Erlang PiXel library

epx is a library for manipulating pixels. Various operation exist to operate on the pixels.

To create a small pixmap and set some pixels you do not even have to start the epx application, just do:

Pixmap = epx:pixmap_create(10, 10, rgb),
epx:pixmap_fill(Pixmap, red),
epx_pixmap_put_pixel(Pixmap, 4, 4, white).

Now you can read the pixels:

{A,R,G,B} = epx:pixmap_get_pixel(Pixmap, 3, 3).
<<R,G,B>> = epx:pixmap_get_pixels(Pixmap, 3, 3, 1, 1).

Available backend parameters for backend_open / backend_adjust / window_adjust

x11 backend

x11_display             string
use_opengl              bool|int       0|1    (0)
use_off_screen          bool|int       0|1    (1)
use_expsure             bool|int       0|1    (0)

x11 window

x                       int
y                       int
width                   int
height                  int
border_width            int
show                    int            0|1
select                  int            0|1
min_width               int
minheight               int
max_width               int
max_height              int
name                    string

%% macos backend (cocoa)

use_opengl              int            0|1  (0)

macos window

width                   int
height                  int
show                    bool|int       0|1
select                  bool|int       0|1

fb backend

framebuffer_device      string    (/dev/fb0)
direct_pixmap_draw	    bool|int   0|1  (0)
double_buffer	        bool|int   0|1  (1)
lcd_pi32		        bool|int   0|1  (0)
input_mouse_device      string
input_keyboard_device   string
input_absolute_device   string
input_relative_device   string

width 	    	    int
virt_width		    int
height		        int
virt_height		    int
pixel_format	    string
pixel_type		    int
pixclock		    int
xoffset		        int
yoffset		        int
left_margin		    int
right_margin        int
upper_margin        int
lower_margin	    int
hsync_len		    int
vsync_len		    int
sync		        uint
vmode		        uint

epx on frame buffer device (linux)

epx:debug(debug).
epx:start().
{ok, BID } = epx_backend:create("fb", [{backend,"fb"}, {width, 1280}, {height, 1024}, {input_mouse_device, "/dev/input/event7"}, {input_keyboard_device, "/dev/input/event5"}]).
B = epx_backend:backend(BID).
W=epx:window_create(0,0,1280,1024, [button_press, key_press, key_release]).
epx:window_attach(W, B).

howto run framebuffer on vmware (ubuntu)

Append "vmwgfx.enable_fbdev=no" to GRUB_CMDLINE_LINUX_DEFAULT in file /etc/default/grub. "no" is not a correct value, driver will complain. But this is a bug workaround :-)

May look something like this:

GRUB_CMDLINE_LINUX_DEFAULT="splash quiet vmwgfx.enable_fbdev=no"

Then the fb driver may be probed:

sudo modprobe uvesafb

Packages needed to build epx using top-level Makefile on Raspberry pi and Ubuntu

sudo apt-get install libx11-dev autoconf libgif-dev