projection_axes.C File Reference

Detailed Description

Scales and tick labels for projected views, using REveProjectionAxis.

A barrel and a few jets are projected in RhoPhi and RhoZ, and each projected view gets an axis. Ticks sit at round numbers in the original space and are drawn where the projection puts them, so with a non-zero distortion their spacing on screen is uneven. Change the distortion with the <<< and >>> buttons in each view, or from the ROOT prompt:

pa_distortion(0.001)   // then 0.005, and back to 0

The browser relayouts the labels on zoom and pan. Only a change of the projection goes back to the server. The axes and buttons are in overlay scenes, which are drawn in front of the geometry.

 
#include <ROOT/REveElement.hxx>
#include <ROOT/REveGeoShape.hxx>
#include <ROOT/REveJetCone.hxx>
#include <ROOT/REveManager.hxx>
#include <ROOT/REveProjectionAxis.hxx>
#include <ROOT/REveProjectionManager.hxx>
#include <ROOT/REveScene.hxx>
#include <ROOT/REveText.hxx>
#include <ROOT/REveViewer.hxx>
 
#include "TROOT.h"
#include "TColor.h"
#include "TGeoTube.h"
#include "TMath.h"
#include "TRandom.h"
 
using namespace ROOT::Experimental;
 
REveProjectionManager *gPaRPhi = nullptr;
REveProjectionManager *gPaRhoZ = nullptr;
/// Ships with ROOT in TROOT::GetDataDir()/fonts.
static const char *kAxisFont = "LiberationSerif-Regular";
 
REveProjectionAxis *gPaAxisRPhi = nullptr;
REveProjectionAxis *gPaAxisRhoZ = nullptr;
 
const Double_t kR_min = 240;
const Double_t kR_max = 250;
const Double_t kZ_d = 300;
 
//------------------------------------------------------------------------------
/// Change the distortion of both projections and rebuild the tick sets.
/// Callable from the ROOT prompt while the macro runs.
 
void pa_distortion(float d)
{
   REveManager::ChangeGuard ch;
   for (auto mng : {gPaRPhi, gPaRhoZ}) {
      if (!mng)
         continue;
      mng->GetProjection()->SetDistortion(d);
      mng->UpdateName();
      mng->ProjectChildren();
   }
   // Update the ticks and the read-out, as REveProjectionManager::BumpDistortion()
   // does for the overlay buttons.
   for (auto ax : {gPaAxisRPhi, gPaAxisRhoZ}) {
      if (!ax)
         continue;
      ax->UpdateTicks();
      ax->UpdateDistortionLabel();
   }
}
 
//------------------------------------------------------------------------------
 
static REveElement *makeSceneContent(REveManager *eveMng)
{
   auto holder = new REveElement("Content");
 
   auto b = new REveGeoShape("Barrel");
   b->SetShape(new TGeoTube(kR_min, kR_max, kZ_d));
   b->SetMainColor(kCyan);
   b->SetMainTransparency(60);
   b->SetNSegments(64);
   holder->AddElement(b);
 
   TRandom &r = *gRandom;
   for (int i = 0; i < 4; ++i) {
      auto jet = new REveJetCone(Form("Jet_%d", i));
      jet->SetCylinder(2 * kR_max, 2 * kZ_d);
      jet->AddEllipticCone(r.Uniform(-2.5, 2.5), r.Uniform(0, TMath::TwoPi()), r.Uniform(0.05, 0.2),
                           r.Uniform(0.05, 0.25));
      jet->SetFillColor(kPink - 8);
      jet->SetLineColor(kBlack);
      holder->AddElement(jet);
   }
 
   eveMng->GetEventScene()->AddElement(holder);
   return holder;
}
 
/// One projected view: a scene for the projected geometry, an overlay scene for
/// its axis, and an orthographic viewer showing both.
static void makeProjectedView(REveManager *eveMng, REveElement *content, REveProjection::EPType_e type,
                              const char *name, REveProjectionManager *&mng, REveProjectionAxis *&axis)
{
   auto scene = eveMng->SpawnNewScene(Form("%s Scene", name), name);
   mng = new REveProjectionManager(type);
   mng->ImportElements(content, scene);
 
   // Add the manager to the element tree. This gives it an element id, which the
   // overlay buttons need as their MIR target, and streams its name, which shows
   // the distortion, e.g. "RhoPhi (5.0)".
   eveMng->GetWorld()->AddElement(mng);
 
   auto ovl = eveMng->SpawnNewScene(Form("%s Axis", name), name);
   ovl->SetIsOverlay(true);
 
   axis = new REveProjectionAxis(mng, Form("%s Axis", name));
   axis->SetFontSize(0.022);
   axis->SetFont(kAxisFont);
   ovl->AddElement(axis);
 
   // Distortion controls: three overlay texts laid out as [ <<< | value | >>> ].
   // SetClickAction() makes a text a button that sends a MIR to the projection
   // manager. BumpDistortion() reprojects and updates the axes and the read-out.
   {
      auto mkbtn = [&](const char *label, Float_t x, const char *mir) {
         auto b = new REveText(Form("%s %s", name, label), label);
         b->SetText(label);
         b->SetFont(kAxisFont);
         // These views are short, so the controls need a larger font than the
         // tick labels to stay legible, and enough clearance from the bottom
         // edge that the frame is not clipped by the pane.
         b->SetFontSize(0.034);
         b->SetMode(1); // relative screen coordinates
         b->SetPosition(REveVector(x, 0.10f, 0.f));
         b->SetTextAlign(REveText::kCenterH, REveText::kBottom);
         b->SetTextColor(TColor::GetColor("#1f2d36"));
         b->SetDrawFrame(true);
         b->SetFillColor(TColor::GetColor("#dfe6ea"));
         b->SetFillAlpha(210);
         b->SetLineColor(TColor::GetColor("#6b8290"));
         b->SetLineAlpha(255);
         b->SetLineWidth(0.06);   // in units of line height
         b->SetExtraBorder(0.18); // padding, in font-size units
         b->SetResizable(false);  // a control is not a resizable annotation
         if (mir)
            b->SetClickAction(mir, mng);
         ovl->AddElement(b);
         return b;
      };
 
      // The x positions are set by hand, since only the client knows the glyph
      // metrics.
      mkbtn("<<<", 0.26f, "BumpDistortion(-1)");
      auto val = mkbtn("0.0", 0.50f, nullptr); // read-out, not a button
      mkbtn(">>>", 0.74f, "BumpDistortion(1)");
 
      axis->SetDistortionLabel(val);
   }
 
   auto view = eveMng->SpawnNewViewer(Form("%s View", name), "");
   view->SetCameraType(REveViewer::kCameraOrthoXOY);
   view->AddScene(scene);
   view->AddScene(ovl);
}
 
void projection_axes()
{
   auto eveMng = REveManager::Create();
   eveMng->AllowMultipleRemoteConnections(false, false);
 
   // Generate the SDF atlas from the font file that ships with ROOT.
   std::string rf = std::string(TROOT::GetDataDir().Data()) + "/fonts/";
   REveText::AssertSdfFont(kAxisFont, rf + kAxisFont + ".ttf");
 
   auto content = makeSceneContent(eveMng);
 
   makeProjectedView(eveMng, content, REveProjection::kPT_RPhi, "RPhi", gPaRPhi, gPaAxisRPhi);
   makeProjectedView(eveMng, content, REveProjection::kPT_RhoZ, "RhoZ", gPaRhoZ, gPaAxisRhoZ);
 
   eveMng->Show();
}

Author

Matevz Tadel

Definition in file projection_axes.C.