#include <map>
#include <string>
#include <iostream>
#include <vector>
#include <cmath>
#include "TStyle.h"
#include "TGraph.h"
#include "TGraph2D.h"
#include "TCanvas.h"
#include "TPad.h"
#include "TLatex.h"
#include "TAxis.h"
#include "TList.h"
#include "TH1F.h"
#include "TLegend.h"
#include "TColor.h"
#include "TROOT.h"
#include "TFrame.h"
#include "TTree.h"
#include "TFile.h"
#include "TLine.h"
#include "TMultiGraph.h"
#include "THStack.h"

Functions
Pad and axis histogram creation
std::vector< TPad * >	OnePad ()
	Just creates a single pad filling the entire canvas. More...

std::vector< TPad * >	TwoPadSplit (double split_point, double gap_low, double gap_high)
	Create two pads, split horizontally, on the current canvas split. More...

TH1 *	CreateAxisHist (TH1 *src, double xmin=0, double xmax=-1)
	Create an empty TH1 from another TH1 for drawing the axes. More...

std::vector< TH1 * >	CreateAxisHists (unsigned n, TH1 *src, double xmin=0, double xmax=-1)
	Create multiple axis TH1s from another TH1. More...

TH1 *	CreateAxisHist (TGraph *src, bool at_limits)
	Create an empty TH1 from a TGraph for drawing the axes. More...

std::vector< TH1 * >	CreateAxisHists (unsigned n, TGraph *src, bool at_limits)
	Create multiple axis TH1s from a TGraph. More...

TH1 *	GetAxisHist (TPad *pad)
	Finds the TH1 used to draw the axes on a given TPad. More...

Object extraction and manipulation
TH1 *	MakeRatioHist (TH1 num, TH1 den, bool num_err, bool den_err)
	Create a new histogram by dividing one by the other. More...

TGraph	TGraphFromTree (TTree *tree, TString const &xvar, TString const &yvar, TString const &selection="")
	Create a TGraph from entries in a TTree. More...

TGraph2D	TGraph2DFromTree (TTree *tree, TString const &xvar, TString const &yvar, TString const &zvar, TString const &selection="")
	Create a TGraph2D from entries in a TTree. More...

void	ReZeroTGraph (TGraph *gr)
	Shift all the graph y-values upwards such that there are no negative values and the minimum point is at zero. More...

Plot decoration (colours, styles, text and legends)
int	CreateTransparentColor (int color, float alpha)
	Create a transparent version of a colour. More...

void	SetupTwoPadSplitAsRatio (std::vector< TPad * > const &pads, TH1 upper, TH1 lower, TString y_title, bool y_centered, float y_min, float y_max)
	Set a few style options for a two-pad setup used to show a data-MC comparison and ratio plot. More...

void	SetupTwoPadSplitAsRatio (std::vector< TPad * > const &pads, TString y_title, bool y_centered, float y_min, float y_max)
	Set a few style options for a two-pad setup used to show a data-MC comparison and ratio plot. More...

void	StandardAxes (TAxis xaxis, TAxis yaxis, TString var, TString units)
	Sets standard x- and y-axis titles with given units. More...

void	UnitAxes (TAxis xaxis, TAxis yaxis, TString var, TString units)
	Sets standard x- and y-axis titles when histograms are drawn divided by bin width. More...

TLegend *	PositionedLegend (double width, double height, int pos, double offset)
	Create a legend with fixed height, width and positioning. More...

TLine *	DrawHorizontalLine (TPad pad, TLine line, double yval)
	Use an existing TLine to draw a new horizontal line across the current frame. More...

void	DrawTitle (TPad *pad, TString text, int align)
	Draw text in the top-margin region of a TPad. More...

void	DrawCMSLogo (TPad *pad, TString cmsText, TString extraText, int iPosX, float relPosX, float relPosY, float relExtraDY)
	Draw the CMS logo and subtitle in the new style. More...

void	DrawCMSLogo (TPad *pad, TString cmsText, TString extraText, int iPosX)
	Call DrawCMSLogo with some sensible defaults for the positioning parameters. More...

Axis adjustment and overlap checks
double	GetPadYMax (TPad *pad, double x_min, double x_max)
	Find the maximum value of all drawn objects in a given x-axis range. More...

double	GetPadYMax (TPad *pad)
	Call GetPadYMax(TPad*, double, double) with the full range of the given TPad. More...

void	FixTopRange (TPad *pad, double fix_y, double fraction)
	Adjusts the y-axis maximum on the pad such that the specified y-value is positioned a fixed fraction from this new maximum. More...

void	FixBoxPadding (TPad pad, TBox box, double frac)
	Modify the pad y-axis range to ensure there is at least a given gap between a particular TBox and the highest drawn element in the x-axis range of this box. More...

void	FixOverlay ()
	Just re-draws the axes on the current TPad. More...

Function Documentation

◆ OnePad()

std::vector< TPad * > OnePad ( )

Just creates a single pad filling the entire canvas.

Exists just to provide a similar output interface to TwoPadSplit()

Returns: A vector containing a single pointer to the newly created TPad

Definition at line 459 of file Plotting.h.

◆ TwoPadSplit()

std::vector< TPad * > TwoPadSplit	(	double	split_point,
		double	gap_low,
		double	gap_high
	)

Create two pads, split horizontally, on the current canvas split.

Note that both pads will actually cover the full area of the canvas. We create the appearance of two separated pads by adjusting the top and bottom margins, and then making the background of each pad transparent.

Parameters

split_point	Fraction of the canvas that should be occuplied by the lower pad.
gap_low	The top margin of the lower pad (with respect to the split point), given as a fraction of the input canvas height
gap_high	The bottom margin of the upper pad (with respect to the split point), given as a fraction of the input canvas height

Returns: A vector of pointers to the new pads: [0] = upper, [1] = lower. The current pad (gPad) will be set to the upper one.

Definition at line 468 of file Plotting.h.

◆ CreateAxisHist() [1/2]

TH1 * CreateAxisHist	(	TH1 *	src,
		double	xmin = `0`,
		double	xmax = `-1`
	)

Create an empty TH1 from another TH1 for drawing the axes.

A copy of the input TH1 is made, and all bin contents and errors are removed.

Parameters

src	TH1 input
xmin	adjust the minimum of the drawn range of the x-axis
xmax	adjust the maximum of the drawn range of the x-axis (only if `xmax > xmin`)

Returns: An empty TH1 with axes built from the input TH1

Definition at line 485 of file Plotting.h.

◆ CreateAxisHists() [1/2]

std::vector< TH1 * > CreateAxisHists	(	unsigned	n,
		TH1 *	src,
		double	xmin = `0`,
		double	xmax = `-1`
	)

Create multiple axis TH1s from another TH1.

Just calls CreateAxisHist(TH1*, double, double) multiple times.

Parameters

n	Number of histograms to make
src	TH1 input
xmin	adjust the minimum of the drawn range of the x-axis
xmax	adjust the maximum of the drawn range of the x-axis (only if `xmax > xmin`)

Definition at line 494 of file Plotting.h.

◆ CreateAxisHist() [2/2]

TH1 * CreateAxisHist	(	TGraph *	src,
		bool	at_limits
	)

Create an empty TH1 from a TGraph for drawing the axes.

This function just draws the input TGraph on a temporary TCanvas and extracts the internal TH1 that ROOT creates to do this. In this process the x- and y-axis ranges are computing automatically.

Parameters

src	TGraph input
at_limits	By default the x-axis range will go beyond the min and max x-values found in the TGraph. Set this option to true to fix the range to these min/max values.

Returns: An empty TH1 with axes built from the input TGraph

Definition at line 503 of file Plotting.h.

◆ CreateAxisHists() [2/2]

std::vector< TH1 * > CreateAxisHists	(	unsigned	n,
		TGraph *	src,
		bool	at_limits
	)

Create multiple axis TH1s from a TGraph.

Just calls CreateAxisHist(TGraph*, bool) multiple times.

Parameters

n	Number of histograms to make
src	TGraph input
at_limits	By default the x-axis range will go beyond the min and max x-values found in the TGraph. Set this option to true to fix the range to these min/max values.

Definition at line 528 of file Plotting.h.

◆ GetAxisHist()

TH1 * GetAxisHist ( TPad * pad )

Finds the TH1 used to draw the axes on a given TPad.

Should be able to find a TH1 regardless of whether a TH1, THStack or TGraph was used to define the axes.

Parameters

pad	The TPad to search

Returns: A pointer to the axis TH1 if it exists, a NULL pointer otherwise

Definition at line 536 of file Plotting.h.

◆ MakeRatioHist()

TH1 * MakeRatioHist	(	TH1 *	num,
		TH1 *	den,
		bool	num_err,
		bool	den_err
	)

Create a new histogram by dividing one by the other.

The errors on the two inputs are optionally propagated. Note that these are just combined in quadrature, thus assuming the inputs are uncorrelated. This does not hold for efficiency calculations.

Parameters

num	Numerator histogram
den	Denominator histogram
num_err	Propagate errors on the numerator
den_err	Propagate errors on the denominator

Returns: Pointer to the newly created TH1

Definition at line 567 of file Plotting.h.

◆ TGraphFromTree()

TGraph TGraphFromTree	(	TTree *	tree,
		TString const &	xvar,
		TString const &	yvar,
		TString const &	selection = `""`
	)

Create a TGraph from entries in a TTree.

Note that the graph entries will be filled in whichever order they are found in the TTree. It may be desirable to call TGraph::Sort on the resulting object.

Parameters

tree	Input TTree
xvar	Branch or expression for the x-values
yvar	Branch or expression for the y-values
selection	Optional cut string to apply to each entry

Definition at line 581 of file Plotting.h.

◆ TGraph2DFromTree()

TGraph2D TGraph2DFromTree	(	TTree *	tree,
		TString const &	xvar,
		TString const &	yvar,
		TString const &	zvar,
		TString const &	selection = `""`
	)

Create a TGraph2D from entries in a TTree.

Note that the graph entries will be filled in whichever order they are found in the TTree. It may be desirable to call TGraph::Sort on the resulting object.

Parameters

tree	Input TTree
xvar	Branch or expression for the x-values
yvar	Branch or expression for the y-values
zvar	Branch or expression for the y-values
selection	Optional cut string to apply to each entry

Definition at line 588 of file Plotting.h.

◆ ReZeroTGraph()

void ReZeroTGraph ( TGraph * gr )

Shift all the graph y-values upwards such that there are no negative values and the minimum point is at zero.

Useful for fixing graphs of log-likelihood scans extracted from combine where the true minimum was not found correctly in the initial fit.

Definition at line 595 of file Plotting.h.

◆ CreateTransparentColor()

int CreateTransparentColor	(	int	color,
		float	alpha
	)

Create a transparent version of a colour.

Parameters

color	ROOT colour code
alpha	Transparency (0 = fully transparent, 1 = opaque)

Returns: The code for the new TColor

Definition at line 614 of file Plotting.h.

◆ SetupTwoPadSplitAsRatio() [1/2]

void SetupTwoPadSplitAsRatio	(	std::vector< TPad * > const &	pads,
		TH1 *	upper,
		TH1 *	lower,
		TString	y_title,
		bool	y_centered,
		float	y_min,
		float	y_max
	)

Set a few style options for a two-pad setup used to show a data-MC comparison and ratio plot.

Use this version of the function if the axis histograms haven't been drawn yet. This function will:

remove the x-axis title and labels on the main plot
fix the axis tick-lengths to be consistent between both plots
enable x- and y-axis ticks on the ratio plot
Set the range and title options for the ratio plot y-axis

Parameters

pads	Vector of TPad pointers where [0] = upper pad, [1] = lower pad
upper	Pointer to the upper pad axis TH1
lower	Pointer to the lower pad axis TH1
y_title	Title for the y-axis of the ratio plot
y_centered	Centre (vertically) the y-axis title on the ratio plot.
y_min	Set the y-axis minimum in the ratio plot
y_max	Set the y-axis maximum in the ratio plot

Definition at line 632 of file Plotting.h.

◆ SetupTwoPadSplitAsRatio() [2/2]

void SetupTwoPadSplitAsRatio	(	std::vector< TPad * > const &	pads,
		TString	y_title,
		bool	y_centered,
		float	y_min,
		float	y_max
	)

Set a few style options for a two-pad setup used to show a data-MC comparison and ratio plot.

This function should be called after the axis histograms have been created in both pads (e.g. after some TH1, TGraph etc. has been drawn). It will:

remove the x-axis title and labels on the main plot
fix the axis tick-lengths to be consistent between both plots
enable x- and y-axis ticks on the ratio plot
Set the range and title options for the ratio plot y-axis

Parameters

pads	Vector of TPad pointers where [0] = upper pad, [1] = lower pad
y_title	Title for the y-axis of the ratio plot
y_centered	Centre (vertically) the y-axis title on the ratio plot.
y_min	Set the y-axis minimum in the ratio plot
y_max	Set the y-axis maximum in the ratio plot

Definition at line 623 of file Plotting.h.

◆ StandardAxes()

void StandardAxes	(	TAxis *	xaxis,
		TAxis *	yaxis,
		TString	var,
		TString	units
	)

Sets standard x- and y-axis titles with given units.

Will create an x-axis title of the form <variable> (<units>) and a y-axis title of the form Events / <bin_width> <units>.

Parameters

xaxis	Target x-axis
yaxis	Target y-axis
var	String of the variable name
units	String of the units, e.g. `GeV`. Leave empty if the variable is dimensionless

Definition at line 651 of file Plotting.h.

◆ UnitAxes()

void UnitAxes	(	TAxis *	xaxis,
		TAxis *	yaxis,
		TString	var,
		TString	units
	)

Sets standard x- and y-axis titles when histograms are drawn divided by bin width.

Will create an x-axis title of the form <variable> (<units>) and a y-axis title of the form dN/d<var> (1/<units>).

Parameters

xaxis	Target x-axis
yaxis	Target y-axis
var	String of the variable name
units	String of the units, e.g. `GeV`

Definition at line 664 of file Plotting.h.

◆ PositionedLegend()

TLegend * PositionedLegend	(	double	width,
		double	height,
		int	pos,
		double	offset
	)

Create a legend with fixed height, width and positioning.

Legend will be created in one three fixed positions:

Top-left corner
Top centered
Top-right corner
Bottom-left corner
Bottom centered
Bottom-right corner

Parameters

width	Legend width as a fraction of the pad
height	Legend height as a fraction of the pad
pos	Position index (see above)
offset	Position offset from edges of frame

Returns: Pointer to newly created TLegend

Definition at line 669 of file Plotting.h.

◆ DrawHorizontalLine()

TLine * DrawHorizontalLine	(	TPad *	pad,
		TLine *	line,
		double	yval
	)

Use an existing TLine to draw a new horizontal line across the current frame.

Will find the TH1 used to draw the axes on the pad, get the min/max x-values and then draw a TLine at the specified y-value

Parameters

pad	TPad where the line should be drawn
line	Existing TLine already customised with the desired colour, width and style
yval	The y-value (given in the axis units) where the line should be drawn

Returns: A pointer to the newly created TLine

Definition at line 705 of file Plotting.h.

◆ DrawTitle()

void DrawTitle	(	TPad *	pad,
		TString	text,
		int	align
	)

Draw text in the top-margin region of a TPad.

Specified text will be latex-rendered in one of three positions:

Left aligned with left side of frame
Centre aligned along top of frame
Right aligned with right side of fram

Note also that the text size will be set automatically to fill the top margin areas.

Parameters

pad	Input Tpad
text	Text to draw
align	Alignment option (see above)

Definition at line 713 of file Plotting.h.

◆ DrawCMSLogo() [1/2]

void DrawCMSLogo	(	TPad *	pad,
		TString	cmsText,
		TString	extraText,
		int	iPosX,
		float	relPosX,
		float	relPosY,
		float	relExtraDY
	)

Draw the CMS logo and subtitle in the new style.

Adapted from the example here.

Position setting:

iPos=0  : out of frame
iPos=11 : top-left, left-aligned
iPos=33 : top-right, right-aligned
iPos=22 : center, centered

mode generally :

iPos = 10*(alignement 1/2/3) + position (1/2/3 = left/center/right)

Parameters

pad	The target TPad
cmsText	Usually just "CMS"
extraText	The subtitle, e.g. "Preliminary"
iPosX	Sets the position and alignment of the text (see above)
relPosX	Sets the x-position of the text relative to the frame
relPosY	Sets the y-position of the text relative to the frame
relExtraDY	Sets the position of the extraText relative to the cmsText

Definition at line 744 of file Plotting.h.

◆ DrawCMSLogo() [2/2]

void DrawCMSLogo	(	TPad *	pad,
		TString	cmsText,
		TString	extraText,
		int	iPosX
	)

Call DrawCMSLogo with some sensible defaults for the positioning parameters.

Parameters

pad	The target TPad
cmsText	Usually just "CMS"
extraText	The subtitle, e.g. "Preliminary"
iPosX	Sets the position and alignment of the text

Definition at line 837 of file Plotting.h.

◆ GetPadYMax() [1/2]

double GetPadYMax	(	TPad *	pad,
		double	x_min,
		double	x_max
	)

Find the maximum value of all drawn objects in a given x-axis range.

Currently only objects derived from TH1 and TGraph are examined.

Parameters

pad	TPad to examine
x_min	Minimum x-axis value to start the scan
x_max	Maximum x-axis alue to conclude the scan

Returns: Value on y-axis where the maximum is found

Definition at line 844 of file Plotting.h.

◆ GetPadYMax() [2/2]

double GetPadYMax ( TPad * pad )

Call GetPadYMax(TPad*, double, double) with the full range of the given TPad.

Definition at line 877 of file Plotting.h.

◆ FixTopRange()

void FixTopRange	(	TPad *	pad,
		double	fix_y,
		double	fraction
	)

Adjusts the y-axis maximum on the pad such that the specified y-value is positioned a fixed fraction from this new maximum.

Should work for both linear and log-scale y-axes. This function is most useful in conjunction with GetPadYMax() to supply the y-axis value to fix, thus ensuring that a fixed fraction at the top of the frame is free of any histogram or graph.

Parameters

pad	TPad to adjust
fix_y	The position on the y-axis that will be fixed
fraction	The fraction of the y-axis that fix_y should be positioned (measured from the top of the frame)

Definition at line 885 of file Plotting.h.

◆ FixBoxPadding()

void FixBoxPadding	(	TPad *	pad,
		TBox *	box,
		double	frac
	)

Modify the pad y-axis range to ensure there is at least a given gap between a particular TBox and the highest drawn element in the x-axis range of this box.

Most useful after drawing a legend somewhere near the top of the frame, which may have overlapped with some of the histograms or graphs that had already been drawn. This function will check for the overlap, then adjust the y-axis range to ensure there is a gap. Note that if a sufficient (or larger) gap already exists, the y-axis range will not be adujusted.

Parameters

pad	TPad to modify
box	Pointer to the reference TBox (e.g. could be a TLegend)
frac	Desired fraction of the frame height between the bottom of the TBox and the top of the drawn objects.

Definition at line 902 of file Plotting.h.

◆ FixOverlay()

void FixOverlay ( )

Just re-draws the axes on the current TPad.

Definition at line 945 of file Plotting.h.

Functions

Function Documentation

◆ OnePad()

◆ TwoPadSplit()

◆ CreateAxisHist() [1/2]

◆ CreateAxisHists() [1/2]

◆ CreateAxisHist() [2/2]

◆ CreateAxisHists() [2/2]

◆ GetAxisHist()

◆ MakeRatioHist()

◆ TGraphFromTree()

◆ TGraph2DFromTree()

◆ ReZeroTGraph()

◆ CreateTransparentColor()

◆ SetupTwoPadSplitAsRatio() [1/2]

◆ SetupTwoPadSplitAsRatio() [2/2]

◆ StandardAxes()

◆ UnitAxes()

◆ PositionedLegend()

◆ DrawHorizontalLine()

◆ DrawTitle()

◆ DrawCMSLogo() [1/2]

◆ DrawCMSLogo() [2/2]

◆ GetPadYMax() [1/2]

◆ GetPadYMax() [2/2]

◆ FixTopRange()

◆ FixBoxPadding()

◆ FixOverlay()