A2osX/LIB/LIBGUI.S.CLIP.txt

NEW
  AUTO 3,1
*--------------------------------------
*  CLIPPING Functions:
* In: 
*  Graphic Context in OBJ.Cache
*  YA = Control Block
* Out:
*  CC : CB.Cache clipped & visible
*  CS : CB.Cache invisible
*--------------------------------------
CLIP.YA			jsr CB.Get				Put CB in cache

CLIP.CB.Cache	ldx CB.Cache+S.CB.CMD
				bpl CLIP.X

				txa
				and #$7F
				tax

CLIP.X			jmp (J.CLIP-2,x)
*--------------------------------------
CLIP.Point
				clc
				rts
*--------------------------------------
CLIP.HLine
				clc
				rts
*--------------------------------------
CLIP.VLine
				clc
				rts
				
				sec
				rts
*--------------------------------------
* OBJ.Cache = Target Context
* CB.Cache =  Src Control Block
*--------------------------------------
CLIP.Rect		jsr CB.Cache.Overlap
				bcs .9

				>LDYA OBJ.Cache+S.OBJ.X1
				>STYAIFGTR CB.Cache+S.CB.X1

				>LDYA OBJ.Cache+S.OBJ.X2
				>STYAIFLWR CB.Cache+S.CB.X2

				>LDYA OBJ.Cache+S.OBJ.Y1
				>STYAIFGTR CB.Cache+S.CB.Y1

				>LDYA OBJ.Cache+S.OBJ.Y2
				>STYAIFLWR CB.Cache+S.CB.Y2

				clc
.9				rts
*--------------------------------------
CLIP.Text
				clc
CLIP.Text.RTS	rts
*--------------------------------------
* BitBlt : 
*--------------------------------------
CLIP.BitBlt		jsr CB.Cache.SetX2Y2	set X2=X1+W-1 Y2=X1+H-1

				jsr CB.Cache.Overlap
				bcs CLIP.Text.RTS

				lda OBJ.Cache+S.OBJ.X1
				sec
				sbc CB.Cache+S.CB.X1
				sta DX
				
				lda OBJ.Cache+S.OBJ.X1+1
				sbc CB.Cache+S.CB.X1+1
				sta DX+1
				bvc .1
				eor #$80
.1				bmi .2
				>DEBUG				
				lda S.CB.X1
				clc
				adc DX
				sta S.CB.X1

				lda CB.Cache+S.CB.X1+1
				adc DX+1
				sta CB.Cache+S.CB.X1+1

				lda CB.Cache+S.CB.SrcX
				clc
				adc DX
				sta CB.Cache+S.CB.SrcX

				lda CB.Cache+S.CB.SrcX+1
				adc DX+1
				sta CB.Cache+S.CB.SrcX+1
				
				lda CB.Cache+S.CB.SrcW
				sec
				sbc DX
				sta CB.Cache+S.CB.SrcW

				lda CB.Cache+S.CB.SrcW+1
				sbc DX+1
				sta CB.Cache+S.CB.SrcW+1
				bcc .9 

.2				lda CB.Cache+S.CB.X2
				sec
				sbc OBJ.Cache+S.OBJ.X2
				sta DX
				
				lda CB.Cache+S.CB.X2+1
				sbc OBJ.Cache+S.OBJ.X2+1
				sta DX+1
				bvc .3
				eor #$80
.3				bmi .4
				>DEBUG
			
				lda CB.Cache+S.CB.SrcW
				sec
				sbc DX
				sta CB.Cache+S.CB.SrcW

				lda CB.Cache+S.CB.SrcW+1
				sbc DX+1
				sta CB.Cache+S.CB.SrcW+1
				bcc .9 



				
.4				clc
.99				rts
				
.9				sec
				rts
*--------------------------------------
CLIP.Line.LEFT	.EQ 1
CLIP.Line.RIGHT	.EQ 2
CLIP.Line.BOTTOM	.EQ 4
CLIP.Line.TOP	.EQ 8
*--------------------------------------
CLIP.Line		jsr CLIP.Line.EncodeP1
				jsr CLIP.Line.EncodeP2
.1				lda CLIP.Line.P1
				ora CLIP.Line.P2
				beq .88
				lda CLIP.Line.P1
				and CLIP.Line.P2
				bne .99
				lda CLIP.Line.P1
				beq .5
				bit #CLIP.Line.TOP
				beq .2
* Y1 is above S.CB.Y1....			
* DY=Y2-Y1;
				jsr CLIP.Line.EncodeP1
				bra .1
.2				bit #CLIP.Line.BOTTOM
				beq .3			
* Y1 is below S.CB.Y2....
				jsr CLIP.Line.EncodeP1
				bra .1
.3				bit #CLIP.Line.RIGHT
				beq .4	
* X1 is after S.CB.X2....
				jsr CLIP.Line.EncodeP1
				bra .1
* X1 is before S.CB.X1....
.4
				jsr CLIP.Line.EncodeP1
				bra .1
* P2
.5				lda CLIP.Line.P2

				bit #CLIP.Line.TOP
				beq .6
* Y2 is above S.CB.Y1....
				jsr CLIP.Line.EncodeP2
				bra .1
.6				bit #CLIP.Line.BOTTOM
				beq .7			
* Y2 is below S.CB.Y2....
				jsr CLIP.Line.EncodeP2
				bra .1
.7				bit #CLIP.Line.RIGHT
				beq .8			
* X2 is after S.CB.X2....
				jsr CLIP.Line.EncodeP2
				bra .1
* X2 is before S.CB.X1....
.8
				jsr CLIP.Line.EncodeP2
				bra .1
.88				clc
				rts

.99				sec
				rts
*--------------------------------------
CLIP.Line.EncodeP1
				ldy #0

				lda CB.Cache+S.CB.X1
				ldx CB.Cache+S.CB.X1+1
				jsr CLIP.Line.EncodeX.AX
				tay
				lda CB.Cache+S.CB.Y1
				ldx CB.Cache+S.CB.Y1+1
				jsr CLIP.Line.EncodeY.AX
				sta CLIP.Line.P1
				rts
*--------------------------------------
CLIP.Line.EncodeP2
				ldy #0

				lda CB.Cache+S.CB.X2
				ldx CB.Cache+S.CB.X2+1
				jsr CLIP.Line.EncodeX.AX
				tay
				lda CB.Cache+S.CB.Y2
				ldx CB.Cache+S.CB.Y2+1
				jsr CLIP.Line.EncodeY.AX
				sta CLIP.Line.P2
				rts
*--------------------------------------
CLIP.Line.EncodeX.AX
				pha
				>SCMPAX OBJ.Cache+S.OBJ.X1
				bmi .1
				tya
				ora #CLIP.Line.LEFT
				plx
				rts
.1				pla
				>SCMPAX OBJ.Cache+S.OBJ.X1
				bpl .8
				tya
				ora #CLIP.Line.RIGHT
.8				rts	
*--------------------------------------
CLIP.Line.EncodeY.AX		
				pha
				>SCMPAX OBJ.Cache+S.OBJ.Y1
				bmi .1
				tya
				ora #CLIP.Line.TOP
				plx
				rts
.1				pla
				>SCMPAX OBJ.Cache+S.OBJ.Y1
				bpl .8
				tya
				ora #CLIP.Line.BOTTOM
.8				rts
*--------------------------------------
CB.Cache.SetX2Y2
				lda CB.Cache+S.CB.SrcW
				clc
				adc CB.Cache+S.CB.X1
				pha

				lda CB.Cache+S.CB.SrcW+1
				adc CB.Cache+S.CB.X1+1
				tax
				pla
				bne .2

				dex
				
.2				dec				
				sta CB.Cache+S.CB.X2
				stx CB.Cache+S.CB.X2+1
				
				lda CB.Cache+S.CB.SrcH
				
				clc
				adc CB.Cache+S.CB.Y1
				pha

				lda CB.Cache+S.CB.SrcH+1
				adc CB.Cache+S.CB.Y1+1
				tax
				pla
				bne .3

				dex
				
.3				dec				
				sta CB.Cache+S.CB.Y2
				stx CB.Cache+S.CB.Y2+1
				rts
*--------------------------------------
CB.Cache.Overlap
				>LDYA CB.Cache+S.CB.X1
				>SCMPYA OBJ.Cache+S.OBJ.X2
				bpl .9

				>LDYA CB.Cache+S.CB.X2
				>SCMPYA OBJ.Cache+S.OBJ.X1
				bmi .9

				>LDYA CB.Cache+S.CB.Y1
				>SCMPYA OBJ.Cache+S.OBJ.Y2
				bpl .9

				>LDYA CB.Cache+S.CB.Y2
				>SCMPYA OBJ.Cache+S.OBJ.Y1
				bmi .9
				
				clc
				rts
				
.9				sec
				rts
*--------------------------------------
MAN
SAVE usr/src/lib/libgui.s.clip
LOAD usr/src/lib/libgui.s
ASM