Displaying a GIF on a Commodore 64 (via WinVICE emulator)

Created: 2020-Apr-04

Last Update: 2020-Apr-04

Tools required:

• WinVICE Commodore 8 bit Emulator [Official Download Site]
• DirMaster Windows-based Commodore floppy file manager (move and delete files on Commodore disk images) [Official Download Site]
• GraphicsMagick Multiplatform image conversion tool. This is necessary to convert images to GIF87a format. Most modern software will only write the later GIF89a format. [Official Download Site] - If you have a GNU/Linux box nearby you may have GraphicsMagick already installed, or ImageMagick, on which it is based. Those will also work.
• GIF File Decoder by John R. Wind - There are several versions of this application online. I am unsure of the difference between them. The one I provide is titled GIFFY C64 2.1 which was modified by someone named SKETCH - [Local Copy]
• Image editor of your choosing to assemble/crop/resize the image you want to display. I use GIMP.

Important Notes:

• The limiting factor here is colors. Because the Commodore 64 can only display 16 colors, color approximations may be inaccurate or severe. Images with a lot of slight color variations (such as you find with heavily anti-aliased lines) will produce blocky, ugly results. Line drawings work best, but you should also consider black and white, as well as color-reduced images. I have had some surprising results with photographs. It will take some experimentation.
• Using index mode in GIMP, I try to reduce the number of colors to less than 16 in the source image. Sometimes this provides better results and sometimes it doesn't.
• GIF87a format is required. All of the image editing and viewing applications I currently have installed do not support this format (nearly all GIFs you encounter online are GIF89a format, a later revision. If GIFFY returns a Not a GIF file! error message, this is likely the problem. GraphicsMagick and ImageMagick both handle conversion of any format to GIF87a. There may be other viewers or editors which also do so.

Install software:

Notes:

• WinVICE: Just unzip it into a convenient directory.
• DirMaster: Standard Windows installer, and it wants a reboot after. Note that Windows may throw up a warning because this is not widely-used software and they don't track it in their database. I have not had any problems with this software over the years, so it is OK to select More Info and allow it to run.
• GraphicsMagick: Run the installer. This application is run at the command line in the same manner as its GNU/Linux counterparts.
• GIFFY: Provided in a .d64 image you can load into WinVICE. As the program is small, I usually just copy any image I want to convert right on to this disk image, rather than use separate disk images. That's up to you though.

Prepare the image

Images should be 320x200 pixels and in GIF87a format.

For the sake of these instructions, we'll be using this image:

In preparing the image, I used Indexed color mode in GIMP and reduced the logo to three colors (red, white, blue). I then cropped the image, reduced it to 200 pixels height, and then adjusted the canvas size to be 320x200 with the logo in the center.

When you are done preparing your image, it is best to save it as PNG or another lossless format. JPG lossiness, especially as you save an image over several generations, is not handled well by GIFFY. This is also true of severely anti-aliased lines which use many shades of the line color. In the case of black lines, the anti-aliased pixels will be some variant of gray, but as the Commodore only has two, plus white, it may deliver sloppy results.

Once you have saved your 320x200 PNG image, it is necessary to use GraphicsMagick to convert the image to GIF87a format:

1. Run cmd.exe and navigate to where you saved your PNG file using the cd command. In my case, my Desktop.
   
   
2. Run the command to convert your PNG to GIF87a which is:
   

   gm convert sourcefile.png gif87:outfile.gif

   ...or in this case..
   

   gm convert clogo.png gif87:clogo.gif

   You should see a new .GIF file, but GraphicsMagick will not return any status.

Move new GIF to the GIFFY .d64 image

Launch DirMaster and select Disk -> Open and select the gifview.d64 disk image. We'll be writing your GIF directly to this image. If you want, you can create a new disk image and put your images there but not that GIFFY expects your image to be on drive 8.

If you see a bunch of garbage, it means you didn't reboot your computer after installing DirMaster:

Rebooting your machine will fix this.

Otherwise you should see the directory listing:

You can drag files into and out of DirMaster, and you can right click on files to remove them or perform other functions.

Using your mouse, drag in the GIF file you created:

Once you have done this, save the image using CTRL-S or DISK -> Save. Then, exit out of DirMaster.

Load GIFFY into WinVICE

Launch the C64 emulator in WinVICE. In File Explorer, navigate to the WinVICE directory and launch preferably x64sc.exe or x64.exe if you are running an older version of WinVICE.

Attach the gifview.d64 image to drive 8 using the ALT-8 shortcut or File -> Attach disk image -> Drive #8.

You may want to load the directory to make sure you've got everything set up properly.

Load GIFFY:

LOAD "GIFFY C64 2.1",8,1

and then type RUN and press enter. Using the ALT-W shortcut in WinVICE will engage warp mode which should speed loading times up.

Now enter the filename of your image without the .GIF file extension as well as the drive number (Drive 8, if that is where your GIF is).

GIFFY will examine your GIF and begin selecting colors to use. If you have many colors, this will take awhile. This is another good place to use Warp mode (ALT-W) to speed things along. In the case of our simple image, it is only three colors. Once colors are selected, you will be instructed that once the image is fully displayed, you can use the S key to save the results in Koala format for editing or use within the Commodore environment, or any other key to exit.

Press any key to continue. The image will be slowly displayed. Again, warp mode is handy here.

At this point you can press the S key to save the image or you can press another key to exit.

Here is the source image and the GIFFY-displayed image for comparison:

Source:

Destination:

Contact information:

See also: frostwarning.com