114 lines
2.8 KiB
C
114 lines
2.8 KiB
C
/*
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u8g2_intersection.c
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Intersection calculation, code taken from u8g_clip.c
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Universal 8bit Graphics Library (https://github.com/olikraus/u8g2/)
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Copyright (c) 2016, olikraus@gmail.com
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All rights reserved.
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Redistribution and use in source and binary forms, with or without modification,
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are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice, this list
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of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright notice, this
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list of conditions and the following disclaimer in the documentation and/or other
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materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
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INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "u8g2.h"
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#ifdef __GNUC__
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#define U8G2_ALWAYS_INLINE __inline__ __attribute__((always_inline))
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#else
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#define U8G2_ALWAYS_INLINE
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#endif
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#ifdef U8G2_WITH_INTERSECTION
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/*
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intersection assumptions:
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a1 <= a2 is always true
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minimized version
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---1----0 1 b1 <= a2 && b1 > b2
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-----1--0 1 b2 >= a1 && b1 > b2
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---1-1--- 1 b1 <= a2 && b2 >= a1
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*/
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//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)
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static uint8_t u8g2_is_intersection_decision_tree(u8g2_uint_t a0, u8g2_uint_t a1, u8g2_uint_t v0, u8g2_uint_t v1)
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{
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if ( v0 <= a1 )
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{
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if ( v1 >= a0 )
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{
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return 1;
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}
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else
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{
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if ( v0 > v1 )
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{
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return 1;
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}
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else
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{
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return 0;
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}
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}
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}
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else
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{
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if ( v1 >= a0 )
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{
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if ( v0 > v1 )
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{
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return 1;
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}
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else
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{
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return 0;
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}
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}
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else
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{
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return 0;
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}
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}
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}
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uint8_t u8g2_IsIntersection(u8g2_t *u8g2, u8g2_uint_t x0, u8g2_uint_t y0, u8g2_uint_t x1, u8g2_uint_t y1)
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{
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if ( u8g2_is_intersection_decision_tree(u8g2->user_y0, u8g2->user_y1, y0, y1) == 0 )
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return 0;
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return u8g2_is_intersection_decision_tree(u8g2->user_x0, u8g2->user_x1, x0, x1);
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}
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#endif /* U8G2_WITH_INTERSECTION */
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