Zoom Lens is a small application (around 17K) that magnifies the portion of the screen under the mouse cursor. The original version of the program was a desk accessory, but as desk accessories are less powerful than regular applications and can be awkward to use, I’ve expanded it into a full application program for use in the background under MultiFinder or System 7.
After releasing the first version, I received letters from people who’d found a lot of uses for this little program, ranging from magnifying displays in a drawing program for extra precision, to enlarging small text to aid the vision-impaired, to just playing around. Hopefully, this new version will be even more useful to an even larger group of people.
Zoom Lens is absolutely, completely, and totally free. Distribute as many copies as you want! All I ask is that you not modify the program, and that you include a copy of this file with each copy you make. And if you include Zoom Lens in a catalog, BBS, CD-ROM, or other software collection, let me know.
I welcome any and all comments about my software, and suggestions for future versions! Send any thoughts or ideas you may have to me at:
Steve Crutchfield
3000 N. Sheridan Rd. #10-D
Chicago, IL 60657
For a quicker response, you can contact me through the Internet. My address is “stevec@imsa.edu”. Most on-line services (including CompuServe, AppleLink, and America On-Line) allow you to send mail to Internet addresses.
OK, now that’s all taken care of...here’s some useful stuff to know about the program.
II. THE OPTIONS DIALOG
Normally, the magnified image in the Lens window is updated whenever the mouse is moved. The Options dialog allows you to specify other times when the window should be updated.
The “Update every ... ticks” option causes the window to be updated at periodic intervals. This is useful if you’re running a program—a menu bar clock, for example—that changes what’s on the screen without your moving the mouse. If you moved the cursor over the clock without this option activated and left it there, the Lens window would not be updated when the clock display changed.
6 ticks (one-tenth of a second) is a good lower limit for the delay time—more frequent updates will slow down the computer and cause the mouse cursor to flicker annoyingly, without producing a perceptible improvement.
If you’re using a word-processing or other text-oriented program, you might want to turn on the “Update when a key is pressed” option. This causes Zoom Lens to update its display whenever it detects a keypress. You’d want to use this option if you’re trying to magnify text as you type. Without it, the Lens window won’t change when you type a character, unless you also move the mouse. (Of course, this option isn’t really necessary if you’re using the periodic updating discussed above with a short enough frequency.)
The final button in the Options dialog, when activated, indicates the position of the mouse cursor in the Lens window with a small box. The box is drawn around the pixel which lies under the current mouse “hot spot” (the spot where a click is registered—the tip of the arrow cursor, or the center of the crosshair, for example). This is a useful feature when you’re using Zoom Lens to magnify a portion of a graphics document as you edit it, because it lets you see exactly which pixel will be affected when you press the mouse button.
III. OTHER FEATURES
Zoom Lens allows you to copy the magnified image in the Lens window to the Clipboard at any time, simply by choosing “Copy” from the Edit menu while Zoom Lens is in the foreground, or by pressing Command-C.
If you hold down the Command key while launching Zoom Lens, it will immediately drop into the background after it loads.
IV. KNOWN LIMITATIONS
When the “Update every ... ticks” option is on, the mouse cursor may appear to blink or flicker, even when Zoom Lens is in the background. This is normal, and is caused by the fact that Zoom Lens briefly hides the cursor in order to magnify the pixels hidden beneath it. To prevent the flicker, simply turn off the periodic update option.
If you have grown the Zoom Lens window so that it fills a large part of the screen, trying to capture the Lens image with the “Copy” command may not work. This is because large images require a lot of memory for storage, and Zoom Lens is pre-configured to use as little memory as possible. To fix this problem, give Zoom Lens a larger memory partition with the “Get Info...” command in the Finder.
Zoom Lens isn’t able to catch every keystroke (with the “Update when a key is pressed” option enabled) while it’s in the background. This is because many keystrokes are processed by the foreground application and removed from the event queue (the system’s list of all user actions) before Zoom Lens notices them them. As a result of this, Lens window updating may seem erratic. This problem will be fixed in the next version.
V. VERSION HISTORY
Version 1.0 (November, 1991):
• A simple desk accessory that allows the user to magnify an area of
the screen at different scales in a fixed-size window.
Version 2.0 (September, 1993):
• Zoom Lens is now an application instead of a desk accessory.
• The window can now be resized.
• Changes made to the Lens settings are now saved to disk.
• The magnified image in the Lens window can now be copied to the Clipboard.
• The available magnification factors were changed to be more useful.
• Added the “Options...” dialog, allowing the user to specify when the Lens
window should be updated.
• Added the option to display the location of the cursor in the Lens window.
• Release notes were written.
• Various bug fixes and minor changes.
VI. CREDIT WHERE DUE
Many thanks to Michael Kim for his great icons.
Thanks, also, to those of you who sent me letters
full of suggestions for this version of the program.
