!456 [206_3] 重构emoji缓存机制

Author: songhahaha66

devel/206_3.md

@@ -0,0 +1,19 @@
+# 206_3: 优化emoji渲染时缓存机制
+
+## 2025/07/27
+
+### What
+
+重构缓存机制：
+
+1. 添加了glyphID -> picture的缓存
+
+### Why
+
+当前Mogan输入emoji有卡顿现象
+
+### How
+
+修改了
+
+1. qtrender.cpp

src/Plugins/Qt/qt_renderer.cpp

@@ -84,6 +84,8 @@ CONCRETE_NULL_CODE (qt_pixmap);
 static hashmap<basic_character, qt_image> character_image;
 // image cache
 static hashmap<string, qt_pixmap> images;
+// emoji cache: glyphID -> (size -> picture)
+static hashmap<int, hashmap<int, picture>> emoji_cache;
 
 /*
 ** hash contents must be removed because
@@ -94,6 +96,7 @@ void
 del_obj_qt_renderer (void) {
   character_image= hashmap<basic_character, qt_image> ();
   images         = hashmap<string, qt_pixmap> ();
+  emoji_cache    = hashmap<int, hashmap<int, picture>> ();
 }
 
 /******************************************************************************
@@ -698,20 +701,35 @@ qt_renderer_rep::draw_emoji (int char_code, font_glyphs fn, SI x, SI y) {
     return;
   }
 
-  // Retrieve SVG data for the glyph
-  string svg_data= tt_font->face->svg_table->get_svg_from_glyphid (glyph_id);
-  if (N (svg_data) == 0) {
-    return;
-  }
-
   // Calculate emoji size
   SI    xo, yo;
   glyph pre_gl= fn->get (char_code);
   glyph gl    = shrink (pre_gl, std_shrinkf, std_shrinkf, xo, yo);
   int   w= gl->width, h= gl->height;
 
-  // Create picture from SVG data
-  picture emoji_picture= svg_string_to_picture (svg_data, w, h);
+  // check cache first
+  picture emoji_picture;
+  if (emoji_cache->contains (glyph_id)) {
+    hashmap<int, picture> size_cache= emoji_cache[glyph_id];
+    if (size_cache->contains (w)) {
+      emoji_picture= size_cache[w];
+    }
+  }
+
+  // cache miss: get SVG data and create picture
+  if (is_nil (emoji_picture)) {
+    string svg_data= tt_font->face->svg_table->get_svg_from_glyphid (glyph_id);
+    if (N (svg_data) == 0) {
+      return;
+    }
+    emoji_picture= svg_string_to_picture (svg_data, w, h);
+    if (!is_nil (emoji_picture)) {
+      if (!emoji_cache->contains (glyph_id)) {
+        emoji_cache (glyph_id)= hashmap<int, picture> ();
+      }
+      emoji_cache[glyph_id](w)= emoji_picture;
+    }
+  }
   if (is_nil (emoji_picture)) {
     return;
   }