pixcan is a convenient header-only "pixel canvas" library based on SDL2. It's a quick and painless way to prototype and experiment with graphics programming in C. While designed primarily for educational use, it's straightforward enough for those familiar with SDL2 to add user input, audio, and more.

For the impatient:

1. #include "pixcan.h".
2. Call pixcan_init.
3. Modify the pixcan_size-sized buffer of RGBA8 pixels pointed to by pixcan.
4. Call pixcan_update to synchronize the buffer with the screen.
5. Call pixcan_poll in a loop to keep the window open until Escape is pressed.
6. Compile with cc sdl-config --cflags -o <program> <program>.c -lSDL2 -lm.

unsigned int pixcan_width The width, in pixels, of the canvas.

unsigned int pixcan_height The height, in pixels, of the canvas.

unsigned int pixcan_size The size, in pixels, of the canvas. Equivalent to pixcan_width * pixcan_height.

uint32_t * pixcan A pointer to pixcan_size uint32_ts, each one pixel on the canvas in row-major order. See Notes.

void pixcan_init( char * title, unsigned int width, unsigned int height ) Initializes the canvas, opening a new width-by-height window with the provided title.

void pixcan_quit() Closes the window, deallocates all of pixcan's resources, and terminates the program.

pixcan_at( x, y ) A macro that expands to pixcan[ ( x ) + ( y ) * pixcan_width ]. See Notes.

uint32_t pixcan_color( uint8_t r, uint8_t g, uint8_t b ) Given red, green, and blue byte values, returns a pixel suitable for storage in pixcan.

void pixcan_update() Synchronizes the contents of the window with the pixel buffer pixcan.

bool pixcan_poll() Keeps the window open until Escape is pressed or the window is closed.

void pixcan_wait( double seconds ) Keeps the window open for roughly seconds seconds unless Escape is pressed or the window is closed.

• Internally, pixcan actually uses ABGR8888. However, because your computer is little-endian, the buffer's arrangement in memory is a more reasonable R, G, B, A, meaning you can cast pixcan to a uint8_t * without surprises.
• Because pixcan_at is a macro, it can be used idiomatically as an lvalue. That is, you can write

pixcan_at( x, y ) = pixcan_color( r, g, b );

• This README is longer than pixcan.h itself. Go read it instead.

http://gigi.nullneuron.net/gigilabs/sdl2-pixel-drawing/