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In contrast, a display engine works in a very different environment. There is no analog of a {{code|showpage}} that will eventually allow queued instructions to be performed, generally any drawing is expected to take place immediately. Moreover, whereas a PS printer could only print one document at a time, in a modern computer with multiple display [[Window (computing)|window]]s, all of the windows could be updating at the same times using different settings. This was addressed with the introduction of ''multiple execution contexts'', each of which approximated the model seen on a printer; that is, each window effectively had its own PS context and instruction stack, and each window could then produce output with different settings, like whether or not the next line should be dashed or solid.The DPS system provided library calls to create the contexts, which could be completely independent or shared.{{sfn|Adobe|1990|p=326}} Shared contexts were useful in windowing systems because they allowed all of the windows within an application, or even across multiple applications, to share settings and especially pre-defined procedures stored in the {{code|userdict}} and {{code|globaldict}}. One particularly important use of the shared {{code|globaldict}} was to store system-wide fonts.{{sfn|Adobe|1990|p=327}}
The font system itself also had to be modified. PS has a powerful system that produces high-quality fonts from outline descriptions including "hints" which improve quality at smaller sizes. These all rely on the output resolution being fairly high, around 300 bps or higher in most cases. For the much lower-resolution monitors, the results were not very good. DPS added a system to allow hand-drawn bitmaps to be cached in the dictionaries, which was used to provide fonts that could be [[Bit blit|bit blitted]] directly to the display.{{sfn|Adobe|1990|p=339}} After the widespread use of 32-bit color displays the need for this sort of solution has been reduced, as [[anti-aliasing]] solves many of these issues. Likewise, DPS added [[halftone]] phase support to ensure newly drawn objects had the same halftone as earlier objects,{{sfn|Adobe|1990|p=337}} but this too has been reduced in importance on modern systems.
PS stored objects and code within the dictionaries using string identifiers. This made finding the definition expensive as the size of the collections grew, which was a side-effect of many of these new features. DPS addressed this by adding the ability to store objects in the dictionary using integers instead of strings. This "encoded system names" concept could greatly improve performance of various tasks like finding a system font or looking up a common routine like "draw title bar". These encoded names were stored on a per-context basis.{{sfn|Adobe|1990|pp=332-333}}
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