Color Reference

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Manipulating colors in FreeFlyer provides an obvious visual indication about the state of a particular object. PlotWindows, ViewWindows, WatchWindows, GridWindows, and ConsoleWindows all support color manipulation.

 

It can be useful to apply different colors to a Spacecraft based on a time sequence of events (for example, red for launch, yellow for ascent, and green once the spacecraft is on orbit). You can also illustrate the beginning and end of events by changing the color of a Spacecraft or GroundStation. In the example below, the Spacecraft color is changed to green when the Spacecraft is in contact with a GroundStation.

 

If (Spacecraft1.Contact(GroundStation1) == 1);

     Spacecraft1.Color = ColorTools.Green;

Else;

     Spacecraft1.Color = ColorTools.Red;

End;

 

There are a variety of Sample Mission Plans (included with your FreeFlyer installation) that demonstrate various applications of these topics. Continue to the Generating Output Samples page to view descriptions and images of these examples or jump to one of the Mission Plans listed below.

 

Generating Output Samples

•GraphicsOverlay Sensor Path

 

 

Color Systems

FreeFlyer allows users to manipulate colors through the following color systems:

 

•ColorTools object

oAllows you to directly specify the name of the desired color.

oDiscussed in detail below.

•RGB

oProvides access to the ratios of red, green, and blue components in the color.

oMore intuitive than Base 10 or Base 16.

•HSV

oIn the HSV color space, colors are determined by evaluating three components, namely:

▪Hue - ranging from 0 to 360, hue represents a color on the color wheel, where 0 corresponds to red, 120 corresponds to green, and 240 corresponds to blue.

▪Saturation - ranging from 0 to 1, saturation represents the amount of gray present, where 0 corresponds to pure gray, and 1 corresponds to the primary color.

▪Value or Lightness - ranging from 0 to 1, this represents the intensity of the color.

•L*A*B*

oIn the L*A*B* color space, colors are determined by evaluating three components, namely:

▪Lightness - ranging from 0 to 100, where 0 corresponds to black and 100 corresponds to white.

▪A* - green-red, negative numbers correspond to green, positive to red. Typically this runs from -100 to 100 or -128 to 127.

▪B* - blue-yellow, negative numbers correspond to blue, positive to yellow. Typically this runs from -100 to 100 or -128 to 127.

•Base 10

oLittle intuitive mapping to the color it represents.

•Base 16

oHexadecimal representation of the color.

oShows the red, green, and blue components on a scale of 0x00 to 0xFF (0 to 255).

oThe red component is specified at the right, green is in the middle, and blue is at the left.

oSo, 0xF0E1D2 has 0xD2 = (13*16+2) = 210 components of Red, 0xE1 = (14*16+1) = 225 components of Green, and 0xF0 = (15*16+0) = 240 components of Blue. This results in a light blue-gray.

 

The table below shows a comparison of the values of some basic colors in each of the systems supported by FreeFlyer.

 

Color

ColorTools

RGB

Base 10

Base 16

White

ColorTools.White

RGB(1,1,1)

16777215

0xFFFFFF

Black

ColorTools.Black

RGB(0,0,0)

0

0x000000

Red

ColorTools.Red

RGB(1,0,0)

255

0x0000FF

Green

ColorTools.Lime

RGB(0,1,0)

65280

0x00FF00

Blue

ColorTools.Blue

RGB(0,0,1)

16711680

0xFF0000

Yellow

ColorTools.Yellow

RGB(1,1,0)

65535

0x00FFFF

Cyan

ColorTools.Cyan

RGB(0,1,1)

16776960

0xFFFF00

Magenta

ColorTools.Magenta

RGB(1,0,1)

16711935

0xFF00FF

Gray

ColorTools.Gray

RGB(0.5,0.5,0.5)

8421504

0x808080

 

You can set colors for Spacecraft, GroundStation, Sensor, ProximityZone, PointGroup, Region, Star, Vector, and GraphicsOverlay objects, as well as some properties of the View, Plot, Grid, Console, and Watch windows. For example, you can set the tail color of a Spacecraft to green as follows:

 

Spacecraft1.Color = ColorTools.Lime

Spacecraft1.Color = RGB(0,1,0);

Spacecraft1.Color = 65280;

Spacecraft1.Color = 0x00FF00;

 

 

The ColorTools Object

The ColorTools object allows you to easily specify and manipulate colors in FreeFlyer.

 

Using Color Names

The ColorTools object provides access to the standard set of named colors, as shown in the example below for the color "yellow":

 

Spacecraft1.Color = ColorTools.Yellow;

 

The GetColorName and GetColorFromName methods allow users to determine the color value based on a known color name, and vice versa.

 

Report ColorTools.GetColorFromName("Yellow");

 

Report ColorTools.GetColorName(RGB(1, 1, 0));

 

Accessing Color Components

The GetRedComponent, GetGreenComponent, and GetBlueComponent methods return a value between 0 and 1 for each component.

 

Report ColorTools.GetRedComponent(ColorTools.Yellow);

Report ColorTools.GetGreenComponent(ColorTools.Yellow);

Report ColorTools.GetBlueComponent(ColorTools.Yellow);

 

Output:

 

ColorTools.GetRedComponent(ColorTools.Yellow)   = 1

ColorTools.GetGreenComponent(ColorTools.Yellow) = 1

ColorTools.GetBlueComponent(ColorTools.Yellow)  = 0

 

Accessing Colors in a Color Palette

The GetPaletteColors method returns the colors contained within the specified color palette.

 

// Return all of the colors contained within the color palette

Report ColorTools.GetPaletteColors("Bright");

 

// Return the first 3 colors contained within the color palette

Report ColorTools.GetPaletteColors("Bright",3);

 

Output:

 

// All colors contained within the "Bright" color palette

15214023.000000000

14805029.000000000

911537.000000000

6954205.000000000

16749867.000000000

 

// The first 3 colors contained within the "Bright" color palette

15214023.000000000

1480529.000000000

911537.000000000

 

ColorTools Palettes

The table below shows the options available for the ColorTools.GetPaletteColors() Method.

 

Value

Palette Colors

Default Type

"Accessible"

Qualitative

"Bright"

Qualitative

"Classic"

Qualitative

"Dark"

Qualitative

"Light"

Qualitative

"Paired"

Qualitative

"Pastel"

Qualitative

"Blues"

Sequential

"CubeHelix"

Sequential

"Grays"

Sequential

"Greens"

Sequential

"Purples"

Sequential

"Reds"

Sequential

"Spectral"

Sequential

"BluePurpleYellow"

Diverging

"GreenCyanBlue"

Diverging

"GreenYellowRed"

Diverging

"PurpleBlueGreen"

Diverging

"YellowRedPurple"

Diverging

"BlueCyanGreen"

"Terrain"

"BlueYellowGreen"

"Terrain"

"BrownWhiteOrange"

"Terrain"

"GreenBrownWhite"

"Terrain"

"YellowTanBeige"

"Terrain"

 

Adjusting Brightness

The AdjustBrightness method takes an input color (dark olive green in the example below) and adjusts its brightness by a specified factor. If the factor is less than 1, the resulting color is darker; a factor greater than 1 results in a lighter color. A factor of 1 causes no change.

 

If any of the red, green, and/or blue components of the input color is equal to 1, the color cannot be brightened. Setting a brightness factor greater than 1 will have no effect.

 

// Create a "triangle strip" GraphicsOverlay with color based on dark olive green with a brightness factor between 0 and 2

 

GraphicsOverlay GO;

GO.ShapeType = "Triangle Strip";

 

For i = 0 to 1 step 0.1;

     color = ColorTools.AdjustBrightness(ColorTools.DarkOliveGreen, i*2);

 

          GO.AddOverlayElement(7000*cos(pi+i*2*pi), 7000*sin(pi+i*2*pi), -10000, color);

     GO.AddOverlayElement(7000*cos(pi+i*2*pi), 7000*sin(pi+i*2*pi), 10000, color);

 

     Map GO;

End;

 

Dark olive green with brightness factor between 0 and 2

Dark olive green with brightness factor between 0 and 2

 

Interpolating Colors

The InterpolateColorRGB method interpolates two or more colors given a designated weight in the RGB color space. The InterpolateColorHSV method interpolates two or more colors given a designated weight in the HSV color space. The InterpolateColorLAB method interpolates two or more colors given a designated weight in the L*A*B* color space. It should be noted, L*A*B* interpolation assumes that colors are in sRGB and use the standard D65 white point. In the example below, the colors crimson, chartreuse, dodger blue, and gold are interpolated into 100 unique colors.

 

// Create a "triangle strip" GraphicsOverlay with colors interpolated based on a set of 4 input colors

 

GraphicsOverlay GO;

GO.ShapeType = "Triangle Strip";

 

For i = 0 to 1 step 0.01;

     color = ColorTools.InterpolateColorRGB({ColorTools.Crimson, ColorTools.Chartreuse, ColorTools.DodgerBlue, ColorTools.Gold}, i);

 

     GO.AddOverlayElement(7000*cos(pi+i*2*pi), 7000*sin(pi+i*2*pi), -10000, color);

     GO.AddOverlayElement(7000*cos(pi+i*2*pi), 7000*sin(pi+i*2*pi), 10000, color);

 

     Map GO;

End;

 

Four interpolated colors

Four interpolated colors

 

Grayscale

The ConvertToGrayscale method gets the grayscale value of the specified color using the formula: 0.30 * R + 0.59 * G + 0.11 * B. The example below shows the grayscale equivalent of the dark olive green AdjustBrightness example above.

 

// Create a "triangle strip" GraphicsOverlay with color based on grayscale version of dark olive green with a brightness factor between 0 and 2

 

GraphicsOverlay GO;

GO.ShapeType = "Triangle Strip";

 

For i = 0 to 1 step 0.1;

     color = ColorTools.AdjustBrightness(ColorTools.DarkOliveGreen, i*2);

     color = ColorTools.ConvertToGrayscale(color);

 

     GO.AddOverlayElement(7000*cos(pi+i*2*pi), 7000*sin(pi+i*2*pi), -10000, color);

     GO.AddOverlayElement(7000*cos(pi+i*2*pi), 7000*sin(pi+i*2*pi), 10000, color);

 

     Map GO;

End;

 

Grayscale equivalent of Dark Olive Green image above

Grayscale equivalent of Dark Olive Green image above

 

 

See Also

•GraphicsOverlays

•BlockageDiagrams