From b3cb19fa1d9feb4c4358110d9ce876502879f513 Mon Sep 17 00:00:00 2001
From: "John Li (Tet)" <tet@tet.moe>
Date: Fri, 10 Feb 2023 23:40:12 -0800
Subject: [PATCH] added font caching

---
 ImageScript.js | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/ImageScript.js b/ImageScript.js
index b43b3a0..523a234 100644
--- a/ImageScript.js
+++ b/ImageScript.js
@@ -18,6 +18,22 @@ const MAGIC_NUMBERS = {
     TIFF: 0x49492a00,
     GIF: 0x474946
 };
+const initFontLib = fontlib.init();
+const fontScaleCache = new Map(); // <scale, Map<font, Font>>
+const getFont= async (font,scale) =>{
+    const { Font, Layout } = await initFontLib;
+    let scaleCache = fontScaleCache.get(scale)
+    if (!scaleCache) {
+        scaleCache = new Map()
+        fontScaleCache.set(scale,scaleCache)
+        scaleCache.set(font, new Font(scale, font))
+    }
+    let fontCache = scaleCache.get(font)
+    if (!fontCache) {
+        scaleCache.set(font, new Font(scale, font))
+    }
+    return scaleCache.get(font)
+}
 
 /**
  * Represents an image; provides utility functions
@@ -1185,11 +1201,11 @@ class Image {
      * @return {Promise<Image>} The rendered text
      */
     static async renderText(font, scale, text, color = 0xffffffff, layout = new TextLayout()) {
-        const { Font, Layout } = await fontlib.init();
 
-        font = new Font(scale, font);
-        const [r, g, b, a] = Image.colorToRGBA(color);
 
+        font = await getFont(font,scale)
+        const [r, g, b, a] = Image.colorToRGBA(color);
+        const Layout = (await initFontLib).Layout;
         const layoutOptions = new Layout();
 
         layoutOptions.reset({
@@ -1210,7 +1226,7 @@ class Image {
         if (image.height > layout.maxHeight)
             image.crop(0, 0, image.width, Math.floor(layoutOptions.lines() / image.height * layout.maxHeight) * (image.height / layoutOptions.lines()));
 
-        font.free();
+        // font.free();
         layoutOptions.free();
         return image.opacity(a / 0xff);
     }