Using graphs
In PowerBuilder, there are two ways to display graphs:
- In a DataWindow, using data retrieved from the DataWindow
data source - In a graph control in a window or user object, using
data supplied by your application code
This chapter discusses the graph control and describes how
your application code can supply data for the graph and manipulate
its appearance.
For information about graphs in DataWindows, see the DataWindow Programmer’s
Guide
and the DataWindow Reference
.
To learn about designing graphs and setting
graph properties in the painters, see the PowerBuilder User’s
Guide
.
Working with graph controls in code
Graph controls in a window can be enabled or disabled, visible
or invisible, and can be used in drag and drop. You can also write
code that uses events of graph controls and additional graph functions.
Properties of graph controls
You can access (and optionally modify) a graph by addressing
its properties in code at runtime. There are two kinds of graph
properties:
- Properties
of the graph definition itself These properties are initially set in the painter when you
create a graph. They include a graph’s type, title, axis
labels, whether axes have major divisions, and so on. - Properties of the data These properties are relevant only at runtime, when data has
been loaded into the graph. They include the number of series in
a graph (series are created at runtime), colors of bars or columns for
a series, whether the series is an overlay, text that identifies
the categories (categories are created at runtime), and so on.
Events of graph controls
Graph controls have the events listed in Table 14-1.
| Clicked | DragLeave |
| Constructor | DragWithin |
| Destructor | GetFocus |
| DoubleClicked | LoseFocus |
| DragDrop | Other |
| DragEnter | RButtonDown |
So, for example, you can write a script that is invoked when
a user clicks a graph or drags an object on a graph (as long as
the graph is enabled).
Functions for graph controls
You use the PowerScript graph functions in Table 14-2 to manipulate data
in a graph.
| Function | Action |
|---|---|
| AddCategory | Adds a category |
| AddData | Adds a data point |
| AddSeries | Adds a series |
| DeleteCategory | Deletes a category |
| DeleteData | Deletes a data point |
| DeleteSeries | Deletes a series |
| ImportClipboard | Copies data from the clipboard to a graph |
| ImportFile | Copies the data in a text file to a graph |
| ImportString | Copies the contents of a string to a graph |
| InsertCategory | Inserts a category before another category |
| InsertData | Inserts a data point before another data point in a series |
| InsertSeries | Inserts a series before another series |
| ModifyData | Changes the value of a data point |
| Reset | Resets the graph’s data |