* attempt at the xanga decoder. roughly 50% success.

* fonts useful to the xanga decoder. x_* fonts are convert'ed with -blur 3.


git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/pwntcha/trunk@453 92316355-f0b4-4df1-b90c-862c8a59935f

src/main.c

@@ -209,6 +209,7 @@ int main(int argc, char *argv[])
         }
 
         printf("%s\n", result);
+        fflush(stdout);
         free(result);
     }
 

src/xanga.c

@@ -19,41 +19,18 @@
 #include "common.h"
 
 static void fill_white_holes(struct image *img);
+static void find_glyphs(struct image *img);
+
+static char *result;
 
 /* Main function */
 char *decode_xanga(struct image *img)
 {
-    static struct font *font1 = NULL, *font2 = NULL, *font3 = NULL;
     struct image *tmp;
-    char *result;
-
-    if(!font1)
-    {
-        font1 = font_load_variable("font_freemonobold_32_az.bmp",
-                                   "abcdefghijklmnopqrstuvwxyz");
-        if(!font1)
-            exit(1);
-    }
-
-    if(!font2)
-    {
-        font2 = font_load_variable("font_freemonobold_32_az.bmp",
-                                   "abcdefghijklmnopqrstuvwxyz");
-        if(!font2)
-            exit(1);
-    }
-
-    if(!font3)
-    {
-        font3 = font_load_variable("font_freemonobold_32_az.bmp",
-                                   "abcdefghijklmnopqrstuvwxyz");
-        if(!font3)
-            exit(1);
-    }
 
-    /* Xanga captchas have 7 characters */
-    result = malloc(8 * sizeof(char));
-    strcpy(result, "       ");
+    /* Xanga captchas have 6 characters */
+    result = malloc(7 * sizeof(char));
+    strcpy(result, "      ");
 
     tmp = image_dup(img);
 image_save(tmp, "xanga1.bmp");
@@ -64,20 +41,26 @@ image_save(tmp, "xanga1.bmp");
 image_save(tmp, "xanga2.bmp");
     fill_white_holes(tmp);
 //    filter_fill_holes(tmp);
+    filter_smooth(tmp);
+    //filter_median(tmp);
 image_save(tmp, "xanga3.bmp");
     //filter_detect_lines(tmp);
 //    filter_median(tmp);
 //image_save(tmp, "xanga4.bmp");
-    filter_equalize(tmp, 128);
+//    filter_equalize(tmp, 128);
+    filter_contrast(tmp);
 image_save(tmp, "xanga4.bmp");
-return NULL;
 
+#if 0
     /* Detect small objects to guess image orientation */
     filter_median(tmp);
     filter_equalize(tmp, 200);
 
     /* Invert rotation and find glyphs */
     filter_median(tmp);
+#endif
+    find_glyphs(tmp);
+image_save(tmp, "xanga5.bmp");
 
     /* Clean up our mess */
     image_free(tmp);
@@ -130,3 +113,123 @@ static void fill_white_holes(struct image *img)
     image_free(tmp);
 }
 
+static void find_glyphs(struct image *img)
+{
+#define FONTS 6
+    static struct font *fonts[FONTS];
+    static char *files[] =
+    {
+        "x_font_freemonobold_32_az.bmp", "abcdefghijklmnopqrstuvwxyz",
+        "x_font_freemonobold_24_az.bmp", "abcdefghijklmnopqrstuvwxyz",
+        "x_font_freesansbold_32_az.bmp", "abcdefghijklmnopqrstuvwxyz",
+        //"x_font_freeserifbold_32_az.bmp", "abcdefghijklmnopqrstuvwxyz",
+        "x_font_comic_32_az.bmp", "abcdefghijklmnopqrstuvwxyz",
+        "x_font_comic_24_az_messed.bmp", "abcdefghijklmnopqrstuvwxyz",
+        "x_font_freesansbold_36_az_messed.bmp", "abcdefghijklmnopqrstuvwxyz",
+    };
+    struct image *tmp;
+    int x, y, i = 0, f;
+    int r, g, b;
+    int xmin, xmax, ymin, ymax, startx = 10, cur = 0;
+    int bestdist, bestfont, bestx, besty, bestch;
+
+    for(f = 0; f < FONTS; f++)
+    {
+        if(!fonts[f])
+        {
+            fonts[f] = font_load_variable(files[f * 2], files[f * 2 + 1]);
+            if(!fonts[f])
+                exit(1);
+            //filter_smooth(fonts[f]->img);
+            //filter_contrast(fonts[f]->img);
+        }
+    }
+
+    tmp = image_new(img->width, img->height);
+
+    for(y = 0; y < img->height; y++)
+        for(x = 0; x < img->width; x++)
+        {
+            getpixel(img, x, y, &r, &g, &b);
+            setpixel(tmp, x, y, 255, g, 255);
+        }
+
+    while(cur < 6)
+    {
+        /* Try to find 1st letter */
+        bestdist = INT_MAX;
+        for(f = 0; f < FONTS; f++) for(i = 0; i < fonts[f]->size; i++)
+        {
+            int localmin = INT_MAX, localx, localy;
+int sqr;
+            if(fonts[f]->glyphs[i].c == 'l' || fonts[f]->glyphs[i].c == 'z')
+                continue;
+            xmin = fonts[f]->glyphs[i].xmin - 5;
+            ymin = fonts[f]->glyphs[i].ymin - 3;
+            xmax = fonts[f]->glyphs[i].xmax + 5;
+            ymax = fonts[f]->glyphs[i].ymax + 3;
+sqr = sqrt(xmax - xmin);
+            for(y = -15; y < 15; y++)
+                //for(x = startx; x < startx + 15; x++)
+                for(x = 22 - (xmax - xmin) / 2 + 25 * cur; x < 28 - (xmax - xmin) / 2 + 25 * cur; x++)
+                {
+                    int z, t, dist;
+                    dist = 0;
+                    for(t = 0; t < ymax - ymin; t++)
+                        for(z = 0; z < xmax - xmin; z++)
+                        {
+                            int r2;
+                            getgray(fonts[f]->img, xmin + z, ymin + t, &r);
+                            getgray(img, x + z, y + t, &r2);
+                            if(r < r2)
+                                dist += (r - r2) * (r - r2);
+                            else
+                                dist += (r - r2) * (r - r2) * 3 / 4;
+                        }
+    //                printf("%i %i -> %i\n", x, y, dist);
+//                    dist /= (xmax - xmin);
+//                    dist = dist / sqrt((ymax - ymin) * (xmax - xmin)) / (xmax - xmin);
+                    dist = dist / (xmax - xmin) / sqr;
+//                    dist = dist * 128 / fonts[f]->glyphs[i].count;
+                    if(dist < localmin)
+                    {
+                        localmin = dist;
+                        localx = x;
+                        localy = y;
+                    }
+                }
+            //fprintf(stderr, "%i (%i,%i)\n", localmin, localx - startx, localy);
+            if(localmin < bestdist)
+            {
+//printf("  bestch is now %i (%c) in font %i\n", i, fonts[f]->glyphs[i].c, f);
+                bestdist = localmin;
+                bestfont = f;
+                bestx = localx;
+                besty = localy;
+                bestch = i;
+            }
+        }
+//printf("%i (%c) in font %i\n", i, fonts[bestfont]->glyphs[bestch].c, bestfont);
+//printf("%i < %i < %i\n", 10 + 25 * cur, bestx, 30 + 25 * cur);
+
+        /* Draw best glyph in picture (debugging purposes) */
+        xmin = fonts[bestfont]->glyphs[bestch].xmin - 5;
+        ymin = fonts[bestfont]->glyphs[bestch].ymin - 3;
+        xmax = fonts[bestfont]->glyphs[bestch].xmax + 5;
+        ymax = fonts[bestfont]->glyphs[bestch].ymax + 3;
+        for(y = 0; y < ymax - ymin; y++)
+            for(x = 0; x < xmax - xmin; x++)
+            {
+                getpixel(fonts[bestfont]->img, xmin + x, ymin + y, &r, &g, &b);
+                if(r > 128) continue;
+                setpixel(tmp, bestx + x, besty + y, r, g, b);
+            }
+
+        startx = bestx + xmax - xmin;
+        result[cur++] = fonts[bestfont]->glyphs[bestch].c;
+    }
+
+    image_swap(img, tmp);
+    image_free(tmp);
+}
+