gg: handle dpi change, when moving window to another monitor (#20886)

Author: jkvatne

vlib/gg/gg.c.v

@@ -406,6 +406,8 @@ fn gg_event_fn(ce voidptr, user_data voidptr) {
 			}
 		}
 		.resized {
+			ctx.scale = dpi_scale()
+			ctx.ft.scale = ctx.scale
 			if ctx.config.resized_fn != unsafe { nil } {
 				ctx.config.resized_fn(e, ctx.config.user_data)
 			}

vlib/gg/text_rendering.c.v

@@ -16,7 +16,8 @@ pub:
 	font_bold   int
 	font_mono   int
 	font_italic int
-	scale       f32 = 1.0
+pub mut:
+	scale f32 = 1.0
 }
 
 fn new_ft(c FTConfig) ?&FT {