• Create a public html directory with the following command

mkdir -p ~/public_html

• Allow public permissions on the directory with the following

chmod 0711 ~/public_html

• While in your gtf0 directory use the make command to build the code

make

• Using the mv command, move the resulting image from your gtf0 dir to your public html dir

mv gtf0.png ~/public_html

• To allow public viewing of the image use the chmod command

chmod 0644 ~/public_html/gtf0.png

• Finally to see the image go to https://lab46.g7n.org/~USER/gtf0.png
• Replacing USER with your username

gdImageLine (image, x1, y1, x2, y2, color);

x1 and y1 are the starting coordinates and x2 and y2 are the ending coordinates

gdImageFilledRectangle (gdImagePtr im, int x1, int y1, int x2, int y2, int color);

gdImagePtr im is the image the function edits

int x1 is the left bound

int y1 is the upper bound

int x2 is the right bound

int y2 is the lower bound

int color is the color the rectangle is drawn as

Official gdImageFilledRectangle wiki page