Comments added$

pgm.c

 #include "pgm.h"
 
+
+/**
+ * pgm_read_from_file reads a pgm file and fills the pgm struct "p" with its data
+ * @param p is a pointer of pgm struct
+ * @param filename is a pointer of characters representing the path of the targeted file
+ * @return pgm_error
+**/
 pgm_error pgm_read_from_file(pgm *p, char *filename){
     if (filename == NULL || p == NULL){
         return failure;
@@ -23,6 +30,13 @@ pgm_error pgm_read_from_file(pgm *p, char *filename){
     return success;
 }
 
+
+/**
+ * pgm_write_to_file creates a pgm file from a pgm struct with a custom name
+ * @param p is a pointer of pgm struct
+ * @param filename is a pointer of characters that defines the custom file name
+ * @return pgm_error
+**/
 pgm_error pgm_write_to_file(pgm *p, char *filename){
     if (filename == NULL || p == NULL){
         return failure;
@@ -45,6 +59,13 @@ pgm_error pgm_write_to_file(pgm *p, char *filename){
     return success;
 }
 
+
+/**
+ * pgm_negative modifies an empty pgm struct with a negative version of the original one
+ * @param neg is a pointer of pgm struct which contains the negative version
+ * @param orig constant pointer of pgm which is the original pgm
+ * @return pgm_error
+**/
 pgm_error pgm_negative(pgm *neg, const pgm *const orig){
     if (neg == NULL || orig == NULL){
         return failure;
@@ -61,6 +82,13 @@ pgm_error pgm_negative(pgm *neg, const pgm *const orig){
     return success;
 }
 
+
+/**
+ * pgm_symmetry_hori modifies an empty pgm struct with a horizontal symmetric version of the original one
+ * @param sym is a pointer of pgm struct which contains the modified version
+ * @param orig constant pointer of pgm which is the original pgm
+ * @return pgm_error
+**/
 pgm_error pgm_symmetry_hori(pgm *sym, const pgm *const orig){
     if (sym == NULL || orig == NULL){
         return failure;
@@ -77,6 +105,13 @@ pgm_error pgm_symmetry_hori(pgm *sym, const pgm *const orig){
     return success;
 }
 
+
+/**
+ * pgm_symmetry_vert modifies an empty pgm struct with a vertical symmetric version of the original one
+ * @param sym is a pointer of pgm struct which contains the modified version
+ * @param orig constant pointer of pgm which is the original pgm
+ * @return pgm_error
+**/
 pgm_error pgm_symmetry_vert(pgm *sym, const pgm *const orig){
      if (sym == NULL || orig == NULL){
         return failure;
@@ -93,6 +128,13 @@ pgm_error pgm_symmetry_vert(pgm *sym, const pgm *const orig){
     return success;
 }
 
+
+/**
+ * pgm_symmetry_cent modifies an empty pgm struct with a central symmetric version of the original one
+ * @param sym is a pointer of pgm struct which contains the modified version
+ * @param orig constant pointer of pgm which is the original pgm
+ * @return pgm_error
+**/
 pgm_error pgm_symmetry_cent(pgm *sym, const pgm *const orig){
      if (sym == NULL || orig == NULL){
         return failure;
@@ -109,6 +151,13 @@ pgm_error pgm_symmetry_cent(pgm *sym, const pgm *const orig){
     return success;
 }
 
+
+/**
+ * pgm_photomaton modifies an empty pgm struct with a x4 photomaton version of the original one
+ * @param photomaton is a pointer of pgm struct which contains the modified version
+ * @param orig constant pointer of pgm which is the original pgm
+ * @return pgm_error
+**/
 pgm_error pgm_photomaton(pgm *photomaton, const pgm *const orig){
     if (photomaton == NULL || orig == NULL){
         return failure;
@@ -134,6 +183,19 @@ pgm_error pgm_photomaton(pgm *photomaton, const pgm *const orig){
     return success;
 }
 
+
+/**
+ * pgm_crop modifies an empty pgm struct with a cropped version of the original one depending on bounds
+ * @param crop is a pointer of pgm struct which contains the cropped version
+ * @param orig constant pointer of pgm which is the original pgm
+ * @param x0 is the lower x axis bound
+ * @param x1 is the upper x axis bound
+ * @param y0 is the lower y axis bound
+ * @param y1 is the upper y axis bound
+ * @return pgm_error
+ * 
+ * WARNING: this function doesn't work properly, only squared bounds make it work
+**/
 pgm_error pgm_crop(pgm *crop, const pgm *const orig, int32_t x0, int32_t x1, int32_t y0, int32_t y1){
     if (crop == NULL || orig == NULL){
         return failure;
@@ -147,6 +209,14 @@ pgm_error pgm_crop(pgm *crop, const pgm *const orig, int32_t x0, int32_t x1, int
     return success;
 }
 
+
+/**
+ * add_zeros_in_pgm modifies an empty pgm struct with a "zero bordered" version of the original one
+ * Used to avoid edge problems when calculating convolutions
+ * @param zeroedPgm is a pointer of pgm struct which contains the "zero bordered" version
+ * @param orig constant pointer of pgm which is the original pgm
+ * @return pgm_error
+**/
 pgm_error add_zeros_in_pgm(pgm *zeroedPgm, const pgm *const orig){
     if (zeroedPgm == NULL || orig == NULL){
         return failure;
@@ -169,6 +239,15 @@ pgm_error add_zeros_in_pgm(pgm *zeroedPgm, const pgm *const orig){
     return success;
 }
 
+
+/**
+ * calculate_pixel_conv calculates the convoluted version of a pixel using a sub matrix from 
+ * an image and a kernel
+ * @param m is a matrix containing pixels from an image
+ * @param kernel constant pointer of matrix containing values to calcuate a convolution
+ * @param max represents the maximum value of a pixel
+ * @return result
+**/
 int calculate_pixel_conv(const matrix m, const matrix *const kernel, int max){
     int result = 0;
 
@@ -184,6 +263,15 @@ int calculate_pixel_conv(const matrix m, const matrix *const kernel, int max){
     return result;
 }
 
+
+/**
+ * pmg_conv modifies an empty pgm struct with a "convoluted" version of the original one depending on a kernel
+ * @param conv is a pointer of pgm which contains the "convoluted" version
+ * @param orig constant pointer of pgm which is the original pgm
+ * @param kernel constant pointer of matrix containing values to calcuate a convolution
+ * @param norm double number added to modify convolution "behaviour"
+ * @return pgm_error
+**/
 pgm_error pmg_conv(pgm *conv, const pgm *const orig, const matrix *const kernel, double norm){
     if (conv == NULL || orig == NULL || kernel == NULL){
         return failure;
@@ -203,8 +291,14 @@ pgm_error pmg_conv(pgm *conv, const pgm *const orig, const matrix *const kernel,
     return success;
 }
 
+
+/**
+ * demo uses SDL2 library to display an image on a window
+ * @param img is a constant pointer of the pgm displayed on screen 
+ * @return pgm_error
+**/
 pgm_error demo(const pgm *const img){
-    int width = img->pixels.l, height = img->pixels.c;
+    int width = img->pixels.c, height = img->pixels.l;
 	struct gfx_context_t *ctxt = gfx_create("Example", width, height);
 
     while (gfx_keypressed() != 27/*ESC btn code*/) {

pgm_main.c

 #include "pgm.h"
 
 int main(){
+    //variables initialization
     pgm a;
     pgm neg;
     pgm sym_hori;
@@ -12,50 +13,52 @@ int main(){
     pgm pgmWithZeros;
     pgm convolution;
 
-
-
     int conv[9] = {1,1,1,1,1,1,1,1,1};
     matrix convKernel;
     matrix_init_from_array(&convKernel, 3, 3, conv, 9);
 
+
+    //Read pgm
     printf("%d", pgm_read_from_file(&a, "mandrill.pgm"));
-    //printf("%d", pgm_write_to_file(&a, "newf.pgm"));
 
+    //Negative
     printf("%d", pgm_negative(&neg, &a));
-    //printf("%d", pgm_write_to_file(&neg, "neg.pgm"));
 
+    //horizontal symmetry
     printf("%d", pgm_symmetry_hori(&sym_hori, &a));
-    //printf("%d", pgm_write_to_file(&sym_hori, "sym_hori.pgm"));
 
+    //vertical symmetry
     printf("%d", pgm_symmetry_vert(&sym_vert, &a));
-    //printf("%d", pgm_write_to_file(&sym_vert, "sym_vert.pgm"));
 
+    //central symmetry
     printf("%d", pgm_symmetry_cent(&sym_cent, &a));
-    //printf("%d", pgm_write_to_file(&sym_cent, "sym_cent.pgm"));
 
+    //Photomaton x4
     printf("%d", pgm_photomaton(&photomatonx4, &a));
-    //printf("%d", pgm_write_to_file(&photomatonx4, "photomatonx4.pgm"));
 
+
+    //Photomaton x16
     printf("%d", pgm_photomaton(&photomatonx16, &photomatonx4));
-    //printf("%d", pgm_write_to_file(&photomatonx16, "photomatonx16.pgm"));
 
+    //Crop
     printf("%d", pgm_crop(&cropped, &a, 100, 200, 200, 500));
-    //printf("%d", pgm_write_to_file(&cropped, "cropped.pgm"));
 
+    //Convolution
     printf("%d", add_zeros_in_pgm(&pgmWithZeros, &a));
     printf("%d", pmg_conv(&convolution, &pgmWithZeros, &convKernel, 1));
-    //printf("%d", pgm_write_to_file(&convolution, "convolution.pgm"));
 
 
-    //demo(&neg);
-    //demo(&sym_hori);
-    //demo(&sym_vert);
-    //demo(&sym_cent);
-    //demo(&photomatonx4);
-    //demo(&photomatonx16);
-    //demo(&cropped);
-    //demo(&convolution);
+    demo(&neg);
+    demo(&sym_hori);
+    demo(&sym_vert);
+    demo(&sym_cent);
+    demo(&photomatonx4);
+    demo(&photomatonx16);
+    demo(&cropped);
+    demo(&convolution);
+
 
+    //Destroying pgm's matrixes
     matrix_destroy(&a.pixels);
     matrix_destroy(&neg.pixels);
     matrix_destroy(&sym_hori.pixels);