Business Graphic Objects

You will see how PrStudio provides an easy way to access the prototypes in C++ applications. It provides a specific set of objects, the Value Source. They are data providers for the prototypes.

PrStudio setup
First, go back to the panel you created in the last step and remove the slider prototype. The connection between the slider and the SuperGauge prototype is automatically destroyed.
Then create the Value Source. The creation command is not directly available in PrStudio through toolbars or menus. You need to access the "Commands" panel by pressing the "Commands" button 
The Commands panel should appear:
 

Select the "AddValueSource" command, and press "Apply". By the way, you can see that all the ILOG Studio commands are shown here. Most of them are available through buttons, menus or inspectors, but it is sometimes useful to see them all in this panel, classified by categories.

When the command is selected, you are asked to select a Value Source from among four possible choices:

• Clock: uses a timer with a variable period. Very useful for animated prototypes.
• Random: random generator.
• File: file reader to provide data.
• Application: provides data that come from the application

Here, you will use an Application value source. Give a name to this value source (for example: "AppliData"). Nothing looks different in your edited panel, but if you click again on the "Group Connection" button , you will see a green rectangle showing the created Value Source:
 
This rectangle is used to create a connection between the application and the prototypes.

Create a link between "AppliData" and your prototype. This operation pops up the connection panel again:
 

Enter any name in the left text field (for example: SuperGaugeValue) to specify the name of the value that will be used later in the C++ code, and select the Gauge Value in the right column.

This operation creates a connection that is represented in the panel by a green arrow. If you click on this arrow, you will see a tooltip with the details about this connection. Save your panel as GaugePanel.ilv for example.

C++ code
You can now use all this in a sample application. Here is the necessary C++ code:
 

IlvDisplay* display = new IlvDisplay("Protos", 0, argc, argv);   if (!display || display->isBad())   {     IlvFatalError("Couldn't open display");     delete display;     return -1;   }   IlvProtoManager* protoman = new IlvProtoManager(display);   IlvView* view = new IlvView(display, "Proto sample", "Proto sample",             IlvRect(0, 0, 400, 180));   protoman->addView(view);

The first part of the code creates a display, a manager and a view. All these points are detailed in the "2D images" section of this tutorial. Note the manager creation: an IlvProtoManager is created instead of the classic IlvManager. It is a specific manager for prototypes.
 

protoman->read("GaugePanel.ilv");

You can read a panel file (.ilv) using the "read" function. It instantiates all the necessary objects in the manager.
 
 

IlvValueSource* source = protoman->getValueSource("AppliData");

You can get the value source created in PrStudio by providing its name ("AppliData").
 

IlvTimer* timer = new IlvTimer(display, 0, 50, TimerAction, source);   timer->run();

The timer is useful for animating the gauge (timer creation process is detailed in the "2D images" section). The "TimerAction" function is called by the timer every 50 milliseconds:
 

static void TimerAction(IlvTimer*, IlvAny arg) {   static IlvUInt currentValue = 0;   static IlvInt  increment = 2;   // Get the Value Source   IlvValueSource* valueSource = (IlvValueSource*)arg;   // Value variation   currentValue += increment;   // Min and Max tests   if ((currentValue < 0) || (currentValue > 100))   {     currentValue -= increment;     increment = -increment;   }   // Push the new value   valueSource->pushValue(IlvValue("SuperGaugeData", currentValue)); }

First, you get the value source pointer passed as a user argument and new gauge value (with limit tests) is computed. The "pushValue" function is used to update the prototype. You just have to specify the value you want to access ("SuperGaugeData" value), and that's it! Because the Gauge Value is now connected to the value source, the prototype is automatically updated and redrawn.

See complete code.

Download source code.

Note: This example is very similar to the "connect" sample provided with ILOG Views, in the "samples/protos" directory.

Conclusion
Once your panel is created with PrStudio using application value sources, it is very easy to transfer data from the application to the prototypes. All the prototypes linked to a specific value source through a value will automatically be updated and redrawn if necessary. The prototypes provide a very easy way to customize data display without affecting your application code.