4.3.6.2 Colormap Tool
Colormap Tool Function:
The Colormap Tool provides a mechanism to visualize the current
X color map. The tool displays a square showing the 256
entries of the color map. This square is active and can be
used to find details of an individual color by picking the
color desired with MB1. A smaller color square will show the
color picked as well. The red, green and blue values for the
color will be shown with the pixel value of the color. The
hue, lightness and saturation of the color can also be shown.
RGB/HLS radio buttons:
These buttons toggle the displayed information for the picked
color in either RGB intensity values from 0-255 or in hue values
from 0-360 degrees, lightness values from 0-1 and saturation
values from 0-1. The method used to visualize the color map is
also toggled by this button. When HLS is chosen, two projections
of the color map in HLS colorspace are displayed.
RGB Color Square:
The RGB color square shows the colors of the current color map
in a 16x16 array of colors. By default the colors are ordered
by the color map pixel value. A sort option is provided to
organize the color representation in different orders. Each
color in the color square is pickable to view the red, green
and blue intensities for the color.
Hue-Saturation Projection:
A display showing hue and saturation provides a tool for
analyzing the color balance of the color map. The HLS hexagon
shows hues as an angle starting at 0 degrees for red.
Saturation is represented by the distance from the center of
the hexagon. An alpha version of the HLS adjustment tool
for hue or saturation modification is availble by selecting
the or toggle buttons. Choosing either of these
buttons displays a representation of the average hue and
saturation in each of the primary color sectors, red, yellow,
green, cyan, blue and majenta. Hue rotation or saturation
adjustment can be performed for a primary color sector by
moving the handle for that primary. The overal average hue
and saturation is shown as an open rectange and can be
manipulated to adjust the entire gamut of colors. Note
that this is an alpha release of the color modification tools
and as such provide a view only capability.
Light-Saturation Projection:
A display showing lightness and saturation provides a view of
the brightness of the image colors. The projection depicts the
cone shape of the HLS space with lightness shown vertically and
saturation as the distance from the center. The projection
corresponds to the hue-saturation projection in orientation with
red, yellow and magenta colors shown to the right and green, cyan
and blue colors shown to the left of center. Selecting the
toggle initiates the display of lightness adjustment
handles which can be manipulated to perform a contrast stretch
a brightness modification. The top handle represents the average
lightness for colors with a lightness > .5 while the bottom handle
if for colors <= .5. An open rectangular handle adjusts the
overall lightness and is position at the average for the range
of colors. Note that this is an alpha release of the color
modification tools and as such provide a view only capability.
Pixel slider:
The pixel slider selects the color information shown by the
following sliders. When HLS projections are displayed, the
color chosen is outlined by a black rectangle.
Red/Green/Blue sliders:
Hue/Light/Sat sliders:
These sliders depict the color map information for the current
pixel number selected. The sliders are also enabled to allow
the modification of the color selection for viewing purposes
only. The color modifications made will be overridden by
the overall adjustments made by the Color Tool.
Sort Option:
The sort option provides a method the order the colors depicted
in the RGB Color Square. The colors can be sorted by pixel
value, red, green or blue intensity or by hue, saturation or
lightness values. Note that only the colors depicted in the
image are sorted.
Show Colormap List:
This option initiates the display of a scrolled list window
which provides details on each color map entry. Information
displayed includes the pixel number, red, green and blue
intensities and hue, lightness and saturation values. The
button toggles to Hide Colormap List to provide a mechanism
to remove the color map list display.
Isolate:
The Isolate button provides a mechanism to view a particular
color in the image by erasing all other colors. The Isolate
button toggles to Restore to reset the color map to the proper
values.
Undo:
The Undo button rolls back the latest modification to the
color map. Pressing undo again, reapplies the latest updates.
Dismiss:
The Dismiss button hides the map tool window.