IDL Interface Guide: Introducing IDL

Getting Help with IDL

IDL's online help system provides access to information on all aspects of IDL. The complete IDL documentation set is available online in HTML format. To use the IDL online help system, do one of the following:

In addition to the online help format, IDL documentation is available in a set of Adobe Acrobat PDF files located on the IDL CD-ROM. See Using the PDF Documentation Set for details.

Using the IDL Online Help Viewer

IDL's online help system uses a cross-platform help viewer — IDL Assistant — based on the help viewer used by the Qt development toolkit from Trolltech. This section describes how to use the IDL Assistant application. For information on creating help content that uses the IDL Assistant for your own IDL applications, see Providing Online Help For Your Application.

The Main Window

The IDL Assistant main window contains the text of the current topic. Within the main window you can:

The Sidebar

The IDL Assistant sidebar provides four tabs that allow you to navigate through the IDL documentation set. All of the tabs provide a context menu that allows you to open the selected topic the current tab, a new tab, or a new window.

The Contents Tab

The Contents tab displays a hierarchical listing of the contents of the various books in the IDL documentation set.

The Index Tab

The Index tab provides a keyword index of the contents of the IDL documentation set. Enter a text string in the Look For: field to see keywords that match the string.

The Search Tab

The Search tab allows you to search the text of the IDL documentation set for words or phrases. Text matching your search string is highlighted when a topic is displayed in the main window.

To search for words, enter one or more strings in the Searching for: field, separated by spaces and click Search. IDL Assistant displays a list of topics that contain all of the words you entered.

To search for a phrase, enclose the phrase in single or double quote marks.

The list of topics containing the search words or phrase is displayed as a list ranked roughly according to the number of occurrences of the words or phrases, with the topics containing the largest number of occurrences listed given higher rankings.

Each entry in the list of topics is followed by an abbreviation of the title of the manual in which the topic appears. See Book Name Abbreviations for the list of abbreviations.

Allowed Characters

The following characters are allowed in the Search tab:

All other characters are disallowed; you cannot enter them in the Searching for: field.

Examples

Book Name Abbreviations

The following abbreviations of book titles are used in the list of topics returned by the search:

The Bookmarks Tab

The Bookmarks tab allows you to save links to specific topics in the IDL documentation set for easy reference.

The Menu Bar

The IDL Assistant menu bar runs across the top of the IDL Assistant window, and provides access to the features listed below. Keyboard shortcuts to invoke various menu items are listed in the menus themselves.

The Tool Bar

The IDL Assistant tool bar provides quick access to a subset of the features available via the menubar.

Table 2-6: IDL Assistant Toolbar

Table 2-6: IDL Assistant Toolbar

Icon	Name	Function
	Previous	Display the current tab's previous topic.
	Next	Display the current tab's next topic.
	Home	Display the IDL online help Home page.
	Copy	Copy text selected in the main window to the system clipboard.
	Find in Text	Search for a text string in the currently displayed topic.
	Print	Print the contents of the currently selected tab. See Printing for details.
	Zoom in	Increase the text size in the main window. See Text Zoom for important notes.
	Zoom out	Decrease the text size in the main window. See Text Zoom for important notes.
	What's this?	Display context-sensitive pop-up help about some portions of the IDL Assistant interface.

Text Zoom

Select Zoom in or Zoom out from the View menu to change the size of the text in the IDL Assistant main window.

The smoothness of the text zoom operation depends on the ability of the operating system to provide fonts of the appropriate size for the zoomed text. On platforms that provide robust font-management mechanisms, the Zoom operations will work smoothly. On platforms that provide more limited font support, a single Zoom operation may, depending on the current text size and font support, change the text size for only some text elements in the main window, or none at all. In these cases, repeated applications of the Zoom operations may change the text size.

If you find that the text zooming feature does not work adequately with the default fonts, try changing the fonts used by IDL Assistant (see Settings for details.) On platforms that use a set of fixed-size fonts, choosing a font with a larger number of available sizes will allow smoother text zooming.

Printing

Select Print from the File menu or toolbar to display a platform-native Print dialog that allows you to select a printer on which to print.

Settings

Select Settings from the Edit menu to display a tabbed dialog that allows you to control several IDL Assistant settings.

General Tab

The General tab allows you to select fonts for text display in the main window. By default, the Font is set to Helvetica, and the Fixed Font is set to Courier.

The General tab also allows you to select a color for hyperlinks and specify whether the links should be underlined. Depending on your platform, changing these values may not produce the effect you expect.

Web Tab

The Web tab allows you to define the web browser that should be invoked when you click on a hyperlink that refers to a web site rather than to a file in the IDL documentation set.

The Web tab also allows you to specify an HTML file that should be displayed when you select Home from the Go menu or click the Home toolbar icon. By default, the home page is defined as

<IDL_DIR>/help/online_help/home.html  

where <IDL_DIR> is the full path to your IDL installation.

PDF Tab

The PDF tab allows you to define a Portable Document Format (Adobe Acrobat) file browser that should be invoked when you click on a hyperlink that refers to a PDF file.

Using the PDF Documentation Set

The complete IDL documentation set is available in a set of Adobe Portable Document Format (PDF) files. The PDF documentation set is hyperlinked, provides navigational bookmarks in the bookmarks pane, and provides a compiled full-text search index.

Adobe Systems Inc. created the Portable Document Format in the early 1990s, basing it on their PostScript language. PDF is intended to allow documents to be displayed in exactly the same manner on a wide variety of computing platforms.

The IDL PDF files are electronic representations of the individual books in the documentation set, and can be either viewed on screen or printed (in full or in part) on a local printer. When viewed on-screen, the PDF books provide hyperlinked cross-references, tables of contents, and indices, allowing for speedy navigation through the set. In addition, some versions of the Adobe Acrobat software provide a fast full-text search capability, using a pre-compiled full-text index of the entire document set.

Viewing PDF Files

Viewing PDF files requires a separate application, not included in the IDL installation. Various PDF viewing applications are in wide use, and one or more may already be installed on your system.

The PDF version of the IDL documentation set is designed to be viewed using Adobe Acrobat or Adobe Reader. Other third-party PDF viewers (notably GhostScript and Apple's Preview) are available, but these viewers may not support all of the features available when viewing the IDL PDF files in Adobe Acrobat. Inter-document hyperlinks may or may not work correctly when using other viewers, and the compiled full-text search index (the Acrobat "Search" feature) will almost surely not work correctly in other viewers.

The Adobe Reader software is available at no charge directly from Adobe:

www.adobe.com/reader