Logo ROOT   6.19/01
Reference Guide
List of all members | Public Member Functions | Protected Member Functions | Protected Attributes | List of all members
TLegend Class Reference

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);
auto h1 = new TH1F("h1","TLegend Example",200,-10,10);
h1->FillRandom("gaus",30000);
h1->SetFillStyle(3003);
h1->Draw();
auto f1=new TF1("f1","1000*TMath::Abs(sin(x)/x)",-10,10);
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->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();
}
pict1_TLegend_001.png

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");

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:

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();
}
pict1_TLegend_002.png

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();
}
pict1_TLegend_003.png
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->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();
}
pict1_TLegend_004.png

Definition at line 23 of file TLegend.h.

Public Member Functions

 TLegend ()
 Default constructor. More...
 
 TLegend (Double_t x1, Double_t y1, Double_t x2, Double_t y2, const char *header="", Option_t *option="brNDC")
 Normal constructor. More...
 
 TLegend (Double_t w, Double_t h, const char *header="", Option_t *option="brNDC")
 Constructor with automatic placement. More...
 
 TLegend (const TLegend &legend)
 Copy constructor. More...
 
virtual ~TLegend ()
 Default destructor. More...
 
TLegendEntryAddEntry (const TObject *obj, const char *label="", Option_t *option="lpf")
 Add a new entry to this legend. More...
 
TLegendEntryAddEntry (const char *name, const char *label="", Option_t *option="lpf")
 Add a new entry to this legend. More...
 
virtual void Clear (Option_t *option="")
 Clear all entries in this legend, including the header. More...
 
virtual void Copy (TObject &obj) const
 Copy this legend into "obj". More...
 
virtual void DeleteEntry ()
 Delete entry at the mouse position. More...
 
virtual void Draw (Option_t *option="")
 Draw this legend with its current attributes. More...
 
virtual void EditEntryAttFill ()
 Edit the fill attributes for the entry pointed by the mouse. More...
 
virtual void EditEntryAttLine ()
 Edit the line attributes for the entry pointed by the mouse. More...
 
virtual void EditEntryAttMarker ()
 Edit the marker attributes for the entry pointed by the mouse. More...
 
virtual void EditEntryAttText ()
 Edit the text attributes for the entry pointed by the mouse. More...
 
Float_t GetColumnSeparation () const
 
TLegendEntryGetEntry () const
 Get entry pointed to by the mouse. More...
 
Float_t GetEntrySeparation () const
 
virtual const char * GetHeader () const
 Returns the header, which is the title that appears at the top of the legend. More...
 
TListGetListOfPrimitives () const
 
Float_t GetMargin () const
 
Int_t GetNColumns () const
 
Int_t GetNRows () const
 Get the number of rows. More...
 
virtual void InsertEntry (const char *objectName="", const char *label="", Option_t *option="lpf")
 Add a new entry before the entry at the mouse position. More...
 
virtual void Paint (Option_t *option="")
 Paint this legend with its current attributes. More...
 
virtual void PaintPrimitives ()
 Paint the entries (list of primitives) for this legend. More...
 
virtual void Print (Option_t *option="") const
 Dump this TLegend and its contents. More...
 
virtual void RecursiveRemove (TObject *obj)
 Reset the legend entries pointing to "obj". More...
 
virtual void SavePrimitive (std::ostream &out, Option_t *option="")
 Save this legend as C++ statements on output stream out to be used with the SaveAs .C option. More...
 
void SetColumnSeparation (Float_t columnSeparation)
 
void SetDefaults ()
 
virtual void SetEntryLabel (const char *label)
 Edit the label of the entry pointed to by the mouse. More...
 
virtual void SetEntryOption (Option_t *option)
 Edit the option of the entry pointed to by the mouse. More...
 
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. More...
 
void SetMargin (Float_t margin)
 
void SetNColumns (Int_t nColumns)
 Set the number of columns for the legend. More...
 
- Public Member Functions inherited from TPave
 TPave ()
 Pave default constructor. More...
 
 TPave (Double_t x1, Double_t y1, Double_t x2, Double_t y2, Int_t bordersize=4, Option_t *option="br")
 Pave normal constructor. More...
 
 TPave (const TPave &pave)
 Pave copy constructor. More...
 
virtual ~TPave ()
 Pave default destructor. More...
 
virtual void ConvertNDCtoPad ()
 Convert pave coordinates from NDC to Pad coordinates. More...
 
void Copy (TObject &pave) const
 Copy this pave to pave. More...
 
virtual Int_t DistancetoPrimitive (Int_t px, Int_t py)
 Compute distance from point px,py to a pave. More...
 
virtual void 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. More...
 
virtual void ExecuteEvent (Int_t event, Int_t px, Int_t py)
 Execute action corresponding to one event. More...
 
Int_t GetBorderSize () const
 
Double_t GetCornerRadius () const
 
Option_tGetName () const
 Returns name of object. More...
 
Option_tGetOption () const
 
Int_t GetShadowColor () const
 
Double_t GetX1NDC () const
 
Double_t GetX2NDC () const
 
Double_t GetY1NDC () const
 
Double_t GetY2NDC () const
 
virtual ULong_t Hash () const
 Return hash value for this object. More...
 
virtual Bool_t IsSortable () const
 
virtual void ls (Option_t *option="") const
 List this pave with its attributes. More...
 
TPaveoperator= (const TPave &src)
 Assignment operator. More...
 
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. More...
 
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. More...
 
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)
 
virtual void SetX1 (Double_t x1)
 Set the X1 value. More...
 
virtual void SetX1NDC (Double_t x1)
 
virtual void SetX2 (Double_t x2)
 Set the X2 value. More...
 
virtual void SetX2NDC (Double_t x2)
 
virtual void SetY1 (Double_t y1)
 Set the Y1 value. More...
 
virtual void SetY1NDC (Double_t y1)
 
virtual void SetY2 (Double_t y2)
 Set the Y2 value. More...
 
virtual void SetY2NDC (Double_t y2)
 
- Public Member Functions inherited from TBox
 TBox ()
 Box default constructor. More...
 
 TBox (Double_t x1, Double_t y1, Double_t x2, Double_t y2)
 Box standard constructor. More...
 
 TBox (const TBox &box)
 Box copy constructor. More...
 
virtual ~TBox ()
 Box destructor. More...
 
virtual TBoxDrawBox (Double_t x1, Double_t y1, Double_t x2, Double_t y2)
 Draw this box with new coordinates. More...
 
virtual Rectangle_t GetBBox ()
 Return the "bounding Box" of the Box. More...
 
virtual TPoint GetBBoxCenter ()
 Return the center of the Box as TPoint in pixels. More...
 
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. More...
 
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. More...
 
TBoxoperator= (const TBox &)
 Assignment operator. More...
 
virtual void PaintBox (Double_t x1, Double_t y1, Double_t x2, Double_t y2, Option_t *option="")
 Draw this box with new coordinates. More...
 
virtual void SetBBoxCenter (const TPoint &p)
 Set center of the Box. More...
 
virtual void SetBBoxCenterX (const Int_t x)
 Set X coordinate of the center of the Box. More...
 
virtual void SetBBoxCenterY (const Int_t y)
 Set Y coordinate of the center of the Box. More...
 
virtual void SetBBoxX1 (const Int_t x)
 Set left hand side of BoundingBox to a value (resize in x direction on left) More...
 
virtual void SetBBoxX2 (const Int_t x)
 Set right hand side of BoundingBox to a value (resize in x direction on right) More...
 
virtual void SetBBoxY1 (const Int_t y)
 Set top of BoundingBox to a value (resize in y direction on top) More...
 
virtual void SetBBoxY2 (const Int_t y)
 Set bottom of BoundingBox to a value (resize in y direction on bottom) More...
 
virtual void SetToolTipText (const char *text, Long_t delayms=1000)
 Set tool tip text associated with this box. More...
 
- Public Member Functions inherited from TObject
 TObject ()
 TObject constructor. More...
 
 TObject (const TObject &object)
 TObject copy ctor. More...
 
virtual ~TObject ()
 TObject destructor. More...
 
void AbstractMethod (const char *method) const
 Use this method to implement an "abstract" method that you don't want to leave purely abstract. More...
 
virtual void AppendPad (Option_t *option="")
 Append graphics object to current pad. More...
 
virtual void Browse (TBrowser *b)
 Browse object. May be overridden for another default action. More...
 
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. More...
 
virtual const char * ClassName () const
 Returns name of class to which the object belongs. More...
 
virtual TObjectClone (const char *newname="") const
 Make a clone of an object using the Streamer facility. More...
 
virtual Int_t Compare (const TObject *obj) const
 Compare abstract method. More...
 
virtual void Delete (Option_t *option="")
 Delete this object. More...
 
virtual void DrawClass () const
 Draw class inheritance tree of the class to which this object belongs. More...
 
virtual TObjectDrawClone (Option_t *option="") const
 Draw a clone of this object in the current selected pad for instance with: gROOT->SetSelectedPad(gPad). More...
 
virtual void Dump () const
 Dump contents of object on stdout. More...
 
virtual void Error (const char *method, const char *msgfmt,...) const
 Issue error message. More...
 
virtual void Execute (const char *method, const char *params, Int_t *error=0)
 Execute method on this object with the given parameter string, e.g. More...
 
virtual void Execute (TMethod *method, TObjArray *params, Int_t *error=0)
 Execute method on this object with parameters stored in the TObjArray. More...
 
virtual void Fatal (const char *method, const char *msgfmt,...) const
 Issue fatal error message. More...
 
virtual TObjectFindObject (const char *name) const
 Must be redefined in derived classes. More...
 
virtual TObjectFindObject (const TObject *obj) const
 Must be redefined in derived classes. More...
 
virtual Option_tGetDrawOption () const
 Get option used by the graphics system to draw this object. More...
 
virtual const char * GetIconName () const
 Returns mime type name of object. More...
 
virtual char * GetObjectInfo (Int_t px, Int_t py) const
 Returns string containing info about the object at position (px,py). More...
 
virtual const char * GetTitle () const
 Returns title of object. More...
 
virtual UInt_t GetUniqueID () const
 Return the unique object id. More...
 
virtual Bool_t HandleTimer (TTimer *timer)
 Execute action in response of a timer timing out. More...
 
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. More...
 
virtual void Info (const char *method, const char *msgfmt,...) const
 Issue info message. More...
 
virtual Bool_t InheritsFrom (const char *classname) const
 Returns kTRUE if object inherits from class "classname". More...
 
virtual Bool_t InheritsFrom (const TClass *cl) const
 Returns kTRUE if object inherits from TClass cl. More...
 
virtual void Inspect () const
 Dump contents of this object in a graphics canvas. More...
 
void InvertBit (UInt_t f)
 
virtual Bool_t IsEqual (const TObject *obj) const
 Default equal comparison (objects are equal if they have the same address in memory). More...
 
virtual Bool_t IsFolder () const
 Returns kTRUE in case object contains browsable objects (like containers or lists of other objects). More...
 
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). More...
 
virtual Bool_t Notify ()
 This method must be overridden to handle object notification. More...
 
void Obsolete (const char *method, const char *asOfVers, const char *removedFromVers) const
 Use this method to declare a method obsolete. More...
 
void operator delete (void *ptr)
 Operator delete. More...
 
void operator delete[] (void *ptr)
 Operator delete []. More...
 
voidoperator new (size_t sz)
 
voidoperator new (size_t sz, void *vp)
 
voidoperator new[] (size_t sz)
 
voidoperator new[] (size_t sz, void *vp)
 
TObjectoperator= (const TObject &rhs)
 TObject assignment operator. More...
 
virtual void Pop ()
 Pop on object drawn in a pad to the top of the display list. More...
 
virtual Int_t Read (const char *name)
 Read contents of object with specified name from the current directory. More...
 
void ResetBit (UInt_t f)
 
virtual void SaveAs (const char *filename="", Option_t *option="") const
 Save this object in the file specified by filename. More...
 
void SetBit (UInt_t f, Bool_t set)
 Set or unset the user status bits as specified in f. More...
 
void SetBit (UInt_t f)
 
virtual void SetDrawOption (Option_t *option="")
 Set drawing option for object. More...
 
virtual void SetUniqueID (UInt_t uid)
 Set the unique object id. More...
 
virtual void SysError (const char *method, const char *msgfmt,...) const
 Issue system error message. More...
 
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. More...
 
virtual void Warning (const char *method, const char *msgfmt,...) const
 Issue warning message. More...
 
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
 Write this object to the current directory. More...
 
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
 Write this object to the current directory. More...
 
- Public Member Functions inherited from TAttLine
 TAttLine ()
 AttLine default constructor. More...
 
 TAttLine (Color_t lcolor, Style_t lstyle, Width_t lwidth)
 AttLine normal constructor. More...
 
virtual ~TAttLine ()
 AttLine destructor. More...
 
void Copy (TAttLine &attline) const
 Copy this line attributes to a new TAttLine. More...
 
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. More...
 
virtual Color_t GetLineColor () const
 Return the line color. More...
 
virtual Style_t GetLineStyle () const
 Return the line style. More...
 
virtual Width_t GetLineWidth () const
 Return the line width. More...
 
virtual void Modify ()
 Change current line attributes if necessary. More...
 
virtual void ResetAttLine (Option_t *option="")
 Reset this line attributes to default values. More...
 
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. More...
 
virtual void SetLineAttributes ()
 Invoke the DialogCanvas Line attributes. More...
 
virtual void SetLineColor (Color_t lcolor)
 Set the line color. More...
 
virtual void SetLineColorAlpha (Color_t lcolor, Float_t lalpha)
 Set a transparent line color. More...
 
virtual void SetLineStyle (Style_t lstyle)
 Set the line style. More...
 
virtual void SetLineWidth (Width_t lwidth)
 Set the line width. More...
 
- Public Member Functions inherited from TAttFill
 TAttFill ()
 AttFill default constructor. More...
 
 TAttFill (Color_t fcolor, Style_t fstyle)
 AttFill normal constructor. More...
 
virtual ~TAttFill ()
 AttFill destructor. More...
 
void Copy (TAttFill &attfill) const
 Copy this fill attributes to a new TAttFill. More...
 
virtual Color_t GetFillColor () const
 Return the fill area color. More...
 
virtual Style_t GetFillStyle () const
 Return the fill area style. More...
 
virtual Bool_t IsTransparent () const
 
virtual void Modify ()
 Change current fill area attributes if necessary. More...
 
virtual void ResetAttFill (Option_t *option="")
 Reset this fill attributes to default values. More...
 
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. More...
 
virtual void SetFillAttributes ()
 Invoke the DialogCanvas Fill attributes. More...
 
virtual void SetFillColor (Color_t fcolor)
 Set the fill area color. More...
 
virtual void SetFillColorAlpha (Color_t fcolor, Float_t falpha)
 Set a transparent fill color. More...
 
virtual void SetFillStyle (Style_t fstyle)
 Set the fill area style. More...
 
- Public Member Functions inherited from TAttBBox2D
virtual ~TAttBBox2D ()
 
- Public Member Functions inherited from TAttText
 TAttText ()
 AttText default constructor. More...
 
 TAttText (Int_t align, Float_t angle, Color_t color, Style_t font, Float_t tsize)
 AttText normal constructor. More...
 
virtual ~TAttText ()
 AttText destructor. More...
 
void Copy (TAttText &atttext) const
 Copy this text attributes to a new TAttText. More...
 
virtual Short_t GetTextAlign () const
 Return the text alignment. More...
 
virtual Float_t GetTextAngle () const
 Return the text angle. More...
 
virtual Color_t GetTextColor () const
 Return the text color. More...
 
virtual Font_t GetTextFont () const
 Return the text font. More...
 
virtual Float_t GetTextSize () const
 Return the text size. More...
 
virtual void Modify ()
 Change current text attributes if necessary. More...
 
virtual void ResetAttText (Option_t *toption="")
 Reset this text attributes to default values. More...
 
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. More...
 
virtual void SetTextAlign (Short_t align=11)
 Set the text alignment. More...
 
virtual void SetTextAngle (Float_t tangle=0)
 Set the text angle. More...
 
virtual void SetTextAttributes ()
 Invoke the DialogCanvas Text attributes. More...
 
virtual void SetTextColor (Color_t tcolor=1)
 Set the text color. More...
 
virtual void SetTextColorAlpha (Color_t tcolor, Float_t talpha)
 Set a transparent marker color. More...
 
virtual void SetTextFont (Font_t tfont=62)
 Set the text font. More...
 
virtual void SetTextSize (Float_t tsize=1)
 Set the text size. More...
 
virtual void SetTextSizePixels (Int_t npixels)
 Set the text size in pixels. More...
 

Protected Member Functions

TLegendoperator= (const TLegend &)
 Assignment operator. More...
 
- 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). More...
 
void MakeZombie ()
 

Protected Attributes

Float_t fColumnSeparation
 Separation between columns, as a fraction of The space allowed to one column. More...
 
Float_t fEntrySeparation
 Separation between entries, as a fraction of The space allocated to one entry. More...
 
Float_t fMargin
 Fraction of total width used for symbol. More...
 
Int_t fNColumns
 Number of columns in the legend. More...
 
TListfPrimitives
 List of TLegendEntries. More...
 
- Protected Attributes inherited from TPave
Int_t fBorderSize
 window box bordersize in pixels More...
 
Double_t fCornerRadius
 Corner radius in case of option arc. More...
 
Int_t fInit
 (=0 if transformation to NDC not yet done) More...
 
TString fName
 Pave name. More...
 
TString fOption
 Pave style. More...
 
Int_t fShadowColor
 Color of the pave's shadow. More...
 
Double_t fX1NDC
 X1 point in NDC coordinates. More...
 
Double_t fX2NDC
 X2 point in NDC coordinates. More...
 
Double_t fY1NDC
 Y1 point in NDC coordinates. More...
 
Double_t fY2NDC
 Y2 point in NDC coordinates. More...
 
- Protected Attributes inherited from TBox
Bool_t fResizing
 ! True if box is being resized More...
 
Double_t fX1
 X of 1st point. More...
 
Double_t fX2
 X of 2nd point. More...
 
Double_t fY1
 Y of 1st point. More...
 
Double_t fY2
 Y of 2nd point. More...
 
- Protected Attributes inherited from TAttLine
Color_t fLineColor
 Line color. More...
 
Style_t fLineStyle
 Line style. More...
 
Width_t fLineWidth
 Line width. More...
 
- Protected Attributes inherited from TAttFill
Color_t fFillColor
 Fill area color. More...
 
Style_t fFillStyle
 Fill area style. More...
 
- Protected Attributes inherited from TAttText
Short_t fTextAlign
 Text alignment. More...
 
Float_t fTextAngle
 Text angle. More...
 
Color_t fTextColor
 Text color. More...
 
Font_t fTextFont
 Text font. More...
 
Float_t fTextSize
 Text size. More...
 

Additional Inherited Members

- Public Types inherited from TPave
enum  { kNameIsAction = BIT(11) }
 
- Public Types inherited from TBox
enum  { kCannotMove = BIT(12) }
 
- Public Types inherited from TObject
enum  {
  kIsOnHeap = 0x01000000, kNotDeleted = 0x02000000, kZombie = 0x04000000, kInconsistent = 0x08000000,
  kBitMask = 0x00ffffff
}
 
enum  { kSingleKey = BIT(0), kOverwrite = BIT(1), kWriteDelete = BIT(2) }
 
enum  EDeprecatedStatusBits { kObjInCanvas = BIT(3) }
 
enum  EStatusBits {
  kCanDelete = BIT(0), kMustCleanup = BIT(3), kIsReferenced = BIT(4), kHasUUID = BIT(5),
  kCannotPick = BIT(6), kNoContextMenu = BIT(8), kInvalidObject = BIT(13)
}
 
- Static Public Member Functions inherited from TObject
static Long_t GetDtorOnly ()
 Return destructor only flag. More...
 
static Bool_t GetObjectStat ()
 Get status of object stat flag. More...
 
static void SetDtorOnly (void *obj)
 Set destructor only flag. More...
 
static void SetObjectStat (Bool_t stat)
 Turn on/off tracking of objects in the TObjectTable. More...
 

#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 ( )
virtual

Default destructor.

Definition at line 311 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 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 330 of file TLegend.cxx.

◆ AddEntry() [2/2]

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 353 of file TLegend.cxx.

◆ Clear()

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

Clear all entries in this legend, including the header.

Reimplemented from TObject.

Definition at line 390 of file TLegend.cxx.

◆ Copy()

void TLegend::Copy ( TObject obj) const
virtual

Copy this legend into "obj".

Reimplemented from TBox.

Definition at line 399 of file TLegend.cxx.

◆ DeleteEntry()

void TLegend::DeleteEntry ( )
virtual

Delete entry at the mouse position.

Definition at line 411 of file TLegend.cxx.

◆ Draw()

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

Draw this legend with its current attributes.

Reimplemented from TPave.

Definition at line 423 of file TLegend.cxx.

◆ EditEntryAttFill()

void TLegend::EditEntryAttFill ( )
virtual

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

Definition at line 431 of file TLegend.cxx.

◆ EditEntryAttLine()

void TLegend::EditEntryAttLine ( )
virtual

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

Definition at line 442 of file TLegend.cxx.

◆ EditEntryAttMarker()

void TLegend::EditEntryAttMarker ( )
virtual

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

Definition at line 453 of file TLegend.cxx.

◆ EditEntryAttText()

void TLegend::EditEntryAttText ( )
virtual

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

Definition at line 464 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 476 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 517 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.

◆ operator=()

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

Assignment operator.

Definition at line 295 of file TLegend.cxx.

◆ Paint()

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

Paint this legend with its current attributes.

Reimplemented from TPave.

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
virtual

Dump this TLegend and its contents.

Reimplemented from TPave.

Definition at line 1027 of file TLegend.cxx.

◆ RecursiveRemove()

void TLegend::RecursiveRemove ( TObject obj)
virtual

Reset the legend entries pointing to "obj".

Reimplemented from TObject.

Definition at line 1036 of file TLegend.cxx.

◆ SavePrimitive()

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

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

Reimplemented from TPave.

Definition at line 1049 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 1080 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 1089 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 1099 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.

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
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: