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GTF0
GRABIT
REPOSITORY STEPS
BUILD THE CODE
- While in your gtf0 directory use the make command to build the code
make gtf0
It is also possible to compile manually
gcc -Wall --std=gnu18 -o gtf0 gtf0.c -lgd
RUN THE PROGRAM
VIEW THE IMAGE
- 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
LIBGD FUNCTIONALITY
MIXING A COLOR
Before anything can be drawn there needs to be a color to draw it in
Colors can be mixed with gdImageColorAllocate
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 googles
DRAWING A LINE
gdImageLine (gdImagePtr im, int x1, int y1, int x2, int y2, int color);
gdImagePtr im is the image the function edits
int x1 is the starting x position of the line
int y1 is the starting y position of the line
int x2 is the ending x position of the line
int y2 is the ending y position of the line
int color is the color the line is drawn as
DRAWING A RECTANGLE
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
FILLING AN ENCLOSED SPACE
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
DRAWING A FILLED RECTANGLE
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
DRAWING A CIRCLE
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
DRAWING A Ellipse
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
