Allows drawing path to solution

include/mazemaker.h

@@ -38,13 +38,18 @@ void mazemaker_generate_maze_opt(int width, int height, mazegrid_t* result, maze
 void mazemaker_free_maze(mazegrid_t* maze);
 int mazemaker_maze_to_png(mazegrid_t const* maze, char const* filename);
 int mazemaker_maze_to_png_opt(mazegrid_t const* maze, char const* filename, mazeoptions_t const*);
+int mazemaker_path_to_png(maze_path_t const* path, char const* filename);
+int mazemaker_path_to_png_opt(maze_path_t const* path, char const* filename, mazeoptions_t const*);
 int mazemaker_maze_to_png_mem(mazegrid_t const* maze, size_t* len, uint8_t** buf);
 int mazemaker_maze_to_png_mem_opt(mazegrid_t const* maze, size_t* len, uint8_t** buf, mazeoptions_t const*);
+int mazemaker_path_to_png_mem(maze_path_t const* maze, size_t* len, uint8_t** buf);
+int mazemaker_path_to_png_mem_opt(maze_path_t const* maze, size_t* len, uint8_t** buf, mazeoptions_t const*);
 
 mazeoptions_t* mazemaker_options_new();
 void mazemaker_options_free(mazeoptions_t*);
 int mazemaker_options_set_wall_color(mazeoptions_t*, char const* color_desc);
 int mazemaker_options_set_background_color(mazeoptions_t*, char const* color_desc);
+int mazemaker_options_set_path_color(mazeoptions_t*, char const* color_desc);
 void mazemaker_options_set_seed(mazeoptions_t*, unsigned int seed);
 
 int mazemaker_solve(mazegrid_t const* maze, maze_path_t* path);

lib/image.c

@@ -37,6 +37,94 @@ static void setBox(img_data_t* img, int x, int y, int w, int h, char v) {
     }
 }
 
+static void setBoxCoords(img_data_t* img, int x1, int y1, int x2, int y2, char v) {
+    if (x1 > x2) setBoxCoords(img, x2, x1, y1, y2, v);
+    else if (y1 > y2) setBoxCoords(img, x1, x2, y2, y1, v);
+    else setBox(img, x1, y1, (x2 - x1 + 1), (y2 - y1 + 1), v);
+}
+
+#if 0
+static void printImageData(img_data_t const* img) {
+    FILE *ptr = fopen("output.txt", "wt");
+    for (int i = 0; i < img->h; i++) {
+        int flip_i = img->h - 1 - i;
+        for (int j = 0; j < img->w; j++) {
+            char v = img->data[img->w * flip_i + j];
+            if (v)
+                fprintf(ptr, "#");
+            else
+                fprintf(ptr, ".");
+        }
+        fprintf(ptr, "\n");
+    }
+    fclose(ptr);
+}
+#endif // 0
+
+static int _box_x(int x) {
+    return MARGIN + LINE_THICKNESS + BLOCK_SIZE * x;
+}
+
+static int _box_y(int y, int height) {
+    return height - MARGIN - LINE_THICKNESS - BLOCK_SIZE * y;
+}
+
+void drawPathSegment(size_t x, size_t y, size_t new_x, size_t new_y, img_data_t* result) {
+    size_t img_height = result->h;
+    if ((x > new_x) || (y > new_y)) {
+        drawPathSegment(new_x, new_y, x, y, result);
+        return;
+    }
+
+    // note: it is ALWAYS the case that either x == new_x OR y == new_y
+    // so the above should not result in infinite recursion
+    
+    if (y == new_y) {
+        // horizontal line (right)
+        setBox(result, _box_x(x) + BLOCK_SIZE / 2 - LINE_THICKNESS / 2,
+                       _box_y(y, img_height) - BLOCK_SIZE / 2 - LINE_THICKNESS / 2,
+                       BLOCK_SIZE + LINE_THICKNESS,
+                       LINE_THICKNESS,
+                       1);
+    } else {
+        // vertical line (up)
+        setBox(result, _box_x(x) + BLOCK_SIZE / 2 - LINE_THICKNESS / 2,
+                       _box_y(new_y, img_height) - BLOCK_SIZE / 2 - LINE_THICKNESS / 2,
+                       LINE_THICKNESS,
+                       BLOCK_SIZE + LINE_THICKNESS,
+                       1);
+    }
+}
+
+static img_data_t* pathToImageData(maze_path_t const* path) {
+    size_t width = path->nodes[path->length - 1].x + 1,
+           height = path->nodes[path->length - 1].y + 1,
+           x, y;
+    img_data_t* result = malloc(sizeof(img_data_t));
+    result->w  = LINE_THICKNESS + width * BLOCK_SIZE + 2 * MARGIN;
+    result->h = LINE_THICKNESS + height * BLOCK_SIZE + 2 * MARGIN;
+    result->data = malloc(result->w * result->h);
+    //fprintf(stderr, "#########\n");
+
+    // set background
+    memset(result->data, 0, result->w * result->h);
+
+    // set start and end points
+    x = y = 0;
+    setBox(result, MARGIN, _box_y(0, result->h) - BLOCK_SIZE / 2 - LINE_THICKNESS / 2, LINE_THICKNESS + BLOCK_SIZE / 2, LINE_THICKNESS, 1);
+    setBox(result, _box_x(width - 1) + BLOCK_SIZE / 2 - LINE_THICKNESS / 2, _box_y(height - 1, result->h) - BLOCK_SIZE / 2 - LINE_THICKNESS / 2, BLOCK_SIZE / 2 + LINE_THICKNESS, LINE_THICKNESS, 1);
+
+    for (int i = 1; i < path->length; i++) {
+        size_t new_x = path->nodes[i].x, new_y = path->nodes[i].y;
+        drawPathSegment(x, y, new_x, new_y, result);
+        x = new_x;
+        y = new_y;
+    }
+
+    //printImageData(result);
+    return result;
+}
+
 static img_data_t* gridToImageData(mazegrid_t const* g) {
     img_data_t* result = malloc(sizeof(img_data_t));
     result->w  = LINE_THICKNESS + g->width  * BLOCK_SIZE + 2 * MARGIN;
@@ -92,11 +180,103 @@ static void writeImageData(img_data_t const* img, png_structp png_ptr, mazeoptio
     }
 }
 
+static void writePathImageData(img_data_t const* img, png_structp png_ptr, mazeoptions_t const* options) {
+    for (int i = 0; i < img->h; i++) {
+        png_byte row[4 * img->w];
+        for (int j = 0; j < img->w; j++) {
+            if (img->data[i * img->w + j]) {
+                // wall color
+                row[4 * j] = options->path_color[0];
+                row[4 * j + 1] = options->path_color[1];
+                row[4 * j + 2] = options->path_color[2];
+                row[4 * j + 3] = 0xff;
+            } else memset(row + 4 * j, 0, 4);
+        }
+        png_write_row(png_ptr, row);
+    }
+}
+
 static void freeImageData(img_data_t* img) {
     free(img->data);
     free(img);
 }
 
+static int
+prepare_png(png_structp* png_ptr, png_infop* info_ptr) {
+    *png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    if (*png_ptr == NULL) {
+        fprintf(stderr, "Could not allocate PNG write struct.\n");
+        return 0;
+    }
+
+    *info_ptr = png_create_info_struct(*png_ptr);
+    if (info_ptr == NULL) {
+        fprintf(stderr, "Could not allocate PNG info struct.\n");
+        return 0;
+    }
+
+    if (setjmp(png_jmpbuf(*png_ptr))) {
+        fprintf(stderr, "Error during PNG creation.\n");
+        return 0;
+    }
+
+    return 1;
+}
+
+static void
+cleanup_png(png_structp png_ptr, png_infop info_ptr) {
+    if (info_ptr != NULL) {
+        png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
+        png_destroy_info_struct(png_ptr, &info_ptr);
+    }
+    if (png_ptr != NULL) png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
+}
+
+int mazemaker_path_to_png_opt(maze_path_t const* path, char const* filename, mazeoptions_t const* options) {
+    int code = 1;
+    img_data_t* img = pathToImageData(path);
+    FILE *f = NULL;
+    png_structp png_ptr = NULL;
+    png_infop info_ptr  = NULL;
+    
+    if (strcmp(filename, "-") == 0) {
+        f = stdout;
+    } else {
+        f = fopen(filename, "wb");
+        if (NULL == f) {
+            fprintf(stderr, "Could not open %s for writing.\n", filename);
+            code = 0;
+            goto exit;
+        }
+    }
+
+    if (prepare_png(&png_ptr, &info_ptr) == 0) {
+        code = 0;
+        goto exit;
+    }
+
+    png_init_io(png_ptr, f);
+
+    // Write header (8 bit color depth)
+    png_set_IHDR(png_ptr, info_ptr, img->w, img->h,
+                 8, PNG_COLOR_TYPE_RGBA, PNG_INTERLACE_NONE,
+                 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+    png_write_info(png_ptr, info_ptr);
+
+    writePathImageData(img, png_ptr, options);
+
+    png_write_end(png_ptr, NULL);
+
+exit:
+    if (strcmp(filename, "-") != 0) {
+        if (f != NULL) fclose(f);
+    }
+    cleanup_png(png_ptr, info_ptr);
+    if (img != NULL) freeImageData(img);
+    return code;
+}
+
 int mazemaker_maze_to_png_opt(mazegrid_t const* g, char const* filename, mazeoptions_t const* options) {
     int code = 1;
     img_data_t* img = gridToImageData(g);
@@ -115,25 +295,11 @@ int mazemaker_maze_to_png_opt(mazegrid_t const* g, char const* filename, mazeopt
         }
     }
 
-    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    if (prepare_png(&png_ptr, &info_ptr) == 0) {
-    if (png_ptr == NULL) {
-        fprintf(stderr, "Could not allocate PNG write struct.\n");
         code = 0;
         goto exit;
     }
 
-    info_ptr = png_create_info_struct(png_ptr);
-    if (info_ptr == NULL) {
-        fprintf(stderr, "Could not allocate PNG info struct.\n");
-        code = 0;
-        goto exit;
-    }
-
-    if (setjmp(png_jmpbuf(png_ptr))) {
-        fprintf(stderr, "Error during PNG creation.\n");
-        code = 0;
-        goto exit;
-    }
 
     png_init_io(png_ptr, f);
 
@@ -152,11 +318,7 @@ exit:
     if (strcmp(filename, "-") != 0) {
         if (f != NULL) fclose(f);
     }
-	if (info_ptr != NULL) {
+    cleanup_png(png_ptr, info_ptr);
-        png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
-        png_destroy_info_struct(png_ptr, &info_ptr);
-    }
-    if (png_ptr != NULL) png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
     if (img != NULL) freeImageData(img);
     return code;
 }
@@ -168,6 +330,13 @@ int mazemaker_maze_to_png(mazegrid_t const* g, char const* filename) {
     return result;
 }
 
+int mazemaker_path_to_png(maze_path_t const* path, char const* filename) {
+    mazeoptions_t* options = mazemaker_options_new(); // use default options
+    int result = mazemaker_path_to_png_opt(path, filename, options);
+    mazemaker_options_free(options);
+    return result;
+}
+
 static void append_png_data(png_structp png_ptr, png_bytep data, png_size_t length) {
     struct mem_encode* p = (struct mem_encode*)png_get_io_ptr(png_ptr);
     size_t nsize = p->size + length;
@@ -192,22 +361,7 @@ int mazemaker_maze_to_png_mem_opt(mazegrid_t const* g, size_t* len, uint8_t** bu
     png_infop info_ptr  = NULL;
     struct mem_encode menc = { .buffer = NULL, .size = 0 };
     
-    png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    if (prepare_png(&png_ptr, &info_ptr) == 0) {
-    if (png_ptr == NULL) {
-        fprintf(stderr, "Could not allocate PNG write struct.\n");
-        code = 0;
-        goto exit;
-    }
-
-    info_ptr = png_create_info_struct(png_ptr);
-    if (info_ptr == NULL) {
-        fprintf(stderr, "Could not allocate PNG info struct.\n");
-        code = 0;
-        goto exit;
-    }
-
-    if (setjmp(png_jmpbuf(png_ptr))) {
-        fprintf(stderr, "Error during PNG creation.\n");
         code = 0;
         goto exit;
     }
@@ -232,11 +386,7 @@ exit:
     if (!code && menc.buffer) {
         free(menc.buffer);
     }
-	if (info_ptr != NULL) {
+    cleanup_png(png_ptr, info_ptr);
-        png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
-        png_destroy_info_struct(png_ptr, &info_ptr);
-    }
-    if (png_ptr != NULL) png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
     if (img != NULL) freeImageData(img);
     return code;
 }
@@ -247,3 +397,47 @@ int mazemaker_maze_to_png_mem(mazegrid_t const* g, size_t* len, uint8_t** buf) {
     mazemaker_options_free(options);
     return result;
 }
+
+int mazemaker_path_to_png_mem_opt(maze_path_t const* path, size_t* len, uint8_t** buf, mazeoptions_t const* options) {
+    int code = 1;
+    img_data_t* img = pathToImageData(path);
+    png_structp png_ptr = NULL;
+    png_infop info_ptr  = NULL;
+    struct mem_encode menc = { .buffer = NULL, .size = 0 };
+    
+    if (prepare_png(&png_ptr, &info_ptr) == 0) {
+        code = 0;
+        goto exit;
+    }
+
+    png_set_write_fn(png_ptr, &menc, append_png_data, png_no_flush);
+
+    // Write header (8 bit color depth)
+    png_set_IHDR(png_ptr, info_ptr, img->w, img->h,
+                 8, PNG_COLOR_TYPE_RGBA, PNG_INTERLACE_NONE,
+                 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+    png_write_info(png_ptr, info_ptr);
+
+    writePathImageData(img, png_ptr, options);
+
+    png_write_end(png_ptr, NULL);
+
+    *len = menc.size;
+    *buf = menc.buffer;
+
+exit:
+    if (!code && menc.buffer) {
+        free(menc.buffer);
+    }
+    cleanup_png(png_ptr, info_ptr);
+    if (img != NULL) freeImageData(img);
+    return code;
+}
+
+int mazemaker_path_to_png_mem(maze_path_t const* path, size_t* len, uint8_t** buf) {
+    mazeoptions_t* options = mazemaker_options_new(); // use default options
+    int result = mazemaker_path_to_png_mem_opt(path, len, buf, options);
+    mazemaker_options_free(options);
+    return result;
+}

lib/options.c

@@ -10,6 +10,8 @@ mazeoptions_t* mazemaker_options_new() {
     // set defaults
     memset(result->wall_color, 0, 3);
     memset(result->background_color, 0xff, 3);
+    result->path_color[0] = 0xff;
+    result->path_color[1] = result->path_color[2] = 0;
     result->seed = 0;
     result->seed_set = false;
 
@@ -80,6 +82,10 @@ int mazemaker_options_set_background_color(mazeoptions_t* options, char const* c
     return stringToColor(color_desc, options->background_color);
 }
 
+int mazemaker_options_set_path_color(mazeoptions_t* options, char const* color_desc) {
+    return stringToColor(color_desc, options->path_color);
+}
+
 void mazemaker_options_set_seed(mazeoptions_t* options, rand_seed_t seed) {
     options->seed = seed;
     options->seed_set = true;

lib/options.h

@@ -10,6 +10,7 @@ typedef unsigned int rand_seed_t;
 typedef struct mazeoptions {
     rgb_color_t wall_color;
     rgb_color_t background_color;
+    rgb_color_t path_color;
     rand_seed_t seed;
     bool seed_set;
 } mazeoptions_t;

lib/path.c

@@ -107,3 +107,7 @@ int mazemaker_solve(mazegrid_t const* maze, maze_path_t* path) {
     return code;
 }
 
+void mazemaker_path_free(maze_path_t* path) {
+    path->length = 0;
+    free(path->nodes);
+}

utils/mazemaker.c

@@ -7,7 +7,7 @@ int main(int argc, char* argv[]) {
     char c;
     int width = 0, height = 0;
     unsigned int seed = 0;
-    char const *filename = NULL, *fg_color = NULL, *bg_color = NULL, *seed_str = NULL;
+    char const *filename = NULL, *fg_color = NULL, *bg_color = NULL, *path_color = NULL, *seed_str = NULL, *solution_fn = NULL;
     struct poptOption options_table[] = {
         { "width", 'w', POPT_ARG_INT, &width, 0,
           "Width of the maze", "BLOCKS" },
@@ -17,8 +17,12 @@ int main(int argc, char* argv[]) {
           "Foreground (wall) color", "#rrggbb" },
         { "background", 'b', POPT_ARG_STRING, &bg_color, 0,
           "Background color", "#rrggbb" },
+        { "path", 'p', POPT_ARG_STRING, &path_color, 0,
+          "Path (solution) color", "#rrggbb" },
         { "seed", 's', POPT_ARG_STRING, &seed_str, 0,
           "Random seed", "SEED" },
+        { "solution", 'u', POPT_ARG_STRING, &solution_fn, 0,
+          "Output solution", "FILENAME" },
         POPT_AUTOHELP
         { NULL, 0, 0, NULL, 0 }
     };
@@ -56,12 +60,27 @@ int main(int argc, char* argv[]) {
             exit(1);
         }
     }
+    if (path_color != NULL) {
+        if (0 > mazemaker_options_set_path_color(options, path_color)) {
+            fprintf(stderr, "Unknown color: \"%s\"\n", path_color);
+            exit(1);
+        }
+    }
     if (seed_str != NULL) {
         seed = (unsigned int)atol(seed_str);
         mazemaker_options_set_seed(options, seed);
     }
     mazemaker_generate_maze_opt(width, height, &maze, options);
     mazemaker_maze_to_png_opt(&maze, filename, options);
+    if (solution_fn != NULL) {
+        maze_path_t solution;
+        if (mazemaker_solve(&maze, &solution) == 0) {
+            fprintf(stderr, "Error: no maze solution!\n");
+        } else {
+            mazemaker_path_to_png_opt(&solution, solution_fn, options);
+            mazemaker_path_free(&solution);
+        }
+    }
     mazemaker_free_maze(&maze);
     mazemaker_options_free(options);
     poptFreeContext(ctx);