Identifies the different image transition effects.

Values:

IG_WIPE_LEFTTORIGHT	Left-to-Right Wipe.
IG_WIPE_RIGHTTOLEFT	Right-To-Left Wipe.
IG_WIPE_UP_TO_DOWN	Up-to-Down Wipe.
IG_WIPE_DOWN_TO_UP	Down-to-Up Wipe.
IG_WIPE_SPARKLE	Sparkle Transition.
IG_WIPE_ULTOLRDIAG	Upper Left to Lower Right wipe.
IG_WIPE_LRTOULDIAG	Lower Right to Upper Left wipe.
IG_WIPE_URTOLLDIAG	Upper Right to Lower Left wipe.
IG_WIPE_LLTOURDIAG	Lower Left to Upper Right wipe.
IG_WIPE_CLOCK	Clockwise wipe.
IG_WIPE_SPARKLE_CLOCK	Clockwise wipe with sparkles.
IG_WIPE_DOUBLE_CLOCK	Two simultaneous clockwise wipes, 180 grades apart.
IG_WIPE_SLIDE_RIGHT	New image slides in from the left.
IG_WIPE_SLIDE_LEFT	New image slides in from the right.
IG_WIPE_SLIDE_UP	New image slides in from the down.
IG_WIPE_SLIDE_DOWN	New image slides in from the up.
IG_WIPE_RANDOM_BARS_DOWN	Vertical bars of old image fall to reveal new image.
IG_WIPE_RAIN	Vertical lines of new image cover over old, like paint running down the side of a bucket.
IG_WIPE_BOOK	Book wipe.
IG_WIPE_ROLL	Old image rolls in from right to left.
IG_WIPE_UNROLL	New image rolls out from left to right.
IG_WIPE_EXPAND_PROPORTIONAL	New image expands from the center of old image in diagonal directions.
IG_WIPE_EXPAND_HORIZONTAL	New image expands from the center of old image in horizontal directions.
IG_WIPE_EXPAND_VERTICAL	New image expands from the center of old image in vertical directions.
IG_WIPE_STRIPS_HORIZONTAL	New image appears as expanding horizontal strips.
IG_WIPE_STRIPS_VERTICAL	New image appears as expanding vertical strips.
IG_WIPE_CELLS	New image appears as expanding square cells.
IG_WIPE_BALL	New image appears as tracks of spirally moving balls.
IG_WIPE_GEARS	New image appears as tracks of moving ImageGear's icons.