What is the usecase for BeginVectorLayer()/EndVectorLayer()

[jacdelad]

Hi #PB_All,
is anyone using BeginVectorLayer()/EndVectorLayer()? I think I understand what it does, but what do I need it for? As far as I understand, after EndVectorLayer() the layers are merged together anyway.

[STARGÅTE]

I use BeginVectorLayer() when I want to draw a set of overlapping figures in a half transparent way.
Without a layer, the individual figures would also blend each other.

[jacdelad]

You mean like the example in the help? Hm, ok. Maybe I just didn't have a use for this up to now.

[Michael Vogel]

I've used it in several situations, one is for creating shadows for objects which are transparent...

Code: Select all

Procedure Min(a,b)
	If a<b
		ProcedureReturn a
	Else
		ProcedureReturn b
	EndIf
EndProcedure
Macro StartClipping()
	SaveVectorState()
	ClipPath()
EndMacro
Macro StopClipping()
	RestoreVectorState()
EndMacro

Procedure AddPathRoundBox(x.d,y.d,w.d,h.d,radius.d,flags=#PB_Path_Default)

	If radius>h/2 : radius=h/2 : EndIf
	If radius>w/2 : radius=w/2 : EndIf

	If radius<0
		radius=0
	EndIf

	MovePathCursor(x+radius,y,flags)

	AddPathArc(w-radius,0,w-radius,radius,radius,#PB_Path_Relative)
	AddPathArc(0,h-radius,-radius,h-radius,radius,#PB_Path_Relative)
	AddPathArc(-w+radius,0,-w+radius,-radius,radius,#PB_Path_Relative)
	AddPathArc(0,-h+radius,radius,-h+radius,radius,#PB_Path_Relative)

	ClosePath()

	MovePathCursor(-radius,0,#PB_Path_Relative)

EndProcedure
Procedure AddPathHighlight(x.d,y.d,w.d,h.d,r.d,angle.d,flags=#PB_Path_Default)

	Protected t1.d,t2.d,t3.d,t4.d,t5.d

	t1=Cos(angle*#PI/180);   1-89°
	t2=Sin(angle*#PI/180)
	t3=r*t1
	t4=r*t2
	t5=2*r-t4

	MovePathCursor(x,y+r,flags)
	AddPathCircle(r,0,r,180,270,#PB_Path_Relative)
	AddPathLine(w-r*2,0,#PB_Path_Relative)
	AddPathCircle(0,r,r,270,270+angle,#PB_Path_Relative|#PB_Path_Connected)
	AddPathLine(-w+t5,0,#PB_Path_Relative)
	AddPathCircle(0,t3,t3,270,180,#PB_Path_Relative|#PB_Path_Connected|#PB_Path_CounterClockwise)
	AddPathLine(0,h-t5,#PB_Path_Relative)
	AddPathCircle(t3,-t4,r,180-angle,180,#PB_Path_Relative|#PB_Path_Connected)

	ClosePath()

EndProcedure
Procedure AddPathShadow(x.d,y.d,w.d,h.d,r.d,angle.d,flags=#PB_Path_Default)

	Protected ro.d
	Protected t1.d,t2.d,t3.d,t4.d,t5.d

	ro=Min(Min(r,h/2),w/2)

	t1=Cos(angle*#PI/180);   1-89°
	t2=Sin(angle*#PI/180)
	t3=r*t1
	t4=r*t2
	t5=2*r-t4

	r=ro
	MovePathCursor(x+w,y+h-r,flags)
	AddPathCircle(-r,0,r,0,90,#PB_Path_Relative)
	AddPathLine(-w+r*2,0,#PB_Path_Relative)
	AddPathCircle(0,-r,r,90,90+angle,#PB_Path_Relative|#PB_Path_Connected)
	AddPathLine(w-t5,0,#PB_Path_Relative)
	AddPathCircle(0,-t3,t3,90,0,#PB_Path_Relative|#PB_Path_Connected|#PB_Path_CounterClockwise)
	AddPathLine(0,-h+t5,#PB_Path_Relative)
	AddPathCircle(-t3,t4,r,360-angle,360,#PB_Path_Relative|#PB_Path_Connected)

	ClosePath()

EndProcedure
Procedure DrawVectorShadow(x.d,y.d,w.d,h.d,radius.d,size.d=20,offset.d=5,alpha.d=20,color=#Black,flags=#PB_Path_Default)

	Protected i
	AddPathBox(0,0,VectorOutputWidth(),VectorOutputHeight())
	AddPathRoundBox(x,y,w,h,radius)
	StartClipping()

	For i=1 To size
		AddPathRoundBox(x+offset-i,y+offset-i,w+i*2,h+i*2,((w+i)*radius/w) )
		VectorSourceColor(RGBA(Red(color), Green(color), Blue(color), Alpha/size))
		FillPath()
	Next
	StopClipping()

EndProcedure

Procedure boxs(x.f,y.f,w.f,h.f,radius.f,col,alpha=255,button.f=8,shadow.f=20,darkness=100,offset.f=15)

	Protected shadowcount=20

	radius=min(min(radius,h/2),w/2)

	 BeginVectorLayer(min(alpha,255))

	; Shadow
	shadow/shadowcount
	darkness=darkness/shadowcount+1
	For i=0 To shadowcount
		AddPathRoundBox(x+offset+shadow*i/2,y+offset+shadow*i/2,w-shadow*i,h-shadow*i,radius-shadow*(i-shadowcount/2)/2)
		VectorSourceColor(darkness<<24)
		FillPath()
	Next i

	; Filled Button
	AddPathRoundBox(x,y,w,h,radius)
	VectorSourceColor($ff000000|col)
	FillPath()

	; Erasing area...
	;AddPathBox(x+50,y+50,150,50)
	;VectorSourceColor($fffffffff)
	;FillPath()

	; Highlight and Shadow
	VectorSourceColor($40ffffff)
	AddPathHighlight(x,y,w,h,radius,button*2)
	FillPath()
	AddPathHighlight(x,y,w,h,radius,button*3)
	FillPath()
	VectorSourceColor($20000000)
	AddPathShadow(x,y,w,h,radius,button*2)
	FillPath()
	AddPathShadow(x,y,w,h,radius,button*3)
	FillPath()

	; Button Border
	AddPathRoundBox(x,y,w,h,radius)
	VectorSourceColor($60000000)
	StrokePath(1)

	 EndVectorLayer()

EndProcedure
Procedure show()

	Protected i

	StartVectorDrawing(CanvasVectorOutput(0))
	AddPathBox(0,0,VectorOutputWidth(),VectorOutputHeight())
	VectorSourceColor($Ff000000|#White)
	FillPath()

	; some random background
	For i=0 To 100
		AddPathBox(Random(VectorOutputWidth())-50,Random(VectorOutputHeight())-50, 50+Random(50), 50+Random(50))
		VectorSourceColor(RGBA(Random(255),Random(255),Random(255),Random(40)))
		FillPath()
	Next

	boxs(300,100,130,400,90,$9AF0B8,160,10)
	boxs(50,50,400,150,90,$D1ADF3,180,5,50,170)
	boxs(50,350,500,100,40,$F3D1AD,250,10,20,50);      smaller radius
	boxs(400,100,300,200,90,$9AF0F8,120,5)
	boxs(500,250,100,300,90,$9AF0B8,180,10)
	boxs(100,100,130,400,90,$9AF0B8,100,10)

	StopVectorDrawing()

EndProcedure

Procedure main()

	#X=800
	#Y=600

	OpenWindow(0,0,0,#X,#Y,"")
	CanvasGadget(0,0,0,#X,#Y)

	show()

	Repeat
		Select WaitWindowEvent()
		Case #PB_Event_CloseWindow
			End
		Case #WM_CHAR
			End
		EndSelect
	ForEver

EndProcedure
main()