So I’m trying to use Root to graph a bunch of functions and points, and then label these points. I’m following the graphtext.C example (cannot link to it due to new user restrictions), but my labels don’t seem to be showing up at all.
I suspect that I might be running into an issue between user coordinates and the large scale of my data (moreover, I’m using log axes). When I try to paint the labels using NCD coordinates they show up fine, but converting from user coordinates to NCD coordinates seems to be discouraged, and moreover it’s pretty difficult and tedious to hunt for the correct scaling factors.
Here is a SCCE that avoids some of the complixities of plotting a whole bunch of curves and finding the proper graph buried in the multigraph. Just trying to label some points on a log-log graph and failing.
void drawtext() {
int i,n;
double x,y;
TText t;
t.SetTextAlign(13);
t.SetTextColor(kBlue);
t.SetTextFont(43);
t.SetTextSize(10000); // I don't know where the limit is, but much larger than this results in an error
auto g = (TGraph*)gPad->GetPrimitive("Points");
n = g->GetN();
const char * labels[] = {"Reactor", "Experiment (torus)", "Experiment (pinch)", "Ionosphere", "Radiofreq plasma", "Flame", "Laser", "Space"};
for (i=0; i<n; i++) {
g->GetPoint(i,x,y);
t.PaintText(x, y, labels[i]);
}
}
void scce() {
const double xmin = 1e6;
const double xmax = 1e28;
const double ymin = 1e-2;
const double ymax = 1e5;
auto cv = new TCanvas("cv", "cv", 1920, 1200);
cv->SetLogx();
cv->SetLogy();
cv->SetGrid();
// plasma points
const int point_count = 8;
const double ns[point_count] = {1e20, 1e19, 1e23, 1e11, 1e17, 1e14, 1e25, 1e6};
const double ts[point_count] = {3e4, 100, 1000, 0.05, 1.5, 0.1, 100, 0.01};
auto *g_points = new TGraph();
g_points->SetName("Points");
auto ex = new TExec("ex", "drawtext();");
g_points->GetListOfFunctions()->Add(ex);
g_points->SetTitle("Various Example Plasmas");
g_points->SetMarkerStyle(20);
for (int i = 0; i < point_count; ++i) {
g_points->SetPoint(i, ns[i], ts[i]);
}
g_points->GetXaxis()->SetLimits(xmin, xmax);
g_points->SetMinimum(ymin);
g_points->SetMaximum(ymax);
g_points->Draw("AP");
}
Note: I have also tried taking the log10 of both x and y before drawing the text, but that doesn’t seem to affect things.
ROOT Version: 6.24/06
Platform: Linux
Compiler: GCC 11.3.0