start with text filter

src/filter/mod.rs

@@ -1,5 +1,6 @@
 use std::path::Path;
 
+use regex::Regex;
 use simplelog::*;
 
 use crate::utils::{is_close, GlobalConfig, Media};
@@ -191,6 +192,35 @@ fn extend_video(node: &mut Media, chain: &mut Filters) {
     }
 }
 
+fn add_text(node: &mut Media, chain: &mut Filters, config: &GlobalConfig) {
+    // add drawtext filter for lower thirds messages
+
+    if config.text.add_text && config.text.over_pre {
+        let mut font: String = "".to_string();
+        let filter: String;
+
+        if Path::new(&config.text.fontfile).is_file() {
+            font = format!(":fontfile='{}'", config.text.fontfile)
+        }
+
+        if config.text.text_from_filename {
+            let source = node.source.clone();
+            let regex: Regex = Regex::new(config.text.regex.as_str()).unwrap();
+            let text: String = regex.captures(source.as_str()).unwrap()[0].to_string();
+
+            let escape = text.replace("'", "'\\\\\\''").replace("%", "\\\\\\%");
+            filter = format!("drawtext=text='{escape}':{}{font}", config.text.style)
+        } else {
+            filter = format!(
+                "null,zmq=b=tcp\\\\://'{}',drawtext=text=''{}",
+                config.text.bind_address, font
+            )
+        }
+
+        chain.add_filter(filter, "video".into())
+    }
+}
+
 fn add_audio(node: &mut Media, chain: &mut Filters) {
     let audio_streams = node.probe.clone().unwrap().audio_streams.unwrap();
     if audio_streams.len() == 0 {
@@ -278,6 +308,7 @@ pub fn filter_chains(node: &mut Media) -> Vec<String> {
             &config,
         );
         extend_video(node, &mut filters);
+        add_text(node, &mut filters, &config);
         add_audio(node, &mut filters);
         extend_audio(node, &mut filters);
     }