diff --git a/Cargo.lock b/Cargo.lock
index c7558c8..f661fe9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -171,6 +171,15 @@ version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ace50bade8e6234aa140d9a2f552bbee1db4d353f69b8217bc503490fc1a9f26"
 
+[[package]]
+name = "bincode"
+version = "1.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b1f45e9417d87227c7a56d22e471c6206462cba514c7590c09aff4cf6d1ddcad"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "bit-set"
 version = "0.8.0"
@@ -556,6 +565,15 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "aa9a19cbb55df58761df49b23516a86d432839add4af60fc256da840f66ed35b"
 
+[[package]]
+name = "form_urlencoded"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e13624c2627564efccf4934284bdd98cbaa14e79b0b5a141218e507b3a823456"
+dependencies = [
+ "percent-encoding",
+]
+
 [[package]]
 name = "futures"
 version = "0.3.31"
@@ -662,8 +680,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "335ff9f135e4384c8150d6f27c6daed433577f86b4750418338c01a1a2528592"
 dependencies = [
  "cfg-if",
+ "js-sys",
  "libc",
  "wasi 0.11.0+wasi-snapshot-preview1",
+ "wasm-bindgen",
 ]
 
 [[package]]
@@ -695,6 +715,190 @@ version = "0.29.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8babf46d4c1c9d92deac9f7be466f76dfc4482b6452fc5024b5e8daf6ffeb3ee"
 
+[[package]]
+name = "gloo"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d15282ece24eaf4bd338d73ef580c6714c8615155c4190c781290ee3fa0fd372"
+dependencies = [
+ "gloo-console",
+ "gloo-dialogs",
+ "gloo-events",
+ "gloo-file",
+ "gloo-history",
+ "gloo-net",
+ "gloo-render",
+ "gloo-storage",
+ "gloo-timers",
+ "gloo-utils",
+ "gloo-worker",
+]
+
+[[package]]
+name = "gloo-console"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2a17868f56b4a24f677b17c8cb69958385102fa879418052d60b50bc1727e261"
+dependencies = [
+ "gloo-utils",
+ "js-sys",
+ "serde",
+ "wasm-bindgen",
+ "web-sys",
+]
+
+[[package]]
+name = "gloo-dialogs"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bf4748e10122b01435750ff530095b1217cf6546173459448b83913ebe7815df"
+dependencies = [
+ "wasm-bindgen",
+ "web-sys",
+]
+
+[[package]]
+name = "gloo-events"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "27c26fb45f7c385ba980f5fa87ac677e363949e065a083722697ef1b2cc91e41"
+dependencies = [
+ "wasm-bindgen",
+ "web-sys",
+]
+
+[[package]]
+name = "gloo-file"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "97563d71863fb2824b2e974e754a81d19c4a7ec47b09ced8a0e6656b6d54bd1f"
+dependencies = [
+ "futures-channel",
+ "gloo-events",
+ "js-sys",
+ "wasm-bindgen",
+ "web-sys",
+]
+
+[[package]]
+name = "gloo-history"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "903f432be5ba34427eac5e16048ef65604a82061fe93789f2212afc73d8617d6"
+dependencies = [
+ "getrandom 0.2.16",
+ "gloo-events",
+ "gloo-utils",
+ "serde",
+ "serde-wasm-bindgen",
+ "serde_urlencoded",
+ "thiserror 1.0.69",
+ "wasm-bindgen",
+ "web-sys",
+]
+
+[[package]]
+name = "gloo-net"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "43aaa242d1239a8822c15c645f02166398da4f8b5c4bae795c1f5b44e9eee173"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "futures-sink",
+ "gloo-utils",
+ "http",
+ "js-sys",
+ "pin-project",
+ "serde",
+ "serde_json",
+ "thiserror 1.0.69",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "web-sys",
+]
+
+[[package]]
+name = "gloo-render"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "56008b6744713a8e8d98ac3dcb7d06543d5662358c9c805b4ce2167ad4649833"
+dependencies = [
+ "wasm-bindgen",
+ "web-sys",
+]
+
+[[package]]
+name = "gloo-storage"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fbc8031e8c92758af912f9bc08fbbadd3c6f3cfcbf6b64cdf3d6a81f0139277a"
+dependencies = [
+ "gloo-utils",
+ "js-sys",
+ "serde",
+ "serde_json",
+ "thiserror 1.0.69",
+ "wasm-bindgen",
+ "web-sys",
+]
+
+[[package]]
+name = "gloo-timers"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbb143cf96099802033e0d4f4963b19fd2e0b728bcf076cd9cf7f6634f092994"
+dependencies = [
+ "futures-channel",
+ "futures-core",
+ "js-sys",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "gloo-utils"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b5555354113b18c547c1d3a98fbf7fb32a9ff4f6fa112ce823a21641a0ba3aa"
+dependencies = [
+ "js-sys",
+ "serde",
+ "serde_json",
+ "wasm-bindgen",
+ "web-sys",
+]
+
+[[package]]
+name = "gloo-worker"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "085f262d7604911c8150162529cefab3782e91adb20202e8658f7275d2aefe5d"
+dependencies = [
+ "bincode",
+ "futures",
+ "gloo-utils",
+ "gloo-worker-macros",
+ "js-sys",
+ "pinned",
+ "serde",
+ "thiserror 1.0.69",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "web-sys",
+]
+
+[[package]]
+name = "gloo-worker-macros"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "956caa58d4857bc9941749d55e4bd3000032d8212762586fa5705632967140e7"
+dependencies = [
+ "proc-macro-crate 1.3.1",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "glow"
 version = "0.16.0"
@@ -805,6 +1009,17 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dfa686283ad6dd069f105e5ab091b04c62850d3e4cf5d67debad1933f55023df"
 
+[[package]]
+name = "http"
+version = "0.2.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "601cbb57e577e2f5ef5be8e7b83f0f63994f25aa94d673e54a92d5c516d101f1"
+dependencies = [
+ "bytes",
+ "fnv",
+ "itoa",
+]
+
 [[package]]
 name = "indexmap"
 version = "2.9.0"
@@ -821,6 +1036,12 @@ version = "1.70.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7943c866cc5cd64cbc25b2e01621d07fa8eb2a1a23160ee81ce38704e97b8ecf"
 
+[[package]]
+name = "itoa"
+version = "1.0.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4a5f13b858c8d314ee3e8f639011f7ccefe71f97f96e50151fb991f267928e2c"
+
 [[package]]
 name = "jiff"
 version = "0.2.13"
@@ -1130,7 +1351,7 @@ version = "0.7.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "af1844ef2428cc3e1cb900be36181049ef3d3193c63e43026cfe202983b27a56"
 dependencies = [
- "proc-macro-crate",
+ "proc-macro-crate 3.3.0",
  "proc-macro2",
  "quote",
  "syn",
@@ -1448,6 +1669,17 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8b870d8c151b6f2fb93e84a13146138f05d02ed11c7e7c54f8826aaaf7c9f184"
 
+[[package]]
+name = "pinned"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a829027bd95e54cfe13e3e258a1ae7b645960553fb82b75ff852c29688ee595b"
+dependencies = [
+ "futures",
+ "rustversion",
+ "thiserror 1.0.69",
+]
+
 [[package]]
 name = "pkg-config"
 version = "0.3.32"
@@ -1499,13 +1731,23 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e8cf8e6a8aa66ce33f63993ffc4ea4271eb5b0530a9002db8455ea6050c77bfa"
 
+[[package]]
+name = "proc-macro-crate"
+version = "1.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7f4c021e1093a56626774e81216a4ce732a735e5bad4868a03f3ed65ca0c3919"
+dependencies = [
+ "once_cell",
+ "toml_edit 0.19.15",
+]
+
 [[package]]
 name = "proc-macro-crate"
 version = "3.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "edce586971a4dfaa28950c6f18ed55e0406c1ab88bbce2c6f6293a7aaba73d35"
 dependencies = [
- "toml_edit",
+ "toml_edit 0.22.26",
 ]
 
 [[package]]
@@ -1553,6 +1795,7 @@ dependencies = [
  "env_logger",
  "futures",
  "glam",
+ "gloo",
  "log",
  "proptest",
  "tiff",
@@ -1749,6 +1992,12 @@ dependencies = [
  "wait-timeout",
 ]
 
+[[package]]
+name = "ryu"
+version = "1.0.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "28d3b2b1366ec20994f1fd18c3c594f05c5dd4bc44d8bb0c1c632c8d6829481f"
+
 [[package]]
 name = "same-file"
 version = "1.0.6"
@@ -1792,6 +2041,17 @@ dependencies = [
  "serde_derive",
 ]
 
+[[package]]
+name = "serde-wasm-bindgen"
+version = "0.6.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8302e169f0eddcc139c70f139d19d6467353af16f9fce27e8c30158036a1e16b"
+dependencies = [
+ "js-sys",
+ "serde",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "serde_derive"
 version = "1.0.219"
@@ -1803,6 +2063,30 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "serde_json"
+version = "1.0.140"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "20068b6e96dc6c9bd23e01df8827e6c7e1f2fddd43c21810382803c136b99373"
+dependencies = [
+ "itoa",
+ "memchr",
+ "ryu",
+ "serde",
+]
+
+[[package]]
+name = "serde_urlencoded"
+version = "0.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3491c14715ca2294c4d6a88f15e84739788c1d030eed8c110436aafdaa2f3fd"
+dependencies = [
+ "form_urlencoded",
+ "itoa",
+ "ryu",
+ "serde",
+]
+
 [[package]]
 name = "shlex"
 version = "1.3.0"
@@ -2025,6 +2309,17 @@ version = "0.6.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3da5db5a963e24bc68be8b17b6fa82814bb22ee8660f192bb182771d498f09a3"
 
+[[package]]
+name = "toml_edit"
+version = "0.19.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b5bb770da30e5cbfde35a2d7b9b8a2c4b8ef89548a7a6aeab5c9a576e3e7421"
+dependencies = [
+ "indexmap",
+ "toml_datetime",
+ "winnow 0.5.40",
+]
+
 [[package]]
 name = "toml_edit"
 version = "0.22.26"
@@ -2033,7 +2328,7 @@ checksum = "310068873db2c5b3e7659d2cc35d21855dbafa50d1ce336397c666e3cb08137e"
 dependencies = [
  "indexmap",
  "toml_datetime",
- "winnow",
+ "winnow 0.7.10",
 ]
 
 [[package]]
@@ -2856,6 +3151,15 @@ dependencies = [
  "xkbcommon-dl",
 ]
 
+[[package]]
+name = "winnow"
+version = "0.5.40"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f593a95398737aeed53e489c785df13f3618e41dbcd6718c6addbf1395aa6876"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "winnow"
 version = "0.7.10"
diff --git a/Cargo.toml b/Cargo.toml
index 8df4f03..0695164 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,10 +25,12 @@ wasm-bindgen = "0.2.84"
 wasm-bindgen-futures = "0.4.42"
 console_log = "1.0"
 console_error_panic_hook = "0.1.7"
+gloo = { version = "0.11.0", features=["file", "futures"] }
 web-sys = { version = "0.3", features = [
     "Document",
     "Window",
     "Element",
+    "File"
 ]}
 
 [dev-dependencies]
diff --git a/src/app/mod.rs b/src/app/mod.rs
index 3dbbc98..7ddcd1e 100644
--- a/src/app/mod.rs
+++ b/src/app/mod.rs
@@ -1,9 +1,9 @@
 use std::rc::Rc;
 
-use crate::mvu::{Event, MvuApp, Size2i};
+use crate::mvu::{Event, File, MvuApp, Size2i};
 use {
     log::info,
-    std::{borrow::Cow, path::PathBuf},
+    std::borrow::Cow,
     wgpu::{Device, Instance, Queue, RenderPipeline, Surface, SurfaceConfiguration, Trace},
 };
 
@@ -55,16 +55,14 @@ impl MvuApp<Model> for App {
         eprintln!("Using {}", adapter.get_info().name);
 
         let (device, queue) = adapter
-            .request_device(
-                &wgpu::DeviceDescriptor {
-                    label: None,
-                    required_features: wgpu::Features::empty(),
-                    required_limits: wgpu::Limits::downlevel_webgl2_defaults()
-                        .using_resolution(adapter.limits()),
-                    memory_hints: wgpu::MemoryHints::MemoryUsage,
-                    trace: Trace::Off,
-                },
-            )
+            .request_device(&wgpu::DeviceDescriptor {
+                label: None,
+                required_features: wgpu::Features::empty(),
+                required_limits: wgpu::Limits::downlevel_webgl2_defaults()
+                    .using_resolution(adapter.limits()),
+                memory_hints: wgpu::MemoryHints::MemoryUsage,
+                trace: Trace::Off,
+            })
             .await
             .expect("Failed to create device");
 
@@ -106,7 +104,7 @@ impl MvuApp<Model> for App {
 
         let mut config = surface
             .get_default_config(&adapter, size.width, size.height)
-            .unwrap();
+            .expect("get default graphics surface");
         config.present_mode = wgpu::PresentMode::AutoVsync;
         config.view_formats.push(config.format);
         surface.configure(&device, &config);
@@ -199,7 +197,7 @@ impl MvuApp<Model> for App {
     }
 }
 
-fn open_test_file(file_path: PathBuf, model: Rc<Model>) -> Rc<Model> {
-    let dem = Some(Rc::new(raster::Dem::load_from_image(&file_path)));
+fn open_test_file(file: Box<dyn File>, model: Rc<Model>) -> Rc<Model> {
+    let dem = Some(Rc::new(raster::Dem::load_from_image(file)));
     Rc::new(Model { dem, ..*model })
 }
diff --git a/src/app/raster/dem.rs b/src/app/raster/dem.rs
index f6033ed..1dc3874 100644
--- a/src/app/raster/dem.rs
+++ b/src/app/raster/dem.rs
@@ -1,4 +1,4 @@
-use std::{fs::File, path::PathBuf};
+use crate::mvu::File;
 
 #[derive(Clone)]
 pub struct Dem {
@@ -168,8 +168,7 @@ fn normalized_f32_to_u16(value: f32) -> u16 {
 }
 
 impl Dem {
-    pub fn load_from_image(file_path: &PathBuf) -> Dem {
-        let file = File::open(file_path).unwrap();
+    pub fn load_from_image(file: Box<dyn File>) -> Dem {
         let mut tiff = tiff::decoder::Decoder::new(file).unwrap();
         let (num_cells_x, num_cells_y) = tiff.dimensions().unwrap();
         match tiff.read_image().unwrap() {
@@ -180,13 +179,13 @@ impl Dem {
                 let y_max = 500.0;
                 let (z_min, z_max) = f32_values[1..]
                     .iter()
-                    .map(|z| z * 0.1)
+                    .map(|z| z * 0.6)
                     .fold((f32_values[0], f32_values[0]), |(min, max), elem| {
                         (min.min(elem), max.max(elem))
                     });
                 let grid = f32_values
                     .iter()
-                    .map(|z| z * 0.1)
+                    .map(|z| z * 0.6)
                     .map(|v| normalized_f32_to_u16(normalize_f32(v, z_min, z_max)))
                     .collect();
                 Dem {
diff --git a/src/lib.rs b/src/lib.rs
index 66f9858..f7359f0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -16,7 +16,13 @@ mod app;
 mod mvu;
 use app::{App, Model};
 
-#[cfg_attr(target_arch = "wasm32", wasm_bindgen(start))]
+#[cfg(target_arch = "x86_64")]
 pub fn main() {
     run(App::new(), Rc::new(Model::new()));
 }
+
+#[cfg(target_arch = "wasm32")]
+#[wasm_bindgen]
+pub async fn init_pteropus() -> wasm::PteropusCanvas {
+    run(App::new(), Rc::new(Model::new())).await
+}
diff --git a/src/mvu/mod.rs b/src/mvu/mod.rs
index ac3b059..5bce9e7 100644
--- a/src/mvu/mod.rs
+++ b/src/mvu/mod.rs
@@ -1,11 +1,20 @@
 use {
-    std::{path::PathBuf, rc::Rc},
+    std::{
+        io::{Read, Seek},
+        rc::Rc,
+    },
     wgpu::{Instance, Surface},
 };
 
+pub trait File: Seek + Read {}
+
+impl File for std::fs::File {}
+
+impl File for std::io::Cursor<Vec<u8>> {}
+
 pub enum Event {
     MouseButtonPressed,
-    OpenTestFile(PathBuf),
+    OpenTestFile(Box<dyn File>),
 }
 
 #[derive(Debug, Clone, Copy)]
diff --git a/src/native/mod.rs b/src/native/mod.rs
index 75a4583..846e019 100644
--- a/src/native/mod.rs
+++ b/src/native/mod.rs
@@ -1,6 +1,6 @@
 use std::{rc::Rc, sync::Arc};
 
-use crate::mvu::{self, MvuApp, Size2i};
+use crate::mvu::{self, File, MvuApp, Size2i};
 use {
     futures::executor::block_on,
     winit::{
@@ -63,9 +63,10 @@ where
                 self.window.as_ref().unwrap().request_redraw();
             }
             WindowEvent::DroppedFile(file_path) => {
+                let file = Box::new(std::fs::File::open(file_path).unwrap()) as Box<dyn File>;
                 self.model = block_on(
                     self.app
-                        .update(self.model.clone(), mvu::Event::OpenTestFile(file_path)),
+                        .update(self.model.clone(), mvu::Event::OpenTestFile(file)),
                 )
             }
             _ => (),
diff --git a/src/wasm/mod.rs b/src/wasm/mod.rs
index 726443e..699b297 100644
--- a/src/wasm/mod.rs
+++ b/src/wasm/mod.rs
@@ -1,38 +1,101 @@
 use {
-    std::rc::Rc, wasm_bindgen::prelude::*, wasm_bindgen_futures::spawn_local,
-    web_sys::HtmlCanvasElement, wgpu::SurfaceTarget,
+    log::info,
+    std::{rc::Rc, sync::Mutex},
+    wasm_bindgen::prelude::*,
+    web_sys::HtmlCanvasElement,
+    wgpu::SurfaceTarget,
 };
 
-use crate::mvu::{MvuApp, Size2i};
+use crate::{
+    app::{App, Model},
+    mvu::{Event, File, MvuApp, Size2i},
+};
 
-async fn run_async<A, M>(mut app: A, model: Rc<M>)
-where
-    A: MvuApp<M> + 'static,
-    M: 'static,
-{
-    let window = web_sys::window().unwrap();
-    let document = window.document().unwrap();
-    let canvas_element = document.get_element_by_id("pteropus-canvas").unwrap();
-    let html_canvas: HtmlCanvasElement = canvas_element.dyn_into().unwrap();
-    let size = Size2i {
-        width: html_canvas.width(),
-        height: html_canvas.height(),
-    };
-    let instance = wgpu::Instance::default();
-    let surface_target = SurfaceTarget::Canvas(html_canvas);
-    let surface = instance.create_surface(surface_target).unwrap();
-
-    app.init(&instance, surface, size).await;
-    app.view(model).await.unwrap();
+#[wasm_bindgen]
+#[derive(Clone)]
+pub struct PteropusCanvas {
+    app: Rc<Mutex<App>>,
+    model: Rc<Model>,
 }
 
-pub fn run<A, M>(app: A, model: Rc<M>)
-where
-    A: MvuApp<M> + 'static,
-    M: 'static,
-{
+/*struct ArrayFile {
+    data: Vec<u8>,
+}
+
+impl std::io::Read for ArrayFile {
+    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
+        todo!()
+    }
+}
+
+impl std::io::Seek for ArrayFile {
+    fn seek(&mut self, pos: std::io::SeekFrom) -> std::io::Result<u64> {
+        todo!()
+    }
+}
+
+impl File for ArrayFile {}*/
+
+#[wasm_bindgen]
+impl PteropusCanvas {
+    async fn init(&self) {
+        let window = web_sys::window().expect("get window");
+        let document = window.document().expect("get HTML document");
+        let canvas_element = document
+            .get_element_by_id("pteropus-canvas")
+            .expect("document contains element with id \"pteropus-canvas\"");
+        let html_canvas: HtmlCanvasElement = canvas_element
+            .dyn_into()
+            .expect("pteropus-canvas element is a canvas");
+        let size = Size2i {
+            width: html_canvas.width(),
+            height: html_canvas.height(),
+        };
+        let instance = wgpu::Instance::default();
+        let surface_target = SurfaceTarget::Canvas(html_canvas);
+        let surface = instance
+            .create_surface(surface_target)
+            .expect("create graphics surface for canvas");
+
+        self.app
+            .lock()
+            .expect("get app mutex")
+            .init(&instance, surface, size)
+            .await;
+    }
+
+    #[wasm_bindgen]
+    pub async fn render(&self) {
+        self.app
+            .lock()
+            .expect("get app mutex")
+            .view(Rc::clone(&self.model))
+            .await
+            .expect("view succeeds");
+    }
+
+    #[wasm_bindgen]
+    pub async fn load_file(&mut self, file: web_sys::File) {
+        let data = gloo::file::futures::read_as_bytes(&file.into())
+            .await
+            .expect("read data from dragged file");
+        self.model = self
+            .app
+            .lock()
+            .expect("get app mutex")
+            .update(
+                Rc::clone(&self.model),
+                Event::OpenTestFile(Box::new(std::io::Cursor::new(data))),
+            )
+            .await;
+    }
+}
+
+pub async fn run(app: App, model: Rc<Model>) -> PteropusCanvas {
+    let app = Rc::new(Mutex::new(app));
     std::panic::set_hook(Box::new(console_error_panic_hook::hook));
     console_log::init_with_level(log::Level::Info).expect("Couldn't initialize logger");
-
-    spawn_local(run_async(app, model));
+    let pteropus_canvas = PteropusCanvas { app, model };
+    pteropus_canvas.init().await;
+    pteropus_canvas
 }
diff --git a/web/index.html b/web/index.html
index 502f4c7..5861cdc 100644
--- a/web/index.html
+++ b/web/index.html
@@ -4,8 +4,8 @@
     <title>Pteropus</title>
    <style>
        #pteropus-canvas {
-           height: 100vh;
-           width: 100vh;
+           height: 100%;
+           width: 100%;
            display: block;
        }
    </style>
@@ -13,10 +13,38 @@
   <body>
     <canvas id="pteropus-canvas"></canvas>
     <script type="module">
-      import init from '../pkg/pteropus.js';
+      import init, {init_pteropus} from '../pkg/pteropus.js';
+
+      function fileDragOverHandler(event) {
+          event.preventDefault();
+      }
 
       async function run() {
-        await init();
+          await init();
+
+          let pteropus = await init_pteropus();
+
+          let test_file_data = null
+
+          let mainCanvas = document.getElementById("pteropus-canvas");
+          mainCanvas.addEventListener("drop", async (event) => {
+              event.preventDefault();
+              test_file_data = event.dataTransfer.files[0]
+          });
+          mainCanvas.addEventListener("dragover", fileDragOverHandler);
+
+          while(true)
+          {
+              await pteropus.render();
+              // TODO: I really want to do this asynchronously, with the drop
+              // event listener calling pteropus_load_file directly, but I need
+              // to figure out how to get that to work.
+              if(test_file_data) {
+                  await pteropus.load_file(test_file_data);
+                  test_file_data = null
+              }
+              await new Promise(requestAnimationFrame);
+          }
       }
 
       run();