A2osX/LIB/LIBGUI.S.DRAW.txt

NEW
  AUTO 3,1
*--------------------------------------
Draw			>PULLW ZPCBPtr			Get CB
				>PULLYA					Get GC
				jsr OBJ.Get
.1				>LDYA ZPCBPtr
				jsr	CB.Get
				ldx CB.Cache+S.CB.CMD	Get Cmd
				beq .8

				jsr CLIP.X
				bcs .7
				ldx CB.Cache+S.CB.CMD
				cpx #S.CB.CMD.DRAWLINE
				bcc .2					Native DRV Cmd
			
				jsr Draw.Jmp
				bra .7
.2				jsr GFXWrite.CB
.7				lda (ZPCBPtr)			Get Cmd
				tax
				lda CB.CmdLen,x
				sec
				adc ZPCBPtr
				sta ZPCBPtr
				bcc .1
				inc ZPCBPtr+1
				bra .1
.8				clc
.9				rts

Draw.Jmp		jmp (J.Cmds-S.CB.CMD.DRAWLINE,x)
*--------------------------------------
* In: Control Block in CB.Cache
*  CMD
*  OP
*  MODE
*  COLOR
*  X1
*  Y1
*  X2
*  Y2
*--------------------------------------
DrawLine		lda CB.Cache+S.CB.X2
				sec
				sbc CB.Cache+S.CB.X1
				sta DX
				lda CB.Cache+S.CB.X2+1
				sbc CB.Cache+S.CB.X1+1
				sta DX+1				DX = X2 - X1

				bmi .1					DX < 0....
				ora DX
				bne .2					DX > 0...

				lda #S.CB.CMD.VLINE
				sta CB.Cache+S.CB.CMD
				jmp GFXWrite.CB			DX=0 : VLIN Y1,Y2 At X1
.1				>SWAP16 CB.Cache+S.CB.X1,CB.Cache+S.CB.X2
*				>SWAP16 CB.Cache+S.CB.Y1,CB.Cache+S.CB.Y2
				lda CB.Cache+S.CB.Y1
				ldx CB.Cache+S.CB.Y2
				stx CB.Cache+S.CB.Y1
				sta CB.Cache+S.CB.Y2

				>NOT16 DX				swap X1/X2, Y1/Y2, set DX=-DX (DX positive)

.2				lda #1
				sta	IY

				lda CB.Cache+S.CB.Y2
				sec
				sbc CB.Cache+S.CB.Y1
				sta DY
*				lda CB.Cache+S.CB.Y2+1
				lda #0
*				sbc CB.Cache+S.CB.Y1+1
				sbc #0
				sta DY+1				DY = Y2 - Y1		
				bmi .3					DY < 0 ...
				ora DY
				bne .4
				lda #S.CB.CMD.HLINE
				sta CB.Cache+S.CB.CMD
				jmp GFXWrite.CB			DY=0 : HLIN X1,X2 At Y1
.3				>NOT16 DY				set DY=-DY
				lda #$ff
				sta IY					set IY=-1

.4				lda #S.CB.CMD.SETPIXEL
				sta CB.Cache+S.CB.CMD
				jsr GFXWrite.CB
				lda DX
				sec
				sbc DY
				tax
				lda DX+1
*				sbc DY+1
				sbc #0
				bmi DrawLine.IncY		DY is greater than DX, we will increase on Y axis
				txa
				beq DrawLine.IncXY		DX=DY, go inc X & Y
				jmp DrawLine.IncX		DY is lower than DX, we will increase on X axis

DrawLine.IncXY	lda DX					DX=DY
				eor #$ff
				sta Counter
				lda DX+1
				eor #$ff
				sta Counter+1

.1				inc Counter
				bne .2
				inc Counter+1
				beq .8
.2				inc CB.Cache+S.CB.X1
				bne .3
				inc CB.Cache+S.CB.X1+1
.3				lda CB.Cache+S.CB.Y1	Y1=Y1+IY
				clc
				adc IY
				sta CB.Cache+S.CB.Y1
				jsr GFXWrite.CB
				bra .1
.8				rts
DrawLine.IncY	lda DY
				eor #$ff
				sta Counter
				lda DY+1
				eor #$ff
				sta Counter+1

				lda DX					IE=2*DX
				asl
				sta IE
				pha
				lda DX+1
				rol
				sta IE+1
				tax

				pla						D=IE-DY
				sec
				sbc DY
				sta D
				txa
				sbc DY+1
				sta D+1
				lda DX					INE=2*(DX-DY)
				sec
				sbc DY
				pha
				lda DX+1
				sbc DY+1
				tax
				pla
				asl
				sta INE
				txa
				rol
				sta INE+1
.1				inc Counter
				bne .2
				inc Counter+1
				beq .8

.2				lda D+1					IF D < 0 ...
				bmi .4
				lda D					D > 0 : D=D+INE
				clc
				adc INE
				sta D
				lda D+1
				adc INE+1
				sta D+1
				inc CB.Cache+S.CB.X1	X1=X1+1
				bne .5
				inc CB.Cache+S.CB.X1+1
				bra .5
.4				lda D					D > 0 : D=D+IE
				clc
				adc IE
				sta D
				lda D+1
				adc IE+1
				sta D+1
.5				lda CB.Cache+S.CB.Y1	Y1=Y1+IY
				clc
				adc IY
				sta CB.Cache+S.CB.Y1
				jsr GFXWrite.CB
				bra .1
.8				rts

DrawLine.IncX	lda DX
				eor #$ff
				sta Counter
				lda DX+1
				eor #$ff
				sta Counter+1			
				lda DY					IE=2*DY
				asl
				sta IE
				pha
*				lda DY+1
				lda #0
				rol
				sta IE+1
				tax
				pla						D=IE-DX
				sec
				sbc DX
				sta D
				txa
				sbc DX+1
				sta D+1
				lda DY					INE=2*(DY-DX)
				sec
				sbc DX
				pha
*				lda DY+1
				lda #0
				sbc DX+1
				tax
				pla
				asl
				sta INE
				txa
				rol
				sta INE+1
.1				inc Counter
				bne .2
				inc Counter+1
				beq .8

.2				lda D+1					ID D < 0 ....
				bmi .4
				lda D					D > 0 : D=D+INE
				clc
				adc INE
				sta D
				lda D+1
				adc INE+1
				sta D+1
				lda CB.Cache+S.CB.Y1	Y1=Y1+IY
				clc
				adc IY
				sta CB.Cache+S.CB.Y1
				bra .5
.4				lda D					D < 0 : D=D+IE
				clc
				adc IE
				sta D
				lda D+1
				adc IE+1
				sta D+1
.5				inc CB.Cache+S.CB.X1	X1=X1+1
				bne .6
				inc CB.Cache+S.CB.X1+1
.6				jsr GFXWrite.CB
				bra .1
.8				rts
*--------------------------------------
DrawText		>LDYA L.CB.Cache
				ldx #0

				>SYSCALL2 OSD
				bcs .9
				jsr GFXWrite.CB
				lda CB.Cache+S.CB.SrcPtr
				>SYSCALL2 FreeStkObj
.9				rts
*--------------------------------------

MAN
SAVE usr/src/lib/libgui.s.draw
LOAD usr/src/lib/libgui.s
ASM