Dear Brun, I will give you a more detailed explanation on the Xlib problem I have Posted on the Root digest(message:Xlib or root?), thanks for quick responding now stuff related to this mail: For example, I have a list of thousands of tracks and 10 times more of hits on a canvas(As is the case for Phenix detector). I would like to have the ability to press and highlight the track under mouse point... But let the Canvas to do a update will be inefficient(redraw everything takes too much time)I want the canvas act as an accumulation buffer which I can continusly modify it.I thought I could use paint. I run into this question also because I want to debug why my application freezes and sleeps in xlib call... as you already see in my yestoday's mail. I want to know a little more about the interaction between root and xlib So, Repeat my problem: Under root prompt: type: TCanvas * c1= new TCanvas("c1","c1",100,100); TLine *a = TLine(0,0,1,1) ; a->Paint(); c1->Flush()[or gVirtualX->Update()] Nothing have been drawn! But paint called from TPad will do the job! this also will not work even call from shared library.. I can't Paint directly onto the canvas, faint...... thanks, Jiangyong On Thu, 25 May 2000, Rene Brun wrote: > You can call the Paint functions only during the Paint process. > See http://root.cern.ch/root/HowtoDraw.html > When the pad must be drawn/redrawn, the Paint function for all > objects in the list of primitives is called. In turn the Paint > functions call gVirtualX drawing functions to draw in the current > pixmap in memory. When the drawing is complete, the pixmap > in memory is copied to the screen memory. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ which command?? XFulsh()?? ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > Could you explain what is the problem you try to solve > and where the current tools are not sufficient? > > Rene Brun > > On Thu, 25 May 2000, > jiangyong jia wrote: > > > > > Hi,Rooters, > > > > Is there a way to use paint function directly from root prompt?? > > I mean instead of Use Draw function and Append the TObject onto > > Primitive list of Current pad, I want to call Paint() function directly > > But I find out it is not working!!!, also gVirtualX will not work also. > > example: > > type gVirtualX->DrawLine(0,1,1,0) from root prompt will draw you nothing. > > cheers. > > Jiangyong > > > > > > > > ************************************************ > > jjia@rcf.rhic.bnl.gov > > Jiangyong Jia > > Department of Physics > > State University New York at Stony Brook > > Stony Brook, New York 11794-3800 > > Tel.631-344-5455 > > ********************************************* > > > > > > > > > > > >
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