diff -r 000000000000 -r 88d965579617 components/u8g2/csrc/u8g2_intersection.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/components/u8g2/csrc/u8g2_intersection.c	Tue Oct 08 12:00:31 2019 +0200
@@ -0,0 +1,176 @@
+/*
+
+  u8g2_intersection.c 
+  
+  Intersection calculation, code taken from u8g_clip.c
+
+  Universal 8bit Graphics Library (https://github.com/olikraus/u8g2/)
+
+  Copyright (c) 2016, olikraus@gmail.com
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without modification, 
+  are permitted provided that the following conditions are met:
+
+  * Redistributions of source code must retain the above copyright notice, this list 
+    of conditions and the following disclaimer.
+    
+  * Redistributions in binary form must reproduce the above copyright notice, this 
+    list of conditions and the following disclaimer in the documentation and/or other 
+    materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
+  CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
+  INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
+  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
+  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
+  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
+  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
+  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
+  STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
+  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  
+
+*/
+
+#include "u8g2.h"
+
+#ifdef __GNUC__
+#define U8G2_ALWAYS_INLINE __inline__ __attribute__((always_inline))
+#else
+#define U8G2_ALWAYS_INLINE
+#endif 
+
+
+#if defined(U8G2_WITH_INTERSECTION) || defined(U8G2_WITH_CLIP_WINDOW_SUPPORT)
+
+#ifdef OLD_VERSION_WITH_SYMETRIC_BOUNDARIES
+
+/*
+  intersection assumptions:
+    a1 <= a2 is always true    
+    
+    minimized version
+    ---1----0 1             b1 <= a2 && b1 > b2
+    -----1--0 1             b2 >= a1 && b1 > b2
+    ---1-1--- 1             b1 <= a2 && b2 >= a1
+  */
+
+
+/*
+  calculate the intersection between a0/a1 and v0/v1
+  The intersection check returns one if the range of a0/a1 has an intersection with v0/v1.
+  The intersection check includes the boundary values v1 and a1.
+
+  The following asserts will succeed:
+    assert( u8g2_is_intersection_decision_tree(4, 6, 7, 9) == 0 );
+    assert( u8g2_is_intersection_decision_tree(4, 6, 6, 9) != 0 );
+    assert( u8g2_is_intersection_decision_tree(6, 9, 4, 6) != 0 );
+    assert( u8g2_is_intersection_decision_tree(7, 9, 4, 6) == 0 );  
+*/
+
+//static uint8_t U8G2_ALWAYS_INLINE u8g2_is_intersection_decision_tree(u8g_uint_t a0, u8g_uint_t a1, u8g_uint_t v0, u8g_uint_t v1) 
+static uint8_t u8g2_is_intersection_decision_tree(u8g2_uint_t a0, u8g2_uint_t a1, u8g2_uint_t v0, u8g2_uint_t v1) 
+{
+  if ( v0 <= a1 )
+  {
+    if ( v1 >= a0 )
+    {
+      return 1;
+    }
+    else
+    {
+      if ( v0 > v1 )
+      {
+	return 1;
+      }
+      else
+      {
+	return 0;
+      }
+    }
+  }
+  else
+  {
+    if ( v1 >= a0 )
+    {
+      if ( v0 > v1 )
+      {
+	return 1;
+      }
+      else
+      {
+	return 0;
+      }
+    }
+    else
+    {
+      return 0;
+    }
+  }
+}
+
+#endif	/* OLD_VERSION_WITH_SYMETRIC_BOUNDARIES */
+
+
+/*
+  version with asymetric boundaries.
+  a1 and v1 are excluded
+  v0 == v1 is not support end return 1
+*/
+uint8_t u8g2_is_intersection_decision_tree(u8g2_uint_t a0, u8g2_uint_t a1, u8g2_uint_t v0, u8g2_uint_t v1)
+{
+  if ( v0 < a1 )		// v0 <= a1
+  {
+    if ( v1 > a0 )	// v1 >= a0
+    {
+      return 1;
+    }
+    else
+    {
+      if ( v0 > v1 )	// v0 > v1
+      {
+	return 1;
+      }
+      else
+      {
+	return 0;
+      }
+    }
+  }
+  else
+  {
+    if ( v1 > a0 )	// v1 >= a0
+    {
+      if ( v0 > v1 )	// v0 > v1
+      {
+	return 1;
+      }
+      else
+      {
+	return 0;
+      }
+    }
+    else
+    {
+      return 0;
+    }
+  }
+}
+
+
+
+/* upper limits are not included (asymetric boundaries) */
+uint8_t u8g2_IsIntersection(u8g2_t *u8g2, u8g2_uint_t x0, u8g2_uint_t y0, u8g2_uint_t x1, u8g2_uint_t y1)
+{
+  if ( u8g2_is_intersection_decision_tree(u8g2->user_y0, u8g2->user_y1, y0, y1) == 0 )
+    return 0; 
+  
+  return u8g2_is_intersection_decision_tree(u8g2->user_x0, u8g2->user_x1, x0, x1);
+}
+
+
+#endif /* U8G2_WITH_INTERSECTION */
+