From 564040def0ab28b40a9571aca3622643e28451f4 Mon Sep 17 00:00:00 2001
From: Kevin Lamonte <kevin.lamonte@gmail.com>
Date: Wed, 13 Nov 2019 12:25:08 -0600
Subject: [PATCH] limit images in scrollback

---
 src/jexer/tterminal/DisplayLine.java | 25 ++++++++++++++++++
 src/jexer/tterminal/ECMA48.java      | 38 +++++++++++++++++++++++++---
 2 files changed, 59 insertions(+), 4 deletions(-)

diff --git a/src/jexer/tterminal/DisplayLine.java b/src/jexer/tterminal/DisplayLine.java
index 06a05a3..87e6952 100644
--- a/src/jexer/tterminal/DisplayLine.java
+++ b/src/jexer/tterminal/DisplayLine.java
@@ -248,4 +248,29 @@ public class DisplayLine {
         chars[chars.length - 1] = new Cell(newCell);
     }
 
+    /**
+     * Determine if line contains image data.
+     *
+     * @return true if the line has image data
+     */
+    public boolean isImage() {
+        for (int i = 0; i < chars.length; i++) {
+            if (chars[i].isImage()) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Clear image data from line.
+     */
+    public void clearImages() {
+        for (int i = 0; i < chars.length; i++) {
+            if (chars[i].isImage()) {
+                chars[i].reset();
+            }
+        }
+    }
+
 }
diff --git a/src/jexer/tterminal/ECMA48.java b/src/jexer/tterminal/ECMA48.java
index c6aa0b2..5d7eaaa 100644
--- a/src/jexer/tterminal/ECMA48.java
+++ b/src/jexer/tterminal/ECMA48.java
@@ -274,7 +274,7 @@ public class ECMA48 implements Runnable {
     /**
      * The maximum number of lines in the scrollback buffer.
      */
-    private int maxScrollback = 10000;
+    private int scrollbackMax = 10000;
 
     /**
      * The terminal's input.  For type == XTERM, this is an InputStreamReader
@@ -1255,10 +1255,29 @@ public class ECMA48 implements Runnable {
             display.add(line);
         }
         while (display.size() > height) {
-            scrollback.add(display.remove(0));
+            appendScrollbackLine(display.remove(0));
         }
     }
 
+    /**
+     * Get the maximum number of lines in the scrollback buffer.
+     *
+     * @return the maximum number of lines in the scrollback buffer
+     */
+    public int getScrollbackMax() {
+        return scrollbackMax;
+    }
+
+    /**
+     * Set the maximum number of lines for the scrollback buffer.
+     *
+     * @param scrollbackMax the maximum number of lines for the scrollback
+     * buffer
+     */
+    public final void setScrollbackMax(final int scrollbackMax) {
+        this.scrollbackMax = scrollbackMax;
+    }
+
     /**
      * Get visible cursor flag.
      *
@@ -1452,14 +1471,25 @@ public class ECMA48 implements Runnable {
         toGround();
     }
 
+    /**
+     * Append a to the scrollback buffer, clearing image data for lines more
+     * than three screenfuls in.
+     */
+    private void appendScrollbackLine(DisplayLine line) {
+        scrollback.add(line);
+        if (scrollback.size() > height * 3) {
+            scrollback.get(scrollback.size() - (height * 3)).clearImages();
+        }
+    }
+
     /**
      * Append a new line to the bottom of the display, adding lines off the
      * top to the scrollback buffer.
      */
     private void newDisplayLine() {
         // Scroll the top line off into the scrollback buffer
-        scrollback.add(display.get(0));
-        if (scrollback.size() > maxScrollback) {
+        appendScrollbackLine(display.get(0));
+        while (scrollback.size() > scrollbackMax) {
             scrollback.remove(0);
             scrollback.trimToSize();
         }
-- 
2.27.0