feat: change orientation (#7)

* feat: change orientation (wip)

* wip

* working rotation

* small fix in help

README.md

@@ -22,7 +22,7 @@ make clean build install
 ## CLI arguments
 
 ```txt
-usage: margen [--help] [-v] [-q] [-w=WIDTH] [-h=HEIGHT] [-o=PATH] [--seed=SEED][-p=PIXEL_SIZE] [-s=SLOPE] [-c=R,G,B] [--var=R,G,B] [-vr=VAR_RANGE]
+usage: margen [--help] [-v] [-q] [-w=WIDTH] [-h=HEIGHT] [-o=PATH] [--seed=SEED][-p=PIXEL_SIZE] [-s=SLOPE] [-c=R,G,B] [-va=R,G,B] [-vr=VAR_RANGE] [-r=ROTATION]
 
 generate a marble-like pattern bitmap image, blazing fast.
 
@@ -38,9 +38,9 @@ options:
   -c, --color        base color [0-255,0-255,0-255] (default: random)
   -va, --variation   fixed variation [0-255,0-255,0-255] (default: random)
   -vr, --var-range   random variation range [0-255] (default: 30)
+  -r, --rotation     start corner rotation [0-3] (default: random)
 ```
 
 ## TODO
 
 - fix monochrome
-- select corner (currently bottom left)

src/args.c

@@ -20,8 +20,9 @@ void print_help(int status_code) {
        "[-p=PIXEL_SIZE] "
        "[-s=SLOPE] "
        "[-c=R,G,B] "
-       "[--var=R,G,B] "
+       "[-va=R,G,B] "
        "[-vr=VAR_RANGE] "
+       "[-r=ROTATION] "
        //  "[-m]"
        "\n\n"
        "generate a marble-like pattern bitmap image, blazing fast.\n\n"
@@ -38,6 +39,7 @@ void print_help(int status_code) {
        "  -va, --variation   fixed variation [0-255,0-255,0-255] (default: "
        "random)\n"
        "  -vr, --var-range   random variation range [0-255] (default: 30)\n"
+       "  -r, --rotation    start corner rotation [0-3] (default: random)\n"
        //  "  -m, --monochrome   black & white generation\n"
   );
   exit(status_code);
@@ -131,6 +133,7 @@ parameters parse_args(int argc, char **argv) {
   bool slope_set = false;
   bool start_set = false;
   bool var_set = false;
+  bool rot_set = false;
 
   int i;
   char *arg;
@@ -182,8 +185,11 @@ parameters parse_args(int argc, char **argv) {
       var_set = true;
     } else if (is_arg(arg, "-vr") || is_arg(arg, "--var-range")) {
       var_range = parse_char(arg, value);
-      // } else if (is_arg(arg, "-m") || is_arg(arg, "--monochrome")) {
-      //   params.monochrome = true;
+    } else if (is_arg(arg, "-r") || is_arg(arg, "--rotation")) {
+      params.rotation = parse_char(arg, value) % 4;
+      rot_set = true;
+    } else if (is_arg(arg, "-m") || is_arg(arg, "--monochrome")) {
+      params.monochrome = true;
     } else {
       invalid_arg(arg);
     }
@@ -216,5 +222,9 @@ parameters parse_args(int argc, char **argv) {
     params.var[2] = rand_uchar(var_range);
   }
 
+  if (!rot_set) {
+    params.rotation = rand_uchar(4);
+  }
+
   return params;
 }

src/bmp.c

@@ -75,7 +75,7 @@ void bmp_data_line(unsigned char *buffer, unsigned short width,
 }
 
 void bmp_generate(unsigned short width, unsigned short height,
-                  unsigned char color_depth, char *file_path,
+                  unsigned char color_depth, bool descending, char *file_path,
                   line_fn generate_line) {
   FILE *fptr;
   fptr = fopen(file_path, "w");
@@ -84,14 +84,17 @@ void bmp_generate(unsigned short width, unsigned short height,
   free(header);
   unsigned int data_length =
       ((unsigned int)width) * ((unsigned int)color_depth);
-  unsigned short y;
+  unsigned int line_length = bmp_data_line_length(width, color_depth);
   unsigned char *data_buffer = (unsigned char *)malloc(data_length);
-  unsigned char *line_buffer =
-      (unsigned char *)malloc(bmp_data_line_length(width, color_depth));
+  unsigned char *line_buffer = (unsigned char *)malloc(line_length);
+  unsigned short y;
   for (y = 0; y < height; y++) {
-    generate_line(height - y - 1, data_buffer, data_length);
+    generate_line(y, data_buffer, data_length);
     bmp_data_line(line_buffer, width, color_depth, data_buffer);
-    fwrite(line_buffer, bmp_data_line_length(width, color_depth), 1, fptr);
+    if (descending) {
+      fseek(fptr, HEADER_SIZE + (height - y - 1) * line_length, SEEK_SET);
+    }
+    fwrite(line_buffer, line_length, 1, fptr);
   }
   free(line_buffer);
   free(data_buffer);

src/bmp.h

@@ -4,7 +4,7 @@
 #define BMP_H
 
 void bmp_generate(unsigned short width, unsigned short height,
-                  unsigned char color_depth, char *file_path,
+                  unsigned char color_depth, bool descending, char *file_path,
                   line_fn generate_line);
 
 #endif

src/generator.c

@@ -43,12 +43,13 @@ void generate_bmp_line(unsigned short y, unsigned char *data_buffer,
                        unsigned int len) {
   unsigned int i;
   unsigned int x;
-  if (y > 0 && (y % global_params.size) == 0) {
+  if (y % global_params.size == 0) {
     generate_line();
   }
   for (i = 0; i < len; i++) {
     x = i / (color_depth * global_params.size);
-    data_buffer[i] = current_line[x * color_depth + (i % color_depth)];
+    data_buffer[(global_params.rotation / 2) == 1 ? i : (len - i - 1)] =
+        current_line[x * color_depth + (i % color_depth)];
   }
 }
 
@@ -68,6 +69,7 @@ void debug_parameters(parameters params) {
       printf("  var.    %u,%u,%u\n", params.var[0], params.var[1],
              params.var[2]);
     }
+    printf("  rot.    %d\n", params.rotation);
   }
 }
 
@@ -84,7 +86,6 @@ void init(parameters params) {
     current_line[i] = params.start[i % color_depth];
   }
   set_seed(params.seed);
-  generate_line();
 }
 
 void clean() {
@@ -105,8 +106,8 @@ void generate(parameters params) {
   }
   clock_t start = clock();
   init(params);
-  bmp_generate(params.width, params.height, color_depth, params.file_path,
-               generate_bmp_line);
+  bmp_generate(params.width, params.height, color_depth,
+               params.rotation % 2 == 1, params.file_path, generate_bmp_line);
   clean();
   print_time(params, start);
 }

src/types.h

@@ -14,6 +14,7 @@ struct Parameters {
   unsigned char slope;
   unsigned char start[3];
   unsigned char var[3];
+  unsigned char rotation;
 };
 
 typedef struct Parameters parameters;