The goal for this project is to observe the skeleton code and understand the functions well enough to meet the project objectives listed at the top of this page. Look at the different functions to divulge information about how this graphics library works and revise the code to meet expectations.

Once you are in your class folder you can make a directory for this project using:

mkdir gtf0

After entering the directory you can retrieve the project files like so:

grabit DESIG gtf0

Where DESIG is your class designation (e.g. cprog).

• 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 gtf0

It is also possible to compile manually as such:

gcc -Wall --std=gnu18 -o gtf0 gtf0.c -lgd

gcc is the name of the compiler or collection of compilers used to compile C/C++ code. It can be invoked with the gcc command with flags such as what is shown above.

To run the program you've modified/created, simply invoke it on the command line while in its directory like so:

./gtf0

You should now notice gtf0.png in the directory that you ran the program.

From here, you can move it to your public_html directory for viewing.

• 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

int color = gdImageColorAllocate (gdImagePtr im, int r, int g, int b);

gdImagePtr im is the image the function edits

int r, int g, and int b are the red, green, and blue components of the color. Typically represented as hex values between 0x00 and 0xFF

There are many ways to find a colors hex value, including google's

Official gdImageColorAllocate wiki page

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

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

gdImageRectangle (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 gdImageRectangle wiki page

gdImageFill (gdImagePtr im, int x, int y, int color);

gdImagePtr im is the image the function edits

int x and int y are the coordinates the fill propagates from

int color is the color that is drawn as

Official gdImageFill wiki page

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

gdImageEllipse (gdImagePtr im, int mx, int my, int w, int h, int color);

gdImagePtr im is the image the function edits

int mx and int my is the coordinates of the circle center

int w is the horizontal diameter of the circle

int h is the vertical diameter of the circle

w and h must be the same to create a circle

int color is the color the circle is drawn as

Official gdImageEllipse wiki page

gdImageEllipse (gdImagePtr im, int mx, int my, int w, int h, int color);

gdImagePtr im is the image the function edits

int mx and int my is the coordinates of the ellipse center

int w is the horizontal diameter of the ellipse

int h is the vertical diameter of the ellipse

int color is the color the ellipse is drawn as

Official gdImageEllipse wiki page