Hello. Thank you for you reply. What I would like to do is the follwing. I have the histogram which has time as x-axis and count as y-axis. When I zoom in along xaxis, I would like to know the points where I press and release to obtain time range of my zoom selection. So, I made the attached macro and I used this macro in my compiled code using c1->AddExec("ex1", ".x GetDist.C"). But, in this case, x1 always 0. So, Can I get both x1 and x2 in the follwing code ? Harufumi Tsuchiya ROOT v3.03.09 g++ 2.95.3 FreeBSD 4.6.2-RELEASE ------------------ GetDist.C --------------------------- void GetDist() { Double_t x1, x2; Int_t event = gPad->GetEvent(); if ( event != kButton1Up && event != kButton1Down ) return; TObject *select = gPad->GetSelected(); if ( strcmp(select->GetName(), "xaxis") != 0 )return; Int_t px = gPad->GetEventX(); Double_t xp = gPad->AbsPixeltoX(px); if ( event == kButton1Down ) { // Get x1 // x1 = gPad->PadtoX(xp); } else if ( event == kButton1Up ) { // Get x2 // x2 = gPad->PadtoX(xp); Double_t dist = x2 - x1; cout << "x1, x2, dist " << x1 << " " << x2 << " " << dist << endl; } } > Hi Harufumi, > Assuming that > Int_t px1,py1 are the mouse pixel coordinates of the point > where you press the button and px2,py2 where you release > the button, you can compute the user coordinates with > Double_t x1 = gPad->AbsPixeltoX(px1); > Double_t y1 = gPad->AbsPixeltoX(py1); > same for x2,y2 > > Rene Brun > > > > On Sat, 9 Nov 2002, Harufumi TSUCHIYA wrote: > > > > > Hello ROOTers > > > > I am now trying to modify exec1.C in $ROOT/tutorials to > > calculate distance two points along x-axis of my histogram. > > The two points are pushed and released by mouse, respectively. > > > > I succeeded in knowing pushed points and released points > > using return values of gPad->GetEvent()(kButton1Down and kButton1Up). > > > > But, the distance between two points could not be obtained. > > > > So, is there the way to get the distance of the two points ? > > > > Harufumi Tsuchiya > > > > ROOT v3.03.09 > > g++ 2.95.3 > > FreeBSD 4.6.2 > > >
This archive was generated by hypermail 2b29 : Sat Jan 04 2003 - 23:51:17 MET