Android Question Wanting to move bitmap along spiral path

[Scotter]

So I've learned how to make a bunch of bitmaps fly out of the center of the screen using the SetLayoutAnimated method and a timer.

What I'd like to do next is move a bitmap along a spiral path starting from the center of the screen. Any ideas on how to accomplish this without using thousands of SetLayoutAnimated method in a loop?

Thanks!

 

[sorex]

use sin & cos to make a circular movement then increase the radius variable.

 

[Scotter]

use sin & cos to make a circular movement then increase the radius variable.

Thanks! I believe I have the math down.
What I need is ideas on how best to use B4A methods to utilize the math functions.

 

[sorex]

here's an example for B4J

Sub Process_Globals
    Private fx As JFX
    Dim l As Label
 Dim s As Float
 Dim r As Float
    Dim cx,cy As Int
    Dim t As Timer
End Sub

Sub AppStart (Form1 As Form, Args() As String)
    Form1.Show
    l.Initialize("")
    l.Text="x"
    Form1.RootPane.AddNode(l,0,0,10,10)
    cx=Form1.Width/2
    cy=Form1.Height/2
    t.Initialize("update",1000/60)
    t.Enabled=True
End Sub

Sub update_Tick
    r=r+.3
    s=s+.1
    l.Left=cx+Sin(s)*r
    l.Top=cy+Cos(s)*r
End Sub

 

[Scotter]

here's an example for B4J

...

THANK YOU!
I'm guessing what you are doing is putting a bitmap on a form and then using the timer to move that form around.
I'll translate this into B4A, which I don't think will be difficult.
MUCH APPRECIATION!

 

[sorex]

I move a label with "x" in it around inside the form (B4J 'activity') with the center as base location (sin/cos is -0.xxx to 0.xxx)

if you comment the r=r+ line you'll have a pure circular movement (if you give r a value first)

 

[Scotter]

Hey @sorex -
The following code causes my bitmap to start in the center small (yes that is what I want) but it then moves diagonal down toward the bottom right corner as it grows.
Ideas?

Private Sub animaSpiralTimer_Tick
    If imvSpiralHeart.Height>=imvBiggestTestFor Then
        imvSpiralHeart.Visible=False
        imvSpiralHeart.Enabled=False
        animaLinearTimer.Enabled = False
    Else
        spiral_r = spiral_r + 0.3
        spiral_s = spiral_s + 0.1
        imvHeartWidth = imvHeartWidth + 10dip
        imvHeartHeight = imvHeartHeight + 10dip
        imvSpiralHeart.left = spiral_x + Sin(spiral_s) * spiral_r
        imvSpiralHeart.top = spiral_y + Cos(spiral_s) * spiral_r
        imvSpiralHeart.Width=imvHeartWidth
        imvSpiralHeart.Height=imvHeartHeight
    End If
End Sub

 

[sorex]

you should substract half the image width and height to have it centered right but that's not related to the problem you describe.

can you upload the entire code?

 

[Scotter]

Thanks. I appreciate you wanting to help! There is no more code that is relevant.

 

[sorex]

ok, give me a few minutes

 

[sorex]

I don't know what the effect you want is but you can play with this and the parameters.

 

[Scotter]

I don't know what the effect you want is but you can play with this and the parameters.

It worked! Thank you!