feat: add text cache size debug display, increase max texture size

src/app.rs

@@ -562,7 +562,12 @@ impl eframe::App for TemplateApp {
 
                     if let Some(ref cache) = self.text_cache {
                         ui.separator();
-                        ui.label(format!("Text cache: {} entries", cache.cache_size()));
+                        let bytes = cache.cache_memory_bytes();
+                        let mb = bytes as f32 / (1024.0 * 1024.0);
+                        ui.label(format!(
+                            "Text cache: {} entries (~{mb:.2} MB)",
+                            cache.cache_size()
+                        ));
                     }
                 });
         }

src/text_cache.rs

@@ -23,7 +23,7 @@ const TEXTURE_OPTIONS: TextureOptions = TextureOptions {
 };
 
 /// Maximum texture dimension to prevent memory issues.
-const MAX_TEXTURE_DIM: u32 = 4096;
+const MAX_TEXTURE_DIM: u32 = 8192;
 
 /// Maximum pixel count (16M pixels = 64MB for RGBA).
 const MAX_PIXEL_COUNT: usize = 16 * 1024 * 1024;
@@ -74,6 +74,14 @@ impl TextCache {
         self.cache.len()
     }
 
+    /// Returns approximate GPU memory used by cached text textures (bytes).
+    pub fn cache_memory_bytes(&self) -> usize {
+        self.cache
+            .values()
+            .map(|cached| cached.width as usize * cached.height as usize * 4)
+            .sum()
+    }
+
     /// Get or create a cached texture for the given text.
     ///
     /// The texture is rendered at the smallest available render scale that can