preload font files into memory to avoid frequent IO.

index.d.ts

@@ -5,6 +5,7 @@ export type ResvgRenderOptions = {
     loadSystemFonts?: boolean // Default: true, if set to false, it will be faster.
     fontFiles?: string[] // A list of local font file paths to load.
     fontDirs?: string[] // A list of local font directories to load.
+    preloadFonts?: boolean // Default: false. When enabled, font files will be read into memory at once to avoid frequent IO.
     defaultFontSize?: number // Default: 12
     defaultFontFamily?: string // Default: "", if `loadSystemFonts` is enabled, it will be set to the first font in the list of system fonts.
     serifFamily?: string

js-binding.d.ts

@@ -4,13 +4,13 @@
 /* auto-generated by NAPI-RS */
 
 export function renderAsync(svg: string | Buffer, options?: string | undefined | null, signal?: AbortSignal | undefined | null): Promise<RenderedImage>
-export class BBox {
+export declare class BBox {
   x: number
   y: number
   width: number
   height: number
 }
-export class Resvg {
+export declare class Resvg {
   constructor(svg: string | Buffer, options?: string | undefined | null)
   /** Renders an SVG in Node.js */
   render(): RenderedImage
@@ -40,7 +40,7 @@ export class Resvg {
   /** Get the SVG height */
   get height(): number
 }
-export class RenderedImage {
+export declare class RenderedImage {
   /** Write the image data to Buffer */
   asPng(): Buffer
   /** Get the RGBA pixels of the image */

src/fonts.rs

@@ -20,20 +20,48 @@ use woff2::decode::{convert_woff2_to_ttf, is_woff2};
 /// Loads fonts.
 #[cfg(not(target_arch = "wasm32"))]
 pub fn load_fonts(font_options: &JsFontOptions) -> Database {
-    // Create a new font database
     let mut fontdb = Database::new();
     let now = std::time::Instant::now();
 
-    // 加载指定路径的字体
-    for path in &font_options.font_files {
-        if let Err(e) = fontdb.load_font_file(path) {
-            warn!("Failed to load '{}' cause {}.", path, e);
+    if font_options.preload_fonts {
+        // 预加载模式: 一次性读取所有字体文件到内存
+        for path in &font_options.font_files {
+            match std::fs::read(path) {
+                Ok(buffer) => {
+                    let _ = fontdb.load_font_data(buffer);
+                }
+                Err(e) => {
+                    warn!("Failed to read font file '{}' cause {}.", path, e);
+                }
+            }
+        }
+
+        // 加载字体目录
+        for dir in &font_options.font_dirs {
+            if let Ok(entries) = std::fs::read_dir(dir) {
+                for entry in entries.flatten() {
+                    if let Ok(path) = entry.path().canonicalize() {
+                        if path.is_file() {
+                            if let Ok(buffer) = std::fs::read(&path) {
+                                let _ = fontdb.load_font_data(buffer);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    } else {
+        // 默认模式: 直接传递文件路径
+        for path in &font_options.font_files {
+            if let Err(e) = fontdb.load_font_file(path) {
+                warn!("Failed to load '{}' cause {}.", path, e);
+            }
         }
-    }
 
-    // Load font directories
-    for path in &font_options.font_dirs {
-        fontdb.load_fonts_dir(path);
+        // Load font directories
+        for path in &font_options.font_dirs {
+            fontdb.load_fonts_dir(path);
+        }
     }
 
     // 加载系统字体

src/options.rs

@@ -238,6 +238,12 @@ pub struct JsFontOptions {
     /// A list of local font directories to load.
     pub font_dirs: Vec<String>,
 
+    /// Whether to preload font files into memory to improve performance.
+    /// When enabled, font files will be read into memory at once to avoid frequent IO.
+    /// 
+    /// Default: false
+    pub preload_fonts: bool,
+
     /// The default font family.
     ///
     /// Will be used when no `font-family` attribute is set in the SVG.
@@ -284,6 +290,7 @@ impl Default for JsFontOptions {
             load_system_fonts: true,
             font_files: vec![],
             font_dirs: vec![],
+            preload_fonts: false,
             default_font_family: "".to_string(),
             default_font_size: 12.0,
             serif_family: "Times New Roman".to_string(),