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Assembly Source File | 1986-05-08 | 23.0 KB | 894 lines

COMMENT ~ GRAPHICS.ASM -- Graphic Plotting Procedures From `BLUEBOOK of ASSEMBLY ROUTINES for the IBM PC & XT' by Christopher L. Morgan Copyright (C) 1984 by The Waite Group, Inc. Contents: --------- CLS -- Clear the screen GET_COLOR -- Get the color of a point on the med res color screen GMSG_OUT -- Plot a string PAINT -- Fill an area with specified color RCHAR -- Plot a raster character SCHAR -- Plot a stroke character SET_BOX -- Fill a rectangular box with specified color SET_LIN -- Draw a line SET_PT -- Plot a point XOR_BOX -- Fill a rectangular box using XOR XOR_PT -- Plot a point using XOR >>>>> See GRAPHICS.DOC for complete descriptions of these routines. <<<<< ------------------------------------------------------------------------------ These variables need to be defined in the source code calling the GRAPHICS routines. See GRAPHICS.DOC. ~ EXTRN CBYTES:BYTE, COLOR:WORD, DELDE:WORD, DELDX:WORD EXTRN DELDY:WORD, DELP:WORD, DELS:WORD, DELSE:WORD EXTRN DELSX:WORD, DELSY:WORD, FONT:BYTE, PAINT_STAK:WORD EXTRN X0:WORD, X1:WORD, X2:WORD, XMAGN:BYTE EXTRN XMSG:WORD, Y0:WORD, Y1:WORD, Y2:WORD EXTRN YMAGN:BYTE, YMSG:WORD ;______________________________________________________________________________ ;These tables would be better included in the source code calling the ; GRAPHICS routines, and then commented out here. See GRAPHICS.DOC ; DATAS SEGMENT PUBLIC CTABLE DW 0003FH,0403FH,0803FH,0C03FH DW 000CFH,010CFH,020CFH,030CFH DW 000F3H,004F3H,008F3H,00CF3H DW 000FCH,001FCH,002FCH,003FCH PTABLE DW 32 DUP(?) ;A dummy (See GRAPHICS.DOC) XTABLE DW 0FFC0H,0FFF0H,0FFFCH,0FFFFH DW 03FC0H,03FF0H,03FFCH,03FFFH DW 00FC0H,00FF0H,00FFCH,00FFFH DW 003C0H,003F0H,003FCH,003FFH DATAS ENDS ;______________________________________________________________________________ ; CODES SEGMENT PUBLIC CLS,SET_PT,XOR_PT,GET_COLOR,SET_BOX,XOR_BOX PUBLIC SET_LIN,SCHAR,RCHAR,GMSG_OUT,PAINT ASSUME CS:CODES,DS:DATAS ;____________________________I/O ROUTINES______________________________________ ;Routine to clear the graphics screen ; CLS PROC FAR PUSH CX ;Save registers PUSH AX ; ;Set up the registers MOV CX,2000H ;Word count of whole screen MOV AX,0 ;Zero pattern for the screen MOV DI,AX ;Set starting address CLD ;Go in forward direction ; ;Clear the screen with a single string operation REP STOSW ;This clears the screen ; POP AX ;Restore registers POP CX RET CLS ENDP ;------------------------------------------------------------------------------ ;Routine to plot a point on medium resolution color screen ; SET_PT PROC FAR PUSH BX ;Save registers PUSH SI PUSH AX ; ;Multiply Y-coord by bytes/row & adjust for even/odd lines MOV AX,DI ;Get Y-coordinate into part MOV AH,AL ; and into high part AND AX,01FEH ;Mask off unwanted parts SAL AX,1 ;Times 4 SAL AX,1 ;Times 8 SAL AX,1 ;Times 16 MOV BX,AX ;Goes into address AND BH,7 ; without adjustment SAL AX,1 ;Times 32 SAL AX,1 ;Times 64 ADD BX,AX ;Addr gets Y-coord times 80 ; ;Add X-coordinate to address MOV AX,SI ;Get X-coordinate SAR AX,1 ;Divide SAR AX,1 ; by 4 ADD BX,AX ;Here is the address ; ;Compute the rotated mask and color AND SI,3 ;Just pixel position into index SAL SI,1 ;Index times 2 SAL SI,1 ;Index times 4 ADD SI,DX ;4 * pixel position + color SAL SI,1 ;8 * pixel position + 2 * color MOV AX,CTABLE[SI] ;Look up rotated color & mask ; ;Insert the color into the video byte AND AL,ES:[BX] ;Get old byte & remove old pixel OR AL,AH ;Insert new color MOV ES:[BX],AL ;Put the byte back ; POP AX ;Restore registers POP SI POP BX RET SET_PT ENDP ;------------------------------------------------------------------------------ ;Routine to XOR a point onto medium resolution color screen ; XOR_PT PROC FAR PUSH BX ;Save registers PUSH SI PUSH AX ; ;Multiply Y-coord by bytes/row & adjust for even/odd lines MOV AX,DI ;Get Y-coordinate into part MOV AH,AL ; and into high part AND AX,01FEH ;Mask off unwanted parts SAL AX,1 ;Times 4 SAL AX,1 ;Times 8 SAL AX,1 ;Times 16 MOV BX,AX ;Goes into address AND BH,7 ; without adjustment SAL AX,1 ;Times 32 SAL AX,1 ;Times 64 ADD BX,AX ;Addr gets Y-coord times 80 ; ;Add X-coordinate to address MOV AX,SI ;Get X-coordinate SAR AX,1 ;Divide SAR AX,1 ; by 4 ADD BX,AX ;Here is the address ; ;Compute the mask for color and use it AND SI,3 ;Just the bit count into index SAL SI,1 ;Index times 2 SAL SI,1 ;Index times 4 ADD SI,DX ;4 * pixel position + color SAL SI,1 ;8 * pixel position + 2 * color MOV AX,CTABLE[SI] ;Look up rotated color & mask XOR ES:[BX],AH ;XOR the byte with the color ; POP AX ;Restore registers POP SI POP BX RET XOR_PT ENDP ;------------------------------------------------------------------------------ ;Routine to return color of a point on med res color screen ; GET_COLOR PROC FAR PUSH BX ;Save registers PUSH CX ; ;Multiply Y-coord by bytes/row & adjust for even/odd lines MOV AX,DI ;Get Y-coordinate into part MOV AH,AL ; and into high part AND AX,01FEH ;Mask off unwanted parts SAL AX,1 ;Times 4 SAL AX,1 ;Times 8 SAL AX,1 ;Times 16 MOV BX,AX ;Goes into address AND BH,7 ; without adjustment SAL AX,1 ;Times 32 SAL AX,1 ;Times 64 ADD BX,AX ;Addr gets Y-coord times 80 ; ;Add X-coordinate to address MOV AX,SI ;Get X-coordinate SAR AX,1 ;Divide SAR AX,1 ; by 4 ADD BX,AX ;Here is the address ; ;Compute the position of the pixel in the byte MOV CX,SI ;Use X-coord to determine count AND CX,3 ;Just the bit count INC CX ; plus one SAL CX,1 ;2 bits/pixel ; ;Get the byte and rotate into place MOV AL,ES:[BX] ;Get old byte ROL AL,CL ;Rotate left this many times AND AX,3 ;Just the pixel color ; POP CX ;Restore registers POP BX RET GET_COLOR ENDP ;------------------------------------------------------------------------------ ;Routine to set & fill a rectangular box ; SET_BOX PROC FAR PUSH SI ;Save registers PUSH DI PUSH DX PUSH BX PUSH CX PUSH AX ; ;Determine byte position for start ; ;Get Y contribution MOV AX,Y1 ;Get starting Y-coordinate MOV AH,AL ;Replicate for odd/even bank AND AX,01FEH ;Mask off unwanted parts SAL AX,1 ;Times 4 SAL AX,1 ;Times 8 SAL AX,1 ;Times 16 MOV DI,AX ;Addr gets Y-coord * 16 AND DI,7FFH ;Not the odd/even bit SAL AX,1 ;Times 32 SAL AX,1 ;Times 64 ADD DI,AX ;Addr gets Y-coord * 80 ; ;Add in X contribution MOV AX,X1 ;Get X-coordinate SAR AX,1 ;Divide SAR AX,1 ; by 4 ADD DI,AX ;Beginning of offset ; ;Count for outer loop MOV CX,Y2 ;Ending Y-coordinate SUB CX,Y1 ; minus starting Y-coordinate INC CX ; plus one ; ;Count for inner loop MOV SI,X2 ;Ending X-coordinate SAR AX,1 ;Divide SAR AX,1 ; by 4 MOV AX,X1 ;Starting X-coordinate SAR AX,1 ;Divide SAR AX,1 ; by 4 SUB SI,AX ;Take the difference ;Get the color MOV BX,COLOR ;Get the color AND BX,3 ;Just between 0 & 3 MOV DL,CBYTES[BX] ;Look up color pattern ; ;Determine mask for start & ending bytes MOV BX,X1 ;Starting byte AND BX,3 ;Just the pixel position SAL BX,1 ;Times 2 SAL BX,1 ;Times 4 MOV AX,X2 ;Ending byte AND AX,3 ;Just the pixel position ADD BX,AX ;4 * starting + ending SAL BX,1 ;8 * starting + 2 * ending MOV BX,XTABLE[BX] ;Look up the masks ; ;Set up masked color bytes MOV DH,DL ;Color for left bytes MOV AH,DL ;Color for middle bytes AND DX,BX ;Mask left & right color bytes ; CLD ;Forward SBOXLOOP: PUSH CX ;Save count of outer loop PUSH DI ;Save initial byte position ; MOV CX,SI ;Count for inner loop ; ;Check for only one byte MOV AL,BH ;Get the mask JCXZ SBOXLOOP2 ;If ending byte coincides ; ;Color leftmost byte of the scan line NOT AL ;Reverse the mask for clearing AND AL,ES:[DI] ;Get byte frm mem & clr pixels OR AL,DH ;Put color in place STOSB ;Put byte in place ; ;Check for just two bytes DEC CX ;Count the byte JCXZ SBOXLOOP1 ;Done? ; ;Color middle bytes of the scan line ; MOV AL,AH ;Color for middle bytes REP STOSB ;Put middle bytes in place ; ;Handle rightmost byte of the scan line ; ;Come here if two or more bytes SBOXLOOP1: MOV AL,0FFH ;Set full mask ; ;In any case, come here to adjust the masks SBOXLOOP2: AND AL,BL ;Bring in right part of mask AND DL,AL ;Clear left part of color ; ;Color the byte NOT AL ;Reverse the mask for clearing AND AL,ES:[DI] ;Get byte from mem & clr pixels OR AL,DL ;Put pixels in the byte STOSB ;Put byte back into video RAM ; ;Compute next scan line POP DI ;Restor addr of lft side of box TEST DI,2000H ;Odd or even line? JZ SBOXLOOP3 ;Skip if even ADD DI,80 ; else add 80 bytes/line SBOXLOOP3: XOR DI,2000H ;Change banks in any case POP CX ;Restore outer loop count LOOP SBOXLOOP ;Next scan line ; POP AX ;Restore registers POP CX POP BX POP DX POP DI POP SI RET SET_BOX ENDP ;------------------------------------------------------------------------------ ;Routine to fill a rectangular box with color using XOR ; XOR_BOX PROC FAR PUSH SI ;Save registers PUSH DI PUSH DX PUSH BX PUSH CX PUSH AX ; ;Determine byte position for start ; ;Get Y contribution MOV AX,Y1 ;Get starting Y-coordinate MOV AH,AL ;Replicate for odd/even bank AND AX,01FEH ;Mask off unwanted parts SAL AX,1 ;Times 4 SAL AX,1 ;Times 8 SAL AX,1 ;Times 16 MOV DI,AX ;Addr gets Y-coord * 16 AND DI,7FFH ;Not the odd/even bit SAL AX,1 ;Times 32 SAL AX,1 ;Times 64 ADD DI,AX ;Addr gets Y-coord * 80 ; ;Add in X contribution MOV AX,X1 ;Get X-coordinate SAR AX,1 ;Divide SAR AX,1 ; by 4 ADD DI,AX ;Beginning of offset ; ;Count for outer loop MOV CX,Y2 ;Ending Y-coordinate SUB CX,Y1 ; minus starting Y-coordinate INC CX ; plus one ; ;Count for inner loop MOV SI,X2 ;Ending X-coordinate SAR AX,1 ;Divide SAR AX,1 ; by 4 MOV AX,X1 ;Starting X-coordinate SAR AX,1 ;Divide SAR AX,1 ; by 4 SUB SI,AX ;Take the difference ; ;Get the color MOV BX,COLOR ;Get the color AND BX,3 ;Just between 0 & 3 MOV DL,CBYTES[BX] ;Look up color pattern ; ;Determine mask for start and ending bytes MOV BX,X1 ;Starting bytes AND BX,3 ;Just the pixel position SAL BX,1 ;Times 2 SAL BX,1 ;Times 4 MOV AX,X2 ;Ending byte AND AX,3 ;Just the pixel position ADD BX,AX ;4 * starting + ending SAL BX,1 ;8 * starting + 2 * ending MOV BX,XTABLE[BX] ;Look up the masks ; ;Set up masked color bytes MOV DH,DL ;Color for left bytes MOV AH,DL ;Color for middle bytes AND DX,BX ;Mask left & right color bytes ; CLD ;Forward XBOXLOOP: PUSH CX ;Save count of outer loop PUSH DI ;Save initial byte position ; MOV CX,SI ;Count for inner loop ; ;Check if only one byte in a scan line MOV AL,BH ;Get the mask JCXZ XBOXLOOP3 ;If ending byte coincides ; ;XOR the leftmost byte XOR ES:[DI],DH ;XOR color into memory INC DI ;Next byte DEC CX ;Count it JCXZ XBOXLOOP2 ;Done? ; ;XOR the middle bytes XBOXLOOP1: XOR ES:[DI],AH ;XOR color byte into memory INC DI ;Next byte LOOP XBOXLOOP1 ;Loop to get all the middle ; ;Handle rightmost byte ; ;Come here if two or more bytes XBOXLOOP2: MOV AL,0FFH ;Set full mask ; ;In any case, come here to adjust the masks XBOXLOOP3: AND AL,BL ;Bring in right part of mask AND DL,AL ;Clear left part of color ; ;XOR the rightmost byte XOR ES:[DI],DL ;XOR byte into memory INC DI ;Next byte ; POP DI ;Restore the leftmost address TEST DI,2000H ;Odd or even line? JZ XBOXLOOP4 ;Skip if even ADD DI,80 ; else add 80 bytes/line XBOXLOOP4: XOR DI,2000H ;Change banks in any case POP CX ;Restore outer loop count LOOP XBOXLOOP ;Next scan line ; POP AX ;Restore registers POP CX POP BX POP DX POP DI POP SI RET XOR_BOX ENDP ;------------------------------------------------------------------------------ ;Routine to draw a line ; SET_LIN PROC FAR PUSH BX ;Save registers PUSH CX PUSH DX PUSH SI PUSH DI PUSH AX ; ;Set up X and Y updates MOV SI,1 ;Start with positive 1 for MOV DI,1 ; X and Y update ; ;Find |Y2-Y1| MOV DX,Y2 ;Get Y2 SUB DX,Y1 ;Subtract Y1 JGE STOR_Y ;Skip if Y2-Y1 is not negative NEG DI ;Mov in negative Y direction NEG DX ;Absolute value of Y2-Y1 STOR_Y: MOV DELDY,DI ;Store Y update for diag moves ; ;Find |X2-X1| MOV CX,X2 ;Get X2 SUB CX,X1 ;Subtract X1 JGE STOR_X ;Skip if X2-X1 is not negative NEG SI ;Mov in negative X direction NEG CX ;Absolute value of X2-X1 STOR_X: MOV DELDX,SI ;Store X update for diag moves ; ;Sort |Y2-Y1| & |X2-X1| CMP CX,DX ;Compare DELS with DELP JGE SET_DIAG ;Skip if straight move along X MOV SI,0 ;If straight=vert, kill X updat XCHG CX,DX ; & exchange differences JMP STOR_DELSXY SET_DIAG: MOV DI,0 ;If straight=horz, kill Y updat ; ;Store DELS, DELP, DELSX, & DELSY STOR_DELSXY: MOV DELS,CX ;Change in straight direction MOV DELP,DX ;Change in perpndic to straight MOV DELSX,SI ;X update in straight direction MOV DELSY,DI ;Y update in straight direction ; ;Get initial values for X & Y MOV SI,X1 ;X-coordinate MOV DI,Y1 ;Y-coordinate ; ;Compute initial value & increments for error function MOV AX,DELP SAL AX,1 ;2 * DELP MOV DELSE,AX ;Change if straight move ; SUB AX,CX ;2 * DELP - DELS MOV BX,AX ;Initial value ; SUB AX,CX ;2 * DELP - 2 * DELS MOV DELDE,AX ;Change if diagonal move ; ;Adjust count INC CX ; ;Set the color MOV DX,COLOR ;Get the color ; ;Main loop structure LIN_LOOP: CALL SET_PT ;Plot the point CMP BX,0 ;Determine straight or JGE DIAGONAL ; diagonal move? ; ;Straight move case STRAIGHT: ADD SI,DELSX ;Update X ADD DI,DELSY ;Update Y ADD BX,DELSE ;Update error term LOOP LIN_LOOP ;Next point JMP LIN_XIT ;Diagonal move case DIAGONAL: ADD SI,DELDX ;Update X ADD DI,DELDY ;Update Y ADD BX,DELDE ;Update error term LOOP LIN_LOOP ;Next point LIN_XIT: POP AX ;Restore registers POP DI POP SI POP DX POP CX POP BX RET SET_LIN ENDP ;------------------------------------------------------------------------------ ;Routine to plot a stroke character ; SCHAR PROC FAR PUSH SI ;Save registers PUSH CX PUSH AX ; CBW ;Make ASCII code into 16-bit SAL AX,1 ;Times 2 MOV SI,AX ;Into the index MOV SI,PTABLE[SI] ;Look up the particular char MOV AX,X0 ;X-coord of upper left corner MOV X2,AX MOV AX,Y0 ;Y-coord of upper left corner MOV Y2,AX ; ;Run through the strokes NEWSTROKE: LODSB ;Get the code byte CMP AL,1AH ;End of strokes? JZ SCHAR_XIT MOV DL,AL ;Save code ; ;Update X-coordinate of current position MOV AX,X2 ;Old X-coordinate MOV X1,AX ; gets pushed back LODSB ;New X-coordinate MOV CL,XMAGN ; times XMAGN MUL CL ;Multiply ADD AX,X0 ;Add to upper left corner MOV X2,AX ; & put into current position ; ;Update Y-coordinate of current position MOV AX,Y2 ;Old Y-coordinate MOV Y1,AX ; gets pushed back LODSB ;New Y-coordinate MOV CL,YMAGN ; times YMAGN MUL CL ;Multiply ADD AX,Y0 ;Add to upper left corner MOV Y2,AX ; & put into current position ; CMP DL,'U' ;Pen up? JE NEWSTROKE ;Skip, if so ; CALL SET_LIN ;Draw the stroke ; JMP NEWSTROKE ;Get next stroke SCHAR_XIT: POP AX ;Restore registers POP CX POP SI RET SCHAR ENDP ;------------------------------------------------------------------------------ ;Routine to plot a raster character ; RCHAR PROC FAR PUSH SI ;Save registers PUSH DX PUSH CX PUSH AX ; ;Look up pattern for character CBW ;Make ASCII code into 16-bit SAL AX,1 ;Times 2 SAL AX,1 ;Times 4 SAL AX,1 ;Times 8 ADD AX,0FA6EH + 7 ;Character table + pattern end MOV SI,AX ;Here is the offset ; MOV DX,DS ;Save old DS MOV AX,0F000H ;Point DS to ROM segment MOV DS,AX ;Here is the data segment ; ;Store the pattern on the stack MOV CX,8 ;For a count of 8 bytes STD ;Backward direction RCHAR1: LODSB ;Load PUSH AX ;Push onto stack LOOP RCHAR1 ; MOV DS,DX ;Restore data segment ; ;Get the starting point MOV AX,X0 ;Get X-coordinate MOV X1,AX MOV AX,Y0 ;Get Y-coordinate MOV Y1,AX ; MOV CX,8 ;For a count of 8 rows RCHAR2: POP DX ;Get the next row PUSH CX ;Save the count ; MOV AL,YMAGN ;Vertical sizing CBW DEC AX ;One less ADD AX,Y1 ;Add to new dot position MOV Y2,AX ; MOV CX,8 ;For a count of 8 dots RCHAR3: PUSH CX ;Save the count ; MOV AL,XMAGN ;Horizontal sizing CBW DEC AX ;One less ADD AX,X1 ;Add to new dot position MOV X2,AX ; TEST DL,80H ;Check the dot JZ RCHAR4 ; & skip if zero ; CALL SET_BOX ;Plot if a one RCHAR4: MOV AX,X2 ;Next column INC AX ;One over from end of box MOV X1,AX ;Into next dot position ROL DL,1 ;Next dot from pattern POP CX ;Restore count of dots LOOP RCHAR3 ;Loop for next dot ; MOV AX,X0 ;Restore to first column MOV X1,AX ;Beginning of row MOV AX,Y2 ;Next row INC AX ;One down from end of box MOV Y1,AX ;Into next row position POP CX ;Restore count of rows LOOP RCHAR2 ;Loop for next row ; POP AX ;Restore registers POP CX POP DX POP SI RET RCHAR ENDP ;------------------------------------------------------------------------------ ;Routine to print a message on the graphics screen ; GMSG_OUT PROC FAR ; ;Get (X,Y) location of message on the screen MOV AX,XMSG ;Get X-coordinate on screen MOV X0,AX ; for first character MOV AX,YMSG ;Get Y-coordinate on screen MOV Y0,AX ; for first character CLD ;Go in forward direction ; ;Main loop through characters of the message GMSG_LOOP: CLD ;Forward direction LODSB ;Get the ASCII code CMP AL,0 ;End of string? JE GMSG_XIT ; ;Check for fonts FONT0: CMP FONT,0 ;Use font 0? JNE FONT1 CALL SCHAR ;Use stroke characters FONT1: CMP FONT,1 ;Use font 1? JNE NEXTCHAR CALL RCHAR ;Use raster characters NEXTCHAR: MOV AL,8 ;Character cell width MOV CL,XMAGN ;Times horizontal magnitude MUL CL ;Multiply ADD X0,AX ;Add to loc of previous char ; JMP GMSG_LOOP ;Loop for next character GMSG_XIT: RET GMSG_OUT ENDP ;------------------------------------------------------------------------------ ;Routine to fill an area with a specified color ; Uses two subroutines: PUSHPAINT & POPPAINT ; ;PUSHPAINT pushes X- & Y-coordinates on paint stack PUSHPAINT PROC NEAR DEC BP ;BP is the paint stack pointer DEC BP ; & gets decremented first MOV [BP],SI ;Push X DEC BP DEC BP MOV [BP],DI ;Push Y RET PUSHPAINT ENDP ; ;POPPAINT pops X- & Y-coordinates on paint stack POPPAINT PROC NEAR MOV DI,[BP] ;Pop Y INC BP ; then increment stack INC BP MOV SI,[BP] ;Pop X INC BP INC BP RET POPPAINT ENDP ; ;Main PAINT routine PAINT PROC FAR ; ;Initialize paint color MOV DX,COLOR ; ;Initialize paint stack LEA BP,PAINT_STAK ;BP is set to top of stack CALL PUSHPAINT ;Push seed onto stack ; ;Main loop for painting PAINT1: LEA AX,PAINT_STAK ;Stack empty? CMP BP,AX JNE PAINT2 ;Continue, if not JMP PAINT_XIT ;Else exit ; ;Get the next place to paint PAINT2: CALL POPPAINT ;Pop the next place to paint CALL GET_COLOR ;Color is returned in AL CMP AL,DL ;Is it filled? JE PAINT1 CMP AL,DH ;Is it boundary? JE PAINT1 CMP DI,0 ;Top of screen? JL PAINT1 CMP DI,199 ;Bottom of screen? JG PAINT1 ; ;Move right until boundary is reached PAINT3: INC SI ;X <-- X + 1 CALL GET_COLOR ;Look right DEC SI ;Restore X ; CMP AL,DL ;Is it filled? JE PAINT4 CMP AL,DH ;Is it boundary color? JE PAINT4 CMP SI,319 ;At right screen boundary? JE PAINT4 INC SI ;X <-- X + 1 JMP PAINT3 ; ;Push above and below PAINT4: DEC DI ;Y <-- Y - 1 CALL GET_COLOR ;Check above MOV BH,AL ;Save above state CMP AL,DL ;Is it filled? JE PAINT5 CMP AL,DH ;Is it boundary color? JE PAINT5 CALL PUSHPAINT ;Push above PAINT5: INC DI ;Restore Y INC DI ;Y <-- Y + 1 CALL GET_COLOR ;Check below MOV BL,AL ;Save below state CMP AL,DL ;Is it filled? JE PAINT6 CMP AL,DH ;Is it boundary color? JE PAINT6 CALL PUSHPAINT ;Push below PAINT6: DEC DI ;Restore Y ; ;Anchor the end point of the scan line MOV X2,SI ;Store X-coord, end of scan lin MOV Y2,DI ;Store Y-coord, end of scan lin ; ;Plot as we scan left, checking above & below PAINT7: ;Check above DEC DI ;Y <-- Y - 1 CALL GET_COLOR ;Check above CMP AL,DL ;Is it filled? JE PAINT9 CMP AL,DH ;Is it boundary color? JE PAINT9 ; CMP BH,DL ;Last above filled? JE PAINT8 CMP BH,DH ;Was it boundary color? JE PAINT8 JMP PAINT9 PAINT8: CALL PUSHPAINT ;Push above if new place ; to paint PAINT9: MOV BH,AL ;Update last above ; INC DI ;Restore Y ; ;Check below INC DI ;Y <-- Y + 1 CALL GET_COLOR ;Check below CMP AL,DL ;Is it filled? JE PAINT11 CMP AL,DH ;Is it boundary color? JE PAINT11 ; CMP BL,DL ;Last below filled? JE PAINT10 CMP BL,DH ;Was it boundary color? JE PAINT10 JMP PAINT11 PAINT10: CALL PUSHPAINT ;Push below if new place ; to paint PAINT11: DEC DI MOV BL,AL ;Update last below ; INC DI ;Restore Y ; ;Move left DEC SI ;X <-- X - 1 JL PAINT12 ;Stop the scan if too far left CALL GET_COLOR ;Check the point CMP AL,DL ;Is it filled yet? JE PAINT12 ; if so, next scan line CMP AL,DH ;Is it boundary yet? JE PAINT12 ; if so, next scan line JMP PAINT7 ;Continue painting scan line PAINT12: INC SI ;Restore X MOV X1,SI ;Store X-coordinate of start MOV Y1,DI ;Store Y-coordinate of start CALL SET_BOX ;Plot the scan line JMP PAINT1 ;Next place to paint ; PAINT_XIT: RET PAINT ENDP ;------------------------------------------------------------------------------ CODES ENDS ; END ;______________________________________________________________________________ ;>>>>> Physical EOF GRAPHICS.ASM <<<<<