GIF is Compuserve╒s standard for defining generalized color raster images. The ╥Graphics Interchange Format╙ allows high-quality, high-resolution graphics to be displayed on a variety of graphics hardware and is intended as an exchange and display mechanism for graphics images.
Vision Lab supports GIF images of any size limited only by the available memory in the Macintosh being used. Images can and be saved and read in both interlaced and non-interlaced formats. GIF color images can contain a maximum of 256 colors and are fully supported on the Macintosh II. (Vision Lab will operate in any color mode but it is recommended that the Macintosh II be set to 8-bit mode for the best possible image display).
Because of the compression method GIF uses in storing images you may find files saved in this format take up the least amount of disk space.
If you are interested in obtaining graphics images in all different colors and sizes and have a Compuserve account, visit the ~SB~PICS~SB~ forum by typing ~SB~GO PICS~SB~ while logged on to Compuserve. The data libraries contain thousands of GIF files for downloading and the message base can be your link to all kinds of helpful graphics information.
~SB~Opening GIF Files:~SB~
When opening a multiple image GIF file you can stop loading images at any point by holding down the Command and period (.) keys.
RLE files can also be opened as ╥GIF╙ files.
Vision Lab considers any ╘~F4~TEXT~F3~╒ file as a possible GIF file. ╘~F4~GIFf~F3~╒ files can also be opened by Vision Lab.
~SB~Saving GIF Files:~SB~
GIF files can contain up to 256 colors. Vision Lab will open multiple image GIF files but it cannot save multiple image GIF files.
~SB~GIF¬ Preferences╔:~SB~
If ~SB~Remap Local Color Maps~SB~ is checked the local color maps found in multi-image GIF files will be remapped. If a global map was present in the GIF file then the local colors will be remapped to the closest matching colors in the global GIF color map. Otherwise remapping depends on the machine you are using. If you are using a Macintosh II the local colors will be remapped to the closest matching colors found in the clut selected for loading PICT files and resources. For non-color machines the local colors will be remapped to the closest matching gray values. Note that if the GIF file does not contain a global color map the image will be opened using eight bits of color (or gray levels) regardless of the local image depths. If this option is not checked then the color environment will be replaced by the local color maps for every image loaded. This will probably make the entire image look like a real mess but you will be able to see the individual images in their true colors by using command-period to stop any more images from loading.
GIF files will be saved in the interlaced format if ~SB~Save Interlaced GIF Files~SB~ is checked. It is better to upload interlaced files to systems that provide on-line GIF viewing because the interlaced format allows the downloader to see pretty much how the image will look while only downloading a fraction of the total image. This way the downloader could abort the download and save connect charges if he is not interested in downloading in full detail.
You have your choice of either saving GIF files as ╘TEXT╒ type files or ╘GIFf╒ type files. Select the ╘GIFf╒ option if you will be using the files with other Macintosh programs. The ╘TEXT╒ option is provided for ease of porting and uploading to other systems.
If ~SB~Convert GIF File Types~SB~ is checked then un-locked GIF files opened on un-locked disks with automatically be converted to either ╘TEXT╒ or ╘GIFf╒ Vision Lab GIF files. This option does not change the contents of the file but simply changes the file type and creator so if you double click on the document╒s icon Vision Lab will open it. The type that the files will be changed to will be the same type Vision Lab is set for saving GIF files.
~SB~Pros:~SB~
GIF images usually take up less room on your disk because of the compression method used with these files. GIF files can be easily ported to other computer systems. GIF files save all the information contained in color images up to a maximum of 256 colors.
~SB~Cons:~SB~
Compression method used may make for slow saving and opening of files. Very few programs are capable of opening GIF files as of yet.
