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The color sequence editor (Clut Editor) is used to create and modify color sequences to be used to color code height, or other values. To start the clut editor, a clut is selected in the "Textures" section of the object panel (Selecting View->Object from the menu enables the object panel) , and the Edit button is clicked.
The layout of the Clut Editor consists of the selected clut's label at the top, with the color panel on the left, and an entry panel on the right. (This layout is subject to change, as more features and enhancements are added to the color sequence editor).
Starting from the left, the color panel consists of two vertical color ranges. The leftmost color range displays the whole range of the color sequence. The next range shows the selected range, which is a magnified subrange of the color sequence. Selecting a sub range is done by left clicking and draging the mouse in the leftmost range. The starting point and ending point of the click and drag operation become the end points of the selected range. Fine white lines visualy indicate in which part of the color sequence the selected sub range belongs.
Selecting a color to be edited is done by clicking the appropriate color in the selected sub range. The color appears in the selected color box, and a white line indicates which of the colors from the selected sub range is the current color. Three scales colored red, green and blue displays the RGB components of the selected color, and allow the color components to be modified by clicking the desired area in the appropriate color scale. To the right, the selected color is displayed and may be adjusted using the HSV color space.
To the right of the selected color box is the clip board box. A color may be stored in the clip board for future use. The three buttons between the selected color box and the clip boead box control the use of the clipboard. The top, left pointing button copies the clipboard color to the current selected color. The middle button, with arrows pointing both left and right, exchanges the clipboard color and the current selected color. The bottom, right pointing arrow copies the currently selected color to the clipboard.
The entry panel allows for the addition, deletion and modifying of color cells. The height of the top of the currently selected color cell is displayed. The bottom of the selected color cell is defined as the top of the next color. If no color exsists below a given color, the color stretches to infinity. The top color also stretches to infinity. A color cell may be added by specifying it's height in the New Height: input box, and clicking add. The new color becomes the selected color, and defaults to black. The selected color may be deleted by clicking the delete button. The selected color's height may be modified by entering the new height in the New Height: entry box, and clicking the Set button.
The extents of the whole color sequence may be modified. In other words, the clut may be scaled and shifted. The current maximum cell hight and minimum cell height are displayed, along with input boxes to enter new values. The modify Extents button scales and translates the clut as necessary to produce a sequence that spans the desired range. For example, a color table designed for a range of 0 to 1000 will display the same color for a whole bathymetric dataset ranging from -800 to -1200. Moving and shrinking the clut to span that range is simply done by entering the limits of the range in the entry boxes, and clicking Modify Extents.
Another feature of the Color Sequence Editor is the ability to create a range of colors which are interpolated from a few key color cells. A range is created by creating a new color starting from the position specified by Range Min: and increasing by the value in Sstep Size: until the position specified by Range Max: is reached. The color added at each of those positions is the average, weighted by relative distance, of the next colors below and above the current position.
Clearing the current clut to start with a clean slate is done
by clicking the Clear Clut button. The button is disabled by default
to prevent accidental clearing of the clut. Checking the Enable
box allows the Clear Clut button to be pressed. This method was
inspired by the power tools method of safetying their trigger,
and avoids the need for an "Are you sure?" dialog box.