[9.2] User Interface Considerations - Texas Instruments TI-89 Tip List

©Save the icon
stopic icon1,1,1,16,16
EndPrgm
You can also use the NewPic command with a matrix to to build an icon.
Frank Westlake has written a program for the 92+ called Image Editor to create icons and other picture
variables. You can get it here:
http://frank.westlake.org/ti/index.html
John Hanna's Iview program at
http://users.bergen.org/~tejohhan/iview.html
can be used to create icons, or to convert other PC graphics files to icons.
Note that you can use the Contents toolbar item in Var-Link to view PIC variables, including the icons
you create.
(credit to Mike Grass for toolbar example)

[9.2] User interface considerations

These suggestions will help make your programs easier to use, and less frustrating. The goal of any
program is to enable the user to accomplish a task as quickly and efficiently as possible, and I think
these ideas work towards that goal. In almost all cases these suggestions will make your program
larger, but rarely make it slower. Not all suggestions are appropriate for all programs.
! Check user inputs for data type and range. If the input should be an integer, warn the user if he
enters a string or floating point number, and give him the chance to try again. If the input should be
between certain limits, and he enters a number outside those limits, display a warning and let the
user try again.
! If a program needs lots of inputs from the user, save those as global variables so they can be used
as defaults with Request in dialog boxes.
! Trap errors (with Try ... EndTry), and display useful warning messages. The message should
display both why there is a problem, and what to do to fix it. Many errors can be trapped before the
code even runs: think about what the program will do with various error conditions, or different
values for variables.
! Use the Title statement in dialog boxes to help the user. For example, you can use titles of INPUT,
RESULTS, ERROR and WARNING to make the message purpose more clear. I find that all caps is
easier to read in the small font used in the dialog box title.
! Don't change the mode settings without notifying the user. The Mode settings include the angle
mode (radians, degrees), display format, complex number format, graph type and so on. If you must
change the modes, notice that exact(), approx(), , and ° can be used to temporarily over-ride the
arithmetic mode and angle mode. If you have to change other modes, use GetMode("ALL") and
SetMode() to save and restore the user's mode settings.
! For large, complex programs consider including a 'help' menu item or custom key. The help should
explain how to use the program and any special features or limitations. The help should be built into
the program so that the user can see it while running the program. Ideally, the help code and text
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