GUACAMOLE-313: Do not render cursor unless mouse has actually moved.

src/guacenc/cursor.c

@@ -26,8 +26,7 @@
 guacenc_cursor* guacenc_cursor_alloc() {
 
     /* Allocate new cursor */
-    guacenc_cursor* cursor = (guacenc_cursor*) calloc(1,
-            sizeof(guacenc_cursor));
+    guacenc_cursor* cursor = (guacenc_cursor*) malloc(sizeof(guacenc_cursor));
     if (cursor == NULL)
         return NULL;
 
@@ -38,6 +37,9 @@ guacenc_cursor* guacenc_cursor_alloc() {
         return NULL;
     }
 
+    /* Do not initially render cursor, unless it moves */
+    cursor->x = cursor->y = -1;
+
     return cursor;
 
 }

src/guacenc/cursor.h

@@ -33,12 +33,16 @@
 typedef struct guacenc_cursor {
 
     /**
-     * The current X coordinate of the mouse cursor, in pixels.
+     * The current X coordinate of the mouse cursor, in pixels. Valid values
+     * are non-negative. Negative values indicate that the cursor should not
+     * be rendered.
      */
     int x;
 
     /**
-     * The current Y coordinate of the mouse cursor, in pixels.
+     * The current Y coordinate of the mouse cursor, in pixels. Valid values
+     * are non-negative. Negative values indicate that the cursor should not
+     * be rendered.
      */
     int y;
 

src/guacenc/display-flatten.c

@@ -93,6 +93,10 @@ static int guacenc_display_render_cursor(guacenc_display* display) {
 
     guacenc_cursor* cursor = display->cursor;
 
+    /* Do not render cursor if coordinates are negative */
+    if (cursor->x < 0 || cursor->y < 0)
+        return 0;
+
     /* Retrieve default layer (guaranteed to not be NULL) */
     guacenc_layer* def_layer = guacenc_display_get_layer(display, 0);
     assert(def_layer != NULL);