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

243 lines
6.5 KiB
Plaintext

;
; File: PutLine.m.a
;
; Contains: xxx put contents here (or delete the whole line) xxx
;
; Written by: xxx put name of writer here (or delete the whole line) xxx
;
; Copyright: © 1988-1990 by Apple Computer, Inc., all rights reserved.
;
; Change History (most recent first):
;
; <2> 10/10/90 JL Change FixRatio to MFixRatio to avoid conflict with Traps.a
; <1.1> 11/11/88 CCH Fixed Header.
; <1.0> 11/9/88 CCH Adding to EASE.
; <1.2> 10/12/88 CCH Changed “m.GrafType.a” to “GrafType.m.a”.
; <1.1> 5/18/88 MSH Changed inclides to use m.GRAPHTYPES to work under EASE.
; <1.0> 2/11/88 BBM Adding file for the first time into EASE…
;
; To Do:
;
;EASE$$$ READ ONLY COPY of file “PUTLINE.m.a”
; 1.1 CCH 11/11/1988 Fixed Header.
; 1.0 CCH 11/ 9/1988 Adding to EASE.
; OLD REVISIONS BELOW
; 1.2 CCH 10/12/1988 Changed “m.GrafType.a” to “GrafType.m.a”.
; 1.1 MSH 5/18/88 Changed inclides to use m.GRAPHTYPES to work under EASE.
; 1.0 BBM 2/11/88 Adding file for the first time into EASE…
; END EASE MODIFICATION HISTORY
BLANKS ON
STRING ASIS
INCLUDE 'GRAFTYPES.m.a'
;-----------------------------------------------------------
;
; --> 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
LSL #3,D0 ;TIMES EIGHT FOR BYTESNEEDED
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
;
ADD (A4),D0 ;NEWSIZE := INDEX + BYTESNEEDED
MOVE.L BUFMAX+32(SP),A0 ;POINT TO BUFMAX
CMP (A0),D0 ;DO WE HAVE TO GROW DSTBUF ?
BLE.S NOGROW ;NO, CONTINUE
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
JSR SETHSIZE ;MAKE THE BUFFER BIGGER
MOVE PT1+H+32(SP),D2 ;RESTORE CLOBBERED REG
NOGROW
MOVE.L (A3),A3 ;DE-REFERENCE DSTHANDLE
ADD (A4),A3 ;ADD INDEX TO BUFPTR
;-----------------------------------------------------
;
; 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
_MFixRatio ;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)
END