Why does the "display all types" option exist?

[Drahken]

I never bothered to give it much thought before, but I find myself wondering why the "display all image file types" option even exists. I mean, why would you ever want to turn it off? "Oh, I have images in 20 different formats, but I only want to be able to view 2 of those."
I can see wanting to turn off non-image files (like audio/video/etc), but that's a seperate option.
I can also see wanting to not open a few specific file types, but that too is a seperate option.
Disabling the ability to view a whole class of file types (especially when you don't even have any way to know WHICH file types will be excluded, except by trial & error) though just doesn't seem to make any sense.

[XnTriq]

When trying Xnview, note the following option:

• General>Startup>[ ]Use all formats available
  • The most popular 150 file types out of about 500 available will be used when this option is off (the recommended default setting).
  • When enabled, extra file types will also appear in 'supported formats list' in program's menu.

• Option has been relocated in v.1.9+ series
  • General>Operations tab>[ ]Display all image file types.

Use all formats available – If checked, XnView can display all avaliable file formats. Otherwise only approx. 100 most popular formats are supported, and other are treated as 'Other' (unrecognized) files. This option also limits contents of the 'Associations' and 'Write>File types' lists in Options window and file types lists in Open and Save windows.
Turning off this option speeds up XnView operations.

"Use all formats available" is for startup (faster start if disabled), I think.

"Write > File types" is for "Save As"...

XnView v1.91.4 (Aug 30 2007) » File » Save As... » Save as type:

• Use all formats available: on = 75 / off = 62

In options dialog, General > Startup there's a setting "Use all formats available". This (more or less) hidden option determines which formats will be available in the drop down lists of the Open & Save dialog.

Determining the formats at startup needed quite some time, this is basically the reason why Pierre has changed this.

Let's look at the way it is now (in 1.80 RC1-3):
With Standard formats active (default), there is about 120 formats listed in the drop down list. This is far too much. Basically I need about four formats, so I have to search the list all the time. No good for most users.

Now image that I need 1 special format which is not amongst the standard formats. I have to activate "Use all formats available" and have too choose the formats in the list with about 300-400 entries. Again: No good.

I think another solution must be found here. The way it is now is too restrictive. We can discuss the current situation in this thread.

Should those Options be removed:

<!--// snip //-->

General>Startup
- Use all formats available
I didn't measure any difference in startup time (1s), nor while navigating through a whole folder (12s) with or without that option.

But... I don't see the use of "Use all formats available"(=>always ON), "Use EXIF DPI"(see 'output DPI' suggested here), "Adjust zoom if X/Y DPI are different"(=>always ON?) and 'Current' for "Startup directory".
If those options could be completely removed, creating a new panel would not be necessary.

Has anyone experienced any improvement by unchecking that option?

Yes. I confirm that program seems more stable. It also makes some options panels less crowded. And, you might not want some extensions seen as images? (ex: ".cat").

[xnview]

Old setting in some case, the speed of loading is better without it