From 79181567e5aeca740ede016692b9d35bdc773bf7 Mon Sep 17 00:00:00 2001
From: Michael Jumper <mike.jumper@guac-dev.org>
Date: Sun, 28 Feb 2016 14:55:29 -0800
Subject: [PATCH] GUAC-236: Store and preseve frame buffer within each layer.

---
 src/guacenc/layer.c | 11 +++++++++++
 src/guacenc/layer.h |  6 ++++++
 2 files changed, 17 insertions(+)

diff --git a/src/guacenc/layer.c b/src/guacenc/layer.c
index 890ad149..f6cd12b7 100644
--- a/src/guacenc/layer.c
+++ b/src/guacenc/layer.c
@@ -40,6 +40,14 @@ guacenc_layer* guacenc_layer_alloc() {
         return NULL;
     }
 
+    /* Allocate buffer for frame rendering */
+    layer->frame = guacenc_buffer_alloc();
+    if (layer->frame== NULL) {
+        guacenc_buffer_free(layer->buffer);
+        free(layer);
+        return NULL;
+    }
+
     /* Layers default to fully opaque */
     layer->opacity = 0xFF;
 
@@ -56,6 +64,9 @@ void guacenc_layer_free(guacenc_layer* layer) {
     if (layer == NULL)
         return;
 
+    /* Free internal frame buffer */
+    guacenc_buffer_free(layer->frame);
+
     /* Free underlying buffer */
     guacenc_buffer_free(layer->buffer);
 
diff --git a/src/guacenc/layer.h b/src/guacenc/layer.h
index 50f47040..d2a9d5a4 100644
--- a/src/guacenc/layer.h
+++ b/src/guacenc/layer.h
@@ -74,6 +74,12 @@ typedef struct guacenc_layer {
      */
     int opacity;
 
+    /**
+     * The internal buffer used by to record the state of this layer in the
+     * previous frame and to render additional frames.
+     */
+    guacenc_buffer* frame;
+
 } guacenc_layer;
 
 /**