sys7.1-doc-wip/QuickDraw/PutLine.a
2019-07-27 22:37:48 +08:00

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;
; File: PutLine.a
;
; Contains: PUTLINE - Decompose a line segment into a list of inversion points
;
; Copyright: © 1981-1990 by Apple Computer, Inc., all rights reserved.
;
; This file is used in these builds: Mac32 Bigbang Sys606
;
; Change History (most recent first):
;
; <4> 9/18/90 BG Removed <2>, <3>. All the offending NOPs have been ripped out.
; 040s are behaving more reliably now.
; <3> 8/15/90 SMC Removed the jiSetHSize jump island that's conditionally used for
; eclipse debugging, and replaced it with a BigJsr to SetHSize.
; The file containing that macro is only included if
; eclipseDebug-ing.
; <2> 6/28/90 BG Added a jump island for SetHSize. Due to the addition of
; various NOPs throughout QD, the distance between PUTLINE and
; SetHSize grew just a bit too long. This is conditionalized so
; that it only happens on builds with -eclipseDebug- and will
; ultimately be removed.
; <•1.4> 5/29/89 BAL Blasting in 32-Bit QuickDraw version 1.0 Final
;
BLANKS ON
STRING ASIS
;-----------------------------------------------------------
;
; --> PUTLINE.TEXT
;
; Decompose a line segment into a list of inversion points.
;
;
PUTLINE PROC EXPORT
IMPORT SetHSize
;------------------------------------------------------------------
;
; PROCEDURE PutLine(pt1,pt2: Point; dst: Handle; VAR index,bufMax: INTEGER);
;
; INVERSION POINTS FOR A LINE SEGMENT
;
; SP OFFSETS OF PARAMETERS:
;
PARAMSIZE EQU 20 ;TOTAL SIZE OF PARAMETERS
PT1 EQU PARAMSIZE+4-4 ;LONG, POINT (VALUE)
PT2 EQU PT1-4 ;LONG, POINT (VALUE)
BUF EQU PT2-4 ;LONG, HANDLE
INDEX EQU BUF-4 ;LONG, (VAR)
BUFMAX EQU INDEX-4 ;LONG, (VAR)
MOVEM.L D3-D7/A2-A4,-(SP) ;SAVE REGS, 8*4 ==> 32
;-----------------------------------------------------
;
; IF LINE IS VERTICAL, IGNORE IT.
;
MOVE PT1+H+32(SP),D2 ;GET 1ST POINT'S HORIZ
MOVE PT2+H+32(SP),D4 ;GET 2ND POINT'S HORIZ
CMP D2,D4 ;IS THIS A VERTICAL LINE ?
BEQ GOHOME ;YES, IGNORE IT
;------------------------------------------------------
;
; CALC BYTESNEEDED = 8 * ( Min(ABS(dh),ABS(dv)) + 1)
;
MOVE D2,D0 ;GET H1
SUB D4,D0 ;SUBTRACT H2
BPL.S DHPOS ;BR IF DH POS
NEG D0 ;ELSE TAKE ABSOLUTE VALUE
DHPOS MOVE PT1+V+32(SP),D1 ;GET V1
SUB PT2+V+32(SP),D1 ;SUBTRACT V2
BPL.S DVPOS ;BR IF DV POS
NEG D1 ;ELSE TAKE ABSOLUTE VALUE
DVPOS CMP D1,D0 ;IS DH <= DV ?
BLE.S DHLESS ;YES, CONTINUE
MOVE D1,D0 ;NO, PUT MIN(DH,DV) INTO D0
DHLESS ADD #1,D0 ;CALC MIN(DH,DV)+1
ext.l d0 ;make into a long <BAL 28Apr89>
LSL.l #3,D0 ;TIMES EIGHT FOR BYTESNEEDED <BAL 28Apr89>
MOVE.L BUF+32(SP),A3 ;GET DSTHANDLE
MOVE.L INDEX+32(SP),A4 ;POINT TO CURRENT INDEX
;-----------------------------------------------------
;
; GROW POINT BUFFER AS NECESSARY TO HOLD BYTESNEEDED
;
moveq #0,d1 ;clear out high end <BAL 28Apr89>
move (a4),d1 ;get index as a long <BAL 28Apr89>
ADD.l d1,d0 ;NEWSIZE := INDEX + BYTESNEEDED
cmp.l #65536-512,d0 ;are we about to overflow? <BAL 28Apr89>
blt.s @sizeOK ;no, don't worry; be happy <BAL 28Apr89>
move #-147,qdErr ;indicate rgnTooBigErr <BAL 28Apr89>
bra GOHOME ;skip this line <BAL 28Apr89>
@sizeOK MOVE.L BUFMAX+32(SP),A0 ;POINT TO BUFMAX
CMP (A0),D0 ;DO WE HAVE TO GROW DSTBUF ?
bls.s NOGROW ;NO, CONTINUE <BAL 28Apr89>
ADD #512,D0 ;GROW IN CHUNKS
MOVE D0,(A0) ;UPDATE NEW BUFMAX
MOVE.L A3,-(SP) ;PUSH DSTBUF HANDLE
MOVE D0,-(SP) ;PUSH NEW BUFMAX
; Even without -eclipseDebug- being set, the access to SetHSize <4>
; requires a BigJSR to get to it. I took out the <4>
; <4>
; INCLUDE InternalOnlyEQU.a <4>
; <4>
; so that it doesn't somehow, someway, screw up one of the QD <4>
; builds. Instead, here is the code that BigJSR expands to <4>
; JSR SetHSize ;MAKE THE BUFFER BIGGER <4>
LEA (SetHSize-*).L,A0 ; == BigJSR SetHSize,A0 <4>
JSR *-6(PC,A0.L) ; <4>
MOVE PT1+H+32(SP),D2 ;RESTORE CLOBBERED REG
NOGROW
MOVE.L (A3),A3 ;DE-REFERENCE DSTHANDLE
moveq #0,d0 ;clear out high end <BAL 28Apr89>
move.w (a4),d0 ;get index as a long <BAL 28Apr89>
add.l d0,A3 ;ADD INDEX TO BUFPTR <BAL 28Apr89>
;-----------------------------------------------------
;
; IF LINE IS HORIZONTAL, PUT ITS TWO ENDPOINTS
;
MOVE PT1+V+32(SP),D1 ;GET 1ST POINT'S VERT
MOVE PT2+V+32(SP),D3 ;GET 2ND POINT'S VERT
CMP D1,D3 ;IS THIS A HORIZONTAL LINE ?
BNE.S SLANTED ;NO, BRANCH
MOVE D1,(A3)+ ;PUT V1 VERT COORD
MOVE D2,(A3)+ ;PUT H1 HORIZ COORD
MOVE D3,(A3)+ ;PUT V2 VERT COORD
MOVE D4,(A3)+ ;PUT H2 HORIZ COORD
BRA.S DONE ;UPDATE INDEX AND QUIT
;------------------------------------------------------
;
; LINE IS SLANTED. DIVIDE IT INTO HORIZONTAL SLABS
; AND PUT THE TWO ENDPOINTS OF EACH SLAB.
;
; START BY SORTING POINTS VERTICALLY.
;
SLANTED BGT.S NOSWAP ;SKIP IF ALREADY IN ORDER
EXG D1,D3 ;SORT POINTS BY VERTICAL
EXG D2,D4 ;SWAP HORIZ TO MATCH
NOSWAP MOVE D1,D6 ;INIT V TO TOPV
;------------------------------------------------------------
;
; CALCULATE FIXED POINT SLOPE = FixRatio(dh,dv);
;
CLR.L -(SP) ;MAKE ROOM FOR FCN RESULT
MOVE D4,-(SP) ;PUSH BOTTOM HORIZ
SUB D2,(SP) ;CALC DH
MOVE D3,-(SP) ;PUSH BOTTOM VERT
SUB D1,(SP) ;CALC DV
_FixRatio ;CALC FIXED POINT SLOPE
MOVE.L (SP)+,D7 ;POP RESULT
;---------------------------------------------------------
;
; SET UP STARTING HORIZ FIXED POINT.
;
MOVE.W D2,D1
SWAP D1 ;HORIZ.INT := TOP HORIZ
MOVE.W #$8000,D1 ;HORIZ.FRACT := 1/2
;
; ADJUST HORIZ DEPENDING ON SIGN AND MAGNITUDE OF SLOPE
;
MOVE.L D7,D0 ;COPY SLOPE
ASR.L #1,D0 ;CALC SLOPE/2
ADD.L D0,D1 ;HORIZ := HORIZ + SLOPE/2
MOVE.L #$00010000,D0
TST.L D7 ;IS SLOPE NEG ?
BMI.S NEGSLOPE ;YES, CONTINUE
CMP.L D0,D7 ;IS SLOPE < ONE ?
BGE.S SLOPEOK ;NO, CONTINUE
ADD.L D7,D1 ;ADD SLOPE TO LEFTEDGE
BRA.S SLOPEOK ;CONTINUE
NEGSLOPE CMP.L #$FFFF0000,D7 ;IS SLOPE > -ONE ?
BGE.S SLOPEOK ;YES, CONTINUE
ADD.L D0,D1 ;YES, HORIZ := HORIZ + 1
SLOPEOK
;------------------------------------------------------
;
; FOR VERT:=TOPV TO BOTV-1 ADD SLOPE TO HORIZ AND PUT SLABS
;
MOVE D2,D5 ;H:=TOPH
LOOP SWAP D1 ;GET HORIZ.INT INTO D1 LOWER
CMP D1,D5 ;HAS HORIZ.INT CHANGED ?
BEQ.S NOCHNG ;NO, CONTINUE
MOVE D6,(A3)+ ;YES, PUT VERT COORD
MOVE D5,(A3)+ ;PUT OLD HORIZ COORD
MOVE.W D1,D5 ;OLDH := HORIZ.INT
MOVE D6,(A3)+ ;PUT VERT COORD
MOVE D5,(A3)+ ;PUT NEW HORIZ COORD
NOCHNG SWAP D1 ;PUTBACK HORIZ.INT INTO D1 UPPER
ADD #1,D6 ;VERT:=VERT+1
ADD.L D7,D1 ;ADD SLOPE TO HORIZ
CMP D6,D3 ;IS VERT AT BOTTOM VERT YET ?
BNE LOOP ;NO, GO FOR MORE
;-------------------------------------------------
;
; FINISH UP LAST SLAB
;
CMP D4,D5 ;IS OLDH = BOTTOM H ?
BEQ.S DONE ;YES, CONTINUE
MOVE D6,(A3)+ ;NO, PUT VERT COORD
MOVE D5,(A3)+ ;PUT HORIZ COORD
MOVE D6,(A3)+ ;PUT VERT COORD
MOVE D4,(A3)+ ;PUT BOTTOM H COORD
;---------------------------------------------------
;
; UPDATE INDEX TO REFLECT POINTS ADDED.
;
DONE MOVE.L BUF+32(SP),A0 ;GET DSTHANDLE
SUB.L (A0),A3 ;INDEX := BUFPTR-BUFSTART
MOVE A3,(A4) ;UPDATE INDEX
GOHOME MOVEM.L (SP)+,D3-D7/A2-A4 ;RESTORE REGS
MOVE.L (SP)+,A0
ADD.W #PARAMSIZE,A7
JMP (A0)
ENDPROC