If a VI serves as a user interface or dialog box, front panel appearance and layout are important. Design front panels to resemble instruments or other devices so users easily can identify which actions to perform. Use front panel controls and indicators, splitter bars and panes, window settings, and so on to improve the usability of the front panel. You also can use events to enhance the functionality of user interfaces.
The main components of the front panel are controls and indicators. Use the following guidelines to design the front panel to serve as a user interface:
You also can improve the usability of user interfaces by configuring system fonts and colors.
LabVIEW uses fonts already installed on the computer. For example, LabVIEW defines its built-in fonts as the default system fonts. When you move VIs between platforms, LabVIEW automatically updates its built-in fonts so that they match the default system font of the current platform. Additionally, if you attempt to open a VI that uses an unavailable font, LabVIEW substitutes the closest match. For example, if you attempt to open a VI that uses the Arial font on a computer that does not have the Arial font, LabVIEW substitutes a similar, installed font. LabVIEW also substitutes colors similarly to how it substitutes fonts. If one of the colors of the VI is unavailable, LabVIEW replaces it with the closest match.
If you use system colors for objects, the front panel background, or the background of the block diagram workspace, then the appearance of the VI varies across systems. To view the available system colors in the color picker, select Tools»Options and select Environment from the Category list. Remove the checkmark from the Use default colors checkbox and click one of the eight color boxes to display the color picker. You can view the available system colors in the lower right corner of the color picker. The system colors vary across computers, so any VI that uses system colors reflects the specific system colors of the current computer. The system colors define the appearance of Panel & Object, Window, and Highlight, as well as the color of the text that appears on top of these system colors. To change the system colors that appear in the color picker, use the color utility on the operating system of the computer.
Refer to the NI Developer Zone at ni.com/zone for more information about system colors.
You can use splitter bars, such as toolbars or status bars, to create professional user interfaces in the front panel window. You can create a splitter bar to separate the front panel into multiple regions, called panes. Each pane acts similarly to a unique front panel, with its own sets of pane coordinates and controls and indicators on it. You can scroll each pane individually. The splitter bar separates the controls on one pane from those on another pane, yet the terminals for all controls are on the same block diagram.
When you create a new, blank VI, the front panel has a single pane that fills the window. The front panel owns this pane and is the pane's parent. When you place a splitter bar on a pane, the splitter bar replaces the pane in the front panel object hierarchy and creates two new child panes. The front panel owns the splitter bar, and the splitter bar owns the two child panes. If you place a new splitter bar on one of the child panes, the new splitter bar replaces that pane and becomes the parent of the two new child panes. This hierarchy forms a binary tree, and the front panel owns the top pane.
Refer to the Resizable Panel with Splitter Bars VI in the labview\examples\Controls and Indicators\Containers for an example of using splitter bars and panes.
Right-click a splitter bar and select one of the following shortcut menu options to configure splitter bars:
You also can use the Splitter properties to configure splitter bars programmatically.
Right-click a scroll bar in the pane, or right-click a splitter bar and select the pane you want to configure and select one of the following shortcut menu options to configure panes:
|Note If you turn off the horizontal or vertical scroll bar by right-clicking the scroll bar in the front panel window, you can display the scroll bar again by enabling the Show horizontal scroll bar option or the Show vertical scroll bar option in the Customize Window Appearance dialog box.|
If there are no splitter bars on the front panel, you can configure some properties of the single pane in the VI Properties dialog box. However, if you add a splitter bar to the front panel, LabVIEW limits the menu options in the VI Properties dialog box because the configurations cannot apply to all panes. You must configure each pane individually. For example, adding a splitter bar to the front panel dims the Scale all objects on front panel as the window resizes checkbox on the Window Size page of the VI Properties dialog box.
You also can use the Pane properties to configure panes programmatically.
Select File»VI Properties, select Window Appearance from the Category pull-down menu, and select the Dialog option to hide the menu bar and scroll bars and to create VIs that look and behave like standard dialog boxes for each platform.
If a VI contains consecutive dialog boxes that appear in the same screen location, organize them so that the buttons in the first dialog box do not directly line up with the buttons in the next dialog box. Users might double-click a button in the first dialog box and unknowingly click a button in the subsequent dialog box.
Users also might attempt to use the keyboard shortcut <Ctrl-Z> to perform an undo operation while a VI is running. This can cause unexpected behavior in dialog boxes, such as a closed dialog box reopening. To avoid this behavior, you can create a custom menu that does not include the Edit»Undo option, or you can add an Event structure to the VI and configure the Menu Selection (App) event to handle the command.
Use the system controls located on the System palette in dialog boxes you create.
When you design a VI, consider whether the front panel can display on computers with different screen resolutions. Select File»VI Properties, select Window Size in the Category pull-down menu, and place a checkmark in the Maintain proportions of window for different monitor resolutions checkbox to maintain front panel window proportions relative to the screen resolution.