ArcObjects Library Reference (Display)

IGradientFillSymbol Interface

Provides access to members that control the gradient fill symbol.

Product Availability

Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.

Description

IGradientFillSymbol is used to draw color ramp within the limits of the filled area. You can set the GradientPercentage to control the saturation and the IntervalCount to set the number of displayed colors. Additionally, Style and GradientAngle can be set to further control the appearance of the ramp within the fill. Use the IFillSymbol interface to set additional properties for IGradientFillSymbols.

Members

		Description
	Color	Fill color.
	ColorRamp	Color ramp property.
	GradientAngle	Direction of fill gradient.
	GradientPercentage	Gradient percentage - controls the bleeding effect of the fill.
	IntervalCount	Interval count - controls number of colors in the color ramp.
	Outline	Line symbol of fill outline.
	Style	Gradient fill style.

Inherited Interfaces

Interfaces	Description
IFillSymbol	Provides access to members that control fill symbols.

CoClasses that implement IGradientFillSymbol

CoClasses and Classes	Description
GradientFillSymbol	A fill symbol composed from a ramp of colors.

Remarks

Set any IColorRamp onto the ColorRamp property and it will be used to fill the areal feature. A graded effect can best be achieved by using an AlgorithmicColorRamp.

Note that you do not need to set a Size or call CreateRamp on your ColorRamp. Instead, the IntervalCount property defines the number of color steps required. Set the IntervalCount property depending on what kind of effect you wish to achieve.

You may wish to use the GradientFillSymbol to produce a smooth gradation of color in an area and therefore need an appropriate IntervalCount. The average computer screen has a resolution at least three times as coarse as the average printer at 300 dpi, as a rough guide. Therefore, a smooth fill on the screen may appear banded in the printed output.

To produce a smooth progression of color in your fill for output to a pirinter, first set the 1:1 scale on the PageLayout view to account for differences in printed scale and onscreen scale. Next, experiment to find the IntervalCount at which the fill appears smooth on the screen--this will be dependent on the characteristics of your ColorRamp, the size of the area to be filled, and the GradientPercentage. Then, multiply the IntervalCount by at least 3 times and try your output.

The GradientPercentage can be a value between 0 and 1. A value of one indicates that the entire shape should be filled with the color ramp, but a value of 0.5 indicates only half the shape should be filled with the color ramp; the first half of the area is filled by the first color in the color ramp, and the remaining area is filled with the color ramp.