Describe the bug
Dear ROOT developers,
I have encountered a minor issue with the rendering of symbols since v6.32.00. The issue happens when some text (TLatex) on a canvas includes a mathematical symbol (such as #pm or #leq) preceded by a space, and the font is set to 42. In this case, the space preceding the symbol is significantly larger than other spaces in the text.
See the following picture as an example. The text strings rendered in it are
- On the first row:
With space 123 #pm 456 123 < 456 123 #leq 456 - On the second row:
Without space 123#pm456 123<456 123#leq456
As you can see from the picture
- not all symbols are affected (seemingly only those generated by
#sequences, but I have not tested all of them); - there is no extra spacing following the symbols;
- there is no unexpected spacing if there is no space character preceding the symbol.
The problem is also visible in PDF files produced with canvas->Print("file.pdf", "pdf"), as you can see in this file bug_texgyreheros.pdf (13.9 KB).
Expected behavior
In ROOT versions before v6.32, and after the fix described in Additional context, the canvas looks like this.
See also this PDF file bug_texgyreheros_fixed.pdf (13.9 KB).
To Reproduce
gStyle->SetTextFont(42);
gStyle->SetTextSize(0.05);
TCanvas *c = new TCanvas;
TLatex l;
l.DrawLatexNDC(0.1, 0.9, "With space 123 #pm 456 123 < 456 123 #leq 456");
l.DrawLatexNDC(0.1, 0.9, "Without space 123#pm456 123<456 123#leq456");
c->Print("file.png");
c->Print("file.pdf", "pdf");
Setup
ROOT v6.32.02
Built for linuxx8664gcc on Jun 22 2024, 18:26:29
From heads/master@tags/v6-32-02
With c++ (GCC) 14.1.1 20240522
Binary directory: /usr/bin
Running on Arch linux using the official package, version 6.32.02-2.
Additional context
It seems that the bug is related to the adoption of the Tex GyreHeros font, which was done in #14841. If I rebuild the root package (v6.32.02) with the following patch (which reverts the changes to graf2d/graf/src/TTF.cxx) I get the correct behaviour.
diff --color --unified --recursive --text root-6.32.02/graf2d/graf/src/TTF.cxx root-6.32.02.patched/graf2d/graf/src/TTF.cxx
--- root-6.32.02/graf2d/graf/src/TTF.cxx 2024-06-18 05:44:55.000000000 +0200
+++ root-6.32.02.patched/graf2d/graf/src/TTF.cxx 2024-06-27 10:09:52.614987725 +0200
@@ -497,10 +497,10 @@
{ "Root.TTFont.1", "FreeSerifItalic.otf" },
{ "Root.TTFont.2", "FreeSerifBold.otf" },
{ "Root.TTFont.3", "FreeSerifBoldItalic.otf" },
- { "Root.TTFont.4", "texgyreheros-regular.otf" },
- { "Root.TTFont.5", "texgyreheros-italic.otf" },
- { "Root.TTFont.6", "texgyreheros-bold.otf" },
- { "Root.TTFont.7", "texgyreheros-bolditalic.otf" },
+ { "Root.TTFont.4", "FreeSans.otf" },
+ { "Root.TTFont.5", "FreeSansOblique.otf" },
+ { "Root.TTFont.6", "FreeSansBold.otf" },
+ { "Root.TTFont.7", "FreeSansBoldOblique.otf" },
{ "Root.TTFont.8", "FreeMono.otf" },
{ "Root.TTFont.9", "FreeMonoOblique.otf" },
{ "Root.TTFont.10", "FreeMonoBold.otf" },