baseline.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

%
% Stuff used to draw or set text along a baseline specified by parametric equations
% for x and y.
%

/left -1 def
/center 0 def
/right 1 def

/baselinedict 50 dict def

/newbaseline {
	baselinedict begin
		/g' exch bind def
		/f' exch bind def
		/g  exch bind def
		/f  exch bind def

		counttomark 2 eq {/hoffset exch def} if
		/res exch def

		/t 0 def
		/s 0 def
		/voffset false def
		cleartomark
	end
} bind def

/drawfunnytext {
	baselinedict begin
		/t exch def
		/mode exch def
		/str exch def

		mode left eq {
			/leftstring emptystring def
			/rightstring str def
		} if

		mode right eq {
			/leftstring str reversestring def
			/rightstring emptystring def
		} if

		mode center eq {
			str splitstring
			/rightstring exch def
			/leftstring exch reversestring def
		} if

		gsave currentpoint translate leftstring left t baselineshow grestore
		gsave currentpoint translate rightstring right t baselineshow grestore

		/t 0 def
		/s 0 def
		/voffset false def
		cleartomark
	end
} bind def

/setfunnytext {
	baselinedict begin
		/vpos exch def
		/hpos exch def
		/str  exch def

		voffset vpos ne {
			/voffset vpos def
			/t 0 def
			/s hoffset def
		} if

		gsave
			hoffset voffset translate
			0 0 moveto
			/ds hpos s sub def
			/dt ds t f' dup mul t g' dup mul add sqrt res mul div def
			/s s ds add def
			/t t dt add def
			str right t baselineshow
		grestore
	end
} bind def

baselinedict begin

/f  {} bind def
/g  {pop 0} bind def
/f' {pop 1} bind def
/g' {pop 0} bind def

/s 0 def
/t 0 def
/res 72 def

/onecharstring ( ) def
/emptystring () def

/baselineshow {
	/t exch def
	/mode exch def
	/str exch def

	gsave
		t f res mul t g res mul translate
		0 0 moveto
		t g' t f' atan rotate
		{
			mode right eq {pop} if
			grestore gsave
			onecharstring 0 3 -1 roll put onecharstring stringwidth pop
			/ds exch mode mul def
			/dt ds t f' dup mul t g' dup mul add sqrt res mul div def
			/t t dt add def
			/s s ds add def
			t f res mul t g res mul translate
			0 0 moveto
			t g' t f' atan rotate
			mode left eq {pop} if
		} str kshow
	grestore
} bind def

/reversestring {
	/str1 exch def

	/str2 str1 length string def
	/i 0 def
	/n str1 length 1 sub def

	{
		str1 n get str2 exch i exch put
		/i i 1 add def
		/n n 1 sub def
		n 0 lt {exit} if
	} loop
	str2
} bind def

/splitstring {
	/str1 exch def

	/len str1 stringwidth pop def
	/s 0 def
	/n 0 def
	str1 length {
		str1 n get onecharstring exch 0 exch put
		/s onecharstring stringwidth pop s add def
		s len 2 div ge {exit} if
		/n n 1 add def
	} repeat
	str1 0 n 1 add getinterval
	str1 n str1 length n sub getinterval
} bind def

end