Service Overview
There are many function calls associated with LHAPI Services, including:
Global LHAPI Control Functions include
- InitializeLHAPI First time initialization by applications to point to a LHAPIBLOCK structure allocated by the application.
- DeactivateLHAPI Application tells LHAPI that it is switching out.
- ReactivateLHAPI Reestablishes the LHAPIBLOCK data structure after being switched back in.
- UninitializeLHAPI Application tells LHAPI it is terminating.
- GetLHAPIBlockPtr Returns the offset address of the currently defined LHAPIBLOCK structure.
Messaging functions include
- SendAllMsg Sends the specified message to all windows in the active application.
- SendFocusMsg Sends the specified message to the focus window.
- SendMsg Sends the specified message to the specified window.
- SubclassMsg Sends the specified message to the specified window using a different class handler than the one specified in the LHWINDOW structure.
Menu functions include
- ResetAlt Resets an internal flag so that the Object class will not generate a <Menu> KEYSTROKE message if it sees an <Alt> release keystroke. Normally only called internally by LHAPI.
Focus functions include
- GetFocus Returns a pointer to the current window with focus.
Error Handling functions include
- SetError Saves the specifed value in ErrorNum in the LHAPIBLOCK structure.
- GetError Returns ErrorNum.
- ClearError Clears both the ErrorNum and the Handler field in the LHAPIBLOCK structure.
- SetErrorHandler Sets the Handler for Error.
- GetErrorHandler Gets current error handler.
LHAPI specialized text display routines include
- DrawText Draws text on the screen.
- DrawNChars Similar to DrawText, but specifies the maximum characters to display.
- DrawChar Displays a single character in the specified Draw style and font.
- DrawFKeys Displays the function-key labels for a window.
LHAPI Graphics functions include
- Rectangle Displays a rectangle.
- Panel Draws a rectangle with a black border and white inside.
- Outline Outlines a rectangle in black.
- ShadowBox Draws a Panel box with a shadow to the right and underneath.
- ClearRect Clears a section of the screen to white.
- Line Draws a line.
- RegisterFont Registers the given font as one of those which will be used by the application.
- SetDefaultFont Sets the default font.
- GetDefaultFont Returns the current default font.
- SetCurrentFont Sets the current system font.
- GetCurrentFont Returns the currently defined system font.
- SetMenuFont Sets the system font to be used for the menus.
- SetGlobalClipping Sets the master clipping against which all local clip regions are clipped.
- SetLocalClipping Sets clipping region within a particular window.
- GetLocalClipping Returns the currently defined local clipping region.
- IntersectLocalClipping Sets the Local clipping region to the intersection of the specified rectangular region and the currently defined Local clipping region.
- ShowSymbol Displays a special symbol at the given location.
- ResetVideo Resets the internal LHAPI video state variables.
- SetRepRule Sets the low-level graphics pixel replacement rule.
- ResetRepRule Sets the low-level graphics pixel replacement rule to default.
- SetHelpKey Sets the application-wide help key.