Text Attributes class.

This class is used (in general by secondary inheritance) by many other classes (graphics, histograms). It holds all the text attributes.

Text attributes

Text attributes are:

Text Alignment

The text alignment is an integer number (align) allowing to control the horizontal and vertical position of the text string with respect to the text position. The text alignment of any class inheriting from TAttText can be changed using the method SetTextAlign and retrieved using the method GetTextAlign.

align = 10*HorizontalAlign + VerticalAlign

For horizontal alignment the following convention applies:

1=left adjusted, 2=centered, 3=right adjusted

For vertical alignment the following convention applies:

1=bottom adjusted, 2=centered, 3=top adjusted

For example:

align = 11 = left adjusted and bottom adjusted

align = 32 = right adjusted and vertically centered

{
   auto *Ta = new TCanvas("Ta","Ta",0,0,500,200);
   Ta->Range(0,0,1,1);
 
   TLine lv;
   lv.SetLineStyle(3);
   lv.SetLineColor(kBlue);
   lv.DrawLine(0.33,0.0,0.33,1.0);
   lv.DrawLine(0.6,0.165,1.,0.165);
   lv.DrawLine(0.6,0.493,1.,0.493);
   lv.DrawLine(0.6,0.823,1.,0.823);
 
   // Horizontal alignment.
   auto *th1 = new TText(0.33,0.165,"Left adjusted");
   th1->SetTextAlign(11); th1->SetTextSize(0.12);
   th1->Draw();
 
   auto *th2 = new TText(0.33,0.493,"Center adjusted");
   th2->SetTextAlign(21); th2->SetTextSize(0.12);
   th2->Draw();
 
   auto *th3 = new TText(0.33,0.823,"Right adjusted");
   th3->SetTextAlign(31); th3->SetTextSize(0.12);
   th3->Draw();
 
   // Vertical alignment.
   auto *tv1 = new TText(0.66,0.165,"Bottom adjusted");
   tv1->SetTextAlign(11); tv1->SetTextSize(0.12);
   tv1->Draw();
 
   auto *tv2 = new TText(0.66,0.493,"Center adjusted");
   tv2->SetTextAlign(12); tv2->SetTextSize(0.12);
   tv2->Draw();
 
   auto *tv3 = new TText(0.66,0.823,"Top adjusted");
   tv3->SetTextAlign(13); tv3->SetTextSize(0.12);
   tv3->Draw();
}

Mnemonic constants are available:

kHAlignLeft = 10, kHAlignCenter = 20, kHAlignRight = 30,

kVAlignBottom = 1, kVAlignCenter = 2, kVAlignTop = 3

kVAlignTop

@ kVAlignTop

Definition TAttText.h:54

kVAlignCenter

@ kVAlignCenter

Definition TAttText.h:54

kHAlignLeft

@ kHAlignLeft

Definition TAttText.h:53

kVAlignBottom

@ kVAlignBottom

Definition TAttText.h:54

kHAlignCenter

@ kHAlignCenter

Definition TAttText.h:53

kHAlignRight

@ kHAlignRight

Definition TAttText.h:53

They allow to write:

object->SetTextAlign(kHAlignLeft+kVAlignTop);

Text Angle

Text angle in degrees. The text angle of any class inheriting from TAttText can be changed using the method SetTextAngle and retrieved using the method GetTextAngle. The following picture shows the text angle:

{
   auto *Ta = new TCanvas("Ta","Text angle",0,0,300,326);
   Ta->Range(0,0,1,1);
   TLine l;
   l.SetLineColor(kRed);
   l.DrawLine(0.1,0.1,0.9,0.1);
   l.DrawLine(0.1,0.1,0.9,0.9);
   TMarker m;
   m.SetMarkerStyle(20);
   m.SetMarkerColor(kBlue);
   m.DrawMarker(0.1,0.1);
   TArc a;
   a.SetFillStyle(0);
   a.SetLineColor(kBlue); a.SetLineStyle(3);
   a.DrawArc(0.1, 0.1, 0.2, 0.,45.,"only");
   auto *tt = new TText(0.1,0.1,"Text angle is 45 degrees");
   tt->SetTextAlign(11); tt->SetTextSize(0.1);
   tt->SetTextAngle(45);
   tt->Draw();
   auto *t1 = new TLatex(0.3,0.18,"45^{o}");
   t1->Draw();
}

Text Color

The text color is a color index (integer) pointing in the ROOT color table. The text color of any class inheriting from TAttText can be changed using the method SetTextColor and retrieved using the method GetTextColor. The following table shows the first 50 default colors.

Color transparency

SetTextColorAlpha(), allows to set a transparent color. In the following example the text color of the text text is set to blue with an opacity of 35% (i.e. a transparency of 65%). (The color kBlue itself is internally stored as fully opaque.)

text->SetTextColorAlpha(kBlue, 0.35);

text

Option_t Option_t TPoint TPoint const char text

Definition TGWin32VirtualXProxy.cxx:68

The transparency is available on all platforms when the flag OpenGL.CanvasPreferGL is set to 1 in $ROOTSYS/etc/system.rootrc, or on Mac with the Cocoa backend. On the file output it is visible with PDF, PNG, Gif, JPEG, SVG, TeX ... but not PostScript.

Alternatively, you can call at the top of your script gSytle->SetCanvasPreferGL();. Or if you prefer to activate GL for a single canvas c, then use c->SetSupportGL(true);.

If the text precision (see next paragraph) is smaller than 3, the text size (textsize) is a fraction of the current pad size. Therefore the same textsize value can generate text outputs with different absolute sizes in two different pads. The text size in pixels (charheight) is computed the following way:

pad_width  = gPad->XtoPixel(gPad->GetX2());
pad_height = gPad->YtoPixel(gPad->GetY1());
if (pad_width < pad_height)  charheight = textsize*pad_width;
else                         charheight = textsize*pad_height;

If the text precision is equal to 3, the text size doesn't depend on the pad's dimensions. A given textsize value always generates the same absolute size. The text size (charheight) is given in pixels:

charheight = textsize;

Note that to scale fonts to the same size as the old True Type package a scale factor of 0.93376068 is apply to the text size before drawing.

The text size of any class inheriting from TAttText can be changed using the method SetTextSize and retrieved using the method GetTextSize.

Text Font and Precision

The text font code is combination of the font number and the precision.

Text font code = 10*fontnumber + precision

fontnumber

Option_t Option_t fontnumber

Definition TGWin32VirtualXProxy.cxx:60

Font numbers must be between 1 and 14.

The precision can be:

precision = 0 fast hardware fonts (steps in the size)
precision = 1 scalable and rotatable hardware fonts (see below)
precision = 2 scalable and rotatable hardware fonts
precision = 3 scalable and rotatable hardware fonts. Text size is given in pixels.

The text font and precision of any class inheriting from TAttText can be changed using the method SetTextFont and retrieved using the method GetTextFont.

Font quality and speed

When precision 0 is used, only the original non-scaled X11 system fonts are used. The fonts have a minimum (4) and maximum (37) size in pixels. These fonts are fast and are of good quality. Their size varies with large steps and they cannot be rotated. Precision 1 and 2 fonts have a different behaviour depending if the True Type Fonts (TTF) are used or not. If TTF are used, you always get very good quality scalable and rotatable fonts. These days TTF fonts are rendered fast enough and can be used in all cases.

How to use True Type Fonts

TTF fonts are used by default. They can be deactivated via the following line in the .rootrc file:

Unix.*.Root.UseTTFonts: false

List of the currently supported fonts

Font number      TTF Names                   PostScript/PDF Names
:       "Free Serif Italic"         "Times-Italic"
:       "Free Serif Bold"           "Times-Bold"
:       "Free Serif Bold Italic"    "Times-BoldItalic"
:       "Tex Gyre Regular"          "Helvetica"
:       "Tex Gyre Italic"           "Helvetica-Oblique"
:       "Tex Gyre Bold"             "Helvetica-Bold"
:       "Tex Gyre Bold Italic"      "Helvetica-BoldOblique"
:       "Free Mono"                 "Courier"
:       "Free Mono Oblique"         "Courier-Oblique"
:       "Free Mono Bold"            "Courier-Bold"
:       "Free Mono Bold Oblique"    "Courier-BoldOblique"
:       "Symbol"                    "Symbol"
:       "Free Serif"                "Times-Roman"
:       "Wingdings"                 "ZapfDingbats"

The PostScript and PDF backends use the original PostScript-defined 13 fonts' styles forming four type families (Courier, Helvetica, Times, Symbol) as listed in the "Core Font Set" section of this page. These fonts are always available and do not need to be loaded in the PS or PDF files allowing to keep the files' sizes small.

On screen, text is rendered using free TTF fonts similar to the PDF ones. The corresponding font files are coming with the ROOT distribution in $ROOTSYS/fonts/Free*.

Definition at line 18 of file TAttText.h.

Public Member Functions
	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 TClass *	IsA () const

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 text 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.

virtual void	Streamer (TBuffer &)

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 ()

Protected Attributes
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.

#include <TAttText.h>

Inheritance diagram for TAttText:

[legend]

Constructor & Destructor Documentation

◆ TAttText() [1/2]

TAttText::TAttText ( )

AttText default constructor.

Default text attributes are taken from the current style.

Definition at line 257 of file TAttText.cxx.

◆ TAttText() [2/2]

TAttText::TAttText	(	Int_t	align,
		Float_t	angle,
		Color_t	color,
		Style_t	font,
		Float_t	tsize
	)

AttText normal constructor.

Text attributes are taken from the argument list.

Definition at line 275 of file TAttText.cxx.

◆ ~TAttText()

TAttText::~TAttText ( )

virtual

AttText destructor.

Definition at line 287 of file TAttText.cxx.

Member Function Documentation

◆ Class()

static TClass * TAttText::Class ( )

static

Returns: TClass describing this class

◆ Class_Name()

static const char * TAttText::Class_Name ( )

static

Returns: Name of this class

◆ Class_Version()

static constexpr Version_t TAttText::Class_Version ( )

inlinestaticconstexpr

Returns: Version of this class

Definition at line 50 of file TAttText.h.

◆ Copy()

void TAttText::Copy ( TAttText & atttext ) const

Copy this text attributes to a new TAttText.

Definition at line 294 of file TAttText.cxx.

◆ DeclFileName()

static const char * TAttText::DeclFileName ( )

inlinestatic

Returns: Name of the file containing the class declaration

Definition at line 50 of file TAttText.h.

◆ GetTextAlign()

virtual Short_t TAttText::GetTextAlign ( ) const

inlinevirtual

Return the text alignment.

Reimplemented in TGWin32VirtualXProxy, and TWebPadPainter.

Definition at line 32 of file TAttText.h.

◆ GetTextAngle()

virtual Float_t TAttText::GetTextAngle ( ) const

inlinevirtual

Return the text angle.

Reimplemented in TGWin32VirtualXProxy, and TWebPadPainter.

Definition at line 33 of file TAttText.h.

◆ GetTextColor()

virtual Color_t TAttText::GetTextColor ( ) const

inlinevirtual

Return the text color.

Reimplemented in TGWin32VirtualXProxy, and TWebPadPainter.

Definition at line 34 of file TAttText.h.

◆ GetTextFont()

virtual Font_t TAttText::GetTextFont ( ) const

inlinevirtual

Return the text font.

Reimplemented in TGWin32VirtualXProxy, and TWebPadPainter.

Definition at line 35 of file TAttText.h.

◆ GetTextSize()

virtual Float_t TAttText::GetTextSize ( ) const

inlinevirtual

Return the text size.

Reimplemented in TGWin32VirtualXProxy, and TWebPadPainter.

Definition at line 36 of file TAttText.h.

◆ GetTextSizePercent()

Float_t TAttText::GetTextSizePercent ( Float_t size )

virtual

Return the text in percent of the pad size.

If the font precision is greater than 2, the text size returned is the size in pixel converted into percent of the pad size, otherwise the size returned is the same as the size given as input parameter.

Definition at line 310 of file TAttText.cxx.

◆ IsA()

virtual TClass * TAttText::IsA ( ) const

inlinevirtual

Returns: TClass describing current object

Reimplemented in TStyle, TVirtualPS, TVirtualX, TGCocoa, TGQuartz, TAnnotation, TButton, TDialogCanvas, TGroupButton, TInspectCanvas, TPaveClass, TDiamond, TGaxis, TGraphPolargram, TLatex, TLegend, TLegendEntry, TLink, TMathText, TPaveLabel, TPaveStats, TPavesText, TPaveText, TPie, TText, TGraphNode, TImageDump, TPDF, TPostScript, TSVG, TTeXDump, TGWin32, TGX11, TGX11TTF, TGLAxis, TGLText, TWebPadPainter, TWebPS, and TAxisModLab.

Definition at line 50 of file TAttText.h.

◆ Modify()

void TAttText::Modify ( )

virtual

Change current text attributes if necessary.

Definition at line 329 of file TAttText.cxx.

◆ ResetAttText()

void TAttText::ResetAttText ( Option_t * toption = "" )

virtual

Reset this text attributes to default values.

Reimplemented in TGWin32VirtualXProxy.

Definition at line 361 of file TAttText.cxx.

◆ SaveTextAttributes()

void TAttText::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`
	)

virtual

Save text attributes as C++ statement(s) on output stream out.

Definition at line 373 of file TAttText.cxx.

◆ SetTextAlign()

virtual void TAttText::SetTextAlign ( Short_t align = 11 )

inlinevirtual

Set the text alignment.

Reimplemented in TWebPadPainter, TVirtualX, TGQuartz, TGWin32, TGWin32VirtualXProxy, and TGX11.

Definition at line 42 of file TAttText.h.

◆ SetTextAngle()

virtual void TAttText::SetTextAngle ( Float_t tangle = 0 )

inlinevirtual

Set the text angle.

Reimplemented in TWebPadPainter, TGWin32VirtualXProxy, and TGraphNode.

Definition at line 43 of file TAttText.h.

◆ SetTextAttributes()

void TAttText::SetTextAttributes ( )

virtual

Invoke the DialogCanvas Text attributes.

Reimplemented in TGWin32VirtualXProxy.

Definition at line 400 of file TAttText.cxx.

◆ SetTextColor()

virtual void TAttText::SetTextColor ( Color_t tcolor = 1 )

inlinevirtual

Set the text color.

Reimplemented in TVirtualX, TGQuartz, TGWin32, TGX11, TPDF, TPostScript, TSVG, TTeXDump, TGWin32VirtualXProxy, and TWebPadPainter.

Definition at line 44 of file TAttText.h.

◆ SetTextColorAlpha()

void TAttText::SetTextColorAlpha	(	Color_t	tcolor,
		Float_t	talpha
	)

virtual

Set a transparent text color.

Parameters

tcolor	defines the text color
talpha	defines the percentage of opacity from 0. (fully transparent) to 1. (fully opaque).

Note: talpha is ignored (treated as 1) if the TCanvas has no GL support activated.

Definition at line 412 of file TAttText.cxx.

◆ SetTextFont()

virtual void TAttText::SetTextFont ( Font_t tfont = 62 )

inlinevirtual

Set the text font.

Reimplemented in TVirtualX, TGQuartz, TGWin32, TGX11, TGX11TTF, TGWin32VirtualXProxy, and TWebPadPainter.

Definition at line 46 of file TAttText.h.

◆ SetTextSize()

virtual void TAttText::SetTextSize ( Float_t tsize = 1 )

inlinevirtual

Set the text size.

Reimplemented in TVirtualX, TGQuartz, TGWin32, TGX11, TGX11TTF, TGWin32VirtualXProxy, and TWebPadPainter.

Definition at line 47 of file TAttText.h.

◆ SetTextSizePixels()

void TAttText::SetTextSizePixels ( Int_t npixels )

virtual

Set the text size in pixel.

Set the text size in pixels.

If the font precision is greater than 2, the text size is set to npixels, otherwise the text size is computed as a percent of the pad size.

Reimplemented in TGWin32VirtualXProxy, and TWebPadPainter.

Definition at line 423 of file TAttText.cxx.

◆ Streamer()

virtual void TAttText::Streamer ( TBuffer & )

virtual

Reimplemented in TStyle, TVirtualPS, TVirtualX, TGCocoa, TGQuartz, TAnnotation, TButton, TDialogCanvas, TGroupButton, TInspectCanvas, TPaveClass, TDiamond, TGaxis, TGraphPolargram, TLatex, TLegend, TLegendEntry, TLink, TMathText, TPaveLabel, TPaveStats, TPavesText, TPaveText, TPie, TText, TGraphNode, TImageDump, TPDF, TPostScript, TSVG, TTeXDump, TGWin32, TGX11, TGX11TTF, TGLAxis, TGLText, TWebPadPainter, TWebPS, and TAxisModLab.

◆ StreamerNVirtual()

void TAttText::StreamerNVirtual ( TBuffer & ClassDef_StreamerNVirtual_b )

inline

Definition at line 50 of file TAttText.h.

Member Data Documentation

◆ fTextAlign

Short_t TAttText::fTextAlign

protected

Text alignment.

Definition at line 23 of file TAttText.h.

◆ fTextAngle

Float_t TAttText::fTextAngle

protected

Text angle.

Definition at line 21 of file TAttText.h.

◆ fTextColor

Color_t TAttText::fTextColor

protected

Text color.

Definition at line 24 of file TAttText.h.

◆ fTextFont

Font_t TAttText::fTextFont

protected

Text font.

Definition at line 25 of file TAttText.h.

◆ fTextSize

Float_t TAttText::fTextSize

protected

Text size.

Definition at line 22 of file TAttText.h.

Libraries for TAttText:

[legend]

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

core/base/inc/TAttText.h
core/base/src/TAttText.cxx

Text attributes

Text Alignment

Text Angle

Text Color

Color transparency

Text Size

Text Font and Precision

Font quality and speed

How to use True Type Fonts

List of the currently supported fonts

Public Member Functions

Static Public Member Functions

Protected Attributes

Constructor & Destructor Documentation

◆ TAttText() [1/2]

◆ TAttText() [2/2]

◆ ~TAttText()

Member Function Documentation

◆ Class()

◆ Class_Name()

◆ Class_Version()

◆ Copy()

◆ DeclFileName()

◆ GetTextAlign()

◆ GetTextAngle()

◆ GetTextColor()

◆ GetTextFont()

◆ GetTextSize()

◆ GetTextSizePercent()

◆ IsA()

◆ Modify()

◆ ResetAttText()

◆ SaveTextAttributes()

◆ SetTextAlign()

◆ SetTextAngle()

◆ SetTextAttributes()

◆ SetTextColor()

◆ SetTextColorAlpha()

◆ SetTextFont()

◆ SetTextSize()

◆ SetTextSizePixels()

◆ Streamer()

◆ StreamerNVirtual()

Member Data Documentation

◆ fTextAlign

◆ fTextAngle

◆ fTextColor

◆ fTextFont

◆ fTextSize