NEC uPD72257, Preliminary User'S Manual

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8.3 Drawing Features
8.3.1 Drawing features summary
8.3.1.1 Colour formats
Supported colour formats are
Framebuffer formats • a(8), aCLUT(8)
• RGB(565)
• RGB(888)
• aRGB(4444)
Texture formats • a(8), aCLUT(8)
• RGB(565)
• RGB(888)
• aRGB(4444)
• aRGB(1555)
• aCLUT(44)
• CLUT(4) via colour expansion unit
8.3.1.2 BitBLT features
BitBLT features are executed by the Drawing Engine similar to vector drawing.
For that the unit draws a rectangle and textures it according to the selected BitBLT
function. This results in the following BitBLT features:
• fill
• copy
• stretch BitBLT
• rotate and scale
• alpha blending
• bilinear filtering
• colour conversion
• subpixel exact placement
8.3.1.3 Vector drawing features
The vector Drawing Engine uses a halfplane rendering approach. Therefore it is
easy to implement edge antialiasing and blurring without much overhead. When
combining some of the units not only linear primitives like lines or polygons but
also quadratic equation based primitives like circles and ellipsoids can be drawn.
• lines
• polygons
• circles and ellipses
• quadratic curves (software driver support)
• 2D texture mapping
• bilinear filtering of the textures
Drawing Engine Chapter 8
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