Beizer Curve - Need some advice to make it interactive

ricardo · Post by **ricardo** » Thu Jun 12, 2003 5:46 am

Hi,

Im with drawing again, now drawig a beizer curve (if you don't know what it is run the code and you will recognize it).

Code: Select all

Structure PointAPI
x.l
y.l
EndStructure

Dim P.PointAPI(3)

Procedure CreateBezier() 
StartDrawing(WindowOutput())
Red = RGB(255,0,0)
Blue = RGB(0,0,255)
P(0)\x = 0
P(0)\y = 0
P(1)\x = 80
P(1)\y = 10
P(2)\x = 150
P(2)\y = 70
P(3)\x = 130
P(3)\y = 230

LineXY(P(0)\x+10,P(0)\y+10,P(1)\x+10,P(1)\y+10,Blue)
Box(P(0)\x+10,P(0)\y+10, 4, 4,Red) 
Box(P(1)\x+10,P(1)\y+10, 4, 4,Red)

LineXY(P(2)\x+10,P(2)\y+10,P(3)\x+10,P(3)\y+10,Blue)
Box(P(2)\x+10,P(2)\y+10, 4, 4,Red) 
Box(P(3)\x+10,P(3)\y+10, 4, 4,Red)
hDC = GetDC_(GadgetID(1)) 
PolyBezier_(hDC,@P(),4)
StopDrawing()
EndProcedure


If OpenWindow(0,100,150,450,300,#PB_Window_SystemMenu,"Create Beizer Curve")
  CreateGadgetList(WindowID())
  ImageGadget(1,10,10,255,255,LoadImage(0,""))
  ButtonGadget(3,300,140,50,25,"Curve")
  Repeat
    EventID=WaitWindowEvent()
    
    Select EventID
    
      Case #PB_EventGadget
        Select EventGadgetID()
            
          Case 3
            CreateBezier()

        EndSelect
    
    EndSelect
    
  Until EventID=#PB_EventCloseWindow
EndIf

Now i need 2 advises:

1.- I want to make it interactive, to let the user drag any of the 4 point to manipulate the curve Â¿any idea of the best way to achieve it?

I need no flickering but need to save the result as BMP.

2.- I want to know all (or many) the points of the curve...

Â¿how to achieve it?

Thanks in advance if any BIG & charitative soul help me i will be greatefull forever

Magi · Post by **Magi** » Thu Jun 12, 2003 3:42 pm

Ricardo:

Not exactly what you want, however, at some point you'll have to click and select the curve, for that you will need what is called " hit testing" so I thought you may be interested in the following docs:

http://msdn.microsoft.com/library/defau ... ttest2.asp

http://msdn.microsoft.com/library/defau ... vector.asp

I hope it helps and let me know if you find anything else, interesting subject

Marc

ricardo · Post by **ricardo** » Thu Jun 12, 2003 4:22 pm

Magi wrote:Ricardo:

Not exactly what you want, however, at some point you'll have to click and select the curve, for that you will need what is called " hit testing" so I thought you may be interested in the following docs:

http://msdn.microsoft.com/library/defau ... ttest2.asp

http://msdn.microsoft.com/library/defau ... vector.asp

I hope it helps and let me know if you find anything else, interesting subject

Marc

Hi,

Exactly what i was looking for!!!!!

The problem is to translate it to PB

Any idea?

Magi · Post by **Magi** » Thu Jun 12, 2003 4:58 pm

ricardo wrote: Exactly what i was looking for!!!!!

The problem is to translate it to PB

Any idea?

If only I was that smart

plus I don't speak any "C" :roll:

But this forum has a lot of "C Gurus"...

Marc

Magi · Post by **Magi** » Thu Jun 12, 2003 6:44 pm

Ricardo:

Just found some code in VB6. It's a 3K zip, if you want I can e-mail it to you direct.

Marc

Cor · Post by **Cor** » Thu Jun 12, 2003 6:52 pm

@Ricardo,

Just curious,

Are you making some visual envelopes for editing sounds for a synth?

ricardo · Post by **ricardo** » Thu Jun 12, 2003 7:27 pm

Cor wrote:@Ricardo,

Just curious,

Are you making some visual envelopes for editing sounds for a synth?

Hi Cor,

No, im making some small app for manipulating some images and i want to be able to manipulate the bevel.

BTW, its not a bad idea about sounds!!

Resolving the way to interact with the curve it can be used on many usefull ways!!

ricardo · Post by **ricardo** » Thu Jun 12, 2003 7:28 pm

Magi wrote:Ricardo:

Just found some code in VB6. It's a 3K zip, if you want I can e-mail it to you direct.

Marc

Hi Magi,

I will be happy if you can send it to me. ricardoarias@yahoo.com

Thanks in advance

Magi · Post by **Magi** » Thu Jun 12, 2003 8:07 pm

Sent... Have fun

Tomcat · Post by **Tomcat** » Thu Jun 12, 2003 11:34 pm

Hello Ricardo,

if you want to know, how many points the bezier curve has, I think the easiest way is by creating the curve by yourself (so you can count the points and even set the accuracy). The hittest can also be done by yourself, since you know the coordinates of the points ;-)

I've already modified your code where the points are counted and where you're able to drag & drop the 4 points (the hittest is not accurate, but it gets the job done :-)

Code: Select all

Structure PointAPI 
x.l 
y.l 
EndStructure 

Dim P.PointAPI(4) 
P(0)\x = 0  :P(0)\y = 250
P(1)\x = 0  :P(1)\y = 0
P(2)\x = 250:P(2)\y = 0
P(3)\x = 250:P(3)\y = 250
    
Procedure CreateBezier()
  CreateImage(0,256,256)
  StartDrawing(ImageOutput())
    Box(0,0,256,256,RGB(160,160,160))
     
    Red = RGB(255,0,0) 
    Blue = RGB(0,0,255) 

    LineXY(P(0)\x,P(0)\y,P(1)\x,P(1)\y,Blue) 
    Box(P(0)\x,P(0)\y, 4, 4,Red) 
    Box(P(1)\x,P(1)\y, 4, 4,Red) 
    LineXY(P(2)\x,P(2)\y,P(3)\x,P(3)\y,Blue) 
    Box(P(2)\x,P(2)\y, 4, 4,Red) 
    Box(P(3)\x,P(3)\y, 4, 4,Red) 

    beziercount.w=2 ;+Start and Endpoint
    accuracy.f=(GetGadgetState(6)/100)
    u.f=0
    Repeat 
      xlast.f=x.f
      ylast.f=y.f
      x.f=p(0)\x*Pow((1-u),3)+p(1)\x*3*u*Pow((1-u),2)+p(2)\x*3*Pow(u,2)*(1-u)+p(3)\x*Pow(u,3)
      y.f=p(0)\y*Pow((1-u),3)+p(1)\y*3*u*Pow((1-u),2)+p(2)\y*3*Pow(u,2)*(1-u)+p(3)\y*Pow(u,3)
      If u.f>0
        LineXY(x,y,xlast,ylast)
      EndIf
      u.f+accuracy.f
      If u.f>1.0 And endpoint.b=0
        endpoint.b=1
        u.f=1.0
      EndIf
      If u.f>0.0 And u.f<1.0
        beziercount.w+1
      EndIf
    Until (u.f>1.0)
  StopDrawing()
  SetGadgetState(1,UseImage(0))
  SetGadgetText(4,"Bezier curve has "+Str(beziercount.w)+" Points")
EndProcedure

If OpenWindow(0,100,150,450,300,#PB_Window_SystemMenu,"Create Bezier Curve") 
  CreateGadgetList(WindowID())
  ImageGadget(1,10,10,256,256,LoadImage(0,""))
  ButtonGadget(3,300,140,100,25,"Reset Points")
  TextGadget(4,270,10,200,18,"")
  TextGadget(5,10,275,50,18,"Accuracy:")
  TrackBarGadget(6,60,270,206,30,1,50):SetGadgetState(6,10)
  
  createBezier()
  Repeat 
    EventID=WaitWindowEvent() 
    Select EventID
      Case #WM_LBUTTONDOWN
        leftmousebutton.b=1
      Case #WM_LBUTTONUP
        leftmousebutton.b=0
      Case #WM_MOUSEMOVE
        mousex=WindowMouseX()-15
        mousey=WindowMouseY()-33
        If leftmousebutton.b=0
          selectedPoint=-1
          For i=0 To 3
            If mousex>p(i)\x-5 And mousex<p(i)\x+5 And mousey>p(i)\y-5 And mousey<p(i)\y+5
              selectedPoint=i
            EndIf
          Next
          If selectedPoint<>-1
            setClassLong_(WindowID(),#GCL_HCURSOR,LoadCursor_(0,32649))
          Else
            setClassLong_(WindowID(),#GCL_HCURSOR,LoadCursor_(0,#IDC_ARROW))
          EndIf
        Else
          If selectedPoint<>-1
            P(selectedPoint)\x=mousex            
            P(selectedPoint)\y=mousey
            CreateBezier()
          EndIf
        EndIf        
      Case #PB_EventGadget 
        Select EventGadgetID() 
          Case 3          
            P(0)\x = 0  :P(0)\y = 250
            P(1)\x = 0  :P(1)\y = 0
            P(2)\x = 250:P(2)\y = 0
            P(3)\x = 250:P(3)\y = 250
            CreateBezier()
            leftmousebutton.b=0
          Case 6
            CreateBezier() 
            leftmousebutton.b=0
        EndSelect 
    EndSelect 
  Until EventID=#PB_EventCloseWindow
EndIf

I hope this helps you a little bit.

Bye,
Tomek

ricardo · Post by **ricardo** » Fri Jun 13, 2003 2:31 am

Tomcat wrote: I hope this helps you a little bit.

Wowwwwwww Its very very nice!!!

Only one question:

In XP the difference betwen the point and the place where it has to be drag it its different to win98 Â¿any idea how to workout this?