Purpose
Ecount When count is zero, a two-byte extended count follows. This allows for Polytriangles of length 256 through 65,791 which are encoded as an integer in the range 0 to 65,535.
X1,Y1 The first vertex (in logical coordinates) of the first triangle in the list.
R1,G1,B1,A1 The color of the first vertex of the first triangle in the list (interpreted as intensities of the red, green, blue, and alpha channels, respectively). Legal intensity values range from zero to 255.
C1 The color of the first vertex of the first triangle in the list (interpreted as 4 bytes representing an RGBA color).
X2,Y2 The second vertex (in logical coordinates) of the first triangle in the list.
R2,G2,B2,A2 The color of the second vertex of the first triangle in the list.
C2 The color of the second vertex in the list (interpreted as four bytes representing an RGBA color).
Xi,Yi A vertex (in logical coordinates) in the list that, when combined with the previous two vertices, defines the ith triangle in the list.
Ri,Gi,Bi,Ai The color of the ith vertex in the list.
Ci The color of the ith vertex in the list (interpreted as 4 bytes representing an RGBA color).
Figure 1. polytriangle of six points
Each triangle is rendered by smoothly interpolating the color from each vertex across the interior.