CW_CLR_INDEX

The CW_CLR_INDEX function creates a compound widget for the selection of a color index. A horizontal color bar is displayed. Clicking on the bar sets the color index.

The returned value of this function is the widget ID of the newly-created color index widget.

This routine is written in the IDL language. Its source code can be found in the file


cw_clr_index.pro

in the

lib

subdirectory of the IDL distribution.

Keywords

COLOR_VALUES

A vector of color indices containing the colors to be displayed in the color bar. If omitted, NCOLORS and START_COLOR specify the range of color indices.

EVENT_FUNCT

A string containing the name of a function to be called by the WIDGET_EVENT function when an event arrives from a widget in the widget hierarchy rooted at the newly-created widget. This function is called with the return value structure whenever a button is pressed, and follows the conventions for user-written event functions.

FRAME

If set, a frame will be drawn around the widget.

LABEL

A text label that appears to the left of the color bar.

NCOLORS

The number of colors to place in the color bar. The default is !D.N_COLORS.

START_COLOR

The starting color index, placed at the left of the bar.

UVALUE

The "user value" to be assigned to the widget.

XSIZE

The width of the color bar in pixels. The default is 192.

YSIZE

The height of the color bar in pixels. The default is 12.

Keywords to WIDGET_CONTROL and WIDGET_INFO

The widget ID returned by most compound widgets is actually the ID of the compound widget's base widget. This means that many keywords to the WIDGET_CONTROL and WIDGET_INFO routines that affect or return information on base widgets can be used with compound widgets.

In addition, you can use the GET_UVALUE and SET_VALUE keywords to WIDGET_CONTROL to obtain or set the value of the color selection widget. The value of a CW_CLR_INDEX widget is the index of the color selected.

See Compound Widgets for a more complete discussion of controlling compound widgets using WIDGET_CONTROL and WIDGET_INFO .

Widget Events Returned by the CW_CLR_INDEX Widget

This widget generates event structures with the following definition:

Event = {CW_COLOR_INDEX, ID: base, TOP: ev.top, HANDLER: 0L, VALUE:c}

The VALUE field is the color index selected.