Prevent unwanted font face changes

When a character appears in the text, that is not in the default font
face, it is looked up in the spare faces of the font. Moreover, the
default range also began to be baked from the spare face. I made that
only characters that are not in the default face are baked from the
spare face.

src/pigui/PiGui.cpp

@@ -122,16 +122,16 @@ Instance::Instance() :
 	// TODO: clang-format doesn't like list initializers inside function calls
 	// clang-format off
 	PiFont uiheading("orbiteer", {
+		PiFace("Orbiteer-Bold.ttf", 1.0), // imgui only supports 0xffff, not 0x10ffff
 		PiFace("DejaVuSans.ttf", /*18.0/20.0*/ 1.2),
-		PiFace("wqy-microhei.ttc", 1.0),
-		PiFace("Orbiteer-Bold.ttf", 1.0) // imgui only supports 0xffff, not 0x10ffff
+		PiFace("wqy-microhei.ttc", 1.0)
 	});
 	AddFontDefinition(uiheading);
 
 	PiFont guifont("pionillium", {
+		PiFace("PionilliumText22L-Medium.ttf", 1.0),
 		PiFace("DejaVuSans.ttf", 13.0 / 14.0),
-		PiFace("wqy-microhei.ttc", 1.0),
-		PiFace("PionilliumText22L-Medium.ttf", 1.0)
+		PiFace("wqy-microhei.ttc", 1.0)
 	});
 	AddFontDefinition(guifont);
 	// clang-format on
@@ -199,7 +199,8 @@ ImFont *Instance::AddFont(const std::string &name, int size)
 
 	PiFont &pifont = iter->second;
 	pifont.setPixelsize(size);
-	pifont.faces().back().addGlyph(0x20); // only add space
+	// only add space to the first face, this will be the default face, faces without ranges are not baked
+	pifont.faces()[0].addGlyph(0x20);
 	m_pi_fonts[std::make_pair(name, size)] = pifont;
 
 	m_should_bake_fonts = true;