examples: simpify text rendering examples

examples/gg/rectangles.v

@@ -0,0 +1,52 @@
+module main
+
+import gg
+import gx
+import os
+
+const (
+	win_width = 600
+	win_height = 300
+)
+
+struct App {
+mut:
+	gg &gg.Context
+}
+
+fn main() {
+	mut app := &App{}
+	app.gg = gg.new_context(
+		bg_color: gx.white
+		width: win_width
+		height: win_height
+		use_ortho: true // This is needed for 2D drawing
+		create_window: true
+		window_title: 'Empty window'
+		frame_fn: frame
+		user_data: app
+		//font_path: os.resource_abs_path('assets/fonts/RobotoMono-Regular.ttf')
+	)
+	app.gg.run()
+}
+
+fn frame(user_data voidptr) {
+	mut app := &App(user_data)
+	mut gg := app.gg
+	gg.begin()
+	/*
+	if gg.fons == 0 {
+		gg.init_font()
+	}
+	*/
+	app.draw()
+	//C.sfons_flush(gg.fons)
+	gg.end()
+}
+
+fn (app &App) draw() {
+	//app.gg.draw_text_def(200,20, 'hello world!')
+	//app.gg.draw_text_def(300,300, 'привет')
+	app.gg.draw_rect(10, 10, 100, 30, gx.blue)
+	app.gg.draw_empty_rect(10, 150, 80, 40, gx.green)
+}