gg: allow fonts loaded with $embed_file() to be used (#8263)

examples/snek/snek.v

@@ -3,7 +3,6 @@ import gx
 import sokol.sapp
 import time
 import rand
-import os
 
 // constants
 const (
@@ -37,11 +36,11 @@ enum Direction {
 
 struct App {
 mut:
-	gg    &gg.Context
+	gg         &gg.Context
-	score int
+	score      int
-	snake []Pos
+	snake      []Pos
-	dir   Direction
+	dir        Direction
-	food  Pos
+	food       Pos
 	start_time i64
 	last_tick  i64
 }
@@ -166,6 +165,8 @@ fn on_frame(mut app App) {
 	app.gg.end()
 }
 
+const font = $embed_file('../assets/fonts/RobotoMono-Regular.ttf')
+
 // setup
 fn main() {
 	mut app := App{
@@ -173,6 +174,11 @@ fn main() {
 	}
 	app.reset_game()
 
+	mut font_copy := font
+	font_bytes := unsafe {
+		font_copy.data().vbytes(font_copy.len)
+	}
+
 	app.gg = gg.new_context(
 		bg_color: gx.white
 		frame_fn: on_frame
@@ -184,7 +190,7 @@ fn main() {
 		create_window: true
 		resizable: false
 		window_title: 'snek'
-		font_path: os.resource_abs_path(os.join_path('../assets/fonts/', 'RobotoMono-Regular.ttf'))
+		font_bytes_normal: font_bytes
 	)
 
 	app.gg.run()

vlib/gg/gg.v

@@ -60,6 +60,11 @@ pub:
 	font_path             string
 	custom_bold_font_path string
 	ui_mode               bool // refreshes only on events to save CPU usage
+	// font bytes for embedding
+	font_bytes_normal []byte
+	font_bytes_bold   []byte
+	font_bytes_mono   []byte
+	font_bytes_italic []byte
 }
 
 pub struct Context {
@@ -131,14 +136,25 @@ fn gg_init_sokol_window(user_data voidptr) {
 		g.font_inited = true
 	} else {
 		if !exists {
-			sfont := system_font_path()
+			if g.config.font_bytes_normal.len > 0 {
-			eprintln('font file "$g.config.font_path" does not exist, the system font was used instead.')
+				g.ft = new_ft(
-			g.ft = new_ft(
+					bytes_normal: g.config.font_bytes_normal
-				font_path: sfont
+					bytes_bold: g.config.font_bytes_bold
-				custom_bold_font_path: g.config.custom_bold_font_path
+					bytes_mono: g.config.font_bytes_mono
-				scale: sapp.dpi_scale()
+					bytes_italic: g.config.font_bytes_italic
-			) or { panic(err) }
+					scale: sapp.dpi_scale()
-			g.font_inited = true
+				) or { panic(err) }
+				g.font_inited = true
+			} else {
+				sfont := system_font_path()
+				eprintln('font file "$g.config.font_path" does not exist, the system font was used instead.')
+				g.ft = new_ft(
+					font_path: sfont
+					custom_bold_font_path: g.config.custom_bold_font_path
+					scale: sapp.dpi_scale()
+				) or { panic(err) }
+				g.font_inited = true
+			}
 		}
 	}
 	//
@@ -237,7 +253,7 @@ pub fn new_context(cfg Config) &Context {
 		width: cfg.width
 		height: cfg.height
 		config: cfg
-		render_text: cfg.font_path != ''
+		render_text: cfg.font_path != '' || cfg.font_bytes_normal.len > 0
 		ft: 0
 		ui_mode: cfg.ui_mode
 	}

vlib/gg/text_rendering.v

@@ -29,11 +29,51 @@ struct FTConfig {
 	custom_bold_font_path string
 	scale                 f32 = 1.0
 	font_size             int
+	bytes_normal          []byte
+	bytes_bold            []byte
+	bytes_mono            []byte
+	bytes_italic          []byte
 }
 
 fn new_ft(c FTConfig) ?&FT {
 	if c.font_path == '' {
-		// Load default font
+		if c.bytes_normal.len > 0 {
+			fons := sfons.create(512, 512, 1)
+			bytes_normal := c.bytes_normal
+			bytes_bold := if c.bytes_bold.len > 0 {
+				c.bytes_bold
+			} else {
+				debug_font_println('setting bold variant to normal')
+				bytes_normal
+			}
+			bytes_mono := if c.bytes_mono.len > 0 {
+				c.bytes_mono
+			} else {
+				debug_font_println('setting mono variant to normal')
+				bytes_normal
+			}
+			bytes_italic := if c.bytes_italic.len > 0 {
+				c.bytes_italic
+			} else {
+				debug_font_println('setting italic variant to normal')
+				bytes_normal
+			}
+
+			return &FT{
+				fons: fons
+				font_normal: C.fonsAddFontMem(fons, 'sans', bytes_normal.data, bytes_normal.len,
+					false)
+				font_bold: C.fonsAddFontMem(fons, 'sans', bytes_bold.data, bytes_bold.len,
+					false)
+				font_mono: C.fonsAddFontMem(fons, 'sans', bytes_mono.data, bytes_mono.len,
+					false)
+				font_italic: C.fonsAddFontMem(fons, 'sans', bytes_italic.data, bytes_italic.len,
+					false)
+				scale: c.scale
+			}
+		} else {
+			// Load default font
+		}
 	}
 	$if !android {
 		if c.font_path == '' || !os.exists(c.font_path) {
@@ -144,7 +184,8 @@ pub fn (ctx &Context) text_width(s string) int {
 	mut buf := [4]f32{}
 	C.fonsTextBounds(ctx.ft.fons, 0, 0, s.str, 0, buf)
 	if s.ends_with(' ') {
-		return int((buf[2] - buf[0]) / ctx.scale) + ctx.text_width('i') // TODO fix this in fontstash?
+		return int((buf[2] - buf[0]) /
+			ctx.scale) + ctx.text_width('i') // TODO fix this in fontstash?
 	}
 	return int((buf[2] - buf[0]) / ctx.scale)
 }