feat(path): add convert_file_src to PathResolver

Adds a Rust equivalent of the JavaScript `convertFileSrc` function to the
PathResolver API, enabling file-to-URL conversion from Rust code.

This is useful when processing file paths in Rust (e.g., parsing markdown
with image references) and needing to convert them to URLs that the webview
can load.

The implementation:
- Uses percent-encoding for URL-safe path encoding
- Uses dunce::simplified to normalize Windows paths
- Returns HTTP URLs on Windows/Android and custom protocol URLs elsewhere

Closes #12022

Author: AndyBodnar

crates/tauri/src/path/android.rs

@@ -4,6 +4,7 @@
 
 use super::Result;
 use crate::{plugin::PluginHandle, Runtime};
+use percent_encoding::{utf8_percent_encode, NON_ALPHANUMERIC};
 use std::path::{Path, PathBuf};
 
 /// A helper class to access the mobile path APIs.
@@ -175,4 +176,36 @@ impl<R: Runtime> PathResolver<R> {
   pub fn home_dir(&self) -> Result<PathBuf> {
     self.call_resolve("getHomeDir")
   }
+
+  /// Converts a file path to a URL that can be loaded by the webview.
+  ///
+  /// This is the Rust equivalent of the JavaScript `convertFileSrc` function.
+  /// Note: The file must be allowed by the app's asset scope for the webview to load it.
+  ///
+  /// # Arguments
+  ///
+  /// * `path` - The file path to convert
+  /// * `protocol` - The protocol to use, defaults to `"asset"` if `None`
+  ///
+  /// # Examples
+  ///
+  /// ```rust,no_run
+  /// use tauri::Manager;
+  /// tauri::Builder::default()
+  ///   .setup(|app| {
+  ///     let video_path = app.path().app_data_dir()?.join("video.mp4");
+  ///     let url = app.path().convert_file_src(&video_path, None);
+  ///     // On Android: http://asset.localhost/...
+  ///     println!("URL: {}", url);
+  ///     Ok(())
+  ///   });
+  /// ```
+  pub fn convert_file_src<P: AsRef<Path>>(&self, path: P, protocol: Option<&str>) -> String {
+    let protocol = protocol.unwrap_or("asset");
+    let path = path.as_ref();
+    let encoded = utf8_percent_encode(&path.to_string_lossy(), NON_ALPHANUMERIC).to_string();
+
+    // Android uses HTTP protocol like Windows
+    format!("http://{protocol}.localhost/{encoded}")
+  }
 }

crates/tauri/src/path/desktop.rs

@@ -4,6 +4,7 @@
 
 use super::{Error, Result};
 use crate::{AppHandle, Manager, Runtime};
+use percent_encoding::{utf8_percent_encode, NON_ALPHANUMERIC};
 use std::path::{Path, PathBuf};
 
 /// The path resolver is a helper class for general and application-specific path APIs.
@@ -293,4 +294,43 @@ impl<R: Runtime> PathResolver<R> {
   pub fn temp_dir(&self) -> Result<PathBuf> {
     Ok(std::env::temp_dir())
   }
+
+  /// Converts a file path to a URL that can be loaded by the webview.
+  ///
+  /// This is the Rust equivalent of the JavaScript `convertFileSrc` function.
+  /// Note: The file must be allowed by the app's asset scope for the webview to load it.
+  ///
+  /// # Arguments
+  ///
+  /// * `path` - The file path to convert
+  /// * `protocol` - The protocol to use, defaults to `"asset"` if `None`
+  ///
+  /// # Examples
+  ///
+  /// ```rust,no_run
+  /// use tauri::Manager;
+  /// tauri::Builder::default()
+  ///   .setup(|app| {
+  ///     let video_path = app.path().app_data_dir()?.join("video.mp4");
+  ///     let url = app.path().convert_file_src(&video_path, None);
+  ///     // On Windows: http://asset.localhost/C%3A%5CUsers%5C...
+  ///     // On macOS/Linux: asset://localhost/%2FUsers%2F...
+  ///     println!("URL: {}", url);
+  ///     Ok(())
+  ///   });
+  /// ```
+  pub fn convert_file_src<P: AsRef<Path>>(&self, path: P, protocol: Option<&str>) -> String {
+    let protocol = protocol.unwrap_or("asset");
+    let path = dunce::simplified(path.as_ref());
+    let encoded = utf8_percent_encode(&path.to_string_lossy(), NON_ALPHANUMERIC).to_string();
+
+    #[cfg(windows)]
+    {
+      format!("http://{protocol}.localhost/{encoded}")
+    }
+    #[cfg(not(windows))]
+    {
+      format!("{protocol}://localhost/{encoded}")
+    }
+  }
 }