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; }
-- end cutting --