From edc1303af16e8dea9243818dc744f521310b3942 Mon Sep 17 00:00:00 2001
From: Autumn Lamonte <AutumnWalksTheLake@gmail.com>
Date: Fri, 4 Feb 2022 18:25:57 -0600
Subject: [PATCH] cache kitty

---
 src/jexer/backend/ECMA48Terminal.java | 37 ++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/src/jexer/backend/ECMA48Terminal.java b/src/jexer/backend/ECMA48Terminal.java
index 7dfadf8..c2a2b52 100644
--- a/src/jexer/backend/ECMA48Terminal.java
+++ b/src/jexer/backend/ECMA48Terminal.java
@@ -272,6 +272,11 @@ public class ECMA48Terminal extends LogicalScreen
      */
     private boolean kittyImages = false;
 
+    /**
+     * The Kitty post-rendered string cache.
+     */
+    private ImageCache kittyCache = null;
+
     /**
      * The number of threads for image rendering.
      */
@@ -1873,6 +1878,10 @@ public class ECMA48Terminal extends LogicalScreen
                         if (jexerCache == null) {
                             jexerCache = new ImageCache(height * width * 10);
                         }
+                    } else if (kittyImages) {
+                        if (kittyCache == null) {
+                            kittyCache = new ImageCache(height * width * 10);
+                        }
                     } else {
                         if (sixelCache == null) {
                             sixelCache = new ImageCache(height * width * 10);
@@ -4240,7 +4249,28 @@ public class ECMA48Terminal extends LogicalScreen
         assert (cells.size() > 0);
         assert (cells.get(0).getImage() != null);
 
-        // We don't cache Kitty images at this time.
+        // Save and get rows to/from the cache that do NOT have inverted
+        // cells.
+        boolean saveInCache = true;
+        for (Cell cell: cells) {
+            if (cell.isInvertedImage()) {
+                saveInCache = false;
+                break;
+            }
+            // Compute the hashcode so that the cell image hash is available
+            // for looking up in the image cache.
+            cell.hashCode();
+        }
+        if (saveInCache) {
+            String cachedResult = kittyCache.get(cells);
+            if (cachedResult != null) {
+                // System.err.println("CACHE HIT");
+                sb.append(gotoXY(x, y));
+                sb.append(cachedResult);
+                return sb.toString();
+            }
+            // System.err.println("CACHE MISS");
+        }
 
         BufferedImage image = cellsToImage(cells);
         int fullHeight = image.getHeight();
@@ -4289,6 +4319,11 @@ public class ECMA48Terminal extends LogicalScreen
             }
         }
 
+        if (saveInCache) {
+            // This row is OK to save into the cache.
+            kittyCache.put(cells, sb.toString());
+        }
+
         return (gotoXY(x, y) + sb.toString());
     }