ken@turtlevax.UUCP (Ken Turkowski) (10/15/84)
> What is a good set of windowing primitives that could be implemented > on any system with rastop, lines, circles, layers and textures? Clipping and redraw (automatic maintenance of the display list) are necessary and useful, respectively, for graphics on window based systems. You also need to decide how to deal with arbitrary sized windows and different resolutions. > How does one write PORTABLE applications for bit-mapped systems? What do you mean by "bit-mapped"? Do you mean to distinguish raster systems from calligraphic (vector) systems? Or are you referring to binary (0-1) images, as distinguished from grey-scale and full-color images? In this response, I am using the former distinction. The object-oriented functions (lines and circles) are simple to use in a resolution- and colorspace-independent way. If your graphics code could be written without the use of raster images, your job would be much easier. The biggest problem is with rasterops, which may well be impossible to use in a resolution independent way, although the NAPLPS method goes a long way through its use of the logical pixel size. Other things to consider with raster systems are 1) the complement of raster modification functions, 2) the topology of the color space, 3) packing of pixels into words, 4) mapping from n-bit pixels to m-bit pixels, 5) use of dithering to make up for lack of grey-scale 6) method of mapping from the logical to the physical pixel size. Has any standards committee addressed the issue of device-independent raster images? -- Ken Turkowski @ CADLINC, Palo Alto, CA UUCP: {amd,decwrl,flairvax,nsc}!turtlevax!ken ARPA: turtlevax!ken@DECWRL.ARPA