DIRECTORYCarets,Imager USING [Context, Create, MaskBits, SetColor],Process USING [Detach, MsecToTicks, SetTimeout],ViewerClasses USING [Viewer],ViewerOps USING [UserToScreenCoords];CaretsImpl: CEDAR MONITORIMPORTS Imager, Process, ViewerOpsEXPORTS Carets =BEGIN OPEN Carets;StartCaret: PUBLIC ENTRY PROC [viewer: ViewerClasses.Viewer, x, y: INTEGER, id: CaretId] = BEGINENABLE UNWIND => NULL;IF viewer = NIL THEN RETURN;InvertCaret[id, TRUE];	-- kill off old visible caretIF x =-10000 AND y =-10000 THEN SELECT id FROM -- special reset for ViewerBLTImpl to move viewersprimary => {x _ pViewerX; y _ pViewerY};secondary => {x _ sViewerX; y _ sViewerY};ENDCASE;x _ MIN[x, viewer.cw];IF id=primary THEN {pViewerX _ x; pViewerY _ y;[pCaretX, pCaretY] _ViewerOps.UserToScreenCoords[pCaretViewer _ viewer, x, y]}	ELSE {sViewerX _ x; sViewerY _ y;[sCaretX, sCaretY] _ ViewerOps.UserToScreenCoords[sCaretViewer _ viewer, x, y]};END;StopCaret: PUBLIC ENTRY PROC [id: CaretId] = BEGINENABLE UNWIND => NULL;InvertCaret[id, TRUE];END;caretHoldCount: INTEGER _ 0;	-- number of requests pending to suspend caretSuspendCarets: PUBLIC ENTRY PROC = BEGINENABLE UNWIND => NULL;IF pDark AND pCaretViewer#NIL THEN InvertCaret[primary];IF sDark AND sCaretViewer#NIL THEN InvertCaret[secondary];caretHoldCount _ caretHoldCount+1;END;ResumeCarets: PUBLIC ENTRY PROC = BEGINENABLE UNWIND => NULL;caretHoldCount _ MAX[0, caretHoldCount-1];END;InvertCaret: INTERNAL PROC [id: CaretId, kill: BOOL _ FALSE] = BEGINcontext: Imager.Context _ screen;IF pCaretY IN [-caretH..16000) THEN {IF id=primary THEN BEGINIF (~kill OR pDark) AND pCaretViewer#NIL THEN BEGINIF pCaretViewer.column=color THEN BEGINIF colorScreen=NIL THEN InitColorCaret;context _ colorScreen;END;TRUSTED {Imager.MaskBits[context, @pCaret, 1, [pCaretX-caretXOffset,pCaretY-caretH,caretW,caretH], [pCaretX-caretXOffset,pCaretY-caretH,caretW,caretH]]};pDark _ ~pDark;END;IF kill THEN pCaretViewer _ NIL;ENDELSE BEGINIF (~kill OR sDark) AND sCaretViewer#NIL THEN BEGINIF sCaretViewer.column=color THEN BEGINIF colorScreen=NIL THEN InitColorCaret;context _ colorScreen;END;TRUSTED {Imager.MaskBits[context, @sCaret, 1, [sCaretX-caretXOffset,sCaretY-caretH,caretW,caretH], [sCaretX-caretXOffset,sCaretY-caretH,caretW,caretH]]};sDark _ ~sDark;END;IF kill THEN sCaretViewer _ NIL;END;};END;CaretProcess: ENTRY PROC = BEGINENABLE UNWIND => NULL;TRUSTED {Process.SetTimeout[@timeOut, Process.MsecToTicks[500]]};DO WAIT timeOut;IF caretHoldCount#0 THEN LOOP;	-- suspendedIF pCaretViewer#NIL THEN InvertCaret[primary];IF sCaretViewer#NIL THEN InvertCaret[secondary];ENDLOOP;END;InitColorCaret: PROC = BEGINcolorScreen _ Imager.Create[$ColorDisplay];[] _ Imager.SetColor[colorScreen, $XOR];END;timeOut: CONDITION;caretH: INTEGER = 6;caretW: INTEGER = 16;caretXOffset: CARDINAL = 8;CaretArray : TYPE = ARRAY [0..caretH) OF UNSPECIFIED;pCaretX, pCaretY, sCaretX, sCaretY: INTEGER;pViewerX, pViewerY, sViewerX, sViewerY: INTEGER;pDark, sDark: BOOLEAN _ FALSE;pCaretViewer, sCaretViewer: PUBLIC ViewerClasses.Viewer;screen: Imager.Context _ Imager.Create[$LFDisplay];colorScreen: Imager.Context;pCaret: CaretArray _ [000400B,001600B,003700B,003300B,006140B,004040B];sCaret: CaretArray _ [000400B,001200B,002100B,002100B,004040B,004040B];[] _ Imager.SetColor[screen, $XOR];TRUSTED {Process.Detach[FORK CaretProcess]};	-- start the blinkerEND.   ■  CaretsImpl.mesa; Written by S. McGregorEdited by McGregor on August 4, 1983 12:53 pmLast Edited by: Maxwell, May 19, 1983 1:24 pmMichael Plass, August 16, 1983 9:12 amScrew the NOTIFY; CaretProcess will eventually wake up and notice new caret Э╩b  Ц"cedar" styleШ JЪ╧c'Щ'JЪЭ-Щ-JЩ-JЩ&JШ Ъ╧k	Ш	JШJЪЬЮЬ'Ш3JЪЬЮЬ#Ш0JЪЬЮЬ
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