window, image_view: Resize window based on image size

Allows us to have a more appropriate size for the window
based on the content, instead of sticking with the small
default window size.

src/widgets/image_view.rs

@@ -128,6 +128,26 @@ mod imp {
             PROPERTIES.as_ref()
         }
 
+        fn signals() -> &'static [glib::subclass::Signal] {
+            static SIGNALS: Lazy<Vec<glib::subclass::Signal>> = Lazy::new(|| {
+                vec![subclass::Signal::builder(
+                    // Called when the dimensions of the image
+                    // have been found.
+                    "dimensions-loaded",
+                    &[
+                        // The width of the image
+                        i32::static_type().into(),
+                        // The height of the image
+                        i32::static_type().into(),
+                    ],
+                    glib::Type::UNIT.into(),
+                )
+                .build()]
+            });
+
+            SIGNALS.as_ref()
+        }
+
         fn get_property(
             &self,
             _obj: &Self::Type,
@@ -204,6 +224,21 @@ impl IvImageView {
         let imp = imp::IvImageView::from_instance(&self);
 
         imp.picture.set_file(Some(file));
+
+        if let Err(e) = self.load_dimensions_from_file(file) {
+            log::error!("Could not load image dimensions: {}", e);
+        };
+    }
+
+    fn load_dimensions_from_file(&self, file: &gio::File) -> anyhow::Result<()> {
+        let pb = file.get_path().context("No path for current file")?;
+        let (_, width, height) =
+            gdk_pixbuf::Pixbuf::get_file_info(&pb.as_path()).context("Could not get file info")?;
+
+        log::debug!("Image dimensions: {} x {}", width, height);
+        let _ = self.emit_by_name("dimensions-loaded", &[&width, &height]);
+
+        Ok(())
     }
 
     pub fn set_wallpaper(&self) -> anyhow::Result<()> {
@@ -220,7 +255,7 @@ impl IvImageView {
 
         let request = RequestProxy::new(&imp.connection, &request_handle)?;
         request.on_response(|response: Response<Basic>| {
-            log::debug!("Response is OK: {}", response.is_ok());
+            log::debug!("Wallpaper set: {}", response.is_ok());
         })?;
 
         Ok(())
@@ -281,4 +316,20 @@ impl IvImageView {
         imp.popover.set_pointing_to(&rect);
         imp.popover.popup();
     }
+
+    pub fn connect_dimensions_loaded<F: Fn(&Self, i32, i32) + 'static>(
+        &self,
+        f: F,
+    ) -> glib::SignalHandlerId {
+        self.connect_local("dimensions-loaded", true, move |values| {
+            let view = values[0].get::<Self>().unwrap().unwrap();
+            let width = values[1].get::<i32>().unwrap().unwrap();
+            let height = values[2].get::<i32>().unwrap().unwrap();
+
+            f(&view, width, height);
+
+            None
+        })
+        .unwrap()
+    }
 }

src/window.rs

@@ -115,6 +115,12 @@ mod imp {
                 .connect_released(clone!(@weak obj => move |_, _, _, _| {
                     obj.pick_file();
                 }));
+
+            self.image_view.connect_dimensions_loaded(
+                clone!(@weak obj => move |_, width, height| {
+                    obj.resize_from_dimensions(width, height);
+                }),
+            );
         }
     }
 
@@ -243,11 +249,11 @@ impl IvWindow {
     pub fn set_image_from_file(&self, file: &gio::File) {
         let imp = imp::IvWindow::from_instance(self);
 
+        log::debug!("Loading file: {}", file.get_uri().to_string());
+
         imp.image_view.set_image_from_file(file);
         imp.stack.set_visible_child(&*imp.image_view);
 
-        log::debug!("Loading file: {}", file.get_uri().to_string());
-
         if let Some(name) = file.get_basename() {
             self.set_title(Some(
                 name.file_name().expect("Missing name").to_str().unwrap(),
@@ -281,4 +287,40 @@ impl IvWindow {
             .unwrap()
             .set_enabled(enabled);
     }
+
+    // Adapted from https://gitlab.gnome.org/GNOME/eog/-/blob/master/src/eog-window.c:eog_window_obtain_desired_size
+    pub fn resize_from_dimensions(&self, img_width: i32, img_height: i32) {
+        let imp = imp::IvWindow::from_instance(self);
+        let mut final_width = img_width;
+        let mut final_height = img_height;
+
+        let header_height = imp.headerbar.get_height();
+
+        // Ensure the window surface exists
+        if !self.get_realized() {
+            self.realize();
+        }
+
+        let display = gdk::Display::get_default().unwrap();
+        let monitor = display
+            .get_monitor_at_surface(&self.get_native().unwrap().get_surface().unwrap())
+            .unwrap();
+        let monitor_geometry = monitor.get_geometry();
+
+        let monitor_width = monitor_geometry.width;
+        let monitor_height = monitor_geometry.height;
+
+        if img_width > monitor_width || img_height + header_height > monitor_height {
+            let width_factor = (monitor_width as f32 * 0.85) / img_width as f32;
+            let height_factor =
+                (monitor_height as f32 * 0.85 - header_height as f32) / img_height as f32;
+            let factor = width_factor.min(height_factor);
+
+            final_width = (final_width as f32 * factor).round() as i32;
+            final_height = (final_height as f32 * factor).round() as i32;
+        }
+
+        self.set_default_size(final_width, final_height);
+        log::debug!("Window resized to {} x {}", final_width, final_height);
+    }
 }