The offset percentage represents the ratio between how far the image is shifted from the projector lens center and half the image size. At 0% offset, the image is centered on the lens with half appearing above and half below. For example:
- At +100% offset : the entire image appears above the lens center.
- At -100% offset : the entire image appears below the lens center.
- At +40% offset : the image is shifted up by 40% of half the image height.
For a practical example: if you have a WUXGA projector and shift the image up by 600 pixels (when half the image height is 600 pixels), this would result in a 100% offset. If you shift it up by 720 pixels, this would give you a 120% offset.