The principle and practical method of realizing hand-to-hand imposition for PS files

This article through the analysis of the PS file structure and the introduction of related Postscript statements. This paper presents a practical method for the hand-off imposition processing of PS files, and uses PageMaker software as an example to illustrate the principle and steps of the imposition, and realizes this imposition method through programming on the Windows platform.

There are two commonly used imposition methods when using the color desktop publishing system to make a plate: one is to manually splicing the film into big version after the publication, and the other is to put together the prepared pages on the computer. Both of these methods have problems such as low efficiency and easy error. At present, some imposition software is also sold on the market. However, its price is generally very expensive, and it is usually only possible to make a layout for a layout produced by one application software.

Due to the application of color desktop publishing system software, the pages are described in Postscript page description language. Therefore, when the operator uses the software to design the layout, he actually performs postscript programming through the computer. The edited Postscript program is interpreted by the raster image processor (RIP) as a bitmap image when it is output to the output device. Depending on the RIP used or the process flow. There are usually two methods at the output: one is output directly to the RIP interpretation and output. The other is that Mr. into a PS file, and then by the RIP call PS file, interpreted and then sent to the output device.

The PS files generated by the application software are all described in Postscript language. Includes layout, graphics, images, text, and output resolution, screen descriptions, user coordinates, and device coordinates. Any changes made to this PS file will change the layout or layout of the layout. Therefore, the imposition can be implemented by modifying the coordinate description in the PS file. This article intends to briefly discuss the Postscript page description language. Take PageMaker software as an example to illustrate how to implement a hand-to-hand imposition on a PS file.

First, the structure of the PS file

A complete PS file can be roughly divided into four parts: preamble, description, subject, and ending. as the picture shows. The preambular part is also called the PS file header and consists of some comment statements. It is used to make some necessary explanations and comments on the PS file, such as the name of the generated software, job name, production date and time, page size, number of pages, included Font resources etc.

The description part usually begins with the comment statement "%%BeginProlog". This part includes the definition of the resource used in the file, the definition of the description statement, the definition of the dictionary and the page size, and so on. The description of the PS file generated by different application software and different print driver software will be very different, so the resulting PS file will look completely different.

The main part of the program is the description of the page content, which is the main part of the PS file. The more complex the page, the greater the capacity that this part occupies. But this part of the description does not directly use the generic Postscript statement. The main purpose is to use the various definitions of Postscript statements in the description section. The purpose of doing so is to increase the speed of interpretation of PS files.

The final part of the final section is also composed of a number of commentary statements that are necessary to supplement the preambular part. There are many unclear annotation items in the preamble, all of which are marked with "(atend)". Then at the end of the description. The total number of pages is not specified in the comment statement "%%Pages: (atend)" in which the following example illustrates the total number of pages. So at the end there will be a corresponding statement "%%Pages: 16" to supplement the number of pages in the documentation.

Example:
%!PS-Adobo-3.0
%%title: 16p
%%creator: PageMaker 6.0C
%%CreationDate:5-19-1999,2226
%%For: Powermacb
%%Page: (atend)
%%PageOrder: Ascend
%%BoundingBox: 0 0 658 904
%%ALDBoundingBOX: 0 0 6583 9049
%%documentNeededResources: (atend)
%%documentSuppliedResources: (atend)

%%CMYKCustomColor: (atend)
%%documentCustomColors: (atend)
%%documentProcessColors: (atend)
%ADBdocument Inks: (atend)
%ADBdocumentMutilnkColors: (atend)
%ALDOriginal Files: PowerB HDesktop Folder: 16P
%%EndCommentS