Enhancement: Add File Dialog to Browse for Images

Add the ability to use a file browse dialog to open a file from another folder
on disk using Ctrl+O / F1. This is useful when testing or launching the tool
from a shortcut, where it may not be started with a filename.

This makes use of the "nfd" crate (which uses the "nativedialog" library
under the hood, requiring a working C/C++ compiler for compilation to work)

Limitations:
* The file dialog allows selecting any file types, and not just supported
  image file formats.

Cargo.toml

@@ -85,6 +85,7 @@ usvg = "0.14.1"
 tiny-skia = "0.5.1"
 log = "0.4"
 env_logger = "0.8"
+nfd = "0.0.4"
 
 [dependencies.libavif-image]
 version = "0.6.0"

src/input_handling.rs

@@ -9,6 +9,7 @@ use lazy_static::lazy_static;
 
 pub static TOGGLE_FULLSCREEN_NAME: &str = "toggle_fullscreen";
 pub static ESCAPE_NAME: &str = "escape";
+pub static IMG_BROWSE_NAME: &str = "img_browse";
 pub static IMG_NEXT_NAME: &str = "img_next";
 pub static IMG_PREV_NAME: &str = "img_prev";
 pub static IMG_ORIG_NAME: &str = "img_orig";
@@ -34,6 +35,7 @@ lazy_static! {
 		let mut m = HashMap::new();
 		m.insert(TOGGLE_FULLSCREEN_NAME, vec!["F11", "Return"]);
 		m.insert(ESCAPE_NAME, vec!["Escape"]);
+		m.insert(IMG_BROWSE_NAME, vec!["F1", "CmdCtrl+O"]);
 		m.insert(IMG_NEXT_NAME, vec!["D", "Right", "PageDown"]);
 		m.insert(IMG_PREV_NAME, vec!["A", "Left", "PageUp"]);
 		m.insert(IMG_ORIG_NAME, vec!["Q", "1"]);

src/main.rs

@@ -237,6 +237,7 @@ fn main() {
 		bottom_bar.slider.set_on_value_change(move || {
 			picture_widget.jump_to_index(slider.value());
 		});
+		// TODO: Right-click to launch file browser?
 	}
 	{
 		let picture_widget = picture_widget.clone();

src/widgets/picture_widget.rs

@@ -4,6 +4,9 @@ use std::rc::{Rc, Weak};
 use std::sync::{Arc, Mutex};
 use std::time::{Duration, Instant};
 
+extern crate nfd;
+use nfd::Response;
+
 use gelatin::cgmath::{Matrix4, Vector2, Vector3};
 use gelatin::glium::glutin::event::{ElementState, ModifiersState, MouseButton};
 use gelatin::glium::{
@@ -619,6 +622,22 @@ impl PictureWidget {
 				}
 			}
 		}
+		if triggered!(IMG_BROWSE_NAME) {
+			match nfd::open_file_dialog(None, None).expect("file dialog error") {
+			// TODO: Restrict to only supported image types
+				Response::Okay(file_path) => {
+					println!("Selected File Path = {:?}", file_path);
+					let file_path_buf = PathBuf::from(file_path.clone());
+
+					borrowed.playback_manager.request_load(LoadRequest::FilePath(file_path_buf.clone()));
+					borrowed.render_validity.invalidate();
+				},
+
+				Response::Cancel => println!("File browse cancelled"),
+				_ => (),
+			}
+
+		}
 		if let Some(img_path) = borrowed.playback_manager.shown_file_path() {
 			if let Some(folder_path) = img_path.parent() {
 				let img_and_folder = (img_path.to_str(), folder_path.to_str());