What Is a Raster Operation Processor?

A raster operator is just one part of a graphics processor that helps assign pixel values.

A raster operation processor is a technology employed to display computer graphics. Raster operators, as they're also known, do their work at the end of graphics rendering process. According to GPU Review, this entails anti-aliasing, compression and writing tasks.

Anti-Aliasing

Anti-aliasing is a technique for smoothing the edges of images to achieve a less jagged effect. According to TrueType Typography, anti-aliasing changes the shade of pixels along the boarders of lines meant to be seen as diagonal or curved. These changes blur the edges, giving the lines a smoother, less-pixilated appearance.

Compression

Raster operators perform color compression and Z compression tasks. The former of these involves assigning specific color values to pixels to generate an image. The latter involves assigning depth values to pixels to specify which objects appear to be in front of others.

Writing

Once the graphics processor assigns all necessary attributes to a pixel, the raster operator writes the pixel data to an output buffer. This is one of the last things the graphics processing unit does before the image is actually displayed. According to Computer Hope, this data remains in the buffer until the display is ready to put it on screen.

References

• GPU Review: Raster Operator
• TrueType Typography: TrueType and Anti-Aliasing
• Computer Hope: Output Buffer

Resources

• Read this Article in Spanish
• Tom's Hardware: ROP Pixel Pipelines (Raster Operations)