clear canvas

[Cor]

How to clear canvas?

draw circle above an bitmap image

imageview1 is defined in layout

Dim ImageView1 As ImageView
fretBoardCanvas.Initialize(Imageview1)

fretBoardCanvas.DrawCircle(22dip,45dip,20dip,Colors.Blue,True,1dip)

above works, but now how to clear the fretBoardCanvas?

grCor



grCor

 

[Cor]

anyone suggestions?

grCor

 

[klaus]

Can you be more precise:
Where is the bitmap ?
On the Activity or also on the ImageView ?
What do you mean with but now how to clear the fretBoardCanvas?

Do you want to erase the circle?

Do you have some code to look at?

Best regards.

 

[Cor]

I have a background bitmap

above that i have a canvas

on which i draw circles

I want the circles to be removed from the canvas

and start drawing some new ones over the background

just like the program i wrote for the pc

see the green circles over the background

grCor

 

[derez]

If I am not mistaken, the canvas.bitmap is updated only when you initialize it. This means that the canvas.bitmap does not include the circle, although it drew it on the imageview.
Try to do drawbitmap by the canvas, using its own bitmap and see what happens (I have not tried what I suggest so I'm not sure it works).

 

[klaus]

A Canvas is not a layer above the ImageView View, but 'only' a class of drawing routines that are referenced to a View's bitmap ot to a bitmap.


I could suggest you 2 possibilities:

1. In your example, add a bitmap with the original image.
   Draw the circles as you did on the ImageView.
   To erase the circles, set the ImageView's image to the original bitmap.
   
2. Add a transparent Panel over the ImageView.
   Draw the circles onto the Panel.
   To erase the circles, set the Panel's colot to transparent.

Attached a small test program showing both possibilities.

Best regards.

 

[Cor]

thanks

this shows me the right direction

grCor