85 lines
1.4 KiB
C
85 lines
1.4 KiB
C
/*
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u8g2_intersection.c
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code taken from u8g_clip.c
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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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