Printing systems for typesetter emulation

A method of creating a proof which comprises at least one glyph reproduced on a reproduction medium from page and font data encoded in any of a plurality of formats, such data including an identification of the particular format in which the data is encoded, comprising the steps of:

• processing the font data and page data a first time in accordance with the identification to derive an encoded representation of the glyph to be reproduced;
• processing the page data a second time in accordance with the identification to derive character and typesetting commands which together define the placement of the glyph on the reproduction medium;
• and
• controlling an output device to create the proof on the reproduction medium in accordance with the encoded glyph representation and the character and the typesetting commands.

A phototypesetter emulator capable of emulating a plurality of phototypesetters to create a proof comprising glyphs reproduced on a reproduction medium from page and font data including an identification of the particular phototypesetter to be emulated, comprising:

• a preprocessor including
• means responsive to the identification, the page data and the converted font data for creating bit-maps of the glyphs to be reproduced and
• means responsive to the identification and to the page data for deriving character and typesetting commands from the page data which together define the placement of glyphs on the proof;
• an image processor coupled to the preprocessor including means for storing the bit-maps therein;
• and
• an output device coupled to the image processor and controlled thereby in accordance with the character and typesetting commands and the bit-maps to create the proof.

In a system for causing an output device to print a glyph in response to composition data specifying a character in a first resolution, wherein the composition data defines the character as a series of black and white segments disposed in adjacent columns and the output device is responsive to data defining the glyph in a second, lower resolution, a method of operating the output device with data defining the glyph in the second resolution in accordance with the composition data, comprising the steps of:

• creating groups of columns, each group having a number of columns defined in the first resolution;
• determining for each group the column having the longest black segment;
• and
• utilizing the column having the longest black segment to define the column in the second resolution to represent the group

In a system for creating a proof from composition data, wherein the proof comprises at least two pages having at least one glyph reproduced on a reproduction medium, the system having a preprocessor for creating glyph data in response to character commands included in the composition data, an image processor for storing the glyph data for each page, and an output device responsive to the stored glyph data for creating glyphs, a method of minimizing redundant creation of glyph data, comprising the steps of:

• creating glyph data for a first page;
• storing the glyph data for the first page in the image processor;
• preselecting a safe limit representing an estimate of how many additional glyphs not presently stored in the image processor will be required to complete the next page;
• determining, upon completion of each page, whether the safe limit has been exceeded;
• and
• reinitializing the image processor if the safe limit has been exceeded and subsequently storing the glyph data for the next page in the image processor.