This section describes properties of a graph that are used regardless of whether the graph is in a DataWindow object or in a window.To define the properties of a graph, you use the graph's Properties view. For general information about the property pages, see Using the graph's Properties view.
You name a graph and define its basic properties on the General page in the graph's Properties view.
To specify the basic properties of a graph
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Select Properties from the graph's pop-up menu and then select the General page in the Properties view.
About the model graph in the Design view
As you modify a graph's properties, PowerBuilder updates the model graph shown in the Design view so that you can get an idea of the graph's basic layout:
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PowerBuilder uses the graph title and axis labels you specify.
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PowerBuilder uses sample data (not data from your DataWindow object) to illustrate series, categories, and values.
In Preview view, PowerBuilder displays the graph with data.
Naming a graph
You can modify graphs at runtime. To reference a graph in code, you use its name. By default, the graph is named gr_n.
To name a graph
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On the General properties page for the graph, assign a meaningful name to the graph in the Name box.
Defining a graph's title
The title displays at the top of the graph.
To specify a graph's title
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On the General properties page for the graph, enter a title in the Title box.
Multiline titles
You can force a new line in a title by embedding ~n.
For information about specifying properties for the title text, see Specifying text properties for titles, labels, axes, and legends.
Specifying the type of graph
You can change the graph type at any time in the development environment. (To change the type at runtime, modify a graph's GraphType property.)
To specify the graph type
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On the General properties page for the graph, select a graph type from the Graph Type drop-down list.
Using legends
A legend provides a key to your graph's series.
To include a legend for a series in a graph
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On the General properties page for the graph, specify where you want the legend to appear by selecting a value in the Legend drop-down list.
For information on specifying text properties for the legend, see Specifying text properties for titles, labels, axes, and legends.
Specifying point of view in 3D graphs
If you are defining a 3D graph, you can specify the point of view that PowerBuilder uses when displaying the graph.
To specify a 3D graph's point of view
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On the General properties page for the graph, adjust the point of view along the three dimensions of the graph:
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To change the perspective, move the Perspective slider.
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To rotate the graph, move the Rotation slider.
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To change the elevation, move the Elevation slider.
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Define the depth of the graph (the percent the depth is of the width of the graph) by using the Depth slider.
You can specify how to sort the data for series and categories. By default, the data is sorted in ascending order.
To specify how to sort the data for series and categories in a graph
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Select Properties from the graph's pop-up menu and then select the Axis page in the Properties view.
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Select the axis for which you want to specify sorting.
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Scroll to Sort, the last option on the Axis page, and select Ascending, Descending, or Unsorted.
A graph can have four text elements:
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Title
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Labels for the axes
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Text that shows the values along the axes
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Legend
You can specify properties for each text element.
To specify text properties for the title, labels, axis values, and legend of a graph
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Select Properties from the graph's pop-up menu and then select the Text page in the Properties view.
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Select a text element from the list in the Text Object drop-down list.
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Specify the font and its characteristics.
Using Auto Size
With Auto Size in effect, PowerBuilder resizes the text appropriately whenever the graph is resized. With Auto Size disabled, you specify the font size of a text element explicitly.
To have PowerBuilder automatically size a text element in a graph
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On the Text properties page for the graph, select a text element from the list in the Text Object drop-down list.
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Select the Autosize check box (this is the default).
To specify a font size for a text element in a graph
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On the Text properties page for the graph, select a text element from the list in the Text Object drop-down list.
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Clear the Autosize check box.
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Select the Font size in the Size drop-down list.
Rotating text
For all the text elements, you can specify the number of degrees by which you want to rotate the text.
To specify rotation for a text element in a graph
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On the Text properties page for the graph, select a text element from the list in the Text Object drop-down list.
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Specify the rotation you want in the Escapement box using tenths of a degree (450 means 45 degrees).
Changes you make here are shown in the model graph in the Design view and in the Preview view.
Using display formats
To use a display format for a text element in a graph
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On the Text properties page for the graph, select a text element from the list in the Text Object drop-down list.
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Type a display format in the Format box or choose one from the pop-up menu. To display the pop-up menu, click the button to the right of the Format box.
Modifying display expressions
You can specify an expression for the text that is used for each graph element. The expression is evaluated at execution time.
To specify an expression for a text element in a graph
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On the Text properties page for the graph, select a text element from the list in the Text Object drop-down list.
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Click the button next to the Display Expression box.
The Modify Expression dialog box displays.
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Specify the expression.
You can paste functions, column names, and operators. Included with column names in the Columns box are statistics about the columns, such as counts and sums.
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Click OK to return to the graph's Properties view.
Example
By default, when you generate a pie graph, PowerBuilder puts the title at the top and labels each slice of the pie with the percentage each slice represents of the whole. Percentages are accurate to two decimal places.
The following graph has been enhanced as follows:
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The current date displays in the title
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The percentages are rounded to integers
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The raw data for each slice is shown in addition to the percentages
To accomplish this, the display expressions were modified for the title and pie graph labels:
|
Element |
Original expression |
Modified expression |
|---|---|---|
|
Title |
title |
title + " as of " + date(today()) |
|
Pie graph labels |
if(seriescount > 1, series, string(percentofseries, "0.00%")) |
if(seriescount > 1, series, string(percentofseries,"0%") + " (" + value + ")" ) |
With bar and column charts, you can specify the properties in the following table.
|
Property |
Meaning |
|---|---|
|
Overlap |
The percentage by which bars or columns overlap each other. The default is 0 percent, meaning no overlap. |
|
Spacing |
The amount of space to leave between bars or columns. The default is 100 percent, which leaves a space equal to the width of a bar or column. |
Graphs have two or three axes. You specify the axes' properties in the Axis page in the graph's Properties view.
To specify properties for an axis of a graph
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Select Properties from the graph's pop-up menu and then select the Axis page in the Properties view.
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Select the Category, the Value, or the Series axis from the Axis drop-down list.
If you are not working with a 3D graph, the Series Axis options are disabled.
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Specify the properties as described next.
Specifying text properties
You can specify the characteristics of the text that displays for each axis. The following table shows the two kinds of text associated with an axis.
|
Type of text |
Meaning |
|---|---|
|
Text |
Text that identifies the values for an axis. |
|
Label |
Text that describes the axis. You specify the label text in a painter. You can use ~n to embed a new line within a label. |
For information on specifying properties for the text, see Specifying text properties for titles, labels, axes, and legends.
Specifying datatypes
The data graphed along the Value, Category, and Series axes has an assigned datatype. The Series axis always has the datatype String. The Value and Category axes can have the datatypes listed in the following table.
|
Axis |
Possible datatypes |
|---|---|
|
Both axes (for scatter graph) |
Number, Date, Time |
|
Value (other graph types) |
Number, Date, DateTime, Time |
|
Category (other graph types) |
String, Number, Date, DateTime, Time |
For graphs in DataWindow objects, PowerBuilder automatically assigns the datatypes based on the datatype of the corresponding column; you do not specify them.
For graphs in windows, you specify the datatypes yourself. Be sure you specify the appropriate datatypes so that when you populate the graph (using the AddData method), the data matches the datatype.
Scaling axes
You can specify the properties listed in the following table to define the scaling used along numeric axes.
|
Property |
Meaning |
|---|---|
|
Autoscale |
If selected (the default), PowerBuilder automatically assigns a scaling for the numbers along the axis. |
|
RoundTo, RoundToUnit |
Specifies how to round the end points of the axis (note that this just rounds the range displayed along the axis; it does not round the data itself). You can specify a number and a unit. The unit is based on the datatype; you can specify Default as the unit to have PowerBuilder decide for you. For example, if the Value axis is a Date column, you can specify that you want to round the end points of the axis to the nearest five years. In this case, if the largest data value is the year 1993, the axis extends up to 1995, which is 1993 rounded to the next highest five-year interval. |
|
MinimumValue, MaximumValue |
The smallest and largest numbers to appear on the axis (disabled if you have selected Autoscale). |
|
ScaleType |
Specifies linear or logarithmic scaling (common or natural). |
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ScaleValue |
Specifies whether values are displayed as actual values or as a cumulative value, a percentage, or a cumulative percentage. |
Using major and minor divisions
You can divide axes into divisions. Each division is identified by a tick mark, which is a short line that intersects an axis. In the Sales by Printer graphs shown in Examples, the graph's Value axis is divided into major divisions of 50 units each. PowerBuilder divides the axes automatically into major divisions.
To define divisions for an axis of a graph
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To divide an axis into a specific number of major divisions, type the number of divisions you want in the MajorDivisions box.
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Leave the number 0 to have PowerBuilder automatically create divisions. PowerBuilder labels each tick mark in major divisions. If you do not want each tick mark labeled, enter a value in the DisplayEveryNLabels box. For example, if you enter 2, PowerBuilder labels every second tick mark for the major divisions.
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To use minor divisions, which are divisions within each major division, type the appropriate number in the MinorDivisions box. To use no minor divisions, leave the number 0.
When using logarithmic axes
If you want minor divisions, specify 1; otherwise, specify 0.
Representing divisions with grid and drop lines
You can specify lines to represent the divisions as described in the following table and illustrated in the following figure.
|
Line |
Meaning |
|---|---|
|
Grid line |
A line that extends from a tick mark across the graph. Grid lines make graphs easier to read. |
|
Drop line |
A line that extends vertically from a data point to its axis (not available for all graph types). |
Using line styles
You can define line styles for the components of a graph listed in The following table.
|
Component |
Meaning |
|---|---|
|
PrimaryLine |
The axis itself |
|
SecondaryLine |
The axis parallel to and opposite the primary axis |
|
OriginLine |
A grid line that represents the value zero |
|
Frame |
The frame for the axis in 3D graphs (disabled for 2D graphs) |
You can specify a pointer to use when the mouse is over a graph at runtime.
