Provides access to members that control the AlgorithmicColorRamp. A color ramp defined by two colors and the algorithm used to traverse the intervening color space between them.

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Description

The IAlgorithmicColorRamp interface allows you to specify how the series of colors is created using several properties.

You can use any objects that supports the IColor interface to set the FromColor or ToColor properties, although returning the FromColor or ToColor always gives an HSVColor object. Note that the FromColor and ToColor properties are set by value; therefore you cannot change the RGB values directly from the IColor interface returned by the IAlgorithmicColorRamp interface.

There are three algorithms that the IAlgorithmicColorRamp interface uses: esriCIELabAlgorithm, esriHSVAlgorithm, and esriLabLChAlgorithm. There is very little difference between these Algorithms when the FromColor and the ToColor are of the same or very similar hue (for the sake of simplicity we will base this discussion on the HSV color model). But when the hues for the FromColor and the ToColor are different (Hue is different by 40 or more on a 0-360 scale), the algorithms produce different results. The esriHSVAlgorithm traverses the hue difference in a purely linear fashion, resulting in a bright ramp where all intermediate colors are represented. For instance, a ramp from red to green would include orange, yellow, and yellow-green. The esriCIELabAlgorithm and esriLabLChAlgorithm produce a more blended result. Thus, a ramp from dark green to orange would not contain a bright yellow, but instead a more brown and green-gold or green-brown intermediate color. The advantage of the CIELAB algorithm is that the colors of the ramp are visually equidistant, which produces a better ramp.

When To Use

Use the IAlgorithmicColorRamp when representing data in a layer that is sequential (interval or ratio data). Or, use the IAlgorithmicColorRamp when creating an IGradientFill symbol.

Members

Inherited Interfaces

CoClasses that implement IAlgorithmicColorRamp

See Also

AlgorithmicColorRampPropertyPage Class | IMultiPartColorRamp Interface | IColorRamp.Color Property | IColorRamp.CreateRamp Method | IRandomColorRamp Interface | IColorRamp Interface | IPresetColorRamp Interface | IAlgorithmicColorRamp Interface

.NET Snippets

Create Gradient Fill Symbol

.NET Samples

Use an AlgorithmicColorRamp to color a ClassBreaksRenderer (Code Files: frmAlgorithmicColorRamp) | Create a custom default raster catalog renderer (Code Files: CustomRasterCatalogRenderer_VBNET) | Multivariate renderer (Code Files: MultivariateRenderer)

.NET Related Topics

How to create a raster classify renderer | How to create a raster stretch renderer | How to make a gradient fill symbol | How to make different types of colors and color ramps