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-
- DropShadow Copyright James Mackraz, 1987
- Version 2, Revision 0 April 7, 1987
-
- ----- ----------------------------------------- -----
- Notes for source release May 2, 1987
-
- This program and all or any part of the source cannot be
- distributed for profit. Inclusion on not-for-profit disk
- collections is permitted. The program may not be modified
- to omit or modify the title in the control window.
-
- Notice that this program still has holes from the early
- versions. For one thing, it assues that layers activity
- always happens on the workbench, and will recalculate
- the shadow. Another, is that it doesn't take any care to
- be sure that no other program has pre-empted the layer vectors
- that it steals. So in the words of Sidekick: load me last.
-
- Also, the option to make the shadows move with the hour
- and the season (after you configure virtual north) has
- not been implemented.
- ----- ----------------------------------------- -----
- Notes for Version 2, Revision 0 April 7, 1987
-
- Added the following from the wish list:
-
- -A slider gadget is implemented to adjust the 3-dimensional
- distance between the planes of the windows.
-
- -A slider gadget is implemented to adjust shadow darkness. If
- desired, full independent control of the shadow colors is
- possible.
-
- I had some problems with the latter, so I now increase the
- task priority while the darkness slider is selected. It
- has not been tested thoroughly. (May 2: haven't heard any
- complaints yet.)
-
- ----- ----------------------------------------- -----
- Notes for Version 1, Revision 1 March 12,1987
-
- When Windows are moved, created, sized, deleted, or depth-
- arranged, Intuition calls layers.library. This program
- intercepts those calls to determine that the shadow needs
- to be recalculated. Before this version, this recalculating
- and redrawing was done before Intuition got a chance to
- redraw Window borders and Gadgets.
-
- This version of DropShadow performs the work on its schedule,
- and is only signaled by the code which intercepts the
- layers calls. This makes for a smoother and less dangerous
- implementation.
- ----- ----------------------------------------- -----
- Notes for Version 1, Revision 0 March 1, 1987
-
-
- The program on this disk creates and maintains multi-level
- transparent drop shadows of windows on the Workbench screen.
-
- The program creates its own window, and is terminated by closing
- that window. The program, named DropShadow, may be run from
- the CLI, or if associated with an icon, from the Workbench.
-
- The shadows are created by attaching an additional bitplane to
- the Workbench's display bit map, but doing so in a way which
- is transparent to the Workbench or its application programs.
-
- Unfortunately, this third bitplane brings the Workbench screen
- to a point which causes processor cycles to be stolen by the
- display generation hardware. Thus, this program is probably
- best used only for demos and having fun, at least for users
- without "Fast" RAM.
-
- Enhancements which are planned include:
-
- -The program detects that the shadow image needs to be
- recalculated by monitoring the layers library. That section
- of code should check that the layers activity is in fact in
- the Workbench screen.
-
- -A way to detect color changes in preferences would allow the
- shadow colors to track user changes to the Workbench colors.
- In the meantime, the program must be restarted to initialize the
- shadow colors. Commodities Exchange can be used for this.
-
- -A technique of unknown type is planned for user control of
- the light source which casts shadows. Shadows cast according
- to the position of the sun (time of day and season) are possible
- but unlikely.
-
- -This program is not yet a safe Library vector stealer. It should
- refuse to exit if some other program has displaced its vectors,
- lest that other program call DropShadow after it has exited.
-
-
- Jim Mackraz
- 4021 Second St.
- Palo Alto, CA 94306
-
-