unleashed-firmware/lib/u8g2/u8g2_intersection.c
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153 lines
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C

/*
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 */