YP Shadow simulates a light source projecting the shadow of an opaque body on a screen. Using the mouse, it is easy to change the position and the size of the light source, the position and the size of the opaque body, and the position of the screen. YP Shadow draws the rays of light used to mark the boundaries of the umbra and the penumbra, and it displays the shadow as it appears on the screen.
System Requirements: YP Shadow runs on any Macintosh computer with MAC OS 7.0 or later. It needs about 180 Kb on your hard disk and 700 Kb of RAM. The software runs on older models with 68000 processors (Mac Plus, Mac Classic), but simulations are slower.
Program operation:
When you launch YP Shadow, the animation window is displayed; it includes a spherical light source (yellow circle), an circular opaque body (blue line), a screen (streaked rectangle, at the right of the window) and four rays of light (red lines).
To move the light source, the opaque body or the screen, place the mouse pointer over it; the pointer looks like crossed arrows. Press the mouse button, and move the pointer to the correct position.
To resize the light source or the opaque body, place the mouse pointer over one of the "handles" located at the corners of the light source or at the extremities of the opaque body; the pointer becomes a little cross: "+". Press the mouse button, and move the pointer until the light source or the opaque body has the correct size.
The shadow as it appears on the screen is displayed in the "Screen" window. The black circle is the umbra (region of total shadow) and the gray ring is the penumbra (partially shadowed region).
Using YP Shadow:
Note: To help you explore all menus of the program, you may use balloon help (with the "?" menu, in the top right corner of the screen).
Menus:
"Apple" Menu:
Use this menu to
- open an item from the Apple Menu Folder,
- consult online help
- unlock your copy of the program.
• "About YP Shadow..." item: When you select this item from the Apple menu, a dialog box showing information about the version number and copyright is displayed, as well as whether your copy of the software has been registered or not.
 
"Unlock" button: This button is visible only if your copy of the software has not yet been personalized. After receiving your personal unlocking code, click on this button to open another dialog box so that you may enter (or paste) your name and your unlocking code in the appropriate zones.
"Help & Info" Button: This button gives access to online help.
"File" Menu:
Use the "File Menu" to
- save content of the active window as a PICT file,
- close the active window,
- print the active window,
- quit YP Shadow.
"Save as PICT..." item: Saves the content of the active window (main window or "Screen" window) as a PICT file, which can be open by any draw of paint program.
"Close Window" item: Closes the active window.
"Page Setup..." item: Use this item when you want to use a different paper size, or orientation.
"Print" item: Use this item to print the content of the active window.
"Quit" item: Use this item from the file menu to quit the program "YP Shadow".
"Edit" Menu:
The "Cut", "Paste" and Delete" items are available only when a dialog box in which you may enter text is active.
The "Copy" item is also available when the main window or the "Screen" window is active, so you can easily copy the picture in the clipboard.
"Optics" Menu:
Use this menu
- to display the "Screen" window
- to show or hide the grid
- to show or hide the rays of light.
"Screen Window..." item: Displays the "Screen" window, if it is not visible already.
"Show/Hide Grid" item: Shows or hides a grid in the main window and in the "Screen" window.
"Show All Rays" item: Shows all the rays of light.
"Hide All Rays" item: Hides all the rays of light.
"Show/Hide Ray 1", etc. item: Shows or hides each ray of light individually. Useful if you want to explain to the class how to draw this kind of diagram.
"Help" Menu:
YP Shadow supports Balloon Help. Use this menu to show or hide help balloons, and to display online help.
Ordering information:
The demo (unregistered) version of YP Shadow may be freely distributed to allow anybody to try it before registering. You are permitted to upload it to an internet site, distribute it on a CD-ROM, or give a copy to a friend.
If you want to use YP Shadow on a regular basis, you must pay for a user license. You will then receive an unlocking code that will permit you to personalize your copy of the program.
The unregistered version have the following limitations:
• a window indicating how to order the full version is displayed at startup.
• the mention "This copy is for evaluation only." is permanently displayed in the main window.
• Several items from the "File" menu and the "Optics" menu are not available.
• The program quits after 10 minutes of use.
Your unlocked version will have the following advantages:
• the window indicating how to order the full version is not displayed at startup.
• the mention "This copy is for evaluation only." will never be displayed again in the main window.
• All items from the "File" menu and the "Optics" menu will be available.
• In the theory window, all the pages will be available.
• The program does not quit after 10 minutes of use.
In addition, you will be able to unlock all future updates of YP Shadow with the same unlocking code.
Methods of Payment:
Kagi, a company located in the United States, handles the payments for my software. You can pay by credit card (Visa, Master Card, American Express), by check or postal money order (in american dollars) or with cash. Schools located in Canada or in the United States can send me a purchase order. For more information about registering YP Shadow, please read the file"How to Order".
Detailed Prices:
Single User License: A $18.00 US registration fee will license one copy of YP Shadow for use on any one computer at any one time. For example, one copy may be used by any number of people and may be freely moved from one computer to another as long as there is no possibility of it being used simultaneously on more than one machine.
Site License: A license covering all computers located in the same building is available at the price of $250.00 US.
Technical Support:
If you have any comments or suggestions, please feel free to e-mail me at pelletier@kagi.com (or ch865@freenet.carleton.ca).
YP Shadow is provided “as-is”. Yves Pelletier hereby disclaims all warranties relating to this software, whether express or implied, including without limitation any implied warranties of merchantability or fitness for a particular purpose. Yves Pelletier will not be liable for any special, incidental, consequential, indirect or similar damages due to loss of data or any other reason, even if Yves Pelletier or an agent of his has been advised of the possibility of such damages. In no event shall Yves Pelletier be liable for any damages, regardless of the form of the claim. The person using the software bears all risk as to the quality and performance of the software.
