On 24 Jul 98 at 11:44, Frederic FAURE wrote:
> Hello,
> In a C++ programm, i would like to know if a mouse button has been
> pushed, and
> what is the location (x,y)
> of the mouse cursor.
> I guess that virtual void TCanvas::HandleInput(const
> EEventType button,
> Int_t x, Int_t y)
> could do that, but i don't succeed to make it work.
>
> i tried:
>
> EEventType event;
> Int_t px;
> Int_t py;
>
> c->HandleInput(event,px,py);
>
> cout<<"px="<<px<<endl;
> cout<<"py="<<py<<endl;
> cout<<"event="<<event<<endl;
>
> which gives nothing.
>
> Is there a possibility?
Please have a look at
http://root.cern.ch/root/HowtoPick.html
This means if you create any "abstract" object derived from
TObject and apply method Draw() somehow
obj->Draw()
the pointer to your object will be included into the list of the
TPad objects and the method ExecuteMethod(Int_t px, Int_t py) of very
your class will be called just the mouse will be moving within TPad.
If your DistancetoPrimitive method will "return 0" always then TPad
will ALWAYS call
veryyourobject->ExecuteEvent(event,px,py)
as well. Where the "event" is defined with TButton.h file, px, py are the
current mouse position in pixels. (I'd like to mention the
"veryyourobject" may have NO real graphical view on the screen at
all. i.e. it could be "fantom" object. The last means you do
not supply any Paint() method for your class).
Just the class as follows will do job for you
#include <TObject.h>
class Picker: public TObject {
public:
Int_t DistancetoPrimitive(Int_t px, Int_t py){ return 0;)
void ExecuteEvent(Int_t event, Int_t px, Int_t py){ printf(
the event %d with px=%d, py=%d has been caught\n"
,event,px,py); }
};
Hope this helps,
Valery
=================================================================
Dr. Valeri Faine (Fine)
------------------- Phone: +1 516 344 7806
Brookhaven National Laboratory FAX : +1 516 344 4206
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Dr. Valery Fine Telex : 911621 dubna su
-----------
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