Keystrokes detection for non-control, meta key

ruby-talk
1

I have tried

@canvas.bind('k', proc{|e| })
@canvas.bind('KeyPress-k', proc{|e| })
@canvas.bind('Key-k', proc{|e| })

well... none of them work.
Any wise words?

Thank you.

Tee Shift

2

teeshift wrote:

I have tried

@canvas.bind('k', proc{|e| })
@canvas.bind('KeyPress-k', proc{|e| })
@canvas.bind('Key-k', proc{|e| })

well... none of them work.

Try
       root.bind("Key-k") {...}

IIRC, the reason is that key events are sent to the top level window unless you have focused on a subwindow.

···

--
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407

3

Thank you Joel.

I tried and it worked. Now, is there a way to find which key users have
pressed without
specifying it first?

@canvas.bind('Key', proc{})

what should be inside the 'proc'? I know e.x, e.y but have tried
e.keys, e.key, e.value
without success and did not find any valuable information on Event.

Thank you.

Tee

Joel VanderWerf wrote:

···

teeshift wrote:
> I have tried
>
> @canvas.bind('k', proc{|e| })
> @canvas.bind('KeyPress-k', proc{|e| })
> @canvas.bind('Key-k', proc{|e| })
>
> well... none of them work.

Try
       root.bind("Key-k") {...}

IIRC, the reason is that key events are sent to the top level window
unless you have focused on a subwindow.

--
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407

4

teeshift wrote:

Thank you Joel.

You're welcome!

I tried and it worked. Now, is there a way to find which key users have
pressed without
specifying it first?

@canvas.bind('Key', proc{})

I was curious about this too.

To find out, add something like this:

       root.bind "Key" do |stuff|
         p stuff, stuff.methods
       end

Then press a key in your window. It turns out that the "stuff" is an Event instance, and it has @keysym="h", and there are #keycode and #keysym methods.

If you add the line

         p stuff.keycode, stuff.keysym

then you can see that pressing the "h" key gives this output:

43
"h"

So probably the #keysym method is what you want.

···

--
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407

5

Thanks. Joel.

Sorry for the late reply. Did not have much time doing doodling on
Ruby.

The other question, I will post it on the group with a different
title.
Is there any method to get a pixel from the canvas? I can draw a pixel
(painfully by using either
line or rectangle, same storage anyway) but can I sample a pixel ?

I vaguely recall that Java seems to do that. Do not know if Qt 4 does
it. ( A complete novice on Qt4
and haven't coded Java for years.)

6

Ignore my previous message. The answer is at

http://groups.google.com/group/comp.lang.ruby/browse_thread/thread/f0cd7b379e8b195f/e9fded6c453a28bb?lnk=gst&q=get+pixel+canvas&rnum=1#e9fded6c453a28bb

However, I would love to know about the Qt4 and Java. Does it work on
their canvas?