Direct Graphics Access

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Direct Graphics Access is a plug-in for the X Window System that allows client programs direct access to the frame-buffer. Graphics hardware communicates via a chunk of memory called a frame-buffer. This is an array of values that represent pixel color values on the screen. Writing the appropriate values into the frame buffer therefore allows a program to paint areas of the screen. However, as with any shared resource, problems occur when multiple programs attempt to access the same resource, as they tend to write over each others work. In the X Window System, this is solved by having a central server program that mediates between programs that want to draw on the screen. The server also performs a lot of the drawing work, allowing programs to say Draw me a circle of this radius filled with this pattern or draw this text in this font.