4 ms·

Was the animation use-case forseen or accidental? If they thought they were making a slide show / ad / page flipping tool, I can understand prioritizing longer

Was the animation use-case forseen or accidental? If they thought they were making a slide show / ad / page flipping tool, I can understand prioritizing longer durations.

Sakos 4y ago
Apparently, GIF didn't originally support animation. It was added in GIF89a (https://www.w3.org/Graphics/GIF/spec-gif89a.txt https://www.w3.org/Graphics/GIF/spec-gif89a.txt) with the GCE (Graphic Control Extension). Which adds the delay time field which is the issue. > vii) Delay Time - If not 0, this field specifies the number of hundredths (1/100) of a second to wait before continuing with the processing of the Data Stream. The clock starts ticking immediately after the graphic is rendered. This field may be used in conjunction with the User Input Flag field. Additional info: https://en.wikipedia.org/wiki/GIF#Animated_GIF https://en.wikipedia.org/wiki/GIF#Animated_GIF This doesn't really answer your question, but it's all I could find so far.
- banana_giraffe 4y ago
  Given the "announcement" GIF image BOB_89A.GIF was itself a slide show with about 10 seconds between frames, clearly GCE was done with at least slide shows in mind. Incidentally, that same GIF uses the text extension, something basically no modern thing that can show GIFs supports anymore.
  - Sakos 4y ago
    It's such a weird use case. Why would anybody want a 30 second to 10 minute per image slideshow where you can't control the images?
    - banana_giraffe 4y ago
      Well, I think a poor-man screen saver was a common enough use case for that. That said, you can (or, rather, could) control the images. There's a flag in GIF89a that allows the viewer to skip ahead to the next frame on user input. No modern GIF viewer supports this anymore either. BOB_89A.GIF used this feature to let you skip ahead if you didn't want to just passively watch the slide show.

4 ms·

Was the animation use-case forseen or accidental? If they thought they were making a slide show / ad / page flipping tool, I can understand prioritizing longer

by jjoonathan 4y ago

Was the animation use-case forseen or accidental? If they thought they were making a slide show / ad / page flipping tool, I can understand prioritizing longer durations.

Sakos 4y ago
Apparently, GIF didn't originally support animation. It was added in GIF89a (https://www.w3.org/Graphics/GIF/spec-gif89a.txt https://www.w3.org/Graphics/GIF/spec-gif89a.txt) with the GCE (Graphic Control Extension). Which adds the delay time field which is the issue. > vii) Delay Time - If not 0, this field specifies the number of hundredths (1/100) of a second to wait before continuing with the processing of the Data Stream. The clock starts ticking immediately after the graphic is rendered. This field may be used in conjunction with the User Input Flag field. Additional info: https://en.wikipedia.org/wiki/GIF#Animated_GIF https://en.wikipedia.org/wiki/GIF#Animated_GIF This doesn't really answer your question, but it's all I could find so far.
- banana_giraffe 4y ago
  Given the "announcement" GIF image BOB_89A.GIF was itself a slide show with about 10 seconds between frames, clearly GCE was done with at least slide shows in mind. Incidentally, that same GIF uses the text extension, something basically no modern thing that can show GIFs supports anymore.
  - Sakos 4y ago
    It's such a weird use case. Why would anybody want a 30 second to 10 minute per image slideshow where you can't control the images?
    - banana_giraffe 4y ago
      Well, I think a poor-man screen saver was a common enough use case for that. That said, you can (or, rather, could) control the images. There's a flag in GIF89a that allows the viewer to skip ahead to the next frame on user input. No modern GIF viewer supports this anymore either. BOB_89A.GIF used this feature to let you skip ahead if you didn't want to just passively watch the slide show.