Provided by: libg15daemon-client1_1.9.5.3-8.2ubuntu3_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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