PDF Watermark GhostScript

Perintah bash:
gs -q -dNOPAUSE -dSAFER -dBATCH -sOutputFile=watermarked3ok.pdf -sDEVICE=pdfwrite logo2.txt -f tambahinlogo.pdf

Penjelasan:
1. tambahinlogo.pdf >> file asli
2. watermarked.pdf >> file hasil + waterwark
3. logo2.txt >> file berisi kode tekx waterwark, isi kodenya adalah:

/watermarkText { (WATERMARK TEXT) } def
/watermarkFont { /Helvetica-Bold 72 selectfont } def
/watermarkColor { .75 setgray } def
/watermarkAngle { 45 } def

/pageWidth { currentpagedevice /PageSize get 0 get } def
/pageHeight { currentpagedevice /PageSize get 1 get } def

<<
	/EndPage {
		2 eq { pop false }
		{
			gsave
			watermarkFont
			watermarkColor
			pageWidth .5 mul pageHeight .5 mul translate
			0 0 moveto
			watermarkText false charpath flattenpath pathbbox
			4 2 roll pop pop
			0 0 moveto
			watermarkAngle rotate
			-.5 mul exch -.5 mul exch
			rmoveto
			watermarkText show
			grestore
			true
		} ifelse
	} bind
>> setpagedevice

4. Hasilnya nanti file pdf berisi watermark dengan tulisan WATERMARK TEXT melintang miring di setiap halaman PDF