| ADDING OUTPUT FORMATS - VERSION 1.0
Preface
In order to handle the vast range of input types
Liquid is expected to, sensory data is constrained to a single
format per sensor class called the output format.
The output format describes what kind of data (type)
sensors from a given class should return, and how it should be
formatted (constrained).
INFO: The component-based architecture
of Liquid which is suppose to allow the toolkits output format
library to be extended has not yet been fully finalized (as of
version 1.0). The process of adding new output formats requires
hard-coding the new medium into the toolkit at all levels of its
hierarchy, Liquid, Liquid Device Drivers (LDD) and Liquid Client
Applications (LCA).
TO ADD A NEW OUTPUT FORMAT
Before beginning this tutorial identity the type
of your data your new output format will be facilitating and the
constraints that can/will be placed upon it (see Output
Descriptors for Developers). The process of adding
a new output format to the toolkits library involves 6 stages:
STAGE 1: CREATE A NEW OUTPUT TYPE
The output type defines the type of data the output
format supports e.g. binary, numeric and so on. Open a copy of
the source file Device Driver.h and under the comment
heading output types (maybe labeled as comparison
or display type) create a new data type definition.
This is so the toolkit can identify how sensor input
should be extracted and manipulated when passed from an LDD to
Liquid to an LCA.
STAGE
2: UPDATE THE SENSOR DATA STRUCTURE
The structure SENSOR_DATA
is used to facilitate the storage and transfer of sensory input.
Still using the file Device Driver.h add a suitable input
container to the structure to handle the storage of the new data
type.
After updating Device Driver.h distribute
it to all other members of the toolkit hierarchy and recompile
the project spaces.
STAGE 3: UPDATE THE DISPLAY TYPES
STRUCTURE
The structure DISPLAY_TYPES is
used by the toolkit to quickly load the relevant input collect
and rendering methods. Open a copy of the source file Utilities.h
and add a new boolean to the structure describing the new
data type.
STAGE 4: UPDATE parseTypeFlag(..)
The parseTypeFlag(..)
method is used to switch the relevant elements of the DISPLAY_TYPES
structure based on the value of the output
type definition stored in an LDD. It also returns a
description of the output type. Still using the file Utilities.h
insert the necessary code to handle the new output type.
Consult the source code on how to do this.
After updating Utilities.h distribute it
to all other members of the toolkit hierarchy and recompile the
project spaces.
STAGE 5: UPDATE LDD_DRIVER
Liquid uses a structure called LDD_DRIVER
to command & control the sensors it has access to.
Within this structure is a link to a variable called dataFormats
of type FORMATS. It is here were the
various parameters used to constrain sensor input are listed and
set.
The FORMATS structure
can be located in the source file Loader.h of the Liquid
project space, download it here.
Append the required parameter constraints to the structure using
the format used in the source file. If no parameters are required
do not alter the structure.
Do not recompile the Liquid project space yet, move
onto the next step.
STAGE 6: UPDATE LOADFORMAT
Steps 1-5 have now added your output format (its
type and parameter constraints) to the toolkit. The final step
in this tutorial is to get Liquid to load the parameter constraints
from the file format.ini and into the relevant elements
of the FORMATS structure.
Open the source file Selection.cpp (located
in the Liquid project space) and move to the LoadFormat()
method. This method is called whenever the user selects a sensor
from the sensor
selection process GUI. The PPM
key is extracted from the menu and converted into the
section
key where the constraint
values will be listed.
Following the format used in the source file insert
the necessary source code to find the section key and extract
the constraint values from their respective keys and place them
into the relevant elements of the FORMATS
structure.
Technically you would need to complete stage 2 of
the Adding
Sensor Classes tutorial before doing this as the keys
you would load don't currently exist. Therefore treat the names
you associate with the constraint parameters in stage
5 as the parameter keys e.g. int
rr_max; in the source becomes the parameter key rr_max=
in the file format.ini.
If no constraint values are to be loaded set the
method to automatically return TRUE
(see base of method).
INFO: A basic knowledge of extracting
information from ini files will be required in order to carry
out this stage.
******************************************************************************************
Now you have completed this tutorial move onto
Adding Visualization
Modes.
.
. back to Manual Index |
