pzl / libovg

Drawing library based on OpenVG and OpenGL to draw on either X11 or Raspberry Pi's DispmanX

LibOVG

LibOVG is a thin drawing library on top of OpenVG. It is designed to allow unified drawing commands between platforms (Raspberry Pi, BeagleBone, pcDuino, ...) and allowing for development on a desktop or laptop of choice. It can be run on these embedded devices without an X11 environment, greatly improving speed of your application. On your development machine, you can debug and preview your graphics with X running!

Requirements

OpenVG

On embedded devices like the Raspberry Pi, this should come pre-installed. For development environments (e.g. your laptop), support is provided through the ShivaVG project, which implements OpenVG API on top of OpenGL.

Installation

make
sudo make install

Usage

Simple example usage is provided below. You can compile with gcc -o ovg_demo temp.c -l ovg and run with ./ovg_demo. You should get a yellowish rectangle at the bottom of the screen that appears.

#include <stdio.h>
#include <ovg.h>

int main(int argc, char **argv) {
    Path rect;

    ovg_init(); //initialize OpenGL contexts, etc

    ovg_open(0,0,400,400); //open a 400x400 window at 0,0 on your monitor

    ovg_fill(255,200,128,255);     //R,G,B,A
    rect = ovg_rect(76,50,200,90); //X,Y,W,H

    //perform the drawing commands
    ovg_draw_path(rect, FILL_PATH);
    ovg_draw();


    getchar(); //quick way to pause and wait for user input. press enter to close

    ovg_cleanup(); //properly destroy windows and release memory

    return 0;
}

Filename Conventions

any filename ending in _pi.c or _x11.c will only get compiled on their target platforms. all other filenames get compiled for all targets.