fully automated legend sizing!

Plotting/KCode/KBase.h

@@ -3,6 +3,7 @@
 
 //custom headers
 #include "KMap.h"
+#include "KLegend.h"
 
 //ROOT headers
 #include <TROOT.h>
@@ -142,7 +143,7 @@ class KBase {
 
 		//other virtual functions (unimplemented at this level)
 		virtual void Draw(TPad* pad) {}
-		virtual int GetLegendInfo() {}
+		virtual void GetLegendInfo(KLegend* kleg) {}
 		virtual void AddToLegend(TLegend* leg) {}
 		virtual void AddChild(KBase* ch) {}
 		virtual void Normalize(double nn, bool toYield=true) {}

Plotting/KCode/KLegend.h

@@ -5,11 +5,14 @@
 #include <TROOT.h>
 #include <TLegend.h>
 #include <TH1F.h>
+#include <TLatex.h>
+#include <TPad.h>
 
 //STL headers
 #include <vector>
 #include <string>
 #include <sstream>
+#include <iostream>
 #include <utility>
 #include <iomanip>
 #include <cmath>
@@ -19,19 +22,20 @@ using namespace std;
 class KLegend{
 	public:
 		//constructor
-		KLegend(int nentries_, string chan_label_="") : nentries(nentries_), leg(0), ymin(0), ymax(0), manual_ymin(false), chan_label(chan_label_) {
+		KLegend(TPad* pad_, string chan_label_="") : pad(pad_), legwidth(0), legheight(0), leg(0), ymin(0), ymax(0), manual_ymin(false), chan_label(chan_label_) {
+			padH = pad->GetWh()*pad->GetAbsHNDC();
+			legentry = 26/padH; //line height for each entry
 			//todo: allow multiple lines of text at top of legend?
-			if(chan_label.size()>0) ++nentries; //will be added to top of legend
+			if(chan_label.size()>0) CheckSize(chan_label); //will be added to top of legend
 			//chan_label = "#mu#tau channel";
 		}
 		//destructor
 		virtual ~KLegend() {}
 
 		//functions
-		void Build(TPad* pad){
+		void Build(){
 			bool logy = pad->GetLogy();
 			bool logx = pad->GetLogx();
-			double padH = pad->GetWh()*pad->GetAbsHNDC();
 			double ytick = (hists.size()>0) ? hists[0]->GetYaxis()->GetTickLength() : 0;
 			double xtick = (hists.size()>0) ? hists[0]->GetXaxis()->GetTickLength() : 0;
 
@@ -54,8 +58,10 @@ class KLegend{
 			double lbound = pad->GetLeftMargin() + ytick;
 			double rbound = 1 - (pad->GetRightMargin() + ytick);
 
-			//how to determine width?
-			double legwidth = 0.33;
+			//symbol box takes up fMargin = 0.25 by default
+			legwidth /= 0.75;
+			//add a little padding for each line
+			legheight *= 1.2;
 
 			if(p > nbins/2) {
 				umin = lbound;
@@ -65,10 +71,6 @@ class KLegend{
 				umax = rbound;
 				umin = umax - legwidth;
 			}
-
-			//double legentry = 0.05; //line height for each entry
-			double legentry = 26/padH; //line height for each entry
-			double legheight = legentry*nentries; //total height of all entries
 
 			vmax = 1 - (pad->GetTopMargin() + xtick);
 			vmin = vmax - legheight;		
@@ -166,10 +168,17 @@ class KLegend{
 
 			if(chan_label.size()>0) leg->AddEntry((TObject*)NULL,chan_label.c_str(),"");
 		}
-		void Draw(TPad* pad){
+		void Draw(){
 			pad->cd();
 			if(leg) leg->Draw("same");
 		}
+		void CheckSize(string line){
+			pad->cd();
+			TLatex size_test(0,0,line.c_str());
+			size_test.SetTextSize(legentry);
+			legheight += size_test.GetYsize();
+			if(size_test.GetXsize() > legwidth) legwidth = size_test.GetXsize();
+		}
 
 		//accessors
 		void AddHist(TH1F* h) { hists.push_back(h); }
@@ -179,8 +188,9 @@ class KLegend{
 
 	protected:
 		//member variables
-		int nentries;
-		string fbname;
+		TPad* pad;
+		double legwidth, legheight;
+		double padH, legentry;
 		vector<TH1F*> hists;
 		TLegend* leg;
 		double ymin, ymax;

Plotting/KCode/KManager.h

@@ -82,12 +82,9 @@ class KManager {
 				}
 			}
 
-			//build everything, check for legend height
-			//add some kind of check for legend width here?
-			double nentries = 0;
+			//build everything
 			for(unsigned s = 0; s < MySets.size(); s++){
 				MySets[s]->Build();
-				nentries += MySets[s]->GetLegendInfo();
 			}
 
 			//fake tau estimation is calculated during build
@@ -112,6 +109,14 @@ class KManager {
 				TCanvas* can = p->second->GetCanvas();
 				TPad* pad1 = p->second->GetPad1();
 
+				//create legend
+				string chan_label = "";
+				option->Get("chan_label",chan_label);
+				KLegend* kleg = new KLegend(pad1,chan_label);
+				double ymin = 1;
+				if(option->Get("ymin",ymin)) kleg->SetManualYmin(ymin);
+				p->second->SetLegend(kleg);
+
 				//select current histogram in sets
 				for(unsigned s = 0; s < MySets.size(); s++){
 					MySets[s]->GetHisto(p->first);
@@ -147,23 +152,17 @@ class KManager {
 						MySets[s]->BinDivide();
 					}
 				}
-
-				//create legend
-				string chan_label = "";
-				option->Get("chan_label",chan_label);
-				KLegend* kleg = new KLegend(nentries,chan_label);
-				double ymin = 1;
-				if(option->Get("ymin",ymin)) kleg->SetManualYmin(ymin);
-				p->second->SetLegend(kleg);
 
 				//pass current histogram to legend
 				//AFTER bindivide if requested
+				//and calculate legend size
 				for(unsigned s = 0; s < MySets.size(); s++){
 					kleg->AddHist(MySets[s]->GetHisto());
+					MySets[s]->GetLegendInfo(kleg);
 				}
 
 				//build legend
-				kleg->Build(pad1);
+				kleg->Build();
 
 				//add sets to legend
 				for(unsigned s = 0; s < MySets.size(); s++){

Plotting/KCode/KPlot.h

@@ -187,7 +187,7 @@ class KPlot{
 		}
 		void DrawText(){
 			pad1->cd();
-			leg->Draw(pad1);
+			leg->Draw();
 			paveCMS->Draw("same");
 			paveExtra->Draw("same");
 			paveLumi->Draw("same");

Plotting/KCode/KSet.h

@@ -5,6 +5,7 @@
 #include "KMap.h"
 #include "KBase.h"
 #include "KBuilder.h"
+#include "KLegend.h"
 
 //ROOT headers
 #include <TROOT.h>
@@ -68,8 +69,8 @@ class KSet : public KBase {
 			}
 			else return NULL; //do not reset if the histo does not exist
 		}
-		//reports number of entries for the legend
-		virtual int GetLegendInfo() { return 1; }
+		//provides size of entries for the legend
+		virtual void GetLegendInfo(KLegend* kleg) { kleg->CheckSize(name); }
 		virtual void CloseFile(){
 			for(unsigned c = 0; c < children.size(); c++){
 				children[c]->CloseFile();
@@ -134,6 +135,7 @@ class KSetData: public KSet {
 			if(option->Get("horizerrbars",false) || htmp->GetXaxis()->IsVariableBinSize()){
 				leg->AddEntry(htmp,name.c_str(),"pel");
 			}
+			//note: this setting only works in ROOT 5.34.11+
 			else leg->AddEntry(htmp,name.c_str(),"pe");
 		}
 		//draw function
@@ -324,12 +326,12 @@ class KSetMCStack : public KSet {
 			}
 			else return NULL; //do not reset if the histo does not exist
 		}
-		//reports number of entries for the legend
-		int GetLegendInfo() { 
-			int num = children.size();
-			//error band enabled by default
-			if(option->Get("errband",true)) num++;
-			return num;
+		//provides size of entries for the legend
+		void GetLegendInfo(KLegend* kleg) {
+			for(unsigned c = 0; c < children.size(); c++){
+				children[c]->GetLegendInfo(kleg);
+			}
+			if(option->Get("errband",true)) kleg->CheckSize("uncertainty");
 		}
 		//adds child histos to legend
 		void AddToLegend(TLegend* leg) {