GPS: introduce the graph object

The graph object stores information about the graphical
representation of a gst pipeline including
the element box, the pads and the connections.

src/app.rs

@@ -27,14 +27,17 @@ use std::cell::RefCell;
 use std::rc::{Rc, Weak};
 use std::{error, ops};
 
+use crate::graph::{Element, Graph};
 use crate::pipeline::Pipeline;
 use crate::pluginlistwindow;
 
 #[derive(Debug)]
 pub struct GPSAppInner {
     pub window: gtk::ApplicationWindow,
+    pub drawing_area: DrawingArea,
     pub builder: Builder,
-    pipeline: Pipeline,
+    pub pipeline: RefCell<Pipeline>,
+    pub graph: RefCell<Graph>,
 }
 
 // This represents our main application window.
@@ -63,12 +66,6 @@ impl GPSAppWeak {
     }
 }
 
-#[derive(Debug, Clone, Default)]
-struct Element {
-    name: String,
-    position: (f64, f64),
-    size: (f64, f64),
-}
 fn draw_elements(elements: &Vec<Element>, c: &Context) {
     for element in elements {
         c.rectangle(element.position.0, element.position.1, 80.0, 45.0);
@@ -86,11 +83,13 @@ impl GPSApp {
         window.set_position(WindowPosition::Center);
         window.set_size_request(800, 600);
         let pipeline = Pipeline::new().expect("Unable to initialize the pipeline");
-
+        let drawing_area = DrawingArea::new();
         let app = GPSApp(Rc::new(GPSAppInner {
             window,
+            drawing_area,
             builder,
-            pipeline,
+            pipeline: RefCell::new(pipeline),
+            graph: RefCell::new(Graph::default()),
         }));
         Ok(app)
     }
@@ -126,29 +125,31 @@ impl GPSApp {
     }
 
     pub fn build_ui(&self) {
-        let drawing_area = DrawingArea::new();
         let view_port: Viewport = self
             .builder
             .object("drawing_area")
             .expect("Couldn't get window");
         let event_box = EventBox::new();
-        event_box.add(&drawing_area);
+        event_box.add(&self.drawing_area);
         view_port.add(&event_box);
-        let elements: Rc<RefCell<Vec<Element>>> = Rc::new(RefCell::new(vec![]));
-        let e_clone = elements.clone();
-        drawing_area.connect_draw(move |w, c| {
-            println!("w: {} c:{} e: {:?}", w, c, e_clone);
-            draw_elements(&e_clone.borrow().to_vec(), c);
+
+        let app_weak = self.downgrade();
+        self.drawing_area.connect_draw(move |w, c| {
+            let app = upgrade_weak!(app_weak, gtk::Inhibit(false));
+            println!("w: {} c:{}", w, c);
+            let mut graph = app.graph.borrow_mut();
+            let elements = graph.elements();
+            draw_elements(&elements, c);
             gtk::Inhibit(false)
         });
-
+        let app_weak = self.downgrade();
         event_box.connect_button_release_event(move |_w, evt| {
-            let mut elements = elements.borrow_mut();
+            let app = upgrade_weak!(app_weak, gtk::Inhibit(false));
             let mut element: Element = Default::default();
             element.position.0 = evt.position().0;
             element.position.1 = evt.position().1;
-            elements.push(element);
-            drawing_area.queue_draw();
+            app.add_new_element(element);
+            app.drawing_area.queue_draw();
             gtk::Inhibit(false)
         });
         let window = &self.window;
@@ -235,4 +236,9 @@ impl GPSApp {
 
     // Called when the application shuts down. We drop our app struct here
     fn drop(self) {}
+
+    pub fn add_new_element(&self, element: Element) {
+        self.graph.borrow_mut().add_element(element);
+        self.drawing_area.queue_draw();
+    }
 }

src/graph.rs

@@ -0,0 +1,36 @@
+#[derive(Debug, Clone, Default)]
+pub struct Element {
+    pub name: String,
+    pub position: (f64, f64),
+    pub size: (f64, f64),
+}
+
+#[derive(Debug)]
+pub struct Graph {
+    elements: Vec<Element>,
+    last_x_position: u32,
+}
+
+impl Default for Graph {
+    fn default() -> Graph {
+        Graph {
+            elements: vec![],
+            last_x_position: 0,
+        }
+    }
+}
+
+impl Graph {
+    pub fn elements(&mut self) -> &Vec<Element> {
+        &self.elements
+    }
+
+    pub fn add_element(&mut self, element: Element) {
+        self.elements.push(element);
+    }
+
+    pub fn remove_element(&mut self, name: &str) {
+        let index = self.elements.iter().position(|x| x.name == name).unwrap();
+        self.elements.remove(index);
+    }
+}

src/main.rs

@@ -20,6 +20,7 @@
 #[macro_use]
 mod macros;
 mod app;
+mod graph;
 mod pipeline;
 mod pluginlistwindow;
 

src/pluginlistwindow.rs

@@ -1,4 +1,5 @@
 use crate::app::GPSApp;
+use crate::graph::Element;
 use crate::pipeline::ElementInfo;
 use gtk::{
     glib::{self, clone},
@@ -75,7 +76,9 @@ pub fn build_plugin_list(app: &GPSApp, elements: &Vec<ElementInfo>) {
 
     // The closure responds to selection changes by connection to "::cursor-changed" signal,
     // that gets emitted when the cursor moves (focus changes).
+    let app_weak = app.downgrade();
     tree.connect_cursor_changed(clone!(@weak dialog => move |tree_view| {
+        let app = upgrade_weak!(app_weak);
         let selection = tree_view.selection();
         if let Some((model, iter)) = selection.selected() {
             // Now getting back the values from the row corresponding to the
@@ -93,18 +96,21 @@ pub fn build_plugin_list(app: &GPSApp, elements: &Vec<ElementInfo>) {
                     .get::<u32>()
                     .expect("Treeview selection, column 0"),
             ));
-            println!(
-                "{}",
-                model
+            let element = Element {
+                name: model
                 .value(&iter, 1)
                 .get::<String>()
-                    .expect("Treeview selection, column 1")
-            );
+                .expect("Treeview selection, column 1"),
+                position: (100.0,100.0),
+                size: (100.0,100.0),
+            };
 
             let element_name = model
             .value(&iter, 1)
             .get::<String>()
             .expect("Treeview selection, column 1");
+            app.add_new_element(element);
+
             //dialog.close();
             println!("{}", element_name);
         }