; Copyright (c) 1985 Harold Long›; Permission granted to distribute›; for non-commercial purposes.››INCLUDE "D:READPIC.ACT" ; Available on Action! BBS.››MODULE ;ÇÒÔÏÎÅ - GR15 Pseudo-halftone›; screen print routine.  Supports›; 800XL and Epson printer only.  See›; program comments for adaptation to›; other hardware environments.››; Screen to print translation:›; Each pixel on the screen occupies›; two bits in memory. This is trans-›; lated into a 6x2 matrix to keep›; the h x w aspect ratios similar.›; The default is for color 1 to be›; the least dark, and color 4 to be›; the most dark. A translator table›; is provided to allow hackers›; the ability to redefine halftone›; values to their heart's content.››BYTE J,K,L             ;counters››CARD M, SAVMSC=$58     ;counters, reg's››BYTE ARRAY dots(960)  ;pin values››BYTE POINTER dotptr, scrnptr››; Turns on a line of graphics output.›; Epson printer supports 960 bits in›; "L" (Low speed double density) mode.›; ªªªª Ãèáîçå åóãáðå ãïäåó âåìï÷ æïò›; ïôèåò ðòéîôåòó áó òåñõéòåä® ªªªª›PROC GrOn()            ;turn on graphics›Print("L")            ;double density›Put(192) Put(3)        ;920 bits/line›RETURN››; Convert a pixel to a halftone value.››PROC DoPix(BYTE p)     ;process a pixel›; Halftone value table:›; Values are selected to approximate›; 0%, 25%, 50%, and 100% density for›; color registers 1 through 4. Note›; that lookup alternates between table›; tone1 and tone2 to give maximum›; pattern flexibility.›BYTE ARRAY tone1(4)=[$00 $00 $40 $C0]›BYTE ARRAY tone2(4)=[$00 $40 $80 $C0]››FOR J=0 TO 5           ;6 bytes wide›DO› IF (J MOD 2)=0 THEN   ;odd values›  dotptr^=tone1(p)     ;assumes dotptr is›  dotptr==+1           ;properly set up› ELSE                  ;even values›  dotptr^=tone2(p)     ;base halftone›  dotptr==+1› FI›OD›RETURN››PROC DoByte(BYTE b)    ;process a screen byte›BYTE p                 ;the pixel value›FOR K=0 TO 6 STEP 2    ;do it 4 times›DO› p=(b RSH (6-K)) & $03 ;mask it to get reg #› DoPix(p)              ;go convert pixel to halftone›OD›RETURN››PROC DoLine(BYTE r)    ;process a screen line›Zero(dots,960)         ;clear array›dotptr=dots            ;initialize pointer›scrnptr=SAVMSC+40*r    ;row pointer›FOR L=0 TO 39          ;40 bytes to a line›DO› DoByte(scrnptr^)      ;the next screen byte› scrnptr==+1           ;bump pointer›OD›GrOn()                 ;flame on!›dotptr=dots            ;reset pointer›FOR M=0 TO 959         ;full double density line›DO› Put(dotptr^)› dotptr==+1›OD›PutE()›RETURN››; Initialization and control loop.›; Open printer, get input file name›; and read it in (Micro Illustrator›; format only).  ››PROC Main()›BYTE i         ›BYTE ARRAY fname(18)›Close(2)›Open(2,"P:",8,0)›Close(1)›Print("Input file: ")›InputS(fname)›PutE()›Open(1,fname,4,0)›Graphics(15+16)        ;´°°¯¸°° ï÷îåòó ÷éìì›                       ;îååä ôï âõéìä ìéóô íáîõáììù®›ReadPic()›Close(1)›device=2›; Ãèáîçå åóãáðå ãïäåó æïò ïôèåò ðòéîôåòó›Print("3")            ;Set printer to›Put(6)                 ;6/216 inch (2 dots)›FOR i=0 TO 191         ;192 screen rows›DO› DoLine(i)›OD›device=0›Close(2)›RETURN›››Put(6)                 ;6/216 inch (2 dots)›FOR i=0 TO 191         ;192 screen rows›DO› ¦; Copyright (c) 1985 Harold Long›; Permission granted to distribute›; for non-commercial purposes.››INCLUDE "D:READPIC.ACT" ; Available on Action! BBS.››MODULE ;ÇÒÔ