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update documentation to reality (as far as I know it ;-)

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This commit is contained in:
marschap
2006-04-11 17:54:58 +00:00
parent 1b40d2b47a
commit 66e38659cb
3 changed files with 377 additions and 327 deletions
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docs/API-v0.5.txt
+176 -151
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@@ -23,18 +23,27 @@ I will walk through the driver struct here.
typedef struct lcd_logical_driver {
//////// Variables in the driver module
//////// Variables to be provided by the driver module
// The driver loader will look for symbols with these names !
char *api_version;
int *stay_in_foreground; // Does this driver require to be in foreground ?
int *does_input; // Does this driver do output ?
int *does_output; // Does this driver do output ?
// pointer to a string describing the API version
char *api_version;
// Does this driver require to be in foreground ?
int *stay_in_foreground;// Does this driver require to be in foreground ?
/ Does this driver support multiple instances ?
int *supports_multiple;
// What should alternatively be prepended to the function names ?
char **symbol_prefix;
/*
The programmer should define the following symbols:
char * api_version = API_VERSION; // <-- this symbol is defined by make
int stay_in_foreground = 0; // This driver does not need to be in foreground
int does_input = 0; // This driver does not do input
int does_output = 1; // But only output
int stay_in_foreground = 0; // This driver does not need to be in foreground
int supports_multiple = 0; // This driver does not c$support multiple instances
char *symbol_prefix = "MyDriver_"; // Driver functions start with MyDriver_
And fill these values with the correct values. Upon loading the driver module,
the server will locate these symbols and store pointers to them in the
driver struct.
@@ -45,103 +54,120 @@ the api_version symbol (a string). For the v0.5 version this should be "0.5".
If the version is incompatible, the driver will not be loaded. The current
API version can always be determined by inserting the compiler define
API_VERSION in the code.
*/
//////// Functions to be provided by the driver module
//// Mandatory functions (necessary for all drivers)
// initialize driver: return >= 0 on success
int (*init) (Driver *drvthis);
// close driver
void (*close) (Driver *drvthis);
//// Essential output functions (necessary for output drivers)
// get display width & height (in characters)
int (*width) (Driver *drvthis);
int (*height) (Driver *drvthis);
// clear screen
void (*clear) (Driver *drvthis);
// flush screen contents to LCD
void (*flush) (Driver *drvthis);
// write string s at position (x,y)
void (*string) (Driver *drvthis, int x, int y, char *str);
// write char c at position (x,y)
void (*chr) (Driver *drvthis, int x, int y, char c);
//// essential input functions (necessary for input drivers)
// get key from driver: returns a string denoting the key pressed
const char *(*get_key) (Driver *drvthis);
//// Extended output functions (optional; core provides alternatives)
// draw a bar from pos (x,y) upward / to the right filling promille of len chars
void (*vbar) (Driver *drvthis, int x, int y, int len, int promille, int options);
void (*hbar) (Driver *drvthis, int x, int y, int len, int promille, int options);
// display (big) number num at horizontal position x
void (*num) (Driver *drvthis, int x, int num);
// set heartbeat state; animalte heartbeat
void (*heartbeat) (Driver *drvthis, int state);
// draw named icon at position (x,y)
void (*icon) (Driver *drvthis, int x, int y, int icon);
//// User-defined character functions
// set special character / get free characters
// - It is currently unclear how this system should work exactly
// - The set_char function expects a simple block of data with 1 byte for each pixel-line.
// (So that is 8 bytes for a 5x8 char)
void (*set_char) (Driver *drvthis, char ch, char *dat);
int (*get_free_chars) (Driver *drvthis);
// get width & height of a character cell (in pixels)
// - necessary to provide info about cell size to clients
// - if not defined, the core will provide alternatives returning default values
int (*cellwidth) (Driver *drvthis);
int (*cellheight) (Driver *drvthis);
//// Hardware functions
// get & set ithe display's contrast
int (*get_contrast) (Driver *drvthis);
int (*set_contrast) (Driver *drvthis, int promille);
// get & set brightness for given backlight state
int (*get_brightness) (Driver *drvthis, int state);
int (*set_brightness) (Driver *drvthis, int state, int promille);
// set backlight state
void (*backlight) (Driver *drvthis, int state);
// set output
void (*output) (Driver *drvthis, int state);
//// Informational functions
// get a string describing the driver and it's features
char * (*get_info) (Driver *drvthis);
//////// Functions in the driver module
// Basic functions
//////// Variables in server core, available for drivers
All these Basic functions should be implemented !
// name of the driver instance (name of the config file section)
// - do not change from the driver; consider it read-only
// - to be used to access the driver's own section in the config file
char * name;
int (*init) (drvthis);
void (*close) (drvthis);
int (*width) (drvthis);
int (*height) (drvthis);
void (*clear) (drvthis);
void (*flush) (drvthis);
void (*string) (drvthis, int x, int y, char *str);
void (*chr) (drvthis, int x, int y, char c);
// Extended functions
void (*vbar) (drvthis, int x, int y, int len, int promille, int options);
void (*hbar) (drvthis, int x, int y, int len, int promille, int options);
These functions have been extended since v0.4. They now now expext complete
coordinates, a length (in chars, not pixels!) a promillage (0 to 1000) and an
option.
void (*num) (drvthis, int x, int num);
Draw big numbers on your display. Only 6 positions exist, 1 to 6.
David GLAUDE:
"
I don't think this is valid... There are as many position as wanted.
A BigNum could be at any column from 1 to end of the LCD.
It could also be at -1 and -2 (where only the end is visible).
Optionaly it could be on a specific raw from -3 to end of the LCD.
This permit scrolling of BIGNUM or in the futur BIGFONT.
"
void (*heartbeat) (drvthis, int state);
Should be called to animate the heartbeat. The driver should thererfor
probably call the icon function below.
void (*icon) (drvthis, int x, int y, int icon);
Tells to place a certain icon at a position.
// Userdef characters
void (*set_char) (drvthis, char ch, char *dat);
int (*get_free_chars) (drvthis);
int (*cellwidth) (drvthis);
int (*cellheight) (drvthis);
Functions to define a character. It is currently unclear how this system
should exactly work. The set_char function expects a simple block of data
with 1 byte for each pixel-line. So that is 8 bytes for a 5x8 char.
// Hardware functions
int (*contrast) (drvthis, int contrast);
void (*backlight) (drvthis, int brightness);
void (*output) (drvthis, int state);
// Key functions
const char *(*get_key) (drvthis);
Returns a string. This string is withing driver's memory space and the server
should therefor never try to modify this string.
char * (*get_info) ();
Returns a string describing the driver and it's features.
//////// Variables in server core available for drivers
char * name; // Name of this driver.
// pointer to the driver instance's private data
// - filled by the server by calling store_private_ptr()
// - the driver should cast this to it's own private structure pointer
void * private_data;
These variables should be taken read-only for the drivers. The name variable
should be used to access the driver's own section in the config file.
The private_data pointer is the pointer to the driver's own data block. This
pointer should be stored using the store_private_ptr function below. The
driver should cast this to it's own private structure pointer.
//////// Functions in server core, available for drivers
//////// Functions in server core available for drivers
// store a pointer to the driver instance's private data
int (*store_private_ptr) (struct lcd_logical_driver * driver, void * private_data);
Store the driver's private data:
// Config file functions, filled by server
// Config file functions, cwprovided by the server
// - see configfile.h on how to use these functions
// - as sectionname, always use the driver name: drvthis->name
char (*config_get_bool) (char * sectionname, char * keyname,
int skip, char default_value);
int (*config_get_int) (char * sectionname, char * keyname,
@@ -155,33 +181,17 @@ Store the driver's private data:
int config_has_section (char *sectionname);
int config_has_key (char *sectionname, char *keyname);
See configfile.h on how to use these functions. As sectionname, always use the
driver name: drvthis->name
// Reporting function
// error reporting function
// - see drivers/report.h for details
void (*report) ( const int level, const char *format, .../*args*/ );
Easily usable report functions by including drivers/report.h. See that file
for details.
// Display properties functions (for drivers that adapt to other loaded drivers)
// - the return the size of another already loaded driver
// - if no driver is loaded yet, the return values will be 0
int (*get_display_width) ();
int (*get_display_height) ();
If you have a driver that can adapt its size to the size of an other driver,
it should read these values. If there is no other driver loaded yet, the
returned values will be 0.
// Driver private data
void * private_data; // Filled by server by calling store_private_ptr()
} Driver;
The flush_box and draw_frame functions have been removed for v0.5.
PRIVATE DATA
@@ -195,112 +205,126 @@ daemons on one machine. They will then use the same variables !
In the driver's private structure will probably at least be something like:
typedef struct my_driver_private {
// Size in cells of the LCD
int width, height;
// Size of each LCD cell, in pixels
int cellwidth, cellheight;
// Frame buffer...
char *framebuf;
int fd; // file descriptor for the LCD device
int width, height; // dimension of the LCD (in characters, 1-based
int cellwidth, cellheight; // Size of each LCD cell, in pixels
unsigned char *framebuf; // Frame buffer...
} PrivateData;
You allocate and store this structure like this:
PrivateData * p;
PrivateData *p;
// Alocate and store private data
p = (PrivateData *) malloc( sizeof(PrivateData) );
if( p == NULL )
p = (PrivateData *) malloc(sizeof(PrivateData));
if (p == NULL)
return -1;
if( drvthis->store_private_ptr( drvthis, p ) < 0 )
if (drvthis->store_private_ptr(drvthis, p) < 0)
return -1;
// initialize private data
p->fd = -1;
p->cellheight = 8;
p->cellwidth = 6;
(... continue with the rest of your init routine)
You retrieve this private data pointer by adding the following code to the
beginning of your functions:
PrivateData * p = (PrivateData*) drvthis->private_data;
PrivateData *p = (PrivateData *) drvthis->private_data;
Then you can access your data like:
p->framebuf
p->framebuf
FUNCTIONS IN DETAIL
int (*init) (drvthis, char *args);
int (*init) (Driver *drvthis, char *args);
// The init function
// Starts up the LCD, initializes all vars. Allocates private data space
// and stores the pointer by calling store_private_ptr();
void (*close) (drvthis);
void (*close) (Driver *drvthis);
// Shuts down the connection with the LCD.
// Called just before unloading the driver.
int (*width) (drvthis);
int (*width) (Driver *drvthis);
// Get the screen width.
int (*height) (drvthis);
int (*height) (Driver *drvthis);
// Get the screen height.
void (*clear) (drvthis);
void (*clear) (Driver *drvthis);
// Clears the framebuffer
void (*flush) (drvthis);
void (*flush) (Driver *drvthis);
// Flushes the framebuffer to the LCD.
void (*string) (drvthis, int x, int y, char *str);
void (*string) (Driver *drvthis, int x, int y, char *str);
// Places a string in the framebuffer
// All coordinates are 1-based, (1,1) is top left.
// Driver should check for overflows
void (*chr) (drvthis, int x, int y, char c);
void (*chr) (Driver *drvthis, int x, int y, char c);
// Places a char in the framebuffer
// Driver should check for overflows
void (*vbar) (drvthis, int x, int len);
void (*vbar) (Driver *drvthis, int x, int len);
// Draws a vertical bar at horizontal position x and with length len.
// init_vbar will be called once before this functions.
void (*hbar) (drvthis, int x, int y, int len);
void (*hbar) (Driver *drvthis, int x, int y, int len);
// Draws a horizontal bar at position x,y and with length len.
// init_hbar will be called once before this functions.
void (*num) (drvthis, int x, int num);
// Displays a big number at position x.
void (*num) (Driver *drvthis, int x, int num);
// Displays a big number at horizontal position x.
void (*heartbeat) (drvthis, int state);
// Sets the heartbeat to the indicated state.
// 0=off 1=graph1 2=graph2
David GLAUDE:
"state is apparently type and it could have the value
HEARTBEAT_ON to say that we want to display/refresh the heartbeat.
The driver choose how to do it. See MtxOrb.c"
void (*heartbeat) (Driver *drvthis, int type);
// Sets the heartbeat to the indicated type: 0=off 1=graph1 2=graph2
//HEARTBEAT_ON to say that we want to display/refresh the heartbeat.
//The driver choose how to do it. See MtxOrb.c"
int (*contrast) (drvthis, int contrast);
int (*get_contrast) (Driver *drvthis);
// Gets the contrast from the driver.
// the value returned is in the ramnge 0 - 1000
// Many displays do not support software setting of contrast.
void (*set_contrast) (Driver *drvthis, int contrast);
// Sets the contrast to the given value. Values should be 0 to 1000.
// Many displays do not support software setting of contrast.
int (*get_brightness) (Driver *drvthis, int state);
// Get the brightness for the given backlight state.
// Returned values are in the range from 0 - 1000.
// Many displays do not support software setting of contrast.
void (*set_brightness) (Driver *drvthis, int state, int int brightness);
// Sets the contrast to the given value. Values should be 0 to 255.
// Many displays do not support software setting of contrast.
// Use -1 to get the current value returned.
void (*backlight) (drvthis, int on);
void (*backlight) (Driver *drvthis, int state);
// Sets the backlight to brightness 'on'.
// Often hardware can only support on and off, in that case any value
// of on>0 will switch the backlight on.
void (*output) (drvthis, int on);
void (*output) (Driver *drvthis, int state);
// Sets the output value. Some displays/wirings have a general purpose
// output, which can be controlled by calling this function. See the
// 'output' command in the 'widget language'.
char *(*getkey) ();
char *(*get_key) (Driver *drvthis);
// Checks if a key has been pressed on the device.
// Returns NULL for "no key pressed", or a string describing the pressd key.
// These characters should match the keypad-layout.
char *(*getinfo) ();
char *(*get_info) (Driver *drvthis);
// Returns a string describing the driver and its features.
@@ -340,4 +364,5 @@ int config_has_key (char *sectionname, char *keyname);
First version, Joris Robijn, 20011016
Corrected and expanded, Peter Marschall 20060411