General preferences

You can access the program's general preferences dialog box by selecting "General preferences" from the Options menu, or pressing Command-K.

Black borders

When this option is unchecked, QuickSlideshow automatically draws a coloured border around pictures which do not fully fill your screen. The colour of the border is selected for each picture at random. If you prefer to always have a black border check the "Black borders" option. Sometimes pictures will seem to be off-centre or still have a black border. This is because the black border is part of the picture, and is therefore drawn on the screen before the coloured border is added.

Dither if monitor less than 256 colours

When this option is checked, QuickSlideshow automatically dithers pictures when your monitor is set to less than 256 colours. The dithering process approximates colours by blending available colours to simulate other colours. This process slows down the drawing of the picture.

Dither if scaled to other than 100%

When this option is checked, QuickSlideshow automatically dithers pictures when they are being scaled up or down (enlarged or reduced). The dithering process can make scaled pictures look more natural by reducing "banding" (vertical or horizontal lines), particularly when pictures are being scaled down (reduced). This process slows down the drawing of the picture. We suggest that unless you have a very fast Mac (or don't mind waiting about twice as long for each picture) that you leave this option unchecked.

Ignore single errors

Out of a collection of a few thousand pictures there will usually be a couple that cannot be displayed either because:

• The picture was incorrectly saved and cannot be processed; or
• The picture uses a file format the QuickSlideshow does not recognise.

If the "Ignore single errors" option is checked then non-consecutive errors will be quietly ignored.

If however there are multiple consecutive errors (because, for example there is not enough memory to display pictures) then an error alert will appear.

This is particularly useful for running unattended displays of many GIF pictures.

Note that QuickSlideshow has been tested with thousands of commercially available GIF pictures with only very occasional errors.

Minimum free memory

Selecting this option displays an alert box showing the smallest amount of memory that QuickSlideshow had free in the current session. You can use this to "tune" the amount of memory that it needs to display a particular series of pictures. For example, if you had 6000K allocated to QuickSlideshow, and after displaying an entire CDROM the minimum free memory available was 1500K, then you can probably safely allocate only 4500K to QuickSlideshow next time you want to display that CDROM. You would be advised to allow a "safety margin" of, say, 200K to be added to any figure obtained by the above method.

Mouse click advances

If this option is checked then clicking the mouse when viewing a picture advances to the next picture.

If the option is not checked then the mouse automatically becomes a "grabber hand" when clicked while viewing a picture that is larger than the screen.

Warn if screen less than 256 colours

Because QuickSlideshow displays pictures most efficiently (quickly) when your screen is set to 256 colours or more, it automatically warns you if your screen is set to less then 256 colours when the application starts up (providing your screen supports 256 colour mode or more). You can disable this warning message if you find it annoying by unchecking this option.

Automatically switch to 256 colours

If this option is checked, the program will automatically change your screen to display 256 colours if your screen is set to less than 256 colours when the application starts up (providing your screen supports 256 colour mode). You can disable this behaviour by unchecking this option.

Disable read-ahead of pictures

If this option is checked, the program does not read ahead the next picture while viewing the current one. This has been added (in version 1.4) for the benefit of uses who are planning to go backwards through the picture sequence a lot, or who are randomly jumping around the picture sequence by name. Although reading ahead normally speeds up program operation (when the program knows what the next picture in sequence is), is actually slows it down if you are viewing single pictures, or going backwards.

Do not show milestone while loading pictures

Normally, QuickSlideshow keeps you informed of its progress by showing a "loading picture" dialog box while it is loading the first two pictures in a sequence. If you are going backwards through the pictures, or jumping around through the sequence a lot (or doing a demonstration) you may find this dialog box distracting. By checking this option the dialog box is disabled.

Slideshow control options

You can access the program's slideshow options dialog box by selecting "Slideshow options" from the Options menu, or pressing Command-J. The first three options (automatic advance, random sequencing and looping) are also directly available from the menu bar under the "Slideshow" menu, however it is sometimes helpful to be able to see all of the program options at once (i.e. to see if they are on or off), and in those cases using this dialog box is more useful.

Automatic advance

If this option is checked then the program automatically advances to the next picture in the current sequence after the time delay specified by the "Delay between pictures" dialog box (you can access that dialog box by pressing Command-D). If the option is not checked then you must manually advance to the next picture by:

• Clicking the mouse; or
• Pressing the "return" or "enter" keys; or
• Pressing the space bar; or
• Pressing a key in the range "A" to "Z"

The "automatic advance" option can also be toggled (turned on and off) by pressing Command-A.

The "automatic advance" option can also be turned off by pressing F5, if you have an extended keyboard.

The "automatic advance" option can also be turned on by pressing F6, if you have an extended keyboard.

Random sequencing

If this option is checked then pictures are displayed in random sequence from the current picture list. If the option is unchecked then pictures are displayed sequentially.

• The "random" option can also be toggled (turned on and off) by pressing Command-R.
• The "random" option can also be turned off by pressing F7, if you have an extended keyboard.
• The "random" option can also be turned on by pressing F8, if you have an extended keyboard.

Loop at end of picture list

If this option is checked then when the entire list of pictures has been displayed the program starts displaying them again from the start. If the option is unchecked then pictures are only displayed once.

The "loop" option can also be toggled (turned on and off) by pressing Command-L.

Shrink pictures which are larger than the screen

When this option is checked, QuickSlideshow automatically scales down (reduces) pictures which are smaller than the screen. This makes the picture fit on the screen, but at the sacrifice of losing some picture detail. If you prefer large pictures to be shown at their actual size un-check this option. When a picture that is too large to fit is being drawn on the screen QuickSlideshow automatically draws a 3D-style border around the picture as a visual indication that there is more of the picture available. You can scroll around and see the rest of the picture by option-clicking with the mouse (the mouse pointer will turn into a "grabber hand"), and then - whilst holding the mouse down - moving the mouse around to see the rest of the picture. Alternatively, you can use the arrow keys on the keyboard, or the "page up", "page down", "home" and "end" keys.

The "shrink large pictures" option can also be turned off by pressing F9, if you have an extended keyboard.

The "shrink large pictures" option can also be turned on by pressing F10, if you have an extended keyboard.

Enlarge pictures which are smaller than the screen

When this option is checked, QuickSlideshow automatically scales up (enlarges) pictures which are smaller than the screen. This makes the picture bigger, but at the sacrifice of looking more "chunky". If you prefer smaller pictures to be shown at their actual size and centred on the screen, un-check this option.

Replace black pixels with best guess

When this option is checked, QuickSlideshow automatically replaces black pixels in the picture with its best guess about what colour should be there instead.

Experience has shown that a small percentage of GIF pictures (about 1%) have been erroneously saved with the colour black in their colour palettes where a non-black colour should have been (this is a fault in the GIF picture file, not QuickSlideshow). This is probably because the Mac's "Palette Manager" insists on the colours black and white being present in each palette.

In order to fix black pixels, the program scans the entire picture, counting the number of instances of each colour that is adjacent to black pixels. It then chooses the second-most popular one, and then replaces each black pixel in the picture with this colour.

In about 70% of pictures which have unsightly black pixels in the middle of them, this technique improves the picture considerably.

However, unless the picture you are viewing has a "black pixel" problem, we suggest leaving this option unchecked, because:

• The black pixels may be correct (i.e. genuine black areas); and
• Sometimes the guess gives a completely incorrect colour, which makes the picture worse; and
• The process described above takes time, because of the calculations involved

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