D-Type Direct Color Rasterizer is an advanced rasterizer that ships with more recent versions of D-Type Engine. Unlike D-Type Grayscale Rasterizer which is designed to render one grayscale (or single color) shape at a time, D-Type Direct Color Rasterizer can generate an entire multi-color RGBA scene during the very rasterization process. Best of all, this is all done in a single rasterization pass! This unique feature makes it possible for D-Type Direct Color Rasterizer to render high-quality scalable anti-aliased graphics with perfect stitching between adjacent fill areas of different color amazingly fast.
More specifically, with D-Type Direct Color Rasterizer, color and transparency are an essential part of the rasterization process. Applications only need to assign different RGBA values to different contours during the scene construction phase. Coloring and pixel stitching is then performed automatically by D-Type Direct Color Rasterizer. We say that the color is directly applied, which is why this rasterizer is known as D-Type Direct Color Rasterizer.
In contrast, D-Type Grayscale Rasterizer is unaware of the final color that will be applied to the pixels; coloring and pixel stitching is not performed during the rasterization process but at display time, when rasterized pixels are alpha-blended into the background.
To better illustrate the difference between perfect stitching offered by D-Type Direct Color Rasterizer and standard stitching offered by D-Type Grayscale Rasterizer, compare the following two images:
D-Type Direct Color Rasterizer
D-Type Grayscale Rasterizer
Both images were generated by rasterizing the same vector art. However, the image generated by D-Type Direct Color Rasterizer (left) looks better than the image generated by D-Type Grayscale Rasterizer (right). This is because D-Type Direct Color Rasterizer features perfect stitching between adjacent fill areas of different color.
The following magnified images show a little bit more clearly the difference between perfect pixel stitching offered by D-Type Direct Color Rasterizer and standard (alpha blended) pixel stitching offered by D-Type Grayscale Rasterizer. The difference is only noticeable when the contour edges are adjacent or extremely close to each other (i.e. less than 1 pixel). When they are spaced further apart (i.e. more than 1 pixel) or when they overlap, D-Type Direct Color Rasterizer and D-Type Grayscale Rasterizer will produce the same result.
Perfect pixel stitching of adjacent contour edges
(D-Type Direct Color Rasterizer)
Standard pixel stitching of adjacent contour edges
(alpha blending)