Texas Instruments TI89 Developer Guide - Page 57

4. 4.1. 15 User Interface Overview The TI-92 Plus has a display of 240 by 128 pixels. The TI-89 display size is 160 by 100 pixels. On both calculators, the display is divided into two regions: the window region and the status line. The bottom seven lines of the display are always used for the status line. The remaining lines constitute the window region which is available to the app. The window region is shared with the app's toolbar (if it has one) which is normally in the top 18 pixels of the display of the TI-92 Plus and the top 16 pixels of the TI-89. The window region will be different if an app is running in split screen mode (an app is given the size of its window region when it is started). The user interface consists of windows, menus, dialog boxes, fonts, and the status line. An overview of these is presented in the following sections. Windows All characters, lines, figures, and images that appear on the display must be drawn to an open window. Note that menus and dialog boxes open and close their own windows and that dialog box windows may overlap the app's toolbar (dialog boxes are modal so the app's toolbar is inactive when a dialog box is active). Window routines exist to: • Open, resize, and close windows • Draw characters, strings, lines, ellipses, rectangles, and pixels • Fill regions (rectangular or triangular) • Store and recall bitmaps • Scroll horizontally or vertically If an app opens a window, that window must eventually be closed. All output to a window is clipped and will not exceed the window boundaries. An app's main window normally has no border but if it is in split screen mode, then it has a two-pixel border (one pixel thick if not active, two pixels thick if the active window). Note that by convention, windows that are overlapped on-top of the main window, such as dialog boxes, have single pixel borders and usually have rounded borders unlike pop-ups. TI-89 / TI-92 Plus Developer Guide Not for Distribution Beta Version January 26, 2001