- #BASIC BUILDING BLOCKS OF RASTER GRAPHICS EDITOR FULL#
- #BASIC BUILDING BLOCKS OF RASTER GRAPHICS EDITOR PC#
#BASIC BUILDING BLOCKS OF RASTER GRAPHICS EDITOR FULL#
Sometimes the number of characters in the font, dedicated to block graphics, could be halved if the system also supported an "invert" attribute, as half the characters in a full block graphics font set are the logical inverse of the other half of the font set. If the system also supported color, the color resolution of the resulting pixels was normally equal to the text resolution, often leading to attribute clash as the color of a pixel could not be changed on a per pixel basis, but only to one "ink", and one "background" color for all pixels within a character position. An earlier system using the same pseudo-graphics array of a 2 by 3 matrix was the Video Terminal Interface (VTI) of the Poly-88 by polymorphic systems, an S-100 bus based system predating the TRS-80. In the case of the TRS-80 these block graphics were not incorporated into a font ROM, as later became the norm, but were generated directly from the logic pattern of six bits from the video RAM using a dedicated circuit made from logic gates.
![basic building blocks of raster graphics editor basic building blocks of raster graphics editor](https://thumb.bibliocad.com/images/content/00060000/8000/68991.gif)
The seminal use of this technology was in the TRS-80 where the only way to get discrete pixels on the screen that could be turned on and off individually, (all points addressable) was by the use of a 2×3 pixel matrix of block graphics. The Galaksija's graphics mode is an example, although with a 4:5:4 scheme the distortion effect was minimal. In rare cases a character matrix wasn't dividable vertically by three, for example in an 8×8 matrix the mosaic is sometimes divided so that it uses a 3:2:3 scan line scheme. Sometimes the text semigraphical characters are simply incorporated into the systems font-set, sometimes special video hardware is used to directly convert the bit-pattern from video memory into the pixels. But dividing an 8×8 character in 2×2 "pixels" called quadrants was also common (it was, for example, used in the Sinclair ZX81). Less often used versions use a 1×6 "matrix", in which case these six "pixels" are sometimes referred to as sixels. Sample character set display showing block graphics as used in the TRS-80 Color Computer (CoCo), and Dragon 32/64įor example, an 8×12 character could be divided vertically in two halves and horizontally in three parts, and then assigning "ink" and "background" values to the elements of the matrix in a binary pattern, corresponding to the binary sequence of the position in the font table of a 2×3 mosaic matrix of so-called squots (square dots) or sextants. Many of these historical ideas have been adopted into Unicode, in, for example in the Symbols for Legacy Computing, Block Elements, Box Drawing and Geometric Shapes Unicode blocks. Single and double lines are still often drawn with this method when the system uses text mode for example when running the BIOS setup program.
#BASIC BUILDING BLOCKS OF RASTER GRAPHICS EDITOR PC#
Semigraphical characters (including some block elements) are still incorporated into the BIOS of any VGA compatible video card, so any PC can display these characters from the moment it is turned on, even when no operating system is yet loaded. The second one is to use special shapes instead of glyphs (letters and figures) that appear as if drawn in raster graphics mode, sometimes referred to as semi- or pseudo-graphics an important example of this is box-drawing characters.
![basic building blocks of raster graphics editor basic building blocks of raster graphics editor](https://cdn.soft112.com/progecad-standard-intellicad-software/00/00/00/1L/0000001L08/pad_screenshot.jpg)
The first one is to create a low-resolution all points addressable mode using a set of special characters with all binary combinations of a certain subdivision matrix of the text mode character size this method is referred to as block graphics, or sometimes mosaic graphics. There are two different ways to accomplish the emulation of raster graphics. Text-based semigraphics or pseudographics is a primitive method used in early text mode video hardware to emulate raster graphics without having to implement the logic for such a display mode.
![basic building blocks of raster graphics editor basic building blocks of raster graphics editor](https://venturebeat.com/wp-content/uploads/2018/05/star-treke284a2_-bridge-crew_20180520212416.jpg)
Color image rendered using Teletext semigraphic characters