Provided by: libg15daemon-client1t64_1.9.5.3-14.1build1_amd64 
NAME g15daemon_client - G15Daemon Server / Client communication for g15daemon.
SYNOPSIS
#include <libg15.h>
#include <g15daemon_client.h>
link with
-lg15daemon_client
int new_g15_screen(int screentype);
int g15_close_screen(int sock);
int g15_send(int sock, char *buf, unsigned int len);
int g15_recv(int sock, char *buf, unsigned int len);
int g15_send_cmd (int sock, unsigned char command, unsigned char value);
G15Daemon Server / Client communication
G15Daemon uses INET sockets to talk to its clients, listening on localhost port 15550 for connection
requests. Once connected, the server sends the text string "G15 daemon HELLO" to confirm to the client
that it is a valid g15daemon process, creates a new screen, and waits for LCD buffers or commands to be
sent from the client. Clients are able to create multiple screens simply by opening more socket
connections to the server process. If the socket is closed or the client exits, all LCD buffers and the
screen associated with that socket are automatically destroyed.
Clients wishing to display on the LCD must send entire screens in the format of their choice. Currently
partial screen updates (icons etc) are not supported.
G15Daemon commands are sent to the daemon via the OOB (out-of-band) messagetype, replies are sent inband
back to the client.
int new_g15_screen(int screentype)
Opens a new connection and returns a network socket for use. Creates a screen with one of the following
pixel formats defined in g15daemon_client.h:
G15_PIXELBUF: this buffer must be exactly 6880 bytes, and uses 1 byte per pixel.
G15_TEXTBUF: currently ignored by the daemon.
G15_WBMPBUF: this is a packed pixel buffer in WBMP format with 8 pixels per byte. Useful for perl
programmers using the GD:: and G15Daemon.pm (see lang_bindings directory) perl modules.
G15_G15RBUF: another packed pixel buffer type, also with 8 pixels/byte, and is the native libg15render
format.
Example of use:
int screen_fd = new_g15_screen( G15_WBMPBUF );
int g15_close_screen (int screen_fd)
Simply closes a socket previously opened with new_g15_screen(). The daemon will automatically clean up
any buffers and remove the LCD screen from the display list.
Returns 0 if successful, or errno if there was an error.
Example:
int retval = 0; int screen_fd = new_g15_screen( G15_WBMPBUF );
... do processing and display here ...
retval = g15_close_screen( screen_fd );
int g15_send (int sock, char *buf, unsigned int len)
A simple wrapper around send() to ensure that all 'len' bytes of data is sent to the daemon. It simply
uses poll() to block until the entire message is sent.
Returns 0 on success, -1 if the send failed due to timeout or socket error.
int g15_recv (int sock, char *buf, unsigned int len)
A simple wrapper around recv() to ensure that all 'len' bytes of data are received from the daemon. It
simply uses poll() to block until the entire message is received.
Returns 0 on success, -1 if the recv failed due to timeout or socket error.
int g15_send_cmd ( int sock, unsigned char command, unsigned char value)
Sends a command to the daemon (possible commands are listed below). Returns 0 or the return value of the
command on success, -1 on failure.
See examples for usage.
G15Daemon Command Types
Commands and requests to the daemon are sent via OOB data packets. Changes to the backlight and mkey
state will only affect the calling client. The following commands are supported as defined in
g15daemon_client.h:
G15DAEMON_KEY_HANDLER
Requests that all M and G key presses are sent to this client. All keys are packed into an
unsigned int, and sent to the client inband when a key is pressed.
G15DAEMON_MKEYLEDS
Sets the M key LED state. In order to change LED state, each LED that is to be turned on is OR'd
with the command byte. See libg15.h for values. For examples see the end of this document.
G15DAEMON_BACKLIGHT
Sets the LCD Backlight brightness. Brightness level (0|1|2) is OR'd with the command byte. For
examples see the end of this document.
G15DAEMON_CONTRAST
Sets the LCD contrast. Contrast level (0|1|2) is OR'd with the command byte. For examples see
the end of this document.
G15DAEMON_GET_KEYSTATE
Requests a packet containing the current keystate. The daemon will return an unsigned int
containing any keys pressed. See libg15.h for details on key values, and lcdclient_test.c in the
source distribution for an example.
G15DAEMON_SWITCH_PRIORITIES
Toggles the client's LCD screen to/from the front. Clients can check their foreground/background
state with the following:
G15DAEMON_IS_FOREGROUND
On reciept of this command, G15Daemon will send a 1 byte packet back with the value 1 if the
client is foreground, or 0 if not.
G15DAEMON_IS_USER_SELECTED
On reciept of this command, G15daemon will return a byte indicating if the user selected the
client be foreground or background.
EXAMPLES
Below is a completely nonsensical client which (poorly) demonstrates the usage of most of the commands.
--- Cut here ---
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <errno.h>
#include <poll.h>
#include <g15daemon_client.h>
#include <libg15.h>
/* #define TEST_KEYHANDLER */
int main(int argc, char *argv[]) {
int g15screen_fd, retval;
char lcdbuffer[6880];
unsigned int keystate;
char msgbuf[256];
int foo = 0;
if((g15screen_fd = new_g15_screen(G15_PIXELBUF))<0){
printf("Sorry, cant connect to the G15daemon0);
return 5;
}else
printf("Connected to g15daemon. sending image0);
if(argc<2)
retval = g15_send(g15screen_fd,(char*)logo_data,6880);
else {
memset(lcdbuffer,0,6880);
memset(lcdbuffer,1,6880/2);
retval = g15_send(g15screen_fd,(char*)lcdbuffer,6880);
}
printf("checking key status - press G1 to exit0,retval);
while(1){
keystate = 0;
int foo;
keystate = g15_send_cmd (g15screen_fd, G15DAEMON_GET_KEYSTATE, foo);
if(keystate)
printf("keystate = %i0,keystate);
if(keystate & G15_KEY_G1) //G1 key. See libg15.h for details on key values.
break;
/* G2,G3 & G4 change LCD backlight */
if(keystate & G15_KEY_G2){
retval = g15_send_cmd (g15screen_fd, G15DAEMON_BACKLIGHT, G15_BRIGHTNESS_DARK);
}
if(keystate & G15_KEY_G3){
retval = g15_send_cmd (g15screen_fd, G15DAEMON_BACKLIGHT, G15_BRIGHTNESS_MEDIUM);
}
if(keystate & G15_KEY_G4){
retval = g15_send_cmd (g15screen_fd, G15DAEMON_BACKLIGHT, G15_BRIGHTNESS_BRIGHT);
}
/* is this client in the foreground?? */
retval = g15_send_cmd (g15screen_fd, G15DAEMON_IS_FOREGROUND, foo);
if(retval)
printf("Hey, we are in the foreground, Doc0);
else
printf("What dastardly wabbit put me in the background?0);
retval = g15_send_cmd (g15screen_fd, G15DAEMON_IS_USER_SELECTED, foo);
if(retval)
printf("You wanted me in the foreground, right Doc?0);
else
printf("You dastardly wabbit !0);
if(retval){ /* we've been backgrounded! */
sleep(2); /* remain in the background for a bit */
retval = g15_send_cmd (g15screen_fd, G15DAEMON_SWITCH_PRIORITIES, foo);
sleep(2); /* switch to foreground */
retval = g15_send_cmd (g15screen_fd, G15DAEMON_SWITCH_PRIORITIES, foo);
}
usleep(500); #ifdef TEST_KEYHANDLER
/* ok.. request that all G&M keys are passed to us.. */
retval = g15_send_cmd (g15screen_fd, G15DAEMON_KEY_HANDLER, foo);
while(1){
printf("waiting on keystate0);
keystate=0;
retval = recv(g15screen_fd, &keystate , sizeof(keystate),0);
if(keystate)
printf("Recieved %i as keystate",keystate);
} #endif
}
g15_close_screen(g15screen_fd);
return 0; }
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