GrayView is made especially for converting Thunderscan SCAN files (that's the big file that results from a scanning session) into actual 32 gray shade images. These can be viewed just for pleasure, or used as StartupScreens, and should be usable in a variety of new products sure to come for the
Mac II. It is also very handy for viewing any PICT resource, color or black and white.
Menu Items
Apple Menu:
About GrayView: Look in here for information about the program, and the amount of bytes available for a picture. You can watch this number decrease as you open windows to see how much space your pictures take.
File Menu:
Open: Open presents a box allowing the user to specify a file to view. Two types of files will be presented: files of type 'gray' (those created by this program) and files of type 'PICT' (those created by MacDraw and programs that adhere to this standard, like Cricket Draw). Note that if you open a 'PICT' type file any object oriented graphics within will be converted to bit map graphics. This could be important if you intend to resave the file as a PICT file in GrayView and print it in another application.
If you hold down the Option key while choosing "Open" you will be able to select ANY type file. But the program will expect to find a PICT resource of ID = 0 inside the file, even if it is a MacDraw PICT file. If this is not found an error message will be presented. This is useful for looking at StartupScreens that might not have been created with GrayView.
Note that while this program was especially created for converting gray scale Thunderscan images, any PICT, including color ones, can be viewed.
Close: This closes the active window or desk accessory.
Save as...: When this is chosen the image in the active window is saved in a file. There are two options: the user can select to save the file as PICT resource with ID = 0 or to save it as MacDraw PICT file. The first format allows the image to be used as a StartupScreen (by naming it "StartupScreen" and placing it in your System Folder), allows you to open it later with this program, and allows it to be used with any other applications supporting PICT resources. The MacDraw PICT file can be opened from MacDraw and any application that uses such files.
Save section...: When this is chosen the image in the active window is displayed full screen (not in a window) and the user is given a chance to select only a portion for saving. Use the cross hair pointer to drag a rectangle on the image representing the portion you want to save. If the picture is too big to fit on the screen it will scroll as you drag. It will also scroll as you move the mouse to the edge for choosing where to start the selection. (The screen will scroll really fast if you hold down the option key, too. Try it!) If you change your mind merely click in the image. The user is presented with the same choices for file format as with the "Save as" menu item.
Quit: Quit this program.
Edit Menu:
This program supports Copying and Pasting. You can copy a section of an image in the active window by selecting "Copy". You will be given the opportunity to select a region to copy using the same technique described above for saving a section.
If you select Paste any PICT data currently on the Clipboard will be pasted into a new window.
Images copied with this program can be freely moved to other applications using the Clipboard and the Scrapbook. Similarly, PICTs from other programs can be pasted into a new window in GrayView.
Note that copied pictures can take huge amounts of memory, so please see the warnings below about memory constraints.
Convert Menu:
Thunderscan™ SCAN file: This allows the user to select SCAN file created by Thunderscan for conversion to gray scales. It is not useful at color or gray levels below 16, so be sure the Control Panel is set to at least 16 colors, and 256 if possible.
The user selects a file and the image is drawn on the full screen, 10 lines at time. The program continues until the entire SCAN file has been converted or the user clicks the mouse. So be careful, don't click the mouse accidentally or you'll have to restart the conversion. If the picture is larger than the size of the screen it will scroll as it's being processed.
The converted image is placed in a window. It is important to save this window before closing or quitting or the picture will be lost.
There is an option for this menu item. The process used to do the conversion is fast because it directly accesses the computer's screen memory. But future Macintoshes might be designed so this doesn't work properly. If so, holding down the Option key while selecting "SCAN" file will cause the conversion to be done much more slowly, but using a process that is sure to be compatible with future machines. For now don't worry about it but it's nice to know it's there.
Note: this slower method will also be invoked if the program is run in a mode supporting more than 256 colors. There are no such computers available now, however, and more colors wouldn't help the SCAN conversion process anyway, since it only needs 32 colors.
Thunderscan™ TEXT file: Thunderscan software gives the user another way of getting gray scale information out of a picture. You may notice that if you use the Thunderscan software to adjust the contrast and brightness of a picture, the converted SCAN file is not changed in GrayView. What you can do, however, is this: use Thunderscan to select the region of the picture you're interested in. After adjusting the picture until it looks right, select "Halftone" from the menu WHILE HOLDING DOWN THE OPTION KEY. A (large) TEXT file called GrayMapFile will be created on your disk. Quit Thunderscan and rename the file to anything you want. (If you don't rename the file and try this technique again, Thunderscan will write the new information on top of the old.)
Now run GrayView and select Thunderscan™ TEXT file from the Convert menu and chose your TEXT file. The conversion process from here on out is identical to the SCAN conversion.
Sometimes converting a TEXT file gives better quality pictures, and sometimes not. I don't have any set rules to try, just play around and see if you get nicer results. Be aware, though, that the TEXT file made by Thunderscan is even larger than the SCAN, so be sure to have plenty of disk space. Also be aware that the "Thunderscan™ TEXT file" item will theoretically allow you to convert ANY TEXT file, even a letter to your grandmother. Please be sure to select a picture file or unpredictable results are sure to follow.
Conversion Process
Converting from a Thunderscan file to a gray scale image goes without a hitch if you have your monitor set to at least 256 colors or gray scales. That gives you more than enough for the 32 needed to render the image faithfully. It is currently a fairly slow process, but that is to guarantee support with future Apple products.
If, however, you aren't fortunate enough to have an 8-bit display and are limited to 16 colors you can still convert files. For the time being the pictures will generally look bad, although I guess that's open to interpretation. Some images will take on a distinct Warhol-esque appearance.
It's not a simple matter to convert from 32 gray shades to 16. I've tried the so called "popularity algorithm" that analyzes the picture to find the 16 most used colors, and have had fair success. But it requires fiddling with the 16 colors available to the display hardware to present the image faithfully. That means colors have to be switched around every time a window is activated, or you open a desk accessory, or do anything that means your interested in a new image. The flashing light show on the screen is disconcerting.
Also, saving the image would require saving the 16 colors for use by other applications. This is not difficult, but information on the correct process is still sketchy.
But I haven't given up. More documentation on the Mac II's features should be forthcoming and I will try to fix this 16 color problem if enough people indicate they would find it useful. I have no idea what percentage of Mac II owners have 256 colors.
Known problems
I haven't seen too many problems so far, but whatever problems I have had have had to do with running out of memory. The program does its best to manage the memory properly and alert the user when it's running low, but accidents DO happen. A full screen window at 256 colors level can easily take over 250K. You shouldn't be fearful of opening many windows at once, but remember that saving a window takes memory and scanning a file takes memory. Please close a couple windows before crucial operations that might lose data, i.e. involving newly scanned files or pasted images. And PLEASE inform me if you're having a lot of trouble.
Possible Future Enhancements
• If a picture appears too dark or light, I'd like to have an option to shift the shades one direction or another. This would also be helpful for StartupScreens which generally appear too dark. But as ColorDeskTops become available you'll want the true shade used in this program. For now, you can adjust the shade using the Thunderscan software's brightness and contrast control.
• Some people have mentioned that it would be nice to view TIFF files created by PageMaker, Adobe Ilustrator, and others. I agree, but the TIFF format documentation is 30 pages long and I don't even own any programs that support TIFF. If you'd like this please let me know and I'll think about it.
Fixes and new features since version 1.01
• Groups the bit map properly when saving as a MacDraw PICT
• Ability to read MacDraw PICT files
• Ability to convert ThunderScan TEXT files
• "Zoom" scrolling when selecting large regions for copying or saving
Please send any comments or bug reports to one of the following addresses.
