To draw a graph "g" is enough to do:
g->Draw("AL");The option "AL" in the Draw() method means that the axis syetem should be define (option "A") and that the graph should be drawn as a simple line (option "L"). By default a graph is drawn in the current pad in the current coordinates system. To define a suitable coordinates system and drawn the axis the option "A" must be specified.
TGraphPainter offers many options to paint the various kind of graphs.
The TGraphPainter class specializes in the drawing of graphs. It is separated from the graph so that one can have graphs without the graphics overhead, for example in a batch program.
When a displayed graph is modified, there is not need to call the Draw() method again; the image will be refreshed the next time the pad will be updated.
A pad is updated after one of these three actions:
"A" | Axis are drawn around the graph |
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"L" | A simple polyline between every points is drawn |
"F" | A fill area is drawn ('CF' draw a smooth fill area) |
"C" | A smooth Curve is drawn |
"*" | A Star is plotted at each point |
"P" | Idem with the current marker |
"B" | A Bar chart is drawn at each point |
"1" | ylow=rwymin |
"X+" | The X-axis is drawn on the top side of the plot. |
"Y+" | The Y-axis is drawn on the right side of the plot. |
Several drawing options can be combined. In the following example the graph is drawn as a smooth curve (optiob "C") and with markers (option "P"). The option "A" request the definition of the axis.
{ TCanvas *c1 = new TCanvas("c1","c1",200,10,600,400); c1->SetFillColor(42); c1->SetGrid(); const Int_t n = 20; Double_t x[n], y[n]; for (Int_t i=0;i<n;i++) { x[i] = i*0.1; y[i] = 10*sin(x[i]+0.2); } gr = new TGraph(n,x,y); gr->SetLineColor(2); gr->SetLineWidth(4); gr->SetMarkerColor(4); gr->SetMarkerSize(1.5); gr->SetMarkerStyle(21); gr->SetTitle("Option ACP example"); gr->GetXaxis()->SetTitle("X title"); gr->GetYaxis()->SetTitle("Y title"); gr->Draw("ACP"); // TCanvas::Update() draws the frame, after which one can change it c1->Update(); c1->GetFrame()->SetFillColor(21); c1->GetFrame()->SetBorderSize(12); c1->Modified(); return c1; }
This drawing mode is activated when the absolute value of the graph line width (set thanks to SetLineWidth()) is greater than 99. In that case the line width number is interpreted as:
100*ff+ll = ffll
TCanvas *exclusiongraph() { // Draw three graphs with an exclusion zone. //Author: Olivier Couet TCanvas *c1 = new TCanvas("c1","Exclusion graphs examples",200,10,600,400); c1->SetGrid(); TMultiGraph *mg = new TMultiGraph(); mg->SetTitle("Exclusion graphs"); const Int_t n = 35; Double_t x1[n], x2[n], x3[n], y1[n], y2[n], y3[n]; for (Int_t i=0;i<n;i++) { x1[i] = i*0.1; x2[i] = x1[i]; x3[i] = x1[i]+.5; y1[i] = 10*sin(x1[i]); y2[i] = 10*cos(x1[i]); y3[i] = 10*sin(x1[i])-2; } TGraph *gr1 = new TGraph(n,x1,y1); gr1->SetLineColor(2); gr1->SetLineWidth(1504); gr1->SetFillStyle(3005); TGraph *gr2 = new TGraph(n,x2,y2); gr2->SetLineColor(4); gr2->SetLineWidth(-2002); gr2->SetFillStyle(3004); gr2->SetFillColor(9); TGraph *gr3 = new TGraph(n,x3,y3); gr3->SetLineColor(5); gr3->SetLineWidth(-802); gr3->SetFillStyle(3002); gr3->SetFillColor(2); mg->Add(gr1); mg->Add(gr2); mg->Add(gr3); mg->Draw("AC"); return c1; }
"Z" | By default horizonthal and vertical small lines are drawn at the end of the error bars. If option "z" or "Z" is specified, these lines are not drawn. |
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">" | An arrow is drawn at the end of the error bars. The size of the arrow is set to 2/3 of the marker size. |
"|>" | A filled arrow is drawn at the end of the error bars. The size of the arrow is set to 2/3 of the marker size. |
"X" | By default the error bars are drawn. If option "X" is specified, the errors are not drawn. The graph with errors in drawn like a normal graph. |
"||" | Only the end vertical/horizonthal lines of the error bars are drawn. This option is interesting to superimpose systematic errors on top of a graph with statistical errors. |
"[]" | Does the same as option "||" except that it draws additionnal tick marks at the end of the vertical/horizonthal lines. This makes less ambiguous plots in case several graphs are drawn on the same picture. |
"2" | Error rectangles are drawn. |
"3" | A filled area is drawn through the end points of the vertical error bars. |
"4" | A smoothed filled area is drawn through the end points of the vertical error bars. |
gStyle->SetErrorX(dx) controls the size of the error along x. dx = 0 removes the error along x.
gStyle->SetEndErrorSize(np) controls the size of the lines at the end of the error bars (when option 1 is used). By default np=1. (np represents the number of pixels).
{ TCanvas *c4 = new TCanvas("c4","c4",200,10,600,400); double x[] = {0, 1, 2, 3, 4}; double y[] = {0, 2, 4, 1, 3}; double ex[] = {0.1, 0.2, 0.3, 0.4, 0.5}; double ey[] = {1, 0.5, 1, 0.5, 1}; TGraphErrors* ge = new TGraphErrors(5, x, y, ex, ey); ge->Draw("ap"); return c4; }
The option "3" allows to shows the error as band.
{ TCanvas *c41 = new TCanvas("c41","c41",200,10,600,400); double x[] = {0, 1, 2, 3, 4}; double y[] = {0, 2, 4, 1, 3}; double ex[] = {0.1, 0.2, 0.3, 0.4, 0.5}; double ey[] = {1, 0.5, 1, 0.5, 1}; TGraphErrors* ge = new TGraphErrors(5, x, y, ex, ey); ge->SetFillColor(4); ge->SetFillStyle(3010); ge->Draw("a3"); return c41; }
The option "4" is similar to the option "3" except that the band is smoothed. As the following picture shows, this option should be used carefuly because the smoothing algorithm may show some (huge) "bouncing" effects. In some case looks nicer than the option "3" (because it is smooth) but it can be misleading.
{ TCanvas *c42 = new TCanvas("c42","c42",200,10,600,400); double x[] = {0, 1, 2, 3, 4}; double y[] = {0, 2, 4, 1, 3}; double ex[] = {0.1, 0.2, 0.3, 0.4, 0.5}; double ey[] = {1, 0.5, 1, 0.5, 1}; TGraphErrors* ge = new TGraphErrors(5, x, y, ex, ey); ge->SetFillColor(6); ge->SetFillStyle(3005); ge->Draw("a4"); return c42; }
The following example shows how the option "[]" can be used to superimpose systematic errors on top of a graph with statistical errors.
{ TCanvas *c43 = new TCanvas("c43","c43",200,10,600,400); c43->DrawFrame(0., -0.5, 6., 2); double x[5] = {1, 2, 3, 4, 5}; double zero[5] = {0, 0, 0, 0, 0}; // data set (1) with stat and sys errors double y1[5] = {1.2, 1.15, 1.19, 0.9, 1.4}; double ey_stat1[5] = {0.2, 0.18, 0.17, 0.2, 0.4}; double ey_sys1[5] = {0.5, 0.71, 0.76, 0.5, 0.45}; // data set (2) with stat and sys errors double y2[5] = {0.25, 0.18, 0.29, 0.2, 0.21}; double ey_stat2[5] = {0.2, 0.18, 0.17, 0.2, 0.4}; double ey_sys2[5] = {0.63, 0.19, 0.7, 0.2, 0.7}; // Now draw data set (1) // We first have to draw it only with the stat errors TGraphErrors *graph1 = new TGraphErrors(5, x, y1, zero, ey_stat1); graph1->SetMarkerStyle(20); graph1->Draw("P"); // Now we have to somehow depict the sys errors TGraphErrors *graph1_sys = new TGraphErrors(5, x, y1, zero, ey_sys1); graph1_sys->Draw("[]"); // Now draw data set (2) // We first have to draw it only with the stat errors TGraphErrors *graph2 = new TGraphErrors(5, x, y2, zero, ey_stat2); graph2->SetMarkerStyle(24); graph2->Draw("P"); // Now we have to somehow depict the sys errors TGraphErrors *graph2_sys = new TGraphErrors(5, x, y2, zero, ey_sys2); graph2_sys->Draw("[]"); return c43; }
{ TCanvas *c2 = new TCanvas("c2","c2",200,10,600,400); double ax[] = {0, 1, 2, 3, 4}; double ay[] = {0, 2, 4, 1, 3}; double aexl[] = {0.1, 0.2, 0.3, 0.4, 0.5}; double aexh[] = {0.5, 0.4, 0.3, 0.2, 0.1}; double aeyl[] = {1, 0.5, 1, 0.5, 1}; double aeyh[] = {0.5, 1, 0.5, 1, 0.5}; TGraphAsymmErrors* gae = new TGraphAsymmErrors(5, ax, ay, aexl, aexh, aeyl, aeyh); gae->SetFillColor(2); gae->SetFillStyle(3001); gae->Draw("a2"); gae->Draw("p"); return c2; }
{ TCanvas *c3 = new TCanvas("c3","c3",200,10,600,400); const Int_t n = 10; Double_t x[n] = {-0.22, 0.05, 0.25, 0.35, 0.5, 0.61,0.7,0.85,0.89,0.95}; Double_t y[n] = {1,2.9,5.6,7.4,9,9.6,8.7,6.3,4.5,1}; Double_t exl[n] = {.05,.1,.07,.07,.04,.05,.06,.07,.08,.05}; Double_t eyl[n] = {.8,.7,.6,.5,.4,.4,.5,.6,.7,.8}; Double_t exh[n] = {.02,.08,.05,.05,.03,.03,.04,.05,.06,.03}; Double_t eyh[n] = {.6,.5,.4,.3,.2,.2,.3,.4,.5,.6}; Double_t exld[n] = {.0,.0,.0,.0,.0,.0,.0,.0,.0,.0}; Double_t eyld[n] = {.0,.0,.05,.0,.0,.0,.0,.0,.0,.0}; Double_t exhd[n] = {.0,.0,.0,.0,.0,.0,.0,.0,.0,.0}; Double_t eyhd[n] = {.0,.0,.0,.0,.0,.0,.0,.0,.05,.0}; TGraphBentErrors *gr = new TGraphBentErrors(n,x,y,exl,exh,eyl,eyh,exld,exhd,eyld,eyhd); gr->SetTitle("TGraphBentErrors Example"); gr->SetMarkerColor(4); gr->SetMarkerStyle(21); gr->Draw("ALP"); return c3; }
"O" | Polar labels are paint orthogonally to the polargram radius. |
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"P" | Polymarker are paint at each point position. |
"E" | Paint error bars. |
"F" | Paint fill area (closed polygon). |
"A" | Force axis redrawing even if a polargram already exists. |
"N" | Disable the display of the polar labels. |
{ TCanvas *c1 = new TCanvas("c1","c1",500,500); TGraphPolar * grP1 = new TGraphPolar(); grP1->SetTitle("TGraphPolar example"); grP1->SetPoint(0, (1*TMath::Pi())/4., 0.05); grP1->SetPoint(1, (2*TMath::Pi())/4., 0.10); grP1->SetPoint(2, (3*TMath::Pi())/4., 0.15); grP1->SetPoint(3, (4*TMath::Pi())/4., 0.20); grP1->SetPoint(4, (5*TMath::Pi())/4., 0.25); grP1->SetPoint(5, (6*TMath::Pi())/4., 0.30); grP1->SetPoint(6, (7*TMath::Pi())/4., 0.35); grP1->SetPoint(7, (8*TMath::Pi())/4., 0.40); grP1->SetMarkerStyle(20); grP1->SetMarkerSize(1.); grP1->SetMarkerColor(4); grP1->SetLineColor(4); grP1->Draw("ALP"); // Update, otherwise GetPolargram returns 0 c1->Update(); grP1->GetPolargram()->SetToRadian(); return c1; }
virtual void | TObject::DoError(int level, const char* location, const char* fmt, va_list va) const |
void | TObject::MakeZombie() |
enum TObject::EStatusBits { | kCanDelete | |
kMustCleanup | ||
kObjInCanvas | ||
kIsReferenced | ||
kHasUUID | ||
kCannotPick | ||
kNoContextMenu | ||
kInvalidObject | ||
}; | ||
enum TObject::[unnamed] { | kIsOnHeap | |
kNotDeleted | ||
kZombie | ||
kBitMask | ||
kSingleKey | ||
kOverwrite | ||
kWriteDelete | ||
}; |
Compute the lorarithm of global variables gxwork and gywork according to the value of Options and put the results in the global variables gxworkl and gyworkl.
npoints : Number of points in gxwork and in gywork.
Compute distance from point px,py to a graph.
Compute the closest distance of approach from point px,py to this line. The distance is computed in pixels units.
Execute action corresponding to one event.
This member function is called when a graph is clicked with the locator.
If the left mouse button is clicked on one of the line end points, this point follows the cursor until button is released.
If the middle mouse button clicked, the line is moved parallel to itself until the button is released.
This method is used by THistPainter to paint 1D histograms.
Input parameters:
The aspect of the graph is done according to the value of the chopt.
"R" | Graph is drawn horizontaly, parallel to X axis. // (default is vertically, parallel to Y axis) // If option R is selected the user must give: // 2 values for Y (y[0]=YMIN and y[1]=YMAX) // N values for X, one for each channel. // Otherwise the user must give: // N values for Y, one for each channel. // 2 values for X (x[0]=XMIN and x[1]=XMAX) |
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"L" | A simple polyline beetwen every points is drawn |
"H" | An Histogram with equidistant bins is drawn as a polyline. |
"F" | An histogram with equidistant bins is drawn as a fill area. Contour is not drawn unless chopt='H' is also selected.. |
"N" | Non equidistant bins (default is equidistant) If N is the number of channels array X and Y must be dimensionned as follow: If option R is not selected (default) then the user must give: (N+1) values for X (limits of channels). N values for Y, one for each channel. Otherwise the user must give: (N+1) values for Y (limits of channels). N values for X, one for each channel. |
"F1" | Idem as 'F' except that fill area is no more reparted arround axis X=0 or Y=0 . |
"F2" | Draw a Fill area polyline connecting the center of bins |
"C" | A smooth Curve is drawn. |
"*" | A Star is plotted at the center of each bin. |
"P" | Idem with the current marker |
"P0" | Idem with the current marker. Empty bins also drawn |
"B" | A Bar chart with equidistant bins is drawn as fill areas (Contours are drawn). |
"9" | Force graph to be drawn in high resolution mode. By default, the graph is drawn in low resolution in case the number of points is greater than the number of pixels in the current pad. |
"][" | "Cutoff" style. When this option is selected together with H option, the first and last vertical lines of the histogram are not drawn. |
Paint this graphQQ. No options for the time being.
Paint a simple graph, without errors bars.
Paint a polyline with hatches on one side showing an exclusion zone. x and y are the the vectors holding the polyline and n the number of points in the polyline and w the width of the hatches. w can be negative. This method is not meant to be used directly. It is called automatically according to the line style convention.
Smooth a curve given by N points.
The original code come from an underlaying routine for Draw based on the CERN GD3 routine TVIPTE:
Author - Marlow etc. Modified by - P. Ward Date - 3.10.1973This method draws a smooth tangentially continuous curve through the sequence of data points P(I) I=1,N where P(I)=(X(I),Y(I)) the curve is approximated by a polygonal arc of short vectors . the data points can represent open curves, P(1) != P(N) or closed curves P(2) == P(N) . If a tangential discontinuity at P(I) is required , then set P(I)=P(I+1) . loops are also allowed .
Reference Marlow and Powell,Harwell report No.R.7092.1972 MCCONALOGUE,Computer Journal VOL.13,NO4,NOV1970Pp392 6