Hier ist ein Beispiel. Dies wurde aus einem umfassenderen Satz von Beispielen entnommen, die mit Ghostscript in /ghostpdl/lib/image-qa.ps verteilt wurden, was Tests für Typ 1, 3 und Typ 4 Bilder beinhaltet.
Dies bedeutet, es ist nicht die einfachste Beispiele, aber es sollte für einen kompetenten PostScript-Programmierer ausreichen, Sinn zu machen oder weiter zu vereinfachen.
%!PS
/WidthRGB 83 def
/HeightRGB 89 def
/SX 036 def
/SY 037 def
/XA 060 def
%
% Procedure to generate test mask data
%
% WM and HM must be defined prior to invocation
% MaskGen -
%
% The mask data is stored into a string named /MaskData
%
% The mask consists of a "target". Bits past width WM are
% filled with 1's to make sure that pad bits are ignored.
%
/MaskGen {
/H8 HM 8 div def
/X0 WM 2 div def
/Y0 HM 2 div def
/WB WM 7 add 8 div cvi def
/MaskData WB HM mul string def
/MB [ 128 64 32 16 8 4 2 1 ] def
0 1 HM 1 sub {
/Y exch def
0 1 WB 1 sub {
/B exch def % byte within the row
/C B Y WB mul add def
/P 0 def
0 1 7 {
/b exch def % bit within the character
/X b B 8 mul add def
X WM lt
{ X Y eq
X HM 1 sub Y sub eq or
Y Y0 gt X X0 sub abs 2 le and or
X X0 sub WM div dup mul Y Y0 sub HM div dup mul add sqrt 9 mul cvi 2 mod 1 eq or
}
{ true } % pad bits are always set
ifelse
% stack: true if pixel is set
{
MB b get P or /P exch def
} if
} for % Bits within a byte
MaskData C P put
} for % Bytes within the row
} for % Rows in the mask
} bind def % MaskGen
% -----------------------------------------------------------------------
% -----------------------------------------------------------------------
%
% Procedures for ImageMatrix creation
/IMLRTB { [ WD 0 0 HD neg 0 HD ] } def
% Procedure to generate image data
%
% WD and HD must be defined prior to invocation
% { proc } ImageGen -
%
% The procedure is called once for each pixel
% Local definitions are R, G, B, X and Y
% Example: Generate RGB Chunky pixel data (single data source) BPC = 8
% /WD WidthRGB def
% /HD HeightRGB def
% /RGBData WD HD mul 3 mul string def
% { X Y WD mul add 3 mul RGBData
% dup 2 index R 255 mul cvi put
% dup 2 index 1 add G 255 mul cvi put
% exch 2 add B 255 mul cvi put
% } ImageGen
/ImageGen {
gsave
0 1 HD 1 sub {
/Y exch def
0 1 WD 1 sub {
/X exch def
/D X WD 2 div sub WD div dup mul Y HD 2 div sub HD div dup mul add sqrt def
/D D .6 div def
/A X WD 2 div sub Y HD 2 div sub atan 360 div def
A % Hue
.7 D .3 sub .60 div sub % Saturation
dup 0.05 lt
{ .95 D .8 sub 3 mul sub 3 mul cvi 3 div sqrt } % Level once Saturation < 0
{ .7 D .25 sub .75 div add } % Level inside
ifelse
X WD 2 div gt Y HD 2 div sub abs 2 le and { pop 0 } if % asymmetric marker
sethsbcolor
currentrgbcolor /B exch def /G exch def /R exch def
dup exec
} for
} for
pop % discard the procedure
grestore
} bind def
% -----------------------------------------------------------------------
%
% Procedures to use generated string data as procedure or files
/WD WidthRGB def
/HD HeightRGB def
/sM WidthRGB 2 mul 1 sub string def % long enough to hold more than one mask line
/sD WidthRGB 7 mul 1 sub string def % long enough to hold more than one 12 bit RGB line
% worst case is 12bit ImageType3 InterleaveType 1 == 48 bits
/MaskDProc {
/FM MaskData dup length() /SubFileDecode filter def
{ { FM sM readstring pop } }
} bind def
/MaskDFile {
MaskData dup length() /SubFileDecode filter
/MDF 1 index def
} bind def
/RGBDProc {
/FD RGBData dup length() /SubFileDecode filter def
{ { FD sD readstring pop } }
} bind def
/RGBDFile {
RGBData dup length() /SubFileDecode filter
/RGBDF 1 index def
} bind def
% YY, SX, SY, W, HD (Data) WM, HM (Mask) should be defined prior to invocation
% (IT is InterleaveType)
% X Y BPC matrix source multi MaskDecode DataDecode IT DoImage3 -
%
/DoImage3 {
gsave
/DeviceRGB setcolorspace
/IT exch def
/DD exch def
/DM exch def
/MS exch def
/S exch def % May be an array of sources - For InterleaveType 3
% S[0] is the Mask DataSource
/M exch def
/BPC exch def
/XX 1 index def
YY translate SX SY scale
0 setlinewidth 0 0 moveto 1 0 lineto 1 1 lineto 0 1 lineto 0 0 lineto stroke
/DataImage
<<
/ImageType 1
/Width WD
/Height HD
/ImageMatrix M
/MultipleDataSources MS
/DataSource IT 3 ne { S } { S 1 get exec } ifelse
/BitsPerComponent BPC
/Decode DD
>>
def
/MaskImage
<<
/ImageType 1
/Width WM
/Height HM
/ImageMatrix % construct the mask matrix using signs from the DataImage matrix
/M0 M 0 get WD abs div cvi def
/M3 M 3 get HD abs div cvi def
/M4 M 4 get WD abs div cvi def
/M5 M 5 get HD abs div cvi def
[ WM M0 mul 0 0 HM M3 mul WM M4 mul HM M5 mul ]
IT 3 eq {
/DataSource S 0 get exec % DataSource only allowed for InterleaveType 3
} if
/BitsPerComponent IT 1 eq { BPC } { 1 } ifelse
/Decode DM
>>
def
<<
/ImageType 3
/DataDict DataImage
/MaskDict MaskImage
/InterleaveType IT
>>
image
grestore
} bind def
% ----------------------------------------------------------------------
% InterleaveType 3, BPC==8, WM=WD, HM=HD
% IT 3 is line interleave -- Mask and Data in separate sources
% RGB Image Data chunky (MultipleDatasources==false).
/YY 50 def
% Generate the MaskData first
/WM WD def
/HM HD def
MaskGen
% Generate the Data Image
/RGBData WD HD mul 3 mul string def
{ X Y WD mul add 3 mul RGBData
dup 2 index R 255 mul cvi put
dup 2 index 1 add G 255 mul cvi put
exch 2 add B 255 mul cvi put
} ImageGen
50 8 IMLRTB [ MaskData RGBData ] false [0 1] [1 0 1 0 1 0] 3 DoImage3
% ----------------------------------------------------------------------
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