Logo ROOT  
Reference Guide
draw_mt.cxx File Reference

Detailed Description

This macro demonstrate usage of ROOT7 graphics from many threads Three different canvases in three different threads are started and regularly updated. Extra thread created in background and used to run http protocol, in/out websocket communications and process http requests Main application thread (CLING interactive session) remains fully functional

/*************************************************************************
* Copyright (C) 1995-2015, Rene Brun and Fons Rademakers. *
* All rights reserved. *
* *
* For the licensing terms see $ROOTSYS/LICENSE. *
* For the list of contributors see $ROOTSYS/README/CREDITS. *
*************************************************************************/
#include "ROOT/RCanvas.hxx"
#include "TRandom3.h"
#include "TEnv.h"
#include "TROOT.h"
#include <thread>
// macro must be here while cling is not capable to load
// library automatically for outlined function see ROOT-10336
R__LOAD_LIBRARY(libROOTHistDraw)
using namespace ROOT::Experimental;
void draw_canvas(const std::string &title, RColor col)
{
// Create histograms
RAxisConfig xaxis(100, -10., 10.);
auto pHist = std::make_shared<RH1D>(xaxis);
auto pHist2 = std::make_shared<RH1D>(xaxis);
TRandom3 random;
Float_t px, py;
for (int n = 0; n < 10000; ++n) {
random.Rannor(px, py);
pHist->Fill(px - 2);
pHist2->Fill(py + 2);
}
// Create a canvas to be displayed.
auto canvas = RCanvas::Create(title + " canvas");
canvas->Draw(pHist)->AttrLine().SetColor(col);
canvas->Draw(pHist2)->AttrLine().SetColor(RColor::kBlue);
int maxloop = 50;
canvas->Show();
printf("%s started\n", title.c_str());
for (int loop = 0; loop < maxloop; ++loop) {
for (int n = 0; n < 10000; ++n) {
random.Rannor(px, py);
pHist->Fill(px - 2);
pHist2->Fill(py + 2);
}
canvas->Modified();
canvas->Update();
canvas->Run(0.5); // let run canvas code for next 0.5 seconds
// if (loop == 0)
// canvas->SaveAs(title + "_first.png");
// if (loop == maxloop - 1)
// canvas->SaveAs(title + "_last.png");
}
printf("%s completed\n", title.c_str());
// remove from global list, will be destroyed with thread exit
canvas->Remove();
}
void draw_mt()
{
gEnv->SetValue("WebGui.HttpThrd", "yes");
gEnv->SetValue("WebGui.SenderThrds", "yes");
// create instance in main thread, used to assign thread id as well
std::thread thrd1(draw_canvas, "First", RColor::kRed);
std::thread thrd2(draw_canvas, "Second", RColor::kBlue);
std::thread thrd3(draw_canvas, "Third", RColor::kGreen);
thrd1.join();
thrd2.join();
thrd3.join();
}
Date
2018-08-16
Warning
This is part of the ROOT 7 prototype! It will change without notice. It might trigger earthquakes. Feedback is welcome!
Author
Sergey Linev

Definition in file draw_mt.cxx.

n
const Int_t n
Definition: legend1.C:16
ROOT::Experimental::RAxisConfig
Definition: RAxisConfig.hxx:47
RHistDrawable.hxx
gEnv
R__EXTERN TEnv * gEnv
Definition: TEnv.h:171
ROOT::EnableThreadSafety
void EnableThreadSafety()
Enables the global mutex to make ROOT thread safe/aware.
Definition: TROOT.cxx:494
ROOT::Experimental::RColor
The color class.
Definition: RColor.hxx:46
ROOT::Experimental::RCanvas::Create
static std::shared_ptr< RCanvas > Create(const std::string &title)
Create new canvas instance.
Definition: RCanvas.cxx:70
TEnv.h
RCanvas.hxx
ROOT::Experimental::RColor::kBlue
static constexpr RGB_t kBlue
Definition: RColor.hxx:235
TROOT.h
TRandom::Rannor
virtual void Rannor(Float_t &a, Float_t &b)
Return 2 numbers distributed following a gaussian with mean=0 and sigma=1.
Definition: TRandom.cxx:489
TPad::Modified
void Modified(Bool_t flag=1)
Definition: TPad.h:414
TCanvas::Draw
virtual void Draw(Option_t *option="")
Draw a canvas.
Definition: TCanvas.cxx:841
TRandom3
Definition: TRandom3.h:27
TCanvas::Show
void Show()
Show canvas.
Definition: TCanvas.cxx:2236
TRandom3.h
ROOT::Experimental::RColor::kGreen
static constexpr RGB_t kGreen
Definition: RColor.hxx:228
TCanvas::Update
virtual void Update()
Update canvas pad buffers.
Definition: TCanvas.cxx:2500
ROOT::Experimental::RWebWindowsManager::Instance
static std::shared_ptr< RWebWindowsManager > & Instance()
Returns default window manager Used to display all standard ROOT elements like TCanvas or TFitPanel.
Definition: RWebWindowsManager.cxx:53
TEnv::SetValue
virtual void SetValue(const char *name, const char *value, EEnvLevel level=kEnvChange, const char *type=0)
Set the value of a resource or create a new resource.
Definition: TEnv.cxx:736
ROOT::Experimental
Definition: RDirectory.hxx:36
Float_t
R__LOAD_LIBRARY
#define R__LOAD_LIBRARY(LIBRARY)
Definition: Rtypes.h:472
ROOT::Experimental::RColor::kRed
static constexpr RGB_t kRed
Definition: RColor.hxx:240