VAXuisx

The VAXuisx User's Guide introduces the VAXuisx Runtime Library for VMS, designed to allow existing User Interface Services (UIS) applications to run on DECwindows without requiring conversion, rewriting, or relinking. It functions by redirecting UIS routines to use the Xlib program interface.

The document highlights several key operational differences and emulations:

• Backing Store: VAXuisx emulates VWS backing store using an off-screen PIXMAP for output buffering and window damage repair. This can be configured or disabled.
• Colormaps: It emulates UIS virtual colormaps using X11 routines, which may lead to different color allocation behaviors or the use of private X11 colormaps, potentially changing colors in other display windows.
• User Preferences: It supports reading user-preferred color setup files (DECW$SM_COLOR.DAT) for window backgrounds and cursor colors.
• Drawing & Input: VAXuisx supports UIS drawing operations, writing modes, and patterns, though some device-dependent modes and line pattern behaviors differ from native UIS. Input is handled via Asynchronous System Trap (AST) routines, with mouse movement reporting approximated and tablet/digitizer input treated as mouse input due to X11 limitations.
• Output Primitives & Window Management: Implementation details for output primitives like lines, polygons, ellipses, text, images, and scrolling vary. Window management (icons, placement, resizing) also shows distinct behaviors compared to VWS due to the underlying DECwindows/X11 system.
• Customization: VAXuisx offers customization through various logical names (e.g., UISX$FLUSH, UISX$BACKING_STORE, UISX$DPI_X) that control aspects like buffer flushing, error handling, DPI settings, and color customization, though some settings can significantly impact performance. The guide also lists supported font types (77 DPI, 100 DPI, SIGHT).