B4J Question How to make a drawn line invisible again? [newbie]

[stellaferoxx]

Hi,

Newbie Q here. I once used Basic4ppc but that is long gone.

I am trying to make a radar with a sweeping line. How can I make a drawLine invisible again so I can move to the next line in a circle? I don't want to use the background color as it erases everything underneath. Is it possible?

Thx Marc

 

[Erel]

Is it possible?

Of course. The simplest way to do it is to:
1. Use B4XCanvas.
2. Use two transparent panels, one above the other (not as a child), and draw the line in the top panel. This will allow you to clear it without erasing the background.

 

[stellaferoxx]

Of course. The simplest way to do it is to:
1. Use B4XCanvas.
2. Use two transparent panels, one above the other (not as a child), and draw the line in the top panel. This will allow you to clear it without erasing the background.

Thx Erel, still the man who answers every question as in the good days of B4ppc. I will try to accomplish this.

 

[klaus]

You might have a look at the B4X Graphics booklet, there are examples.
You can download the booklets and the code from the B4X Documentation Booklets thread.

 

[stellaferoxx]

You might have a look at the B4X Graphics booklet, there are examples.
You can download the booklets and the code from the B4X Documentation Booklets thread.

Thx Klaus, I started from the examples. Problem is that being brought in machine language, (Turbo)Pascal, Delphi, Basic, C++ etc, I tend to mix up the languages and possibilities

 

[klaus]

Well, every new language needs a bit adaptation time.