Use Digital's Color Mixing widget to provide users with the ability to customize the colors used in your application. For example, if your application includes graphics, such as a pie chart, you can provide access to the Color Mixing widget through an item in a customization menu to allow users to define the pie chart's colors.

The Color Mixing widget provides users with immediate feedback, displaying each new color as it is defined. There is also a scratch pad feature that allows users to save colors that they want to use later or to compare colors.

By default, the Color Mixing widget supports five color models. You can, however, customize the Color Mixing widget to support other color models.

Color models are abstractions that enable users to choose specific colors. The Color Mixing widget supports the following color models:

• Color Picker
  The Color Picker is the default color model for the Color Mixing widget on color systems. (Note that the Color Picker model does not display on noncolor systems or on systems with too few resources.) The Color Picker allows users to pick a color from a static color spectrum (or another color model) and either use that color without changing it, or smear it into a color they want. Users can also pick colors from the spectrum and smear them into each other to create a color they want.
  Figure 4-1 shows the components in a color mixing widget with the color picker model selected.

  Figure 4-1 Color Picker Model

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• Hue, lightness, and saturation (HLS)
  In the HLS (Hue, Lightness, Saturation) color model, a color is specified by three characteristics: hue, lightness, and saturation. Hue is color. Lightness describes the intensity of the color; that is, the amount of the color. Saturation describes the purity of the color; that is, how much the color is diluted by white.
  HLS expresses hue as a continuous spectrum of values arranged in a circular pattern. Red appears at 0 degrees (and again at 360 degrees), magenta is at 60 degrees, blue is at 120 degrees, cyan is at 180 degrees, green is at 240 degrees, and yellow is at 300 degrees. HLS expresses the lightness of a color as a percentage between 0 and 100 percent. One hundred percent lightness creates white light; zero percent lightness creates black.
• Red, green, blue (RGB)
  The RGB color model is the default color model for the color mixing widget on monochrome systems.
  In the RGB color model, a color is specified as a mixture of different intensities of red, green, and blue. You can specify the intensity of red, green, or blue as a value between 0 and 65,535. Zero is the lowest intensity. Black is defined as a zero-intensity value for all three colors; white is 100 percent intensity for all three colors.
• Browser
  The color browser is a window that presents the user with a list of X11 named colors. Each button in the window shows the name of an X11 color. If enough resources are available, the background is set to that color. Users can scroll through this color list. Clicking MB1 on a color in the list causes the color display subwidget to become filled with that color.
• Greyscale Mixer
  The greyscale mixer allows users to create grey shades ranging from black to white. When the greyscale mixer is selected, the current new color is converted to an appropriate shade of grey, which users can then adjust with the scale.

For more information on the Color Mixing widget, see the DECwindows Motif Guide to Application Programming and the DECwindows Extensions to Motif.

Provide online help as part of your application. The methods and techniques of designing online help vary with each company; in some companies, technical communicators design the online help, while in other companies application developers design it. Regardless of who designs and implements the online help, this chapter covers the following:

• Methods of accessing help
• Guidelines for designing and writing help
• Digital tools for creating online help
  • The Help widget
  • The DECwindows Motif Help System

Allow users to access online help through one or more of the following mechanisms:

• Help pull-down menu
• Help command
• Help push button
• Help key

Each type of help corresponds to a menu item in the Help menu. Make sure that your Help menu includes only the types of help that your application provides. For an example Help menu and an explanation of what each menu item is to do, see Figure 2-16.

5.1.2 Help Command

If your application makes use of command dialog boxes or command regions, allow users to invoke help by typing the help command at the prompt and pressing Return.

5.1.3 Help Push Button

Provide a Help push button in most dialog boxes. When users push the Help push button, have them receive an overview of the dialog box and additional topics that describe how to use each control within the dialog box.

If your application uses warning or error dialog boxes, provide a Help push button in each dialog box if the error and a solution cannot be given in one or two lines of text. Have the help that users receive describe the error or warning displayed in the dialog box, and provide a suggestion for solving the problem.

5.1.4 Help Key

When users press the Help key, have them receive context-sensitive help on the component that has the location cursor. However, if the input focus is in a dialog box and users press the Help key, have them receive an overview of help for the entire dialog box, not just the component that had input focus.

5.2 Guidelines for Designing and Writing Online Help

Because online help, especially context-sensitive help, must provide separate information about individual tasks or concepts, the information is divided into separate Help topics.

5.2.1 Planning Help Topics

Before you begin to write, plan the topics on which you will write help. Here is a list of steps to guide you:

1. Create a hierarchical list of all the application's screen objects. This includes menus, menu items, pop-up menus, dialog boxes, and controls (fields) within each dialog box.
   For example, one branch of this hierarchical tree for Mail might begin with the Create-Send menu, as shown in Figure 5-1. Each menu item is a smaller branch off the main branch. Dialog boxes and submenus are still smaller branches, and the controls within the dialog boxes are the leaves at the end of the branch. Your diagram might look similar to the one in Figure 5-1.

   Figure 5-1 Create a Hierarchical Tree

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2. Once you have created your hierarchical list, create a list of tasks that users might want to accomplish and check this list with actual users. Then map the tasks back to menus, menu items or dialog boxes; that is, for each task, see if there is a clear means of accomplishing that task.
   If you have trouble mapping tasks back to screen objects, it may be because you have not listed representative tasks, or because the user interface has not been designed in a task-oriented fashion. If the latter is the case, see if there are menu names or control labels that can be changed to make the interface more task oriented.
   For example, Figure 5-2 shows a Help window that describes the Create-Send menu, and a list of additional topics. Notice that the additional topics correspond to the items in the Create-Send menu, and each task-oriented additional topic can be mapped back to a menu item. For example, the first topic says Creating a New Message and the associated menu item is New Message.

   Figure 5-2 Create Task-Oriented Topics

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Once you have created a hierarchical list of the screen objects and their associated tasks, you are ready to begin organizing your help topics. You may want to use the following steps to help guide you:

1. Write an overview of the application that quickly describes what tasks users can accomplish with it. List as additional topics (or create DECwindows Motif Help System hotspots for) the general tasks that users can perform using the menus in the title bar. You may also have other additional topics.
   For example, Figure 5-3 provides an overview and introduction to mail, and as additional topics it lists "Reading Messages" to correspond with the Read menu, and "Creating and Sending Messages" to correspond with the Create-Send menu.

   Figure 5-3 Write an Overview for the Application

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2. For each menu, write a short overview of what tasks the items in this menu can help users accomplish. List as additional topics the tasks that each menu item will perform; do not just list the menu items. (Users can see a list of menu items by posting the menu. If users are in help, they need information on performing specific tasks.)
   Notice that the overview of the Create-Send menu in Figure 5-2 has additional task-oriented topics that correspond with each menu item.
   Also, consider using additional topics (or hotspots) for more than simply showing the hierarchical breakdown of an interface; use additional topics to show relationships between various parts of an interface. For example, help on the Create-Send menu item might include an additional topic on how to set a personal name or how to set an editor.
3. For each dialog box, write a short overview of the tasks that users can accomplish using that dialog box and tell users how to accomplish those tasks using the dialog box. If the dialog box is large or complicated, list as additional topics (or hotspots) the tasks that users can perform using each control in the dialog box. Then, in a subsequent Help window, provide detailed information on how to use each specific control.
   Notice that the overview of the Send attributes dialog box in Figure 5-4 lists additional topics that correspond with each control (or set of controls) in the dialog box. The additional topics are listed in a specific order; the list begins with the control in the upper left corner of the dialog box, and goes left to right, top to bottom (in left-to-right environments).

   Figure 5-4 Additional Topics in a Help Window

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4. Decide which Help topic will be invoked when users obtain context-sensitive help using the mouse. For example, when users click on the menu bar, but not on a specific menu, will you invoke an overview of the application, an overview of the menu bar (if you have decided to write one), or help on the closest menu?
5. When users press a Help push button in a dialog box, have them receive help on the dialog box as a whole, or receive an overview of the dialog box with additional topics about each control. If users press the Help key when input focus is in the dialog box, provide help on the specific control that has the input focus.

6. Decide how to organize each task-oriented topic. Consider the following:
   • Placing task-oriented information first, followed by definitions of terms (if they are necessary), followed by conceptual information or suggestions on how to obtain additional information. Many users of online help are looking for task-oriented information first.
     For example, Figure 5-5 shows a Help topic with task-oriented information first.

     Figure 5-5 Put Task-Oriented Information First

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   • Segmenting task-oriented information into numbered steps if the task requires more than two user actions. Figure 5-6 shows an example of a task-oriented sequential Help topic.

     Figure 5-6 Number Steps

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7. Decide which additional topics to place in the Additional Topics list.

5.2.1.2 Writing Help Topics

• Be brief
• Be clear
• Be visual

Be Brief

Make help text brief so it can fit in the default size of the Help window, and to make the user's job easier. Use the following guidelines to make your Help topics concise:

• Use as few words as possible, but do not omit words such as the and a for the sake of brevity. The resulting telegraphic style can lead to misinterpretation and mistranslation.
• Avoid a chatty, overly friendly style.
• Use short sentences and short paragraphs. Figure 5-7 compares the use of brief paragraphs with a lengthy one.
• Help the user do a task.
  For example:

  Use Print...to display the Print Attributes dialog box to prepare and send your document to a printer.

• Write imperative sentences and avoid the passive voice; for example:

  Use Save to save your document in a file.

  
  Not:

  The Save menu item is used for saving your document in a file.

Figure 5-7 Use Short Sentences and Paragraphs

Be Clear

Use simple, nontechnical language. Write for the beginning user of the application, and avoid jargon, including computer jargon, product jargon, and help jargon. For example, avoid referring to the list of additional topics as a list box. Use the following guidelines to make your Help topics as clear as possible:

• Use simple language.
• Use direct instructions.
• Define all new terms whenever you use them. Define terms in lower-level topics if users can view the topic without viewing a higher-level topic.
  After defining a term, use it. Avoid synonyms.
• Spell out abbreviations, acronyms, and mnemonics and follow with the shortened form in parentheses.
• Use the same terms that are used in the user interface, where possible. For example, refer to the DECterm window, not the terminal emulator window.

Figure 5-7 shows the first and final drafts of a sample Help topic. The revised Help topic breaks the text into short paragraphs separated by blank lines and reduces the density of the text, thus making it easier to read on the screen. For optimum readability, limit topics to four or fewer short paragraphs whenever possible.

Be Visual

Try to design Help topics that are inviting to the eye and easy to read. Reading information on a screen is more difficult than reading it on a page. Screen resolution may be as much as 20 times lower than the resolution of a printed page; text density that is acceptable on a page is unacceptable on a screen.

You can create a visual format that is easy to read by following these guidelines:

• Break text into short paragraphs separated by blank lines. A high text density with little blank space is hard to read.
• Make the text have a ragged right margin; do not right-justify it. Ragged right margins help readers to keep their place in a section of text.
• Use blank lines between list items, if possible. If the list is short and fits in one Help topic without scrolling, then consider omitting the blank lines.
  Create short list items, if possible.
• Write topics that fit within the default Help window dimensions so users do not need to scroll.
  If your Help topic must exceed the number of lines that your help window displays, you can position the text to give users another cue (in addition to the scroll bar) that more information follows. For example, have the text go to the bottom of the window so that users can see the tops of letters being cut off.

For each Help topic you write, provide a list of additional topics that contain related information.

5.2.2 Remember Translation

It is important to follow the recommendations for writing style given in this chapter in order to assist in the translation of help files.

When a Help topic is translated from an English language version, the amount of text usually increases, so plan for this text expansion.

In addition, to prevent users from having to scroll the help text, translators can request that the default size of the Help window be increased to accommodate the increased amount of text.

5.3 Digital Tools for Creating Online Help

Digital provides two means for creating and displaying online help: the Help widget and the DECwindows Motif Help System.

5.3.1 Using Digital's Help Widget

Digital's Help widget is a special window that users can invoke from the Help menu, the Help command, the Help push button or the Help key. The top pane of the Help window displays the Help topic, that is, information on the object or function on which users request help.

The bottom pane lists additional topics for further help. To select and display an additional topic, users position the pointer over the topic and click MB1.

A Motif Help Window created with Digital's Help widget consists of the following components:

• Title bar with the title centered and a window menu button
• Menu bar
• Help topic
• Additional topics
• Push buttons

The default size provides space for 55 monospaced characters on a line of text, 20 lines of text, and space for 5 subtopics in the Help window. Figure 5-8 shows a sample Help window.

Figure 5-8 Help Window

The title bar consists of the help title and the window menu button. The help title consists of the phrase "Help on" and the name of your application, as shown in Figure 5-8.

5.3.1.2 Menu Bar

• File
  The File menu contains the following menu items:
  • Save As..., which invokes a dialog box that allows users to save a copy of the current Help topic in a specified file.
  • Exit, which dismisses the current Help window.
• Edit
  The Edit menu contains the following menu items:
  • Copy, which copies a selected portion of the current topic to the clipboard.
  • Select All, which selects the entire current topic.
• View
  The View menu contains any or all of the following menu items:
  • Go To, which replaces the current topic with the selected additional topic. If no topic is selected in the Additional topics area, disable this menu item.
  • Go Back, which replaces the current topic with the previous topic. The Go Back menu item duplicates the function of the Go back button. If no previous topic exists, disable this menu item.
  • Go to Overview, which replaces the current topic with the application-specific On Window topic. Each application must have an overview topic.
  • Visit, which creates a new Help window that displays the selected additional topic. The previous window displays the current Help topic and retains the input focus. Note that input focus is not passed to the new help window. If no topic is selected in the Additional topics area, disable this menu item.
  • Go to Glossary, which provides an alphabetic list of terms associated with your application.

• Search
  The Search menu contains the following menu items:
  • History..., which invokes a modeless dialog box that lists the titles of all the Help topics viewed during the current help session. The History dialog box contains a list box with the topic titles and Go To, Visit, and Cancel push buttons.
  • Title..., which invokes a modeless dialog box that allows users to display a list of topic titles that contain a keyword or phrase.
  • Keyword..., which invokes a modeless dialog box that allows users to search for Help topics related to specific words.
• Using Help
  The Using Help menu contains an On Window menu item that invokes help on how to use the Help window.

A Help topic uses text to describe an object, concept, or function on which the user requested help. Have your application display the application-specific On Window topic when users do not request help on a specific topic.