// Copyright Spinochi Andreea - 312CA

...............................................................................

This project was about creating an image editor for PGM and ppm files,
so I started it by creating two structs: one that contains the initial
values of the image(width, height, coloration) and one that contains the
values of the pixels. I added an enumeration used to check if the image is
colored or uncolored. In the main part of the program, I used the repetitive
instruction while for reading the commands and calling the associated
functions.

...............................................................................

->read_command function was used to read every command introduced from stdin

->LOAD <file> command calls the load_file function which loads the file in the
memory. If there's another image loaded, the function deallocates the memory
for it and it closes the file, so it can make space for the new one. First of
all, the function opens the file and allocates memory for the matrix of pixels.
If the magic word is P2 or P3 the file is loaded in an ASCII format, otherwise
if the magic word is P5 or P6 the file is loaded in a BINARY format. Using the
function load_ASCII the matrix is read from an ASCII file and using the
function load_BINARY the matrix is read from a BINARY file. For the binary one,
I saved the position of the cursor in the file, closed it and then reopened it
for binary. Then I returned to the saved position of the cursor and started
reading the matrix. Also, if there are commented lines in the file, I used
the skiplines function to skip the line.

->SELECT ALL command calls the SELECT__ALL function used to select the
coordinates for the edges of the image.

->SELECT <x1> <y1> <x2> <y2> command calls the SELECT function which swaps the
coordinates if there are not in order(x1 should be smaller than x2 and y1
should be smaller than y2). Then, it checks if there is an image loaded. If
it is and the coordinates to be selected are negative numbers, exceed the
bounds of the image or are equal, it means that they are invalid, otherwise if
they are valid, the old coordinates are changed with the new ones.

---check_selection--- this function checks if the selected coordinates are
numbers. If there aren't numbers, it means that the coordinates aren't valid,
so the selection won't be made.

->ROTATE <angle> command calls the ROTATE function which checks if the image is
loaded or not and then if the matrix to be rotated is the full image or just a
portion. If the matrix is just a rectangular portion of the image the rotation
can't be made. If the angle is found among the ones permitted, the matrix will
be rotated. The function ROTATE_angle allocates the memory for the auxiliary
matrix. After that, the full matrix will be copied in the auxiliary one. If the
matrix is rectangular, I deallocated the memory and allocated it again with the
lines and columns switched and then I switched the initial values of the lines
and columns. Then, I rotated the image and in the end, I saved the bounds so they
won't be lost and deallocated the memory for the auxiliary matrix.

->CROP command calls the CROP_image function that crops the image and resets
the initial bounds of the image. This function checks if any image is loaded and
if it is the new bounds of the image are stored. The memory for the auxiliary
matrix is allocated and I copied the cropped matrix in the auxiliary one. Then
I deallocated the memory for the initial matrix. After deallocating the memory,
I copied the cropped matrix into the initial matrix, updated the bounds of
the image and modified the selection with the updated bounds.

->APPLY <parameter> command calls the APPLY function that puts filters on the
image. I allocated the memory for the auxiliary matrix used to apply the
filters. Then I copied the initial matrix into the auxiliary one and applied
the filters by multiplying every pixel of the auxiliary matrix with the ones
found in the kernel. Every multiplication is then added to every pixel of the
auxiliary matrix and this sum is now the new value of the pixel of the image.
Then the memory for the auxiliary matrix is deallocated.

---check_apply--- this function checks if the apply command is valid and
calls the function that applies the filters if it is.

->SAVE <file_name> |ascii| command calls the SAVE_ascii or SAVE_binary
function, depending on the existence of the parameter ASCII. I opened the file
which should hold the modified image, wrote the colorization, width, height and
the max value of the matrix and then the pixels for the image, saved and then
closed the file.

->EXIT command calls the function EXIT and is used to exit the program
gracefully. It deallocates the memory for the image, closes the file and
exits the program.