++)
setpixel(tmp, x, y, 255, 255, 255);
}
for(x = 0; x < tmp->width; x++)
{
for(i = 0; i < 6; i++)
if(x == limits[i])
break;
if(i == 6)
for(y = 15; y < 45; y++)
setpixel(tmp, x, y, 255, 255, 255);
else
x += 11;
}
filter_black_stuff(tmp);
filter_black_stuff(tmp);
/* Fill letters in gray */
for(x = 26; x < 172; x++)
{
getpixel(tmp, x, 15, &r, &g, &b);
if(r == 0)
filter_flood_fill(tmp, x, 15, 127, 0, 255);
}
/* Find remaining black parts and remove them */
for(x = 26; x < 172; x++)
for(y = 15; y < 45; y++)
{
getpixel(tmp, x, y, &r, &g, &b);
if(r == 0)
filter_flood_fill(tmp, x, y, 255, 255, 255);
}
/* Fill letters in black */
for(x = 26; x < 172; x++)
{
getpixel(tmp, x, 44, &r, &g, &b);
if(r == 127)
filter_flood_fill(tmp, x, 44, 0, 0, 0);
}
/* Find remaining gray parts and remove them */
for(x = 26; x < 172; x++)
for(y = 15; y < 45; y++)
{
getpixel(tmp, x, y, &r, &g, &b);
if(r == 127)
filter_flood_fill(tmp, x, y, 255, 255, 255);
}
/* Guess all glyphs */
for(i = 0; i < 6; i++)
{
int mindist = INT_MAX, min = -1;
for(j = 0; j < font->size; j++)
{
int dist = 0;
for(y = 0; y < 30; y++)
for(x = 0; x < 11; x++)
{
int r2, g2, b2;
getpixel(font->img, 12 * j + x, y, &r, &g, &b);
getpixel(tmp, limits[i] + x, 15 + y, &r2, &g2, &b2);
dist += (r - r2) * (r - r2);
}
if(dist < mindist)
{
mindist = dist;
min = j;
}
}
result[i] = font->glyphs[min].c;
}
image_free(tmp);
return result;
}
/* Main function */
char *decode_linuxfr(struct image *img)
{
static struct font *font = NULL;
char *result;
struct image *tmp;
int x, y, r, g, b, i, j, c;
int *stats;
if(!font)
{
font = font_load_fixed(DECODER, "font.png",
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"0123456789");
if(!font)
exit(-1);
}
/* linuxfr captchas have 7 characters */
result = malloc(8 * sizeof(char));
memset(result, '\0', 8);
stats = malloc(img->height * sizeof(int));
tmp = image_dup(img);
filter_threshold(tmp, 150);
for(y = 0; y < tmp->height; y++)
{
int count = 0;
for(x = 0; x < tmp->width; x++)
{
getpixel(tmp, x, y, &r, &g, &b);
if(r == 0)
count++;
}
stats[y] = count;
}
/* Find 7 consecutive lines that have at least 14 pixels; they're
* baseline candidates */
for(y = 0; y < tmp->height - 11; y++)
{
int ycan = 1;
for(j = 3; j < 10; j++)
{
if(stats[y + j] < 14)
{
ycan = 0;
y = y + j - 3;
break;
}
}
if(!ycan)
continue;
/* Find 7 consecutive cells that have at least 2 pixels on
* each line; they're base column candidates */
for(x = 0; x < tmp->width - 9 * 7 + 1; x++)
{
int goodx = 1;
for(c = 0; c < 7 && goodx; c++)
{
for(j = 3; j < 10; j++)
{
int count = 0;
for(i = 0; i < 8; i++)
{
getpixel(tmp, x + c * 9 + i, y + j, &r, &g, &b);
if(r == 0)
{
count++;
if(count == 2)
break;
}
}
if(count < 2)
{
goodx = 0;
break;
}
}
}
if(!goodx)
continue;
/* Now we have an (x,y) candidate - try to fit 7 characters */
for(c = 0; c < 7 && goodx; c++)
{
int r2, g2, b2, ch;
int minerror = INT_MAX;
for(ch = 0; ch < font->size; ch++)
{
int error = 0, goodch = 1;
for(j = 0; j < 12 && goodch; j++)
for(i = 0; i < 8; i++)
{
getpixel(tmp, x + c * 9 + i, y + j, &r, &g, &b);
getpixel(font->img, ch * 9 + i, j, &r2, &g2, &b2);
/* Only die if font is black and image is white */
if(r > r2)
{
goodch = 0;
break;
}
else if(r < r2)
error++;
}
if(goodch && error < minerror)
{
minerror = error;
result[c] = font->glyphs[ch].c;
result[c+1] = '\0';
}
}
if(minerror == INT_MAX)
goodx = 0;
}
/* Wow, that was a good guess! Exit this loop */
if(goodx)
break;
}
}
image_free(tmp);
free(stats);
if(strlen(result) != 7)
{
free(result);
return NULL;
}
return result;
}
