rendfont.cpp,rendlay.cpp: add font support to <text> components

docs/source/techspecs/layout_files.rst

@@ -515,6 +515,18 @@ text
     be an integer, where 0 (zero) means centred, 1 (one) means left-aligned, and
     2 (two) means right-aligned.  If the ``align`` attribute is absent, the text
     will be centred.
+
+    You can also specify the font to use using the ``font`` attribute. This 
+    contains a comma (``,``)-separated list of fonts to use in order of preference.
+    Font styles (Regular, Bold, Italic,oldItalic) are specified after the font name
+    separated by a vertical bar (``|``).
+
+    There are also three standard fonts available: ``serif``, ``sans-serif``
+    and ``monospace``; these can be given styles as above. Finally there is 
+    ``default`` as a fallback if no other fonts can be found.
+
+    A complex font specification might look like
+    ``font="Helvetica|Regular,Arial|Bold,sans-serif|BoldItalic,default"``
 led7seg
     Draws a standard seven-segment (plus decimal point) digital LED/fluorescent
     display in the specified colour.  The low eight bits of the element’s state

src/emu/rendfont.cpp

@@ -491,7 +491,7 @@ inline render_font::glyph &render_font::get_char(char32_t chnum)
 //  render_font - constructor
 //-------------------------------------------------
 
-render_font::render_font(render_manager &manager, const char *filename)
+render_font::render_font(render_manager &manager, const char *filenames)
 	: m_manager(manager)
 	, m_format(format::UNKNOWN)
 	, m_height(0)
@@ -507,27 +507,39 @@ render_font::render_font(render_manager &manager, const char *filename)
 	memset(m_glyphs_cmd, 0, sizeof(m_glyphs_cmd));
 
 	// if this is an OSD font, we're done
-	if (filename)
+	if (filenames)
 	{
+		std::string_view remaining(filenames);
 		m_osdfont = manager.machine().osd().font_alloc();
-		if (m_osdfont && m_osdfont->open(manager.machine().options().font_path(), filename, m_height))
+
+		while (!remaining.empty())
 		{
-			m_scale = 1.0f / float(m_height);
-			m_format = format::OSD;
+			std::string::size_type const separator = remaining.find(',');
+			std::string filename(remaining.substr(0, separator));
+			LOG("Trying OSD font '%s'\n", filename);
+			remaining = separator != std::string::npos ? remaining.substr(separator + 1) : "";
 
-			//mamep: allocate command glyph font
-			render_font_command_glyph();
-			return;
+			if (m_osdfont && m_osdfont->open(manager.machine().options().font_path(), filename, m_height))
+			{
+				LOG("- Using OSD font '%s'\n", filename);
+				m_scale = 1.0f / float(m_height);
+				m_format = format::OSD;
+
+				//mamep: allocate command glyph font
+				render_font_command_glyph();
+				return;
+			}
 		}
+
 		m_osdfont.reset();
 	}
 
 	// if the filename is 'default' default to 'ui.bdf' for backwards compatibility
-	if (filename && !core_stricmp(filename, "default"))
-		filename = "ui.bdf";
+	if (filenames && !core_stricmp(filenames, "default"))
+		filenames = "ui.bdf";
 
 	// attempt to load an external BDF font first
-	if (filename && load_cached_bdf(filename))
+	if (filenames && load_cached_bdf(filenames))
 	{
 		//mamep: allocate command glyph font
 		render_font_command_glyph();

src/emu/rendlay.cpp

@@ -2476,20 +2476,22 @@ class layout_element::text_component : public component
 	{
 		m_string = env.get_attribute_string(compnode, "string");
 		m_textalign = env.get_attribute_int(compnode, "align", 0);
+		m_font = env.get_attribute_string(compnode, "font", "default");
 	}
 
 protected:
 	// overrides
 	virtual void draw_aligned(running_machine &machine, bitmap_argb32 &dest, const rectangle &bounds, int state) override
 	{
-		auto font = machine.render().font_alloc("default");
+		auto font = machine.render().font_alloc(m_font.c_str());
 		draw_text(*font, dest, bounds, m_string, m_textalign, color(state));
 	}
 
 private:
 	// internal state
 	std::string         m_string;                   // string for text components
 	int                 m_textalign;                // text alignment to box
+	std::string         m_font;                     // the font to use
 };