Configures the following options:
Color reduction method
See ``Color reduction'' (Sec. 5.1.1).
Quantization - (Default) Calculates the optimal set of 256
colors to match the image as closely as possible.
Fit current colormap - Calculates the closest match to the currently-selected colormap. This
method can give a smoother result than quantization or it can give garbage,
depending on how closely the colors in the colormap match the image.
If there are several images that need to be converted to the same colormap, one procedure is to convert the first one using quantization then convert the rest by fitting to the current colormap.
This method is used automatically for 3D images.
Update undo buffer
Automatically: Backs up the image after every operation that transforms the image.
Manually: The image is backed up when it is first created. Thereafter, selecting ``Image..Backup'' will back it up.
Never: No backup is created.
``Image...Restore'' will restore the image to its state when it was last backed up. If you make a mistake when filtering or adding text to the image, you can restore the most recent backup from the undo buffer by selecting ``Image...Restore''. See also Sec. 6.7.
Colormap usage
The X Window system allows applications to setting colors in two ways: by allocating individual colors as needed, or by installing a colormap. When one program allocates a color, it cannot be changed by other programs. In many situations, if other programs or the window manager have used most of the color cells, the image quality can be severely degraded. This is common, for example, on Sun workstations. In this case it is recommended to select ``install colormap''. Because this can cause screen flashing if the mouse moves away from the tnimage window, the tnimage window should also be enlarged to full screen in this situation.
This option is set automatically if less than 32 free color cells are available.
Spray factor
Controls the area affected by ``fine spray'', ``math spray'' , etc (in ``Draw...Spray'' menu).
Cursor movement rate
Controls (a) distance moved by the mouse cursor when the arrow keys are pressed, and (b) the distance which an image moves when you click one of the 4 arrows at the top of the screen.
Significant digits
Changes the number of significant digits to display when using a floating-point number.
Active color planes
Selects which colors (red, green, or blue) are capable of being modified. For example, if ``red'' and ``green'' are un-checked, smoothing the image would only smooth the blue component, while the red and green components were unaffected. Using this method to sharpen one color, while leaving the other colors unaffected, or warping a single color, can create an unusual artistic effect.
This feature only works for color images greater than 8 bytes/pixel. To use color planes on an 8 bit/pixel image, select ``Color...Change color depth'' and convert the image to 24 bits/pixel.
Main Cursor
Sets shape of the normal cursor. If ``full screen crosshairs'' is selected, the Xlib cursor is turned off and full window vertical and horizontal lines are drawn in the foreground color.
Raise image on focus
If checked, clicking on an image will bring the image window to the foreground.
Separate windows
If checked, new images will be placed in separate, positionable windows.
Window border
If checked, new images will have a complete X-window border and decoration. This option is only effective if ``Separate windows'' is also checked. The exact appearance will depend on the window manager.
Text spacing Adds extra space between characters (units=pixels).
Object threshold
See ``Selecting Objects'' (Sec. 3.5.2). Selects the RGB distance to use in determining the edge of an object.