Enhancement setup

• Viewer mode
• Save mode
• Copy mode
• Fax mode
• Mail mode
• Gimp plugin

• Gamma correction
• Brightness
• Contrast
• Threshold
• RGB default
• Negative
• Autoenhancement
• Default
• Restore
• Store
• Histogram window
• Pipette functions

• Pipette white
• Pipette gray
• Pipette black
• Unzoom
• Zoom out
• Zoom in
• Undo zoom
• Autoselect scanarea
• Autoraise scanarea
• Select visible area
• Select scanarea
• Move scanarea
• Delete preview cache

• Copy setup
• Display setup
• Enhancement setup
• Fax setup
• Image setup
• Mail setup
• Saving setup

You open the setup window via the menu preferences/setup in the main window of xsane.

THRESHOLD OPTION:

There are three options available:

• Standard options window (lineart)

The threshold option is kept untouched. If the backend makes available a "threshold" option you find it in the standard or advanced options window. You have to do a new preview scan to see changes of the threshold value.

• XSane main window (lineart)

If the backend makes available a "threshold" option it is moved to the main window. The value range is normalized (see THRESHOLD MINIMUM, MAXIMUM, MULTIPLIER, OFFSET). You have to do a new preview scan to see changes of the threshold value.

• XSane main window (grayscale->lineart)

If the backend makes available a "threshold" option it is moved to the main window. The preview scan is done in grayscale mode (see NAME OF GRAYSCALE SCANMODE) and transformed to black/white. Changes of the threshold value are visible in the preview window without a new preview scan. The value range of the threshold option is normalized (see THRESHOLD MINIMUM, MAXIMUM, MULTIPLIER, OFFSET).

THRESHOLD MINIMUM, MAXIMUM, MULTIPLIER, OFFSET:

These values are used to make the threshold function of the backends work the same way XSane does handle it. This is: the threshold value defines the brightness level in % that is needed to get a white point. A value of 0% creates a totally white image, a value of 100% creates a totally black image.
If the threshold function of the backend does not cover the full range (0-100% = white...black), you can reduce the range with the values MINIMUM and MAXIMUM. If the backend defines another value range (e.g 0-255 ) you have to enter a MULTIPLIER (2.55 for rang 0-255), with the OFFSET value you can shift the range linear.

The calculation is:

backend_threshold = OFFSET + MULTIPLIER * xsane_threshold

where the user can select xsane_threshold in the range from MINIMUM to MAXIMUM.

NAME OF GRAYSCALE SCANMODE:

If you want to do a grayscale previewscan when lineart scanmode is selected, you have to tell xsane the name of the grayscale mode. This is because the scanmode is defined by the backend and differen backends may use different names. You have to enter the original name (not translated) case sensitive (take a look at the scanmode selection menu in the xsane main window).
The name should be something like

Gray