roundpage.ps

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

%
% Tries to round clipping path dimensions, as stored in array pagebbox, so they
% match one of the known sizes in the papersizes array. Lower left coordinates
% are always set to 0.
%

/roundpagebbox {
    7 dict begin
	/papersizes [8.5 inch 11 inch 14 inch 17 inch] def

	/mappapersize {
		/val exch def
		/slop .5 inch def
		/diff slop def
		/j 0 def
		0 1 papersizes length 1 sub {
			/i exch def
			papersizes i get val sub abs
			dup diff le {/diff exch def /j i def} {pop} ifelse
		} for
		diff slop lt {papersizes j get} {val} ifelse
	} def

	pagebbox 0 0 put
	pagebbox 1 0 put
	pagebbox dup 2 get mappapersize 2 exch put
	pagebbox dup 3 get mappapersize 3 exch put
    end
} bind def