þa‹RþwQþ mP9þhý oPþ nSystem-wide$NOLIST NAME Grafix Sysdep_CGROUP GROUP Sysdep_CODE PUBLIC GfxSetPixel, GfxClrPixel, GfxInvertPixel, GfxTestPixel PUBLIC GfxDrawLine, GfxEraseLine, GfxInvertLine zero EQU 0 evenMask EQU 0FFFEH ; make a word even true EQU 0FFFFH $EJ Sysdep_CODE SEGMENT PUBLIC 'CODE' ASSUME CS:Sysdep_CGROUP ;************************************************** ;* ;* GfxSetpixel(screen, bytesPerLine, winHeight, x, y: Word) ;* ;* This will set the pixel at X = horizontal ;* and Y = vertical. ;* (0,0) is the upper lefthand corner. ;* ;* REGISTERS CHANGED: AX, BX, CX, DX, ES, DI, SI ;* ;************************************************** ; Params for GfxSetPixel, GfxClrPixel, GfxInvertPixel ; and GfxTestPixel params STRUC oldDS DW ? oldBp DW ? ;----------- returnIP DW ? returnCS DW ? ;----------- y DW ? x DW ? winHeight DW ? bytesPerLine DW ? screen DW ? params ENDS loc EQU [BP] paramBytes EQU 10 GfxSetPixel PROC FAR PUSH BP PUSH DS MOV BP, SP MOV SI, 8000H CALL SetUpPixel OR DS:[BX], SI ; set the pixel POP DS POP BP RET paramBytes GfxSetPixel ENDP ;*************************************************** ;* ;* GfxClrPixel(screen, bytesPerLine, winHeight, x, y : word) ;* ;* This is exactly the same as SetPixel except ;* for the last two statements ;* ;***************************************************** GfxClrPixel PROC FAR PUSH BP PUSH DS MOV BP, SP MOV SI, 7FFFH CALL SetUpPixel AND DS:[BX], SI POP DS POP BP RET paramBytes GfxClrPixel ENDP $EJ ;*************************************************** ;* ;* GfxInvertPixel(screen, bytesPerLine, winHeight, x, y : word) ;* ;* This is exactly the same as SetPixel except ;* for the last two statements ;* ;***************************************************** GfxInvertPixel PROC FAR PUSH BP PUSH DS MOV BP, SP MOV SI, 8000H CALL SetUpPixel XOR DS:[BX], SI POP DS POP BP RET paramBytes GfxInvertPixel ENDP ;*************************************************** ;* ;* GfxTestPixel(screen, bytesPerLine, winHeight, x, y : word) ;* ;* This is exactly the same as SetPixel except ;* for the last two statements ;* ;***************************************************** GfxTestPixel PROC FAR PUSH BP PUSH DS MOV BP, SP MOV SI, 8000H CALL SetUpPixel MOV AX, DS:[BX] ;Get the word AND AX, SI ;Mask out all other bits JZ NotSet ;do nothing if not set MOV AX, true ;Set to true if bit is set. NotSet: POP DS POP BP RET paramBytes GfxTestPixel ENDP $EJ ;************************************************** ;* ;* SetUpPixel ;* ;* entry: ;* SI = original mask ;* ;* Does the setup for Set- and Clr- Pixel. ;* ;* exit: BX ^ word in display ;* DS ^ start of display buffer ;* SI = rotated mask ;* ;************************************************* SetUpPixel PROC NEAR MOV CX, loc.y MOV BX, loc.x ; BX = x MOV AX, loc.screen MOV DS, AX MOV AX, CX MOV DX, loc.bytesPerLine MUL DX MOV CX, AX ; CX = CX * byteWidth MOV AX, BX ; AX = x SAR BX, 1 SAR BX, 1 SAR BX, 1 AND BX, evenMask ; BX = EVEN(x DIV 8) ADD BX, CX ; BX ^ word in display AND AX, 000FH ; AX = x MOD 16 MOV CX, AX ROR SI, CL ; rotate to position RET SetUpPixel ENDP PURGE params PURGE oldBP PURGE oldDS PURGE returnIP PURGE returnCS PURGE x PURGE y PURGE bytesPerLine PURGE screen PURGE loc PURGE paramBytes PURGE winHeight $EJ ;********************************************************* ;* ;* GfxDrawLine(screen, bytesPerLine, winHeight, x1, y1, x2, y2) ;* ;* This will draw a line between the two points (x1, y1) and ;* (x2, y2). It uses the DDA algorithm. The act of ;* drawing a line is split into two cases for efficiency. ;* ;* case AB: dx >= dy ;* case CD: dx < dy ;* ;* During the inner loop of each case, the registers mean: ;* ;* AX = dx BX = dy ;* CX = loop counter DX = temp ;* SI = mask DI ^ display buffer ;* BP = +- wordWidth ;* ;******************************************************** ; Params for GfxDrawLine, GfxEraseLine, GfxInvertLine params STRUC oldDS DW ? oldBp DW ? ;----------- returnIP DW ? returnCS DW ? ;----------- y2 DW ? x2 DW ? y1 DW ? x1 DW ? winHeight DW ? bytesPerLine DW ? screen DW ? params ENDS loc EQU [BP] paramBytes EQU 14 GfxDrawLine PROC FAR PUSH BP PUSH DS MOV BP, SP MOV AX, loc.screen MOV DS,AX MOV DX, loc.y2 ; DX = y2 MOV CX, loc.x2 ; CX = x2 MOV BX, loc.y1 ; BX = y1 MOV AX, loc.x1 ; AX = x1 CMP AX, CX ; x1 <= x2 ? JLE Line10 XCHG AX, CX XCHG BX, DX ; now x1 <= x2 Line10: SUB CX, AX ; CX = dx ( >= 0) SUB DX, BX ; DX = dy MOV SI,8000H ; SI = original mask CALL AInitLine OR DS:[DI],SI CMP AX, BX ; dx < dy ? JL CaseCD ; yes -> case CD CaseAB: ; case AB MOV CX, AX ; loop 'dx' times MOV DX, AX CMP DX, 1 JLE NoShift SAR DX, 1 NoShift: NEG DX ; DX = -dx/2; DX > 0!! JCXZ LoopDone LoopOnAB: ADD DX, BX ; temp += dy JS A10 SUB DX, AX ; temp -= dx ADD DI, BP ; y += wordWidth A10: ROR SI, 1 ; x += 1 JNC SameX ADD DI, 2 ; DI ^ next word SameX: OR DS:[DI], SI ; set the bit LOOP LoopOnAB JMP LoopDone CaseCD: ; case CD MOV CX, BX ; loop 'dy' times MOV DX, BX CMP DX, 1 JLE NoShift2 SAR DX, 1 NoShift2: NEG DX ; DX = -dy / 2 JCXZ LoopDone LoopOnCD: ADD DX, AX ; temp += dx JS C10 SUB DX, BX ; temp -= dy ROR SI, 1 ; x += 1 JNC C10 ADD DI, 2 ; DI ^ next word C10: ADD DI, BP ; next row of bytes OR DS:[DI], SI ; set the bit LOOP LoopOnCD LoopDone: POP DS POP BP RET paramBytes GfxDrawLine ENDP $EJ ;****************************************** ;* * ;* GfxEraseLine(screen, bytesPerLine, * ;* windowHeight, * ;* x1, y1, x2, y2) * ;* * ;****************************************** GfxEraseLine PROC FAR PUSH BP PUSH DS MOV BP, SP MOV AX, loc.screen MOV DS,AX MOV DX, loc.y2 ; DX = y2 MOV CX, loc.x2 ; CX = x2 MOV BX, loc.y1 ; BX = y1 MOV AX, loc.x1 ; AX = x1 CMP AX, CX ; x1 <= x2 ? JLE ELine10 XCHG AX, CX XCHG BX, DX ; now x1 < x2 ELine10: SUB CX, AX ; CX = dx ( >= 0 ) SUB DX, BX ; DX = dy MOV SI, 7FFFH ; SI = original mask CALL AInitLine AND DS:[DI], SI CMP AX, BX ; dx < dy ? JL ECaseCD ; yes -> case CD ECaseAB: ; case AB MOV CX, AX ; loop 'dx' times MOV DX, AX CMP DX, 1 JLE ENoShift SHR DX, 1 ENoShift: NEG DX ; DX = - dx / 2 JCXZ ELoopDone ELoopOnAB: ADD DX, BX ; temp += dy JS ESameY ; next y value ? SUB DX, AX ; temp -= dx ADD DI, BP ; y += wordWidth ESameY: ROR SI, 1 ; x += 1 JC ESameX ; on to next word? ADD DI, 2 ; yes ESameX: AND DS:[DI], SI ; erase the bit LOOP ELoopOnAB JMP ELoopDone ; all finished ECaseCD: ; case CD MOV CX, BX ; loop 'dy' times MOV DX, BX CMP DX, 1 JLE ENoShift2 SHR DX, 1 ENoShift2: NEG DX ; DX = -dy / 2 JCXZ ELoopDone ELoopOnCD: ADD DX, AX ; temp += dx JS EC10 SUB DX, BX ; temp -= dy ROR SI, 1 ; x += 1 JC EC10 ADD DI, 2 ; DI ^ next word EC10: ADD DI, BP ; y += increment AND DS:[DI], SI ; clear the bit LOOP ELoopOnCD ELoopDone: POP DS POP BP RET paramBytes GfxEraseLine ENDP $EJ ;**************************************** ;* ;* GfxInvertLine(screen, bytesPerLine, ;* windowHeight, X, Y, X1, Y1) ;* ;**************************************** GfxInvertLine PROC FAR PUSH BP PUSH DS MOV BP,SP MOV AX, loc.screen MOV DS, AX MOV DX, loc.y2 ; DX = y2 MOV CX, loc.x2 ; CX = x2 MOV BX, loc.y1 ; BX = y1 MOV AX, loc.x1 ; AX = x1 CMP AX, CX ; IS X <= X1 JLE XLine10 ; YES -> JUMP XCHG AX, CX XCHG BX, DX ; NOW X < X1 XLine10: SUB CX, AX ; CX = dx (dx >= 0) SUB DX, BX ; DX = dy MOV SI, 8000H ; SI = original mask CALL AInitLine XOR DS:[DI], SI CMP AX, BX ; IS dx < dy ? JL XCaseCD ; YES -> GOTO CASES C,D XCaseAB: ; MUST BE CASE A OR B MOV CX, AX ; LOOP dx TIMES MOV DX, AX CMP DX, 1 JLE XNoShift SHR DX, 1 XNoShift: NEG DX ; DX = - dx /2 JCXZ XLoopDone XLoopOnAB: ADD DX, BX ; temp += dy JS XA10 ; JUMP IF RESULT < 0 SUB DX, AX ; temp -= dx ADD DI,BP ; Y += INC Y XA10: ROR SI,1 ; X += 1 JNC XA20 ADD DI,2 ; DI ^ next word XA20: XOR DS:[DI],SI ; SET THE BIT LOOP XLoopOnAB JMP XLoopDone XCaseCD: ; MUST BE CASE C OR D MOV CX, BX ; LOOP dy TIMES MOV DX, BX CMP DX, 1 JLE XNoShift2 SHR DX, 1 XNoShift2: NEG DX ; DX = -dy / 2 JCXZ XLoopDone XLoopOnCD: ADD DX, AX ; temp += dx JS XC10 ; JUMP IF RESULT < 0 SUB DX, BX ; temp -= dy ROR SI,1 ; X += 1 JNC XC10 ADD DI,2 ; DI ^ next word XC10: ADD DI,BP ; Y += INC Y XOR DS:[DI],SI ; SET THE BIT LOOP XLoopOnCD XLoopDone: POP DS POP BP RET paramBytes GfxInvertLine ENDP $EJ ;************************************************* ;* ;* AInitLine ;* ;* entry: AX = x ;* BX = y ;* CX = dx (dx >= 0) ;* DX = dy ;* SI = original mask ;* ;* exit: SI = rotated mask ;* DI ^ word in display ;* AX = dx ;* BX = dy ;* BP = +- wordWidth ;* ;************************************************ AInitLine PROC NEAR PUSH CX PUSH DX PUSH AX ; save during multiply MOV AX, BX MOV CX, loc.bytesPerLine MUL CX MOV DI, AX ; DI = y * byteWidth POP AX MOV CX, AX SAR CX, 1 SAR CX, 1 SAR CX, 1 AND CX, evenMask ; CX = EVEN(x DIV 8) ADD DI, CX ; DI ^ word in display AND AX, 000FH ; AX = x MOD 16 MOV CX, AX ROR SI, CL ; rotate to starting pos POP BX ; BX = dy POP AX ; AX = dx MOV BP, loc.bytesPerLine CMP BX, zero JGE DYGE0 ; dy >= 0 NEG BP NEG BX ; dy = |dy| DYGE0: $LIST RET AInitLine ENDP PURGE params PURGE oldBP PURGE oldDS PURGE returnIP PURGE returnCS PURGE x1 PURGE x2 PURGE y1 PURGE y2 PURGE bytesPerLine PURGE screen PURGE loc PURGE paramBytes PURGE winHeight Sysdep_CODE ENDS END