New Method TPad::DivideRatios

New Method TPad::DivideRatios

Author: couet

graf2d/gpad/inc/TPad.h

@@ -186,6 +186,7 @@ friend class TWebCanvas;
    void              CopyPixmaps() override;
    void              DeleteExec(const char *name) override;
    void              Divide(Int_t nx=1, Int_t ny=1, Float_t xmargin=0.01, Float_t ymargin=0.01, Int_t color=0) override; // *MENU*
+   void              DivideRatios(Int_t nrows, Int_t ncolumns, const std::vector<double>& widthRatios={}, const std::vector<double>& heightRatios={}, const double canvasTopMargin=0., const double canvasLeftMargin=0.);
    virtual void      DivideSquare(Int_t n, Float_t xmargin=0.01, Float_t ymargin=0.01, Int_t color=0);
    void              Draw(Option_t *option="") override;
    void              DrawClassObject(const TObject *obj, Option_t *option="") override;

graf2d/gpad/src/TPad.cxx

@@ -1345,6 +1345,108 @@ void TPad::Divide(Int_t nx, Int_t ny, Float_t xmargin, Float_t ymargin, Int_t co
    Modified();
 }
 
+////////////////////////////////////////////////////////////////////////////////
+/// Divide the canvas according to ratios.
+///
+/// The current canvas is divided in nx by ny according to the width and height ratios.
+/// If the ratios are not specified they are assumed to be equal.
+///
+/// Pads are automatically named `canvasname_n` where `n` is the division number
+/// starting from top left pad.
+///
+/// Top and left margins can be defined.
+
+void TPad::DivideRatios(Int_t nx, Int_t ny,
+                        const std::vector<double>& widthRatios,
+                        const std::vector<double>& heightRatios,
+                        const double canvasTopMargin,
+                        const double canvasLeftMargin
+                        )
+{
+   cd();
+
+   int wrs = widthRatios.size();
+   int hrs = heightRatios.size();
+   int nxl = TMath::Min(nx,wrs), nyl = TMath::Min(ny,hrs);
+
+   if (wrs==0) nxl = nx;
+   if (hrs==0) nyl = ny;
+
+   int    pn = 1;
+   double xr = 0.;
+   double yr = 0.;
+   double x  = 0.;
+   double y  = 1.;
+   double x1, y1, x2, y2;
+
+   // Check the validity of the margins
+   if (canvasTopMargin <0 || canvasTopMargin >1 ) {
+      Error("DivideRatios", "The canvas top margin must be >= 0 and <= 1");
+      return;
+   } else {
+      y = 1.- canvasTopMargin;
+   }
+   if (canvasLeftMargin <0 || canvasLeftMargin >1 ) {
+      Error("DivideRatios", "The canvas left margin must be >= 0 and <= 1");
+      return;
+   }
+
+   // Check the validity of the ratios
+   double sumOfHeightRatios = canvasTopMargin;
+   if (hrs) {
+      for (int i=0; i<nyl; i++) {
+         yr = heightRatios[i];
+         sumOfHeightRatios = sumOfHeightRatios + yr;
+         if (yr <0 || yr >1 ) {
+            Error("DivideRatios", "Y ratios plus the top margin must be >= 0 and <= 1");
+            return;
+         }
+      }
+   }
+   if (sumOfHeightRatios > 1.) {
+      Error("DivideRatios", "The sum of Y ratios plus the top margin must be <= 1 %g",sumOfHeightRatios);
+      return;
+   }
+   double sumOfWidthRatios = canvasLeftMargin;
+   if (wrs) {
+      for (int j=0; j<nxl; j++) {
+         xr = widthRatios[j];
+         sumOfWidthRatios = sumOfWidthRatios +xr;
+         if (xr <0 || xr >1 ) {
+            Error("DivideRatios", "X ratios must be >= 0 and <= 1");
+            return;
+         }
+      }
+   }
+   if (sumOfWidthRatios > 1.) {
+      Error("DivideRatios", "The sum of X ratios must be <= 1 %g ",sumOfWidthRatios);
+      return;
+   }
+
+   // Create the pads according to the ratios
+   for (int i=0; i<nyl; i++) {
+      x = canvasLeftMargin;
+      if (hrs) yr = heightRatios[i];
+      else     yr = 1./nyl;
+      for (int j=0; j<nxl; j++) {
+         if (wrs) xr = widthRatios[j];
+         else     xr = 1./nxl;
+         x1 = TMath::Max(0., x);
+         y1 = TMath::Max(0., y - yr);
+         x2 = TMath::Min(1., x + xr);
+         y2 = TMath::Min(1., y);
+         auto pad = new TPad(TString::Format("%s_%d", GetName(), pn),
+                             TString::Format("%s_%d", GetName(), pn),
+                             x1, y1, x2 ,y2);
+         pad->SetNumber(pn);
+         pad->Draw();
+         x = x + xr;
+         pn++;
+      }
+      y = y - yr;
+   }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 /// "n" is the total number of sub-pads. The number of sub-pads along the X
 /// and Y axis are computed according to the square root of n.

tutorials/visualisation/graphics/canvas3.C

@@ -0,0 +1,37 @@
+/// \file
+/// \ingroup tutorial_graphics
+/// \preview Example of canvas partitioning with ratios
+/// The TPad::DivideRatios method enables partitioning of the canvas according to different
+///
+/// \macro_image
+/// \macro_code
+///
+/// \author Olivier Couet
+
+void colorpads(TCanvas *C, int n) {
+   TPad *p;
+   for (int i =1; i<=n; i++) {
+      p = (TPad*)C->cd(i);
+      p->SetFillColor(100+i);
+      p->Modified();
+      p->Update();
+   }
+}
+
+void canvas3() {
+   // canvas divided 2x2 with 4 different ratios along X and Y
+   auto C1 = new TCanvas("C1", "C1", 400, 400);
+   C1->DivideRatios(2, 2, {.2,.8}, {.4,.6}); colorpads(C1,4);
+
+   // canvas divided 2x3 with ratios defined only in X
+   auto C2 = new TCanvas("C2", "C2", 400, 0, 400, 400);
+   C2->DivideRatios(2, 3, {.2,.8}); colorpads(C2,6);
+
+   // canvas divided 2x2 with no ratios defined
+   auto C3 = new TCanvas("C3", "C3", 0, 455, 400, 400);
+   C3->DivideRatios(2, 2); colorpads(C3,4);
+
+   // canvas divided 2x2 with ratios and margins
+   auto C4 = new TCanvas("C4", "C4", 400, 455, 400, 400);
+   C4->DivideRatios(2, 2, {.2,.7}, {.4,.5}, 0.05, 0.01); colorpads(C4,4);
+}