Easyppm

Simple PBM/PGM/PPM image library for C/C++ programs. Use make to run test code with gcc. Check out the Makefile for more. For more information on the PPM image format, check out the Wikipedia page.

The API is fairly simple, and consists of the following functions:

easyppm_create

Takes width, height, and image type. Supported image types are IMAGETYPE_PBM (black and white), IMAGETYPE_PGM (greyscale), and IMAGETYPE_PPM (color).

PPM ppm = easyppm_create(256, 256, IMAGETYPE_PPM);

easyppm_clear

Fills the entire image with the specified color.

easyppm_clear(&ppm, easyppm_rgb(255, 0, 0)); // Red

easyppm_set

Sets pixel at (x,y) to specified color. Origin defaults to upper-left corner.

easyppm_set(&ppm, 0, 0, easyppm_rgb(255, 0, 0));

easyppm_get

Gets pixel at (x,y).

color c = easyppm_get(&ppm, 0, 0);

easyppm_rgb

Returns RGB representation of a color for use in PPM (color) images. Values range from 0 to 255. Attempting to set a pixel in a non-PPM (i.e. PBM/PGM) image using this function will result in a runtime error.

color c = easyppm_rgb(255, 0, 0); // Red

easyppm_grey

Returns the greyscale representation of a color for use in PGM (greyscale) images. Values range from 0 to 255. Attempting to set a pixel in a non-PGM (i.e. PBM/PPM) image will result in a runtime error.

color c = easyppm_grey(128); // Grey

easyppm_black_white

Returns the black-and-white representation of a color for use in PBM (black-and-white) images. Values include 0 (white) and 1 (black). Attempting to set a pixel in a non-PBM (i.e. PGM/PPM) image will result in a runtime error.

color c = easyppm_black_white(0); // White

easyppm_gamma_correct

Gamma-correct entire image by specified amount.

easyppm_gamma_correct(&ppm, 2.2f);

easyppm_invert_y

Invert image across y-axis. Note that this does NOT change the origin from the upper-left corner to the lower-left corner; subsequent calls to easyppm_get() and easyppm_set() will still be relative to the upper-left corner. However, this is useful as a final step before sending the image to a system with a different origin (e.g. OpenGL).

easyppm_invert_y(&ppm);

easyppm_read

Reads non-binary PBM/PGM/PPM images from disk and stores them in the given PPM struct. Because this currently requires max channel values of 255 and one pixel per line, it will likely not work correctly for images not created using easyppm (this is something I hope to address soon).

easyppm_read(&ppm, "image.ppm");

easyppm_write

Writes non-binary PBM/PGM/PPM images to disk from the given PPM struct.

easyppm_write(&ppm, "image.ppm");

easyppm_destroy

Frees all resources.

easyppm_destroy(&ppm);