This class displays a legend box (TPaveText) containing several legend entries.

Each legend entry is made of a reference to a ROOT object, a text label and an option specifying which graphical attributes (marker/line/fill) should be displayed.

The following example shows how to create a legend. In this example the legend contains a histogram, a function and a graph. The histogram is put in the legend using its reference pointer whereas the graph and the function are added using their names. Note that, because TGraph constructors do not have the TGraph name as parameter, the graph name should be specified using the SetName method.

When an object is added by name, a scan is performed on the list of objects contained in the current pad (gPad) and also in the possible TMultiGraph and THStack present in the pad. If a matching name is found, the corresponding object is added in the legend using its pointer.

{
   auto c1 = new TCanvas("c1","c1",600,500);
   gStyle->SetOptStat(0);
 
   auto h1 = new TH1F("h1","TLegend Example",200,-10,10);
   h1->FillRandom("gaus",30000);
   h1->SetFillColor(kGreen);
   h1->SetFillStyle(3003);
   h1->Draw();
 
   auto f1=new TF1("f1","1000*TMath::Abs(sin(x)/x)",-10,10);
   f1->SetLineColor(kBlue);
   f1->SetLineWidth(4);
   f1->Draw("same");
 
   const Int_t n = 20;
   Double_t x[n], y[n], ex[n], ey[n];
   for (Int_t i=0;i<n;i++) {
      x[i]  = i*0.1;
      y[i]  = 1000*sin(x[i]+0.2);
      x[i]  = 17.8*x[i]-8.9;
      ex[i] = 1.0;
      ey[i] = 10.*i;
   }
   auto gr = new TGraphErrors(n,x,y,ex,ey);
   gr->SetName("gr");
   gr->SetLineColor(kRed);
   gr->SetLineWidth(2);
   gr->SetMarkerStyle(21);
   gr->SetMarkerSize(1.3);
   gr->SetMarkerColor(7);
   gr->Draw("P");
 
   auto legend = new TLegend(0.1,0.7,0.48,0.9);
   legend->SetHeader("The Legend Title","C"); // option "C" allows to center the header
   legend->AddEntry(h1,"Histogram filled with random numbers","f");
   legend->AddEntry("f1","Function abs(#frac{sin(x)}{x})","l");
   legend->AddEntry("gr","Graph with error bars","lep");
   legend->Draw();
}

TLegend inherits from TAttText therefore changing any text attributes (text alignment, font, color...) on a legend will changed the text attributes on each line.

In particular it can be interesting to change the text alignement that way. In order to have a base-line vertical alignment instead of a centered one simply do:

legend->SetTextAlign(13);

or

legend->SetTextAlign(11);

The default value of some TLegend attributes can be changed using gStyle. The default settings are:

SetLegendBorderSize(1);
SetLegendFillColor(0);
SetLegendFont(42);
SetLegendTextSize(0.);

The global attributes change the default values for the next created legends.

Text attributes can be also changed individually on each legend entry:

TLegendEntry *le = leg->AddEntry(h1,"Histogram filled with random numbers","f");

le->SetTextColor(kBlue);;

TAttText::SetTextColor

virtual void SetTextColor(Color_t tcolor=1)

Set the text color.

Definition TAttText.h:44

TLegendEntry

Storage class for one entry of a TLegend.

Definition TLegendEntry.h:25

leg

Definition legend1.C:34

Note that the TPad class has a method to build automatically a legend for all objects in the pad. It is called TPad::BuildLegend().

Each item in the legend is added using the AddEntry method. This method defines the object to be added (by reference or name), the label associated to this object and an option which a combination of:

L: draw line associated with TAttLine if obj inherits from TAttLine
P: draw polymarker associated with TAttMarker if obj inherits from TAttMarker
F: draw a box with fill associated wit TAttFill if obj inherits TAttFill
E: draw vertical error bar

As shown in the following example, passing a NULL pointer as first parameter in AddEntry is also valid. This allows to add text or blank lines in a legend.

{
   auto c2 = new TCanvas("c2","c2",500,300);
 
   auto* legend = new TLegend(0.2, 0.2, .8, .8);
   auto h = new TH1F("", "", 1, 0, 1);
 
   legend->AddEntry(h, "Histogram \"h\"", "l");
   legend->AddEntry((TObject*)0, "", "");
   legend->AddEntry((TObject*)0, "Some text", "");
   legend->AddEntry((TObject*)0, "", "");
   legend->AddEntry(h, "Histogram \"h\" again", "l");
 
   legend->Draw();
}

It is possible to draw the legend entries over several columns using the method SetNColumns() like in the following example.

{
   auto c3 = new TCanvas("c2","c2",500,300);
 
   auto legend = new TLegend(0.2, 0.2, .8, .8);
   auto h = new TH1F("", "", 1, 0, 1);
 
   legend->SetNColumns(2);
 
   legend->AddEntry(h, "Column 1 line 1", "l");
   legend->AddEntry(h, "Column 2 line 1", "l");
   legend->AddEntry(h, "Column 1 line 2", "l");
   legend->AddEntry(h, "Column 2 line 2", "l");
 
   legend->Draw();
}

Since: ROOT version 6.09/03

The legend can be placed automatically in the current pad in an empty space found at painting time.

The following example illustrate this facility. Only the width and height of the legend is specified in percentage of the pad size.

 
void legendautoplaced()
{
   auto c4 = new TCanvas("c", "c", 600,500);
   auto hpx = new TH1D("hpx","This is the hpx distribution",100,-4.,4.);
   hpx->FillRandom("gaus", 50000);
   hpx->Draw("E");
   hpx->GetYaxis()->SetTitle("Y Axis title");
   hpx->GetYaxis()->SetTitleOffset(1.3); hpx->GetYaxis()->CenterTitle(true);
   hpx->GetXaxis()->SetTitle("X Axis title");
   hpx->GetXaxis()->CenterTitle(true);
 
   auto h1 = new TH1D("h1","A green histogram",100,-2.,2.);
   h1->FillRandom("gaus", 10000);
   h1->SetLineColor(kGreen);
   h1->Draw("same");
 
   auto g = new TGraph();
   g->SetPoint(0, -3.5, 100 );
   g->SetPoint(1, -3.0, 300 );
   g->SetPoint(2, -2.0, 1000 );
   g->SetPoint(3,  1.0, 800 );
   g->SetPoint(4,  0.0, 200 );
   g->SetPoint(5,  3.0, 200 );
   g->SetPoint(6,  3.0, 700 );
   g->Draw("L");
   g->SetTitle("This is a TGraph");
   g->SetLineColor(kRed);
   g->SetFillColor(0);
 
   // TPad::BuildLegend() default placement values are such that they trigger
   // the automatic placement.
   c4->BuildLegend();
}

Definition at line 23 of file TLegend.h.

Public Member Functions
	TLegend ()
	Default constructor.

	TLegend (const TLegend &legend)
	Copy constructor.

	TLegend (Double_t w, Double_t h, const char header="", Option_t option="brNDC")
	Constructor with automatic placement.

	TLegend (Double_t x1, Double_t y1, Double_t x2, Double_t y2, const char header="", Option_t option="brNDC")
	Normal constructor.

	~TLegend () override
	Default destructor.

TLegendEntry *	AddEntry (const char name, const char label="", Option_t *option="lpf")
	Add a new entry to this legend.

TLegendEntry *	AddEntry (const TObject obj, const char label="", Option_t *option="lpf")
	Add a new entry to this legend.

void	Clear (Option_t *option="") override
	Clear all entries in this legend, including the header.

void	Copy (TObject &obj) const override
	Copy this legend into "obj".

virtual void	DeleteEntry ()
	Delete entry at the mouse position.

void	Draw (Option_t *option="") override
	Draw this legend with its current attributes.

virtual void	EditEntryAttFill ()
	Edit the fill attributes for the entry pointed by the mouse.

virtual void	EditEntryAttLine ()
	Edit the line attributes for the entry pointed by the mouse.

virtual void	EditEntryAttMarker ()
	Edit the marker attributes for the entry pointed by the mouse.

virtual void	EditEntryAttText ()
	Edit the text attributes for the entry pointed by the mouse.

Float_t	GetColumnSeparation () const

TLegendEntry *	GetEntry () const
	Get entry pointed to by the mouse.

Float_t	GetEntrySeparation () const

virtual const char *	GetHeader () const
	Returns the header, which is the title that appears at the top of the legend.

TList *	GetListOfPrimitives () const

Float_t	GetMargin () const

Int_t	GetNColumns () const

Int_t	GetNRows () const
	Get the number of rows.

virtual void	InsertEntry (const char objectName="", const char label="", Option_t *option="lpf")
	Add a new entry before the entry at the mouse position.

TClass *	IsA () const override

void	Paint (Option_t *option="") override
	Paint this legend with its current attributes.

virtual void	PaintPrimitives ()
	Paint the entries (list of primitives) for this legend.

void	Print (Option_t *option="") const override
	Dump this TLegend and its contents.

void	RecursiveRemove (TObject *obj) override
	Reset the legend entries pointing to "obj".

void	SavePrimitive (std::ostream &out, Option_t *option="") override
	Save this legend as C++ statements on output stream out to be used with the SaveAs .C option.

void	SetColumnSeparation (Float_t columnSeparation)

void	SetDefaults ()

virtual void	SetEntryLabel (const char *label)
	Edit the label of the entry pointed to by the mouse.

virtual void	SetEntryOption (Option_t *option)
	Edit the option of the entry pointed to by the mouse.

void	SetEntrySeparation (Float_t entryseparation)

virtual void	SetHeader (const char header="", Option_t option="")
	Sets the header, which is the "title" that appears at the top of the legend.

void	SetMargin (Float_t margin)

void	SetNColumns (Int_t nColumns)
	Set the number of columns for the legend.

void	Streamer (TBuffer &) override
	Stream an object of class TBox.

void	StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

Public Member Functions inherited from TPave
	TPave ()
	Pave default constructor.

	TPave (const TPave &pave)
	Pave copy constructor.

	TPave (Double_t x1, Double_t y1, Double_t x2, Double_t y2, Int_t bordersize=4, Option_t *option="br")
	Pave normal constructor.

	~TPave () override
	Pave default destructor.

virtual void	ConvertNDCtoPad ()
	Convert pave coordinates from NDC to Pad coordinates.

void	Copy (TObject &pave) const override
	Copy this pave to pave.

Int_t	DistancetoPrimitive (Int_t px, Int_t py) override
	Compute distance from point px,py to a pave.

void	Draw (Option_t *option="") override
	Draw this pave with its current attributes.

virtual TPave *	DrawPave (Double_t x1, Double_t y1, Double_t x2, Double_t y2, Int_t bordersize=4, Option_t *option="br")
	Draw this pave with new coordinates.

void	ExecuteEvent (Int_t event, Int_t px, Int_t py) override
	Execute action corresponding to one event.

Int_t	GetBorderSize () const

Double_t	GetCornerRadius () const

const char *	GetName () const override
	Returns name of object.

Option_t *	GetOption () const override

Int_t	GetShadowColor () const

Double_t	GetX1NDC () const

Double_t	GetX2NDC () const

Double_t	GetY1NDC () const

Double_t	GetY2NDC () const

ULong_t	Hash () const override
	Return hash value for this object.

TClass *	IsA () const override

Bool_t	IsSortable () const override

void	ls (Option_t *option="") const override
	List this pave with its attributes.

TPave &	operator= (const TPave &src)
	Assignment operator.

void	Paint (Option_t *option="") override
	Paint this pave with its current attributes.

virtual void	PaintPave (Double_t x1, Double_t y1, Double_t x2, Double_t y2, Int_t bordersize=4, Option_t *option="br")
	Draw this pave with new coordinates.

virtual void	PaintPaveArc (Double_t x1, Double_t y1, Double_t x2, Double_t y2, Int_t bordersize=4, Option_t *option="br")
	Draw this pave with rounded corners.

void	Print (Option_t *option="") const override
	Dump this pave with its attributes.

void	SavePrimitive (std::ostream &out, Option_t *option="") override
	Save primitive as a C++ statement(s) on output stream out.

virtual void	SetBorderSize (Int_t bordersize=4)

virtual void	SetCornerRadius (Double_t rad=0.2)

virtual void	SetName (const char *name="")

virtual void	SetOption (Option_t *option="br")

virtual void	SetShadowColor (Int_t color)

void	SetX1 (Double_t x1) override
	Set the X1 value.

virtual void	SetX1NDC (Double_t x1)

void	SetX2 (Double_t x2) override
	Set the X2 value.

virtual void	SetX2NDC (Double_t x2)

void	SetY1 (Double_t y1) override
	Set the Y1 value.

virtual void	SetY1NDC (Double_t y1)

void	SetY2 (Double_t y2) override
	Set the Y2 value.

virtual void	SetY2NDC (Double_t y2)

void	Streamer (TBuffer &) override
	Stream an object of class TPave.

void	StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

Public Member Functions inherited from TBox
	TBox ()
	Box default constructor.

	TBox (const TBox &box)
	Box copy constructor.

	TBox (Double_t x1, Double_t y1, Double_t x2, Double_t y2)
	Box standard constructor.

	~TBox () override
	Box destructor.

virtual TBox *	DrawBox (Double_t x1, Double_t y1, Double_t x2, Double_t y2)
	Draw this box with new coordinates.

Rectangle_t	GetBBox () override
	Return the "bounding Box" of the Box.

TPoint	GetBBoxCenter () override
	Return the center of the Box as TPoint in pixels.

Double_t	GetX1 () const

Double_t	GetX2 () const

Double_t	GetY1 () const

Double_t	GetY2 () const

virtual void	HideToolTip (Int_t event)
	Hide tool tip depending on the event type.

Bool_t	IsBeingResized () const

virtual Int_t	IsInside (Double_t x, Double_t y) const
	Function which returns 1 if point x,y lies inside the box, 0 otherwise.

TBox &	operator= (const TBox &)
	Assignment operator.

virtual void	PaintBox (Double_t x1, Double_t y1, Double_t x2, Double_t y2, Option_t *option="")
	Draw this box with new coordinates.

void	SetBBoxCenter (const TPoint &p) override
	Set center of the Box.

void	SetBBoxCenterX (const Int_t x) override
	Set X coordinate of the center of the Box.

void	SetBBoxCenterY (const Int_t y) override
	Set Y coordinate of the center of the Box.

void	SetBBoxX1 (const Int_t x) override
	Set left hand side of BoundingBox to a value (resize in x direction on left)

void	SetBBoxX2 (const Int_t x) override
	Set right hand side of BoundingBox to a value (resize in x direction on right)

void	SetBBoxY1 (const Int_t y) override
	Set top of BoundingBox to a value (resize in y direction on top)

void	SetBBoxY2 (const Int_t y) override
	Set bottom of BoundingBox to a value (resize in y direction on bottom)

virtual void	SetToolTipText (const char *text, Long_t delayms=1000)
	Set tool tip text associated with this box.

void	StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

Public Member Functions inherited from TObject
	TObject ()
	TObject constructor.

	TObject (const TObject &object)
	TObject copy ctor.

virtual	~TObject ()
	TObject destructor.

void	AbstractMethod (const char *method) const
	Use this method to implement an "abstract" method that you don't want to leave purely abstract.

virtual void	AppendPad (Option_t *option="")
	Append graphics object to current pad.

virtual void	Browse (TBrowser *b)
	Browse object. May be overridden for another default action.

ULong_t	CheckedHash ()
	Check and record whether this class has a consistent Hash/RecursiveRemove setup (*) and then return the regular Hash value for this object.

virtual const char *	ClassName () const
	Returns name of class to which the object belongs.

virtual TObject *	Clone (const char *newname="") const
	Make a clone of an object using the Streamer facility.

virtual Int_t	Compare (const TObject *obj) const
	Compare abstract method.

virtual void	Delete (Option_t *option="")
	Delete this object.

virtual void	DrawClass () const
	Draw class inheritance tree of the class to which this object belongs.

virtual TObject *	DrawClone (Option_t *option="") const
	Draw a clone of this object in the current selected pad with: `gROOT->SetSelectedPad(c1)`.

virtual void	Dump () const
	Dump contents of object on stdout.

virtual void	Error (const char method, const char msgfmt,...) const
	Issue error message.

virtual void	Execute (const char method, const char params, Int_t *error=nullptr)
	Execute method on this object with the given parameter string, e.g.

virtual void	Execute (TMethod method, TObjArray params, Int_t *error=nullptr)
	Execute method on this object with parameters stored in the TObjArray.

virtual void	Fatal (const char method, const char msgfmt,...) const
	Issue fatal error message.

virtual TObject *	FindObject (const char *name) const
	Must be redefined in derived classes.

virtual TObject *	FindObject (const TObject *obj) const
	Must be redefined in derived classes.

virtual Option_t *	GetDrawOption () const
	Get option used by the graphics system to draw this object.

virtual const char *	GetIconName () const
	Returns mime type name of object.

virtual char *	GetObjectInfo (Int_t px, Int_t py) const
	Returns string containing info about the object at position (px,py).

virtual const char *	GetTitle () const
	Returns title of object.

virtual UInt_t	GetUniqueID () const
	Return the unique object id.

virtual Bool_t	HandleTimer (TTimer *timer)
	Execute action in response of a timer timing out.

Bool_t	HasInconsistentHash () const
	Return true is the type of this object is known to have an inconsistent setup for Hash and RecursiveRemove (i.e.

virtual void	Info (const char method, const char msgfmt,...) const
	Issue info message.

virtual Bool_t	InheritsFrom (const char *classname) const
	Returns kTRUE if object inherits from class "classname".

virtual Bool_t	InheritsFrom (const TClass *cl) const
	Returns kTRUE if object inherits from TClass cl.

virtual void	Inspect () const
	Dump contents of this object in a graphics canvas.

void	InvertBit (UInt_t f)

Bool_t	IsDestructed () const
	IsDestructed.

virtual Bool_t	IsEqual (const TObject *obj) const
	Default equal comparison (objects are equal if they have the same address in memory).

virtual Bool_t	IsFolder () const
	Returns kTRUE in case object contains browsable objects (like containers or lists of other objects).

R__ALWAYS_INLINE Bool_t	IsOnHeap () const

R__ALWAYS_INLINE Bool_t	IsZombie () const

void	MayNotUse (const char *method) const
	Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary).

virtual Bool_t	Notify ()
	This method must be overridden to handle object notification (the base implementation is no-op).

void	Obsolete (const char method, const char asOfVers, const char *removedFromVers) const
	Use this method to declare a method obsolete.

void	operator delete (void *ptr)
	Operator delete.

void	operator delete (void ptr, void vp)
	Only called by placement new when throwing an exception.

void	operator delete[] (void *ptr)
	Operator delete [].

void	operator delete[] (void ptr, void vp)
	Only called by placement new[] when throwing an exception.

void *	operator new (size_t sz)

void *	operator new (size_t sz, void *vp)

void *	operator new[] (size_t sz)

void *	operator new[] (size_t sz, void *vp)

TObject &	operator= (const TObject &rhs)
	TObject assignment operator.

virtual void	Pop ()
	Pop on object drawn in a pad to the top of the display list.

virtual Int_t	Read (const char *name)
	Read contents of object with specified name from the current directory.

void	ResetBit (UInt_t f)

virtual void	SaveAs (const char filename="", Option_t option="") const
	Save this object in the file specified by filename.

void	SetBit (UInt_t f)

void	SetBit (UInt_t f, Bool_t set)
	Set or unset the user status bits as specified in f.

virtual void	SetDrawOption (Option_t *option="")
	Set drawing option for object.

virtual void	SetUniqueID (UInt_t uid)
	Set the unique object id.

void	StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

virtual void	SysError (const char method, const char msgfmt,...) const
	Issue system error message.

R__ALWAYS_INLINE Bool_t	TestBit (UInt_t f) const

Int_t	TestBits (UInt_t f) const

virtual void	UseCurrentStyle ()
	Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked.

virtual void	Warning (const char method, const char msgfmt,...) const
	Issue warning message.

virtual Int_t	Write (const char *name=nullptr, Int_t option=0, Int_t bufsize=0)
	Write this object to the current directory.

virtual Int_t	Write (const char *name=nullptr, Int_t option=0, Int_t bufsize=0) const
	Write this object to the current directory.

Public Member Functions inherited from TAttLine
	TAttLine ()
	AttLine default constructor.

	TAttLine (Color_t lcolor, Style_t lstyle, Width_t lwidth)
	AttLine normal constructor.

virtual	~TAttLine ()
	AttLine destructor.

void	Copy (TAttLine &attline) const
	Copy this line attributes to a new TAttLine.

Int_t	DistancetoLine (Int_t px, Int_t py, Double_t xp1, Double_t yp1, Double_t xp2, Double_t yp2)
	Compute distance from point px,py to a line.

virtual Color_t	GetLineColor () const
	Return the line color.

virtual Style_t	GetLineStyle () const
	Return the line style.

virtual Width_t	GetLineWidth () const
	Return the line width.

virtual void	Modify ()
	Change current line attributes if necessary.

virtual void	ResetAttLine (Option_t *option="")
	Reset this line attributes to default values.

virtual void	SaveLineAttributes (std::ostream &out, const char *name, Int_t coldef=1, Int_t stydef=1, Int_t widdef=1)
	Save line attributes as C++ statement(s) on output stream out.

virtual void	SetLineAttributes ()
	Invoke the DialogCanvas Line attributes.

virtual void	SetLineColor (Color_t lcolor)
	Set the line color.

virtual void	SetLineColorAlpha (Color_t lcolor, Float_t lalpha)
	Set a transparent line color.

virtual void	SetLineStyle (Style_t lstyle)
	Set the line style.

virtual void	SetLineWidth (Width_t lwidth)
	Set the line width.

void	StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

Public Member Functions inherited from TAttFill
	TAttFill ()
	AttFill default constructor.

	TAttFill (Color_t fcolor, Style_t fstyle)
	AttFill normal constructor.

virtual	~TAttFill ()
	AttFill destructor.

void	Copy (TAttFill &attfill) const
	Copy this fill attributes to a new TAttFill.

virtual Color_t	GetFillColor () const
	Return the fill area color.

virtual Style_t	GetFillStyle () const
	Return the fill area style.

virtual Bool_t	IsTransparent () const

virtual void	Modify ()
	Change current fill area attributes if necessary.

virtual void	ResetAttFill (Option_t *option="")
	Reset this fill attributes to default values.

virtual void	SaveFillAttributes (std::ostream &out, const char *name, Int_t coldef=1, Int_t stydef=1001)
	Save fill attributes as C++ statement(s) on output stream out.

virtual void	SetFillAttributes ()
	Invoke the DialogCanvas Fill attributes.

virtual void	SetFillColor (Color_t fcolor)
	Set the fill area color.

virtual void	SetFillColorAlpha (Color_t fcolor, Float_t falpha)
	Set a transparent fill color.

virtual void	SetFillStyle (Style_t fstyle)
	Set the fill area style.

void	StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

Public Member Functions inherited from TAttBBox2D
virtual	~TAttBBox2D ()

void	StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

Public Member Functions inherited from TAttText
	TAttText ()
	AttText default constructor.

	TAttText (Int_t align, Float_t angle, Color_t color, Style_t font, Float_t tsize)
	AttText normal constructor.

virtual	~TAttText ()
	AttText destructor.

void	Copy (TAttText &atttext) const
	Copy this text attributes to a new TAttText.

virtual Short_t	GetTextAlign () const
	Return the text alignment.

virtual Float_t	GetTextAngle () const
	Return the text angle.

virtual Color_t	GetTextColor () const
	Return the text color.

virtual Font_t	GetTextFont () const
	Return the text font.

virtual Float_t	GetTextSize () const
	Return the text size.

virtual Float_t	GetTextSizePercent (Float_t size)
	Return the text in percent of the pad size.

virtual void	Modify ()
	Change current text attributes if necessary.

virtual void	ResetAttText (Option_t *toption="")
	Reset this text attributes to default values.

virtual void	SaveTextAttributes (std::ostream &out, const char *name, Int_t alidef=12, Float_t angdef=0, Int_t coldef=1, Int_t fondef=61, Float_t sizdef=1)
	Save text attributes as C++ statement(s) on output stream out.

virtual void	SetTextAlign (Short_t align=11)
	Set the text alignment.

virtual void	SetTextAngle (Float_t tangle=0)
	Set the text angle.

virtual void	SetTextAttributes ()
	Invoke the DialogCanvas Text attributes.

virtual void	SetTextColor (Color_t tcolor=1)
	Set the text color.

virtual void	SetTextColorAlpha (Color_t tcolor, Float_t talpha)
	Set a transparent marker color.

virtual void	SetTextFont (Font_t tfont=62)
	Set the text font.

virtual void	SetTextSize (Float_t tsize=1)
	Set the text size.

virtual void	SetTextSizePixels (Int_t npixels)
	Set the text size in pixel.

void	StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b)

Static Public Member Functions
static TClass *	Class ()

static const char *	Class_Name ()

static constexpr Version_t	Class_Version ()

static const char *	DeclFileName ()

Static Public Member Functions inherited from TPave
static TClass *	Class ()

static const char *	Class_Name ()

static constexpr Version_t	Class_Version ()

static const char *	DeclFileName ()

Static Public Member Functions inherited from TBox
static TClass *	Class ()

static const char *	Class_Name ()

static constexpr Version_t	Class_Version ()

static const char *	DeclFileName ()

Static Public Member Functions inherited from TObject
static TClass *	Class ()

static const char *	Class_Name ()

static constexpr Version_t	Class_Version ()

static const char *	DeclFileName ()

static Longptr_t	GetDtorOnly ()
	Return destructor only flag.

static Bool_t	GetObjectStat ()
	Get status of object stat flag.

static void	SetDtorOnly (void *obj)
	Set destructor only flag.

static void	SetObjectStat (Bool_t stat)
	Turn on/off tracking of objects in the TObjectTable.

Static Public Member Functions inherited from TAttLine
static TClass *	Class ()

static const char *	Class_Name ()

static constexpr Version_t	Class_Version ()

static const char *	DeclFileName ()

Static Public Member Functions inherited from TAttFill
static TClass *	Class ()

static const char *	Class_Name ()

static constexpr Version_t	Class_Version ()

static const char *	DeclFileName ()

Static Public Member Functions inherited from TAttBBox2D
static TClass *	Class ()

static const char *	Class_Name ()

static constexpr Version_t	Class_Version ()

static const char *	DeclFileName ()

Static Public Member Functions inherited from TAttText
static TClass *	Class ()

static const char *	Class_Name ()

static constexpr Version_t	Class_Version ()

static const char *	DeclFileName ()

Protected Member Functions
TLegend &	operator= (const TLegend &)
	Assignment operator.

Protected Member Functions inherited from TObject
virtual void	DoError (int level, const char location, const char fmt, va_list va) const
	Interface to ErrorHandler (protected).

void	MakeZombie ()

Protected Attributes
Float_t	fColumnSeparation
	Separation between columns, as a fraction of The space allowed to one column.

Float_t	fEntrySeparation
	Separation between entries, as a fraction of The space allocated to one entry.

Float_t	fMargin
	Fraction of total width used for symbol.

Int_t	fNColumns
	Number of columns in the legend.

TList *	fPrimitives {nullptr}
	List of TLegendEntries.

Protected Attributes inherited from TPave
Int_t	fBorderSize
	window box bordersize in pixels

Double_t	fCornerRadius
	Corner radius in case of option arc.

Int_t	fInit
	(=0 if transformation to NDC not yet done)

TString	fName
	Pave name.

TString	fOption
	Pave style.

Int_t	fShadowColor
	Color of the pave's shadow.

Double_t	fX1NDC
	X1 point in NDC coordinates.

Double_t	fX2NDC
	X2 point in NDC coordinates.

Double_t	fY1NDC
	Y1 point in NDC coordinates.

Double_t	fY2NDC
	Y2 point in NDC coordinates.

Protected Attributes inherited from TBox
Bool_t	fResizing
	! True if box is being resized

Double_t	fX1
	X of 1st point.

Double_t	fX2
	X of 2nd point.

Double_t	fY1
	Y of 1st point.

Double_t	fY2
	Y of 2nd point.

Protected Attributes inherited from TAttLine
Color_t	fLineColor
	Line color.

Style_t	fLineStyle
	Line style.

Width_t	fLineWidth
	Line width.

Protected Attributes inherited from TAttFill
Color_t	fFillColor
	Fill area color.

Style_t	fFillStyle
	Fill area style.

Protected Attributes inherited from TAttText
Short_t	fTextAlign
	Text alignment.

Float_t	fTextAngle
	Text angle.

Color_t	fTextColor
	Text color.

Font_t	fTextFont
	Text font.

Float_t	fTextSize
	Text size.

Additional Inherited Members
Public Types inherited from TPave
enum	{ kNameIsAction = (1ULL << ( 11 )) }

Public Types inherited from TBox
enum	{ kCannotMove = (1ULL << ( 12 )) }

Public Types inherited from TObject
enum	{ kIsOnHeap = 0x01000000 , kNotDeleted = 0x02000000 , kZombie = 0x04000000 , kInconsistent = 0x08000000 , kBitMask = 0x00ffffff }

enum	{ kSingleKey = (1ULL << ( 0 )) , kOverwrite = (1ULL << ( 1 )) , kWriteDelete = (1ULL << ( 2 )) }

enum	EDeprecatedStatusBits { kObjInCanvas = (1ULL << ( 3 )) }

enum	EStatusBits { kCanDelete = (1ULL << ( 0 )) , kMustCleanup = (1ULL << ( 3 )) , kIsReferenced = (1ULL << ( 4 )) , kHasUUID = (1ULL << ( 5 )) , kCannotPick = (1ULL << ( 6 )) , kNoContextMenu = (1ULL << ( 8 )) , kInvalidObject = (1ULL << ( 13 )) }

Protected Types inherited from TObject
enum	{ kOnlyPrepStep = (1ULL << ( 3 )) }

#include <TLegend.h>

Inheritance diagram for TLegend:

[legend]

Constructor & Destructor Documentation

◆ TLegend() [1/4]

TLegend::TLegend ( )

Default constructor.

This constructor allows to place automatically the legend with a default width(0.3) and a default height (0.15) in normalize coordinates.

Definition at line 200 of file TLegend.cxx.

◆ TLegend() [2/4]

TLegend::TLegend	(	Double_t	x1,
		Double_t	y1,
		Double_t	x2,
		Double_t	y2,
		const char *	header = `""`,
		Option_t *	option = `"brNDC"`
	)

Normal constructor.

A TLegend is a Pave with several TLegendEntry(s).

x1,y1,x2,y2 are the coordinates of the Legend in the current pad (in normalised coordinates by default)

header is the title displayed at the top of the legend it is a TLatex string treated like a regular entry. The default is no header (header = 0).

The options are the same as for TPave.

Definition at line 223 of file TLegend.cxx.

◆ TLegend() [3/4]

TLegend::TLegend	(	Double_t	w,
		Double_t	h,
		const char *	header = `""`,
		Option_t *	option = `"brNDC"`
	)

Constructor with automatic placement.

A TLegend is a Pave with several TLegendEntry(s).

This constructor doesn't define the legend position. w and h are the width and height of the legend in percentage of the current pad size. The position will be automatically defined at painting time.

header is the title displayed at the top of the legend it is a TLatex string treated like a regular entry. The default is no header (header = 0).

The options are the same as for TPave.

Definition at line 257 of file TLegend.cxx.

◆ ~TLegend()

TLegend::~TLegend ( )

override

Default destructor.

Definition at line 297 of file TLegend.cxx.

◆ TLegend() [4/4]

TLegend::TLegend ( const TLegend & legend )

Copy constructor.

Definition at line 278 of file TLegend.cxx.

Member Function Documentation

◆ AddEntry() [1/2]

TLegendEntry * TLegend::AddEntry	(	const char *	name,
		const char *	label = `""`,
		Option_t *	option = `"lpf"`
	)

Add a new entry to this legend.

"name" is the name of an object in the pad to be represented label is the text you wish to associate with obj in the legend if label is null or empty, the title of the object will be used.

Options are:

L: draw line associated with TAttLine if obj inherits from TAttLine
P: draw polymarker associated with TAttMarker if obj inherits from TAttMarker
F: draw a box with fill associated wit TAttFill if obj inherits TAttFill
E: draw vertical error bar if option "L" is also specified

Definition at line 340 of file TLegend.cxx.

◆ AddEntry() [2/2]

TLegendEntry * TLegend::AddEntry	(	const TObject *	obj,
		const char *	label = `""`,
		Option_t *	option = `"lpf"`
	)

Add a new entry to this legend.

"obj" is the object to be represented. "label" is the text you wish to associate with obj in the legend. If "label" is null or empty, the title of the object will be used.

Options are:

L: draw line associated with TAttLine if obj inherits from TAttLine
P: draw polymarker associated with TAttMarker if obj inherits from TAttMarker
F: draw a box with fill associated wit TAttFill if obj inherits TAttFill
E: draw vertical error bar if option "L" is also specified

Definition at line 317 of file TLegend.cxx.

◆ Class()

static TClass * TLegend::Class ( )

static

Returns: TClass describing this class

◆ Class_Name()

static const char * TLegend::Class_Name ( )

static

Returns: Name of this class

◆ Class_Version()

static constexpr Version_t TLegend::Class_Version ( )

inlinestaticconstexpr

Returns: Version of this class

Definition at line 82 of file TLegend.h.

◆ Clear()

void TLegend::Clear ( Option_t * option = "" )

overridevirtual

Clear all entries in this legend, including the header.

Reimplemented from TObject.

Definition at line 376 of file TLegend.cxx.

◆ Copy()

void TLegend::Copy ( TObject & obj ) const

overridevirtual

Copy this legend into "obj".

Reimplemented from TBox.

Definition at line 385 of file TLegend.cxx.

◆ DeclFileName()

static const char * TLegend::DeclFileName ( )

inlinestatic

Returns: Name of the file containing the class declaration

Definition at line 82 of file TLegend.h.

◆ DeleteEntry()

void TLegend::DeleteEntry ( )

virtual

Delete entry at the mouse position.

Definition at line 410 of file TLegend.cxx.

◆ Draw()

void TLegend::Draw ( Option_t * option = "" )

overridevirtual

Draw this legend with its current attributes.

Reimplemented from TBox.

Definition at line 422 of file TLegend.cxx.

◆ EditEntryAttFill()

void TLegend::EditEntryAttFill ( )

virtual

Edit the fill attributes for the entry pointed by the mouse.

Definition at line 430 of file TLegend.cxx.

◆ EditEntryAttLine()

void TLegend::EditEntryAttLine ( )

virtual

Edit the line attributes for the entry pointed by the mouse.

Definition at line 441 of file TLegend.cxx.

◆ EditEntryAttMarker()

void TLegend::EditEntryAttMarker ( )

virtual

Edit the marker attributes for the entry pointed by the mouse.

Definition at line 452 of file TLegend.cxx.

◆ EditEntryAttText()

void TLegend::EditEntryAttText ( )

virtual

Edit the text attributes for the entry pointed by the mouse.

Definition at line 463 of file TLegend.cxx.

◆ GetColumnSeparation()

Float_t TLegend::GetColumnSeparation ( ) const

inline

Definition at line 46 of file TLegend.h.

◆ GetEntry()

TLegendEntry * TLegend::GetEntry ( ) const

Get entry pointed to by the mouse.

This method is mostly a tool for other methods inside this class.

Definition at line 475 of file TLegend.cxx.

◆ GetEntrySeparation()

Float_t TLegend::GetEntrySeparation ( ) const

inline

Definition at line 48 of file TLegend.h.

◆ GetHeader()

const char * TLegend::GetHeader ( ) const

virtual

Returns the header, which is the title that appears at the top of the legend.

Definition at line 518 of file TLegend.cxx.

◆ GetListOfPrimitives()

TList * TLegend::GetListOfPrimitives ( ) const

inline

Definition at line 50 of file TLegend.h.

◆ GetMargin()

Float_t TLegend::GetMargin ( ) const

inline

Definition at line 51 of file TLegend.h.

◆ GetNColumns()

Int_t TLegend::GetNColumns ( ) const

inline

Definition at line 52 of file TLegend.h.

◆ GetNRows()

Int_t TLegend::GetNRows ( ) const

Get the number of rows.

Definition at line 583 of file TLegend.cxx.

◆ InsertEntry()

void TLegend::InsertEntry	(	const char *	objectName = `""`,
		const char *	label = `""`,
		Option_t *	option = `"lpf"`
	)

virtual

Add a new entry before the entry at the mouse position.

Definition at line 533 of file TLegend.cxx.

◆ IsA()

TClass * TLegend::IsA ( ) const

inlineoverridevirtual

Returns: TClass describing current object

Reimplemented from TBox.

Definition at line 82 of file TLegend.h.

◆ operator=()

TLegend & TLegend::operator= ( const TLegend & lg )

protected

Assignment operator.

Definition at line 287 of file TLegend.cxx.

◆ Paint()

void TLegend::Paint ( Option_t * option = "" )

overridevirtual

Paint this legend with its current attributes.

Reimplemented from TBox.

Definition at line 558 of file TLegend.cxx.

◆ PaintPrimitives()

void TLegend::PaintPrimitives ( )

virtual

Paint the entries (list of primitives) for this legend.

Definition at line 615 of file TLegend.cxx.

◆ Print()

void TLegend::Print ( Option_t * option = "" ) const

overridevirtual

Dump this TLegend and its contents.

Reimplemented from TBox.

Definition at line 1019 of file TLegend.cxx.

◆ RecursiveRemove()

void TLegend::RecursiveRemove ( TObject * obj )

overridevirtual

Reset the legend entries pointing to "obj".

Reimplemented from TObject.

Definition at line 1028 of file TLegend.cxx.

◆ SavePrimitive()

void TLegend::SavePrimitive	(	std::ostream &	out,
		Option_t *	option = `""`
	)

overridevirtual

Save this legend as C++ statements on output stream out to be used with the SaveAs .C option.

Reimplemented from TBox.

Definition at line 1041 of file TLegend.cxx.

◆ SetColumnSeparation()

void TLegend::SetColumnSeparation ( Float_t columnSeparation )

inline

Definition at line 62 of file TLegend.h.

◆ SetDefaults()

void TLegend::SetDefaults ( )

inline

Definition at line 61 of file TLegend.h.

◆ SetEntryLabel()

void TLegend::SetEntryLabel ( const char * label )

virtual

Edit the label of the entry pointed to by the mouse.

Definition at line 1072 of file TLegend.cxx.

◆ SetEntryOption()

void TLegend::SetEntryOption ( Option_t * option )

virtual

Edit the option of the entry pointed to by the mouse.

Definition at line 1081 of file TLegend.cxx.

◆ SetEntrySeparation()

void TLegend::SetEntrySeparation ( Float_t entryseparation )

inline

Definition at line 66 of file TLegend.h.

◆ SetHeader()

void TLegend::SetHeader	(	const char *	header = `""`,
		Option_t *	option = `""`
	)

virtual

Sets the header, which is the "title" that appears at the top of the legend.

If option contains C, the title will be centered.

Definition at line 1091 of file TLegend.cxx.

◆ SetMargin()

void TLegend::SetMargin ( Float_t margin )

inline

Definition at line 69 of file TLegend.h.

◆ SetNColumns()

void TLegend::SetNColumns ( Int_t nColumns )

Set the number of columns for the legend.

The header, if set, is given its own row. After that, every nColumns entries are inserted into the same row. For example, if one calls legend.SetNColumns(2), and there is no header, then the first two TObjects added to the legend will be in the first row, the next two will appear in the second row, and so on.

Definition at line 603 of file TLegend.cxx.

◆ Streamer()

void TLegend::Streamer ( TBuffer & R__b )

overridevirtual

Stream an object of class TBox.

Reimplemented from TBox.

◆ StreamerNVirtual()

void TLegend::StreamerNVirtual ( TBuffer & ClassDef_StreamerNVirtual_b )

inline

Definition at line 82 of file TLegend.h.

Member Data Documentation

◆ fColumnSeparation

Float_t TLegend::fColumnSeparation

protected

Separation between columns, as a fraction of The space allowed to one column.

Definition at line 79 of file TLegend.h.

◆ fEntrySeparation

Float_t TLegend::fEntrySeparation

protected

Separation between entries, as a fraction of The space allocated to one entry.

Typical value is 0.1.

Definition at line 74 of file TLegend.h.

◆ fMargin

Float_t TLegend::fMargin

protected

Fraction of total width used for symbol.

Definition at line 77 of file TLegend.h.

◆ fNColumns

Int_t TLegend::fNColumns

protected

Number of columns in the legend.

Definition at line 78 of file TLegend.h.

◆ fPrimitives

TList* TLegend::fPrimitives {nullptr}

protected

List of TLegendEntries.

Definition at line 73 of file TLegend.h.

Libraries for TLegend:

[legend]

The documentation for this class was generated from the following files:

graf2d/graf/inc/TLegend.h
graf2d/graf/src/TLegend.cxx

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ TLegend() [1/4]

◆ TLegend() [2/4]

◆ TLegend() [3/4]

◆ ~TLegend()

◆ TLegend() [4/4]

Member Function Documentation

◆ AddEntry() [1/2]

◆ AddEntry() [2/2]

◆ Class()

◆ Class_Name()

◆ Class_Version()

◆ Clear()

◆ Copy()

◆ DeclFileName()

◆ DeleteEntry()

◆ Draw()

◆ EditEntryAttFill()

◆ EditEntryAttLine()

◆ EditEntryAttMarker()

◆ EditEntryAttText()

◆ GetColumnSeparation()

◆ GetEntry()

◆ GetEntrySeparation()

◆ GetHeader()

◆ GetListOfPrimitives()

◆ GetMargin()

◆ GetNColumns()

◆ GetNRows()

◆ InsertEntry()

◆ IsA()

◆ operator=()

◆ Paint()

◆ PaintPrimitives()

◆ Print()

◆ RecursiveRemove()

◆ SavePrimitive()

◆ SetColumnSeparation()

◆ SetDefaults()

◆ SetEntryLabel()

◆ SetEntryOption()

◆ SetEntrySeparation()

◆ SetHeader()

◆ SetMargin()

◆ SetNColumns()

◆ Streamer()

◆ StreamerNVirtual()

Member Data Documentation

◆ fColumnSeparation

◆ fEntrySeparation

◆ fMargin

◆ fNColumns

◆ fPrimitives