--- /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 */
+