Example Screen Dumps: HP 9845C Demo
Probably the best example for demonstrating how screenshots can be taken from a running application is the HP 9845C demo program.
The demo package for the HP 9845C is remarkable for several reasons. One aspect is that it is one of the most complex BASIC programs ever developed for the 9845 series. The demo required two full tapes as distribution media, and the main program consisted of more than 4,000 lines of BASIC code. The other, more important aspect lies in the fact, that HP's engineers not only demonstrated the outstanding capabilities of their 9845C system with high resolution graphics, fast vector engine and up to 4,913 colors, they also used the 9845C as platform for implementing many state-of-the-art concepts in computer graphics and human interaction, like 3D shading, ordered dithering, wireframe rendering, interactive light pen control or just using color for better visualization of complex data.
Note that there are (of course) quality differences between the original screen photos and the screendumps. The latter have the advantage of - since digital - having neither geometric distortion nor color mismatches, but being limited to the graphics data (text information will be dropped). The screen photos on the other side, capture the full appearance of the visualization, including all artifacts and text information, however screen photographing is an art of its own, requiring proper lighting, exposure times, focus and so on.
Below are 9845C produced screen dumps taken from the HP9845C demo.