Direction

The simple type ST_HueDir defines the direction of a hue color shift around a color wheel. A user can either define the shift to occur in the clockwise (cw) direction, or in the counterclockwise (ccw) direction. For example, in Figure 4, the span colors are red and green. The behavior shown in figure 4 is a shift in the cw direction. If the hue shift had been defined in the ccw direction, the colors interpolated between colors A and B would have been in the hues purple and blue. Another example of a hue direction shift in the clockwise can be seen in Figure 5 below along with the color shift from red to yellow and then from yellow to blue along the primary colors. Counterclockwise shifts would occur in the direction of yellow to red and blue to yellow in the examples below.

Figure 15: Example hue shifts in the clockwise direction around a color wheel applied to two diagrams. The three primary colors, red, yellow, and blue are used to represent the three major sections of a color wheel which ranges between red to yellow to blue to red.