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sys7.1-doc-wip/Libs/InterfaceSrcs/BitMaptoRegion.a
Horst Beepmanh 33cd9271f4 SuperMarioProj.1994-02-09
2019-07-27 22:37:48 +08:00

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;
; File: BitMaptoRegion.a
;
; Contains: FUNCTION BitMapToRegionGlue(region: RgnHandle;bMap: BitMap): OSErr;
;
; Given a region and bitmap, BitMapRgn makes the region a bounding
; region for the 'map. If it can't get memory it will return a
; Memory Manager-type error and an empty region gibbley. Note that
; the region might also be empty with no error (if the bounds is an
; empty rectangle or there are no 1 bits in the bitmap). Lastly,
; if the region would have to exceed 32K it returns a result of
; -500 (rgnTooBigErr).
;
; The bMap parameter may be a pointer to a bitmap, a pointer to a
; pixmap, or a pointer to a portBits field in a color grafport.
; In the latter two cases, if the pixmap is not 1-bit deep, an error
; result of -148 (pixmapTooDeepErr) is returned.
;
; (the nibble state machine idea is from the Finder MaskToRgn routine)
;
; Copyright: © 1988-1992 by Apple Computer, Inc. All rights reserved.
;
; Change History (most recent first):
;
; <SM3> 10/28/92 SWC Changed the INCLUDEs to a LOAD of StandardEqu.d.
; <SM2> 10/26/92 CSS Change a short branch to a word branch.
; <2> 7/24/91 MH Added conditional wrapper(s) to prevent duplication of public
; interface declarations: rgnTooBigErr, pixmapTooDeepErr
;
LOAD 'StandardEqu.d'
IF (&TYPE('Debugging') = 'UNDEFINED') THEN
Debugging EQU 0 ;debugging flag (1 = TRUE)
ENDIF
;________________________________________________________________________________
;
; FUNCTION BitMapToRegionGlue(region: RgnHandle;bMap: BitMap): OSErr;
;
;________________________________________________________________________________
;
;Theory
; We scan each line of the bitmap and pump inversion points (ip's) into the region
; to put the areas with ones in the bitmap into the region and the areas
; with zeroes outside the region.
;
; In order to keep track of where we are in "inversion land" we use two
; techniques:
; The first is a scanline buffer which records the changes
; (zeroes to ones and vice versa) as we go. Wherever a change occurs (a
; 1 next to a 0 in the buffer) we need to put out an inversion point.
; The second is a togglin' flag which tells us whether we are "inverted" or not.
; Since we use a state machine in the innermost (nibble) loop to churn out
; ip's, the input to the state machine must be complemented if the flag is set.
; The loop stuff looks like this:
; outer line loop (grows handle in anticipation of worst case for next line)
; longword loop for current line (puts out inter-long ip's as needed)
; loop for 4 nibbles in current long (calls state maching for each nibble)
;
;________________________________________________________________________________
BitMapRgnTrap EQU $A8D7
UnimplementedTrap EQU $A89F
isCPort EQU 14 ;bit 14 in rowbytes means portBits in CGrafPort
MACRO
SafeDisposeHandle
MOVE.L A0,D0
BEQ.S @0
_DisposHandle
@0
ENDM
BitMapToRegionGlue PROC EXPORT
;let's check for the existence of the trap
MOVE.W #BitMapRgnTrap,D0
_GetTrapAddress newTool
MOVE.L A0,A1 ;stash address in A1
MOVE.W #UnimplementedTrap,D0
_GetTrapAddress newTool ;unimplemented trap is in A0
CMP.L A0,A1 ;unimplemented?
BEQ.S RunRAM ;skip if so
JMP (A1) ;go to _BitMapRgn
;the trap is unimplemented, run the RAM version
RunRAM
BMFrame RECORD {A6Link},DECR
result DS.W 1
paramTop EQU *
regionH DS.L 1
bMapPtr DS.L 1
paramSize EQU paramTop-*
return DS.L 1
A6Link DS.L 1
rowLongs DS.L 1 ;number of longwords per line
rightMask DS.L 1 ;mask for rightmost long of each line
slHandle DS.L 1 ;handle to scanline buffer
numLines DS.W 1 ;number of lines in bitmap
rowNumBytes DS.W 1 ;rowbytes from the bitmap
startSize DS.W 1 ;size of region at start of line
lastLineH DS.L 1 ;last line (zeroes) handle
handSize DS.L 1 ;size of handle (avoid calls to GetHandleSize)
max2Add DS.L 1 ;worst case for bytes we could add for next line
localSize EQU *
ENDR
WITH BMFrame
LINK A6,#localSize
MOVEM.L A2-A5/D3-D7,-(SP) ;save work registers
CLR.L slHandle(A6) ;no scanline handle, yet
CLR.W result(A6) ;function result presumed zero at start
MOVE.L regionH(A6),A0
MOVE.L (A0),A2
MOVEQ #0,D0
MOVE.W (A2),D0 ;get size of region
MOVE.L D0,handSize(A6) ;save it long
;get boundary rectangle so we can tell how to process the bitmap
MOVE.L bMapPtr(A6),A1 ;get bitmap pointer
MOVE.W rowBytes(A1), D0 ;rowbytes
BPL.S @1 ;it's a bitmap so go ahead
BTST #isCPort, D0 ;is this a ptr to portBits?
BEQ.S @2 ;nope; it's a ptr to a pixmap
MOVE.L baseAddr(A1), A0 ;get the PixMapHandle
MOVE.L (A0), A1 ;and get the real ptr to pixmap
@2
CMP.W #1, pmPixelSize(A1) ;is it 1 bit per pixel deep?
BEQ.S @1 ;if yes, we're fine
MOVE.W #pixmapTooDeepErr, D0 ;return an error otherwise
BRA BMRBadEmpty ;clean up and bail out
@1
MOVE.W rowBytes(A1), rowNumBytes(A6) ;get the rowbytes from the bit/pixmap
ANDI.W #$7FFF, rowNumBytes(A6) ;mask off pixmap flag
MOVE.L bounds+topLeft(A1),D2 ;get topLeft
MOVE.W bounds+right(A1),D0 ;get right
;figure the number of longs per row (according to width, not rowbytes)
;so we can get a scanline buffer
SUB.W D2,D0 ;right - left
BLE BMREmptyOut ;if empty rect. then empty region
EXT.L D0
MOVE.L D0,D4
ADD.L D4,D4 ;double width for 2 bytes/ip
ADDQ.L #4+2,D4 ;add 4 bytes for y value and $7FFF word
;add 2 more for the $7FFF if the last line
ADD.L D4,D4 ;double, just 'cause I feel like it!
MOVE.L D4,max2Add(A6) ;save max. bytes for a given line
MOVEQ #32,D7 ;(side effect: clear high word of D7)
DIVU D7,D0 ;number of longs = width/32
;get a mask for the rightmost long into rightMask
MOVE.L D0,D3 ;save remainder(hi word)
SWAP D3 ;get remainder from width/32
MOVEQ #-1,D1 ;default rightmost long mask
TST.W D3 ;zero remainder?
BEQ.S @0 ;yes, $FFFF is a good mask
ADDQ.W #1,D0 ;we need one more long
SUB.W D3,D7 ;32 - remainder = zero bits to shift in
ASL.L D7,D1 ;get proper mask
@0 MOVE.L D1,rightMask(A6)
EXT.L D0
MOVE.L D0,rowLongs(A6) ;save # of longs
ASL.L #2,D0 ;longs => bytes
;get the scanline buffer (D0 = number of bytes per line)
_NewHandle clear ;get a scanline buffer (of zeroes)
BNE BMRBadEmpty ;if we failed then return a NIL handle
MOVE.L A0,slHandle(A6) ;save buffer handle
;figure the number of lines
MOVE.L D2,D3
SWAP D3 ;get top
MOVE.W bounds+bottom(A1),D0 ;get bottom
SUB.W D3,D0 ;bottom - top
BLE BMREmptyOut ;if empty rect. then empty region
MOVE.W D0,numLines(A6) ;number of lines
MOVE.L baseAddr(A1),A4 ;point to start of map
MOVE.W #rgnData,D7 ;initial region size
;OK, now we start the loops.
; A1 will point to the bitmap long,
; A2 to the region.
; A3 points to the current scanline buffer long.
; A4 will point to the row in the map.
; A5 points to the current word (= size + A2)
; D1 holds the current long (modified).
; D2 holds the leftmost coordinate of bitmap.bounds.
; D3 has the y coordinate, and
; D4 the x coordinate (high word stays clear!).
; D5 has number of longs remaining for current line.
; D6 holds the (on or off) value of the "beam" (for the line).
; D7 holds the size outside the longword loop (used as scratch while nibbling).
; (we assume at the very end that D7's high word has remained clear)
BMRHScramLine
MOVE.L regionH(A6),A2
MOVE.L (A2),A2 ;point to start of region
BMRLineLoop
LEA (A2,D7.W),A5 ;point to new region start + size
MOVE.L handSize(A6),D1 ;get handle size
SUB.W D7,D1 ;handle size - region size
CMP.L max2Add(A6),D1 ;is there enough for worst case on next line?
BGE.S @1 ;skippy if so
MOVE.L handSize(A6),D0 ;get handle size
ADD.L max2Add(A6),D0 ;add more than enough for worst case on next line
MOVE.L D0,handSize(A6) ;save new size
MOVE.L regionH(A6),A0 ;region handle
_SetHandleSize
BNE BMRBadEmpty ;if we failed then return a NIL handle
BRA.S BMRHScramLine ;rederef. handle and recompute current pointer
@1
MOVE.W D2,D4 ;get current x coordinate from left
MOVEQ #0,D6 ;beam initially off
MOVE.L A4,A1 ;start of current line into map pointer
MOVE.L rowLongs(A6),D5 ;longs remaining for current line
MOVE.L slHandle(A6),A3 ;A3 points to the current "differences" long
MOVE.L (A3),A3
; Note: within this loop we assume that nothing will be done to move the heap
MOVE.W D3,D0 ;get y position
BSR OutputRgnWord ;output y pos to region
MOVE.W D7,startSize(A6) ;save size at line start (a la Derwood)
BRA NextBMRLong ;enter the long loop
BMRLongLoop
MOVE.L (A1)+,D0 ;fetch the next long for this line
BMRLastLEntry
MOVE.L (A3),D1 ;get differences long
EOR.L D0,D1 ;compute the differences
BNE BMRDiff ;if not the same, skip ahead
BMRSame
;since we want to skip this long (it matches the previous line) we need to
;put out an ip if the beam is on
TST.B D6 ;beam on?
BEQ.S @1 ;skip if not
MOVE.W D4,(A5)+ ;pump it out
MOVEQ #0,D6 ;beam off
@1
ADD.W #32,D4 ;slip to next long's x coordinate
@2 ADDQ.W #4,A3 ;to next changes buffer long
BRA NextBMRLong
;----------------------------------------------------------------------------------------
; Start of State Machine
; Handle state 0001
BMRState1
ADDQ.W #3,D4 ;bump x by 3
State1Common
MOVE.W D4,(A5)+ ;generate one
;Tog1StateDone
ADDQ.W #1,D4 ;bump x by one more
TogStateDone
NOT.B D6 ;toggle state
RTS
; Handle state 0010
BMRState2
ADDQ.W #2,D4 ;bump x by 2
MOVE.W D4,(A5)+ ;generate one
Gen1BumpBy1
BSR.S Gen1InvPoint ;and another one
BumpBy1
ADDQ.W #1,D4 ;bump once more
RTS ;state doesn't change
; Handle state 0011
BMRState3
ADDQ.W #2,D4 ;bump x by 2
MOVE.W D4,(A5)+ ;generate one
ADDQ.W #2,D4 ;bump
BRA.S TogStateDone ;toggle the state
; Handle state 0100
BMRState4
BSR.S Gen1InvPoint
BSR.S Gen1InvPoint
BumpBy2
ADDQ.W #2,D4
RTS
; Handle state 0101
BMRState5
BSR.S BMRState4 ;start out as state 4
SUBQ #1,D4
BRA.S State1Common ;use common code
; Handle state 0110
BMRState6
BSR.S Gen1InvPoint
ADDQ.W #1,D4
BRA.S Gen1BumpBy1
; Handle state 0111
BMRState7
BSR.S Gen1InvPoint
ADDQ.W #3,D4
BRA.S TogStateDone
; Gen1InvPoint bumps x by one and then generates a horizontal inversion point
Gen1InvPoint
ADDQ.W #1,D4 ;bump by 1, first
MOVE.W D4,(A5)+ ;add x value (ip) to region
RTS
; Handle State 1000
BMRState8
MOVE.W D4,(A5)+
BSR.S Gen1InvPoint
ADDQ.W #3,D4
RTS
; Handle State 1001
BMRState9
MOVE.W D4,(A5)+
BSR.S Gen1InvPoint
ADDQ.W #2,D4
BRA.S State1Common
; Handle State 1010 (most complicated case)
BMRState10
MOVE.W D4,(A5)+
BSR.S Gen1InvPoint
BSR.S Gen1InvPoint
BRA.S Gen1BumpBy1
; Handle State 1011
BMRState11
MOVE.W D4,(A5)+
BSR.S Gen1InvPoint
BSR.S Gen1InvPoint
ADDQ.W #2,D4
BRA.S TogStateDone
; Handle State 1100
BMRState12
MOVE.W D4,(A5)+
ADDQ.W #2,D4
MOVE.W D4,(A5)+
BRA.S BumpBy2
; Handle State 1101
BMRState13
BSR.S BMRState12
SUBQ #1,D4
BRA.S State1Common
; Handle State 1110
BMRState14
MOVE.W D4,(A5)+
ADDQ.W #3,D4
MOVE.W D4,(A5)+
BRA.S BumpBy1
; State table
BMRHandler
BRA.S BMRState0
BRA.S BMRState1
BRA.S BMRState2
BRA.S BMRState3
BRA.S BMRState4
BRA.S BMRState5
BRA.S BMRState6
BRA.S BMRState7
BRA.S BMRState8
BRA.S BMRState9
BRA.S BMRState10
BRA.S BMRState11
BRA.S BMRState12
BRA.S BMRState13
BRA.S BMRState14
; Handle State 15 or 1111
BMRState15
MOVE.W D4,(A5)+ ;generate one now
NOT.B D6 ;toggle the state
; Handle State 0 or 0000
BMRState0
ADDQ.W #4,D4
RTS
; End of the State Guys
;----------------------------------------------------------------------------------------
BMRDiff
MOVE.L D0,(A3)+ ;fix up scanline buffer for next time
; this long is different from the last one, so output a bunch
; of inversion points by pumping it through the state machine, a nibble
; at a time.
MOVEQ #3,D7 ;4 bytes to process (D7 high word clear)
MOVEQ #0,D0 ;prevent need to mask for first nibble
; here is the loop where we feed it through a nibble at a time.
; it's worth it to special case a whole byte of 0
BMRByteLoop
ROL.L #8,D1 ;get next (topmost) byte
TST.B D1 ;is it zero?
BNE.S BMRNibble ;if not, 4 bits at a time
TST.B D6
BNE.S BMRNibble ;if beam on, must pass through
;the top 8 are zero, so we can save some time
ADDQ.W #8,D4 ;bump x
BRA.S BMRNextByte
;take care of the rightmost long for a line
BMRLastLong
MOVE.L (A1),D0 ;fetch the long from the bitmap
AND.L rightMask(A6),D0 ;mask off right bits that aren't in map
BRA BMRLastLEntry ;go process this long
; handle the first nibble
BMRNibble
MOVE.B D1,D0 ;get byte
EOR.B D6,D0 ;invert nibble when beam is on
LSR.B #4,D0 ;get 1st nibble
ADD.W D0,D0 ;double for word index
JSR BMRHandler(D0.W) ;invoke the handler
; handle the second nibble
MOVE.B D1,D0 ;get byte again
EOR.B D6,D0 ;invert nibble when beam is on
AND.W #%1111,D0 ;mask to it
ADD.W D0,D0 ;double for word index
JSR BMRHandler(D0.W) ;invoke the handler
BMRNextByte
DBRA D7,BMRByteLoop ;loop for all 8 nibbles
; bump to the next long
NextBMRLong
SUBQ.W #1,D5 ;decrement longword index
BGT BMRLongLoop ;not at end, loop for whole line
BEQ.S BMRLastLong ;process last long for this line
; we've reached the end of the (this) line
BMREOL
MOVE.W A5,D7 ;current region pointer
SUB.W A2,D7 ;figga region size
CMP.W startSize(A6),D7 ;did we add inv. pts to this line?
BEQ.S BMRNoLine ;br = no, so back up
BLT BMR32KErr ;if the size decreased, we overflowed
; if the state is on, generate one last inversion point
TST.B D6
BEQ.S @1
MOVE.W D4,(A5)+ ;generate a last one
ADDQ.W #2,D7 ;keep sizable advantage
@1
; end the scan line with the traditional $7FFF
BSR.S OutputLastRgnWord
BMREOL2
ADDQ.W #1,D3 ;bump y position
MOVE.W D2,D4 ;start x at left again
ADD.W rowNumBytes(A6),A4 ;bump to next row in map
SUBQ.W #1,numLines(A6)
BGT BMRLineLoop ;if we're not done then do next line
BLT.S BMRFinis ;br if really done
; as the last line process an imaginary line of zeroes to end the region…
MOVE.L rowLongs(A6),D0
ASL.L #2,D0 ;longs => bytes
_NewHandle clear ;get a full line of zero bits
BNE BMRBadEmpty ;if we failed then return a NIL handle <SM2> CSS
MOVE.L A0,lastLineH(A6) ;save handle
MOVE.L (A0),A4 ;start of current line
BRA BMRHScramLine ;do this last one (and rederef handle)
BMRNoLine
SUBQ.L #2,A5 ;back up pointer
SUBQ.W #2,D7 ;back down size
BRA.S BMREOL2 ;go for next line
; Append the "end of line" token to the region
OutputLastRgnWord
MOVE.W #$7FFF,D0
; OutputRgnWord takes the word in D0, appends it to the region,
; and leaves the condition codes set for ADDQ.W D7 (which contains the length)
OutputRgnWord
MOVE.W D0,(A5)+ ;put a word to the region
ADDQ.W #2,D7 ;ink the size
RTS
; all done so clean up, output the final $7FFF
BMRFinis
MOVE.L lastLineH(A6),A0
SafeDisposeHandle ;get rid of that last line of zeroes
CMP.W #10,D7 ;is region empty of inversion points?
BEQ.S BMREmptyOut ;skip if so (it's an empty region)
BSR.S OutputLastRgnWord ;put End-O-Region ($7FFF) word
BMI.S BMR32KErr ;if we went negative, we overflowed!
; find the smallest rectangle that encompasses all the inversion points
; A0 will point to the current region word, A1 to the start of the line
; D1 will have the smallest x, D2 the largest x, D4 will contain $7FFF
; D3 gets the smallest y value (which we know at the start)
LEA rgnData(A2),A0 ;point A0 past the rgnBBox
MOVE.W #$7FFF,D4
MOVE.W D4,D1 ;smallest x so far = $7FFF
MOVE.W #$8000,D2 ;largest x so far = -32768
MOVE.W (A0),D3 ;smallest y there is
BRA.S BMRPackStart ;enter loop
BMRPackY
MOVE.L A0,A1 ;remember where the y value is (sort of)
CMP.W (A0)+,D1 ;less than smallest x so far?
BLE.S @1 ;skip if not
MOVE.W -2(A0),D1 ;new smallest x
@1 CMP.W (A0)+,D4 ;end of line?
BNE.S @1 ;if not then keep looking
CMP.W -4(A0),D2 ;last x greater than largest x so far?
BGE.S BMRPackStart ;skip if not
MOVE.W -4(A0),D2 ;new largest x
BMRPackStart
MOVE.W (A0)+,D0 ;get next word (y value or $7FFF)
CMP.W D4,D0 ;if $7FFF then we're done
BNE.S BMRPackY ;otherwise loop
SWAP D3 ;top into top word
MOVE.W D1,D3 ;left into bottom word
MOVE.W -2(A1),D4 ;bottom (from last y at start of line)
SWAP D4 ;move bottom to high word
MOVE.W D2,D4 ;get right
CMP.W #28,D7 ;size = 28? (do we have a rect. region?)
BEQ.S BMRRect ;skip if so
BRA.S BMROut ;return complex region
;the region would exceed 32K, so we have to error out, man
BMR32KErr
MOVE.W #rgnTooBigErr,D0 ;if >32K needed return error
;we come here after failing a SetHandleSize (or NewHandle)
BMRBadEmpty
MOVE.W D0,result(A6) ;OSErr function result
; emptify the region on errors (or when it should be empty with no error)
BMREmptyOut
MOVE.L regionH(A6),A0 ;handle to region
MOVE.L (A0),A2 ;point to it
CLR.L D3 ;(0, 0) to topLeft
CLR.L D4 ;(0, 0) to botRight
BMRRect
MOVEQ #10,D7 ;the size of the region = 10
;output the region with size (longword, high word clear) in D7
;D3 comes in with topLeft, D4 with botRight
BMROut
MOVE.W D7,(A2)+ ;the size of the region
MOVE.L D3,(A2)+ ;topLeft to rgnBBox
MOVE.L D4,(A2) ;botRight to rgnBBox
MOVE.L D7,D0 ;size
MOVE.L regionH(A6),A0 ;handle to region
_SetHandleSize
BMRDspSL
MOVE.L slHandle(A6),A0
SafeDisposeHandle ;get rid of the scanline buffer (even if NIL)
BMRDone
MOVEM.L (SP)+,A2-A5/D3-D7 ;restore work registers
UNLK A6
MOVE.L (SP)+,A0 ;pop return address
ADD #paramSize,SP ;pop params
JMP (A0)
ENDWITH
END
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