cleaned up existing code

images/bmp-format.c

@@ -3,25 +3,21 @@
 #include "images.h"
 
 // write an int to a byte array
-void bmp__write_int(char* bytes, int num) {
+void bmp__write_int(unsigned char* bytes, int num) {
     for (int i = 0; i < 4; i++) {
         bytes[i] = num >> (i * 8);
     }
 }
 
-void bmp__write_byte(char* bytes, int num) {
+void bmp__write_16bit(unsigned char* bytes, int num) {
-    bytes[0] = (char) num;
-}
-
-void bmp__write_16bit(char* bytes, int num) {
     for (int i = 0; i < 2; i++) {
         bytes[i] = num >> (i * 8);
     }
 }
 
-int bmp__align_to_four_bytes(int size) {
+int bmp__align_to_four_bytes(int row_length) {
-    int os = size % 4;
+    int os =row_length % 4;
-    return os == 0 ? size : size + (4 - os);
+    return os == 0 ?row_length : row_length + (4 - os);
 }
 
 int bmp__image_byte_size(Image image) {
@@ -30,9 +26,9 @@ int bmp__image_byte_size(Image image) {
     // BITMAPCOREHEADER = 12 bytes
     int size = 14 + 12;
     // width must be padded to align to 4 bytes
-    int width_bytes = bmp__align_to_four_bytes(image.width * 3); // 3 bytes per pixel
+    int row_bytes = bmp__align_to_four_bytes(image.width * 3); // 3 bytes per pixel
-    // add width_bytes * height to total size
+    // add row_bytes * height to total size
-    size += width_bytes * image.height;
+    size += row_bytes * image.height;
 
     return size;
 }
@@ -50,22 +46,30 @@ int bmp__image_byte_size(Image image) {
 // 0x01 0x00            number of color planes (must be 1)
 // 0x18 0x00            number of bits per pixel (3 * 8 = 24)
 
-int image_save_bmp(Image image, char* path) {
+
+// char* bytes;
+
+// bytes + 2    => zeigt auf offset 2   (ist char*)
+// bytes[2]     => wert an offset 2     (ist char)
+
+int image_save_bmp(Image image, const char* path) {
     int size = bmp__image_byte_size(image);
-    char* bytes = calloc(sizeof(char), size);
+    unsigned char* bytes = calloc(sizeof(char), size);
     // magic bytes, signature "BM"
-    bytes[0] = 0x42;
+    // bmp header:
-    bytes[1] = 0x4d;
+    bytes[0] = 'B';
+    bytes[1] = 'M';
     // write size to header
     bmp__write_int(bytes + 2, size);
     // the next 4 byte are zeros
-    // piyel array offset
+    // pixel array offset
     bmp__write_int(bytes + 10, 14 + 12);
-    bmp__write_int(bytes + 14, 12);
+    // DIB header: 
+    bmp__write_int(bytes + 14, 12);             // header size
     bmp__write_16bit(bytes + 18, image.width);  // width
     bmp__write_16bit(bytes + 20, image.height); // height
-    bmp__write_16bit(bytes + 22, 1);             // color planes
+    bmp__write_16bit(bytes + 22, 1);            // color planes
-    bmp__write_16bit(bytes + 24, 3 * 8);         // bits per pixel
+    bmp__write_16bit(bytes + 24, 3 * 8);        // bits per pixel
 
     int byte_offset = 26;
     int byte_pos = 0;

images/images.c

@@ -12,9 +12,9 @@ int image_new(int width, int height, Image* img) {
     img->width = width;
 
     // initialize bitmap...
-    img->bitmap = malloc(height * sizeof(int*));
+    img->bitmap = malloc(height * sizeof(char*));
     for (int i = 0; i < height; i++) {
-        img->bitmap[i] = malloc(3 * width * sizeof(int));
+        img->bitmap[i] = malloc(3 * width * sizeof(char));
     }
 
     //*image = *img;
@@ -24,9 +24,9 @@ int image_new(int width, int height, Image* img) {
 int image_set_px(Image image, int x, int y, int r, int g, int b) {
     if (!image_check_coords(image, x, y)) return 0;
 
-    image.bitmap[y][(3 * x) + 0] = (char) r;
+    image.bitmap[y][(3 * x) + 0] = r;
-    image.bitmap[y][(3 * x) + 1] = (char) g;
+    image.bitmap[y][(3 * x) + 1] = g;
-    image.bitmap[y][(3 * x) + 2] = (char) b;
+    image.bitmap[y][(3 * x) + 2] = b;
 
     return 1;
 }
@@ -39,13 +39,10 @@ int image_set_px_c(Image image, int x, int y, Color color) {
         image.bitmap[y][(3 * x) + 0] = color.r;
         image.bitmap[y][(3 * x) + 1] = color.g;
         image.bitmap[y][(3 * x) + 2] = color.b;
-    } else { 
+    } else {
-        
+        image.bitmap[y][(3 * x) + 0] = (color.alpha * (color.r)) + ((1.0f - color.alpha) * (image.bitmap[y][(3 * x) + 0]));
-        //printf("adding %d to %f\n",  (color.alpha * color.r), ((1.0f - color.alpha) * (image.bitmap[y][(3 * x) + 0]/*  & 0x000000ff */)));
+        image.bitmap[y][(3 * x) + 1] = (color.alpha * (color.g)) + ((1.0f - color.alpha) * (image.bitmap[y][(3 * x) + 1]));
-
+        image.bitmap[y][(3 * x) + 2] = (color.alpha * (color.b)) + ((1.0f - color.alpha) * (image.bitmap[y][(3 * x) + 2]));
-        image.bitmap[y][(3 * x) + 0] = (color.alpha * (color.r/*  & 0x000000ff */)) + ((1.0f - color.alpha) * (image.bitmap[y][(3 * x) + 0]/*  & 0x000000ff */));
-        image.bitmap[y][(3 * x) + 1] = (color.alpha * (color.g/*  & 0x000000ff */)) + ((1.0f - color.alpha) * (image.bitmap[y][(3 * x) + 1]/*  & 0x000000ff */));
-        image.bitmap[y][(3 * x) + 2] = (color.alpha * (color.b/*  & 0x000000ff */)) + ((1.0f - color.alpha) * (image.bitmap[y][(3 * x) + 2]/*  & 0x000000ff */));
     }
 
     return 1;

images/images.h

@@ -43,7 +43,7 @@ int image_draw_square(Image image, int x, int y, int s, Color color);
 
 
 // bmp format specifics:
-int image_save_bmp(Image image, char* path);
+int image_save_bmp(Image image, const char* path);
 
 #include "images.c"
 #include "bmp-format.c"