Cannot modify font used to render charts

[TheGreatRambler]

Bug category

• bug - compilation error
• bug - compilation warning
• bug - runtime error
• bug - runtime warning
• bug - logic error

Describe the bug
The font cannot be modified, and on Windows compiled with MinGW64 it incorrectly sets Helvetica and doesn't render any text in the affected charts (pie chart, word cloud, etc).

Steps to Reproduce

	auto ax = figure->current_axes ();
	ax->font ("Hack");
	figure->save (path, "png");

# Your steps go here
make build -j8

Output

gdImageStringFT: fontconfig: Didn't find expected font family. Perhaps URW Type 1 fonts need installing? while printing string Larry with font Helvetica
gdImageStringFT: fontconfig: Didn't find expected font family. Perhaps URW Type 1 fonts need installing? while printing string Wendy with font Helvetica
gdImageStringFT: fontconfig: Didn't find expected font family. Perhaps URW Type 1 fonts need installing? while printing string Iggy with font Helvetica
gdImageStringFT: fontconfig: Didn't find expected font family. Perhaps URW Type 1 fonts need installing? while printing string Roy with font Helvetica
gdImageStringFT: fontconfig: Didn't find expected font family. Perhaps URW Type 1 fonts need installing? while printing string Ludwig with font Helvetica
gdImageStringFT: fontconfig: Didn't find expected font family. Perhaps URW Type 1 fonts need installing? while printing string Cannon Box with font Helvetica
gdImageStringFT: fontconfig: Didn't find expected font family. Perhaps URW Type 1 fonts need installing? while printing string Propeller Box with font Helvetica
gdImageStringFT: fontconfig: Didn't find expected font family. Perhaps URW Type 1 fonts need installing? while printing string Goomba Mask with font Helvetica
gdImageStringFT: fontconfig: Didn't find expected font family. Perhaps URW Type 1 fonts need installing? while printing string Bullet Bill Mask with font Helvetica
gdImageStringFT: fontconfig: Didn't find expected font family. Perhaps URW Type 1 fonts need installing? while printing string Red POW Box with font Helvetica
gdImageStringFT: fontconfig: Didn't find expected font family. Perhaps URW Type 1 fonts need installing? while printing string ON/OFF Trampoline with font Helvetica
etc...

Platform

• cross-platform issue - linux
• cross-platform issue - windows
• cross-platform issue - macos

Environment Details:

• OS: Windows 10
• OS Version: 21H2
• Compiler: MinGW64 GCC
• Compiler version: 11.2.0

[alandefreitas]

Maybe try to use this font directly with Gnuplot and see what happens?