diff options
Diffstat (limited to 'ArduinoAddons/Arduino_1.0.x/libraries/U8glib/utility/u8g_clip.c')
| -rwxr-xr-x | ArduinoAddons/Arduino_1.0.x/libraries/U8glib/utility/u8g_clip.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/ArduinoAddons/Arduino_1.0.x/libraries/U8glib/utility/u8g_clip.c b/ArduinoAddons/Arduino_1.0.x/libraries/U8glib/utility/u8g_clip.c new file mode 100755 index 000000000..1ca223e43 --- /dev/null +++ b/ArduinoAddons/Arduino_1.0.x/libraries/U8glib/utility/u8g_clip.c @@ -0,0 +1,156 @@ +/* + + u8g_clip.c + + procedures for clipping + taken over from procs in u8g_pb.c + + Universal 8bit Graphics Library + + Copyright (c) 2012, 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. + + Notes + + This is one of the most critical parts of u8glib. It must be fast, but still reliable. + Based on the intersection program (see tools folder), there is minimized version of + the condition for the intersaction test: + minimized version + ---1----0 1 b1 <= a2 && b1 > b2 + -----1--0 1 b2 >= a1 && b1 > b2 + ---1-1--- 1 b1 <= a2 && b2 >= a1 + It includes the assumption, that a1 <= a2 is always true (correct, because + a1, a2 are the page dimensions. + + The direct implementation of the above result is done in: + uint8_t u8g_is_intersection_boolean(u8g_uint_t a0, u8g_uint_t a1, u8g_uint_t v0, u8g_uint_t v1) + However, this is slower than a decision tree version: + static uint8_t u8g_is_intersection_decision_tree(u8g_uint_t a0, u8g_uint_t a1, u8g_uint_t v0, u8g_uint_t v1) + Also suprising is, that the macro implementation is slower than the inlined version. + + The decision tree is based on the expansion of the truth table. + +*/ + +#include "u8g.h" + +#ifdef __GNUC__ +#define U8G_ALWAYS_INLINE __inline__ __attribute__((always_inline)) +#else +#define U8G_ALWAYS_INLINE + #endif + +/* + 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 + */ + +#ifdef OLD_CODE_WHICH_IS_TOO_SLOW +static uint8_t u8g_is_intersection_boolean(u8g_uint_t a0, u8g_uint_t a1, u8g_uint_t v0, u8g_uint_t v1) +{ + uint8_t c1, c2, c3, tmp; + c1 = v0 <= a1; + c2 = v1 >= a0; + c3 = v0 > v1; + + tmp = c1; + c1 &= c2; + c2 &= c3; + c3 &= tmp; + c1 |= c2; + c1 |= c3; + return c1 & 1; +} +#endif + +#define U8G_IS_INTERSECTION_MACRO(a0,a1,v0,v1) ((uint8_t)( (v0) <= (a1) ) ? ( ( (v1) >= (a0) ) ? ( 1 ) : ( (v0) > (v1) ) ) : ( ( (v1) >= (a0) ) ? ( (v0) > (v1) ) : ( 0 ) )) + +//static uint8_t u8g_is_intersection_decision_tree(u8g_uint_t a0, u8g_uint_t a1, u8g_uint_t v0, u8g_uint_t v1) U8G_ALWAYS_INLINE; +static uint8_t U8G_ALWAYS_INLINE u8g_is_intersection_decision_tree(u8g_uint_t a0, u8g_uint_t a1, u8g_uint_t v0, u8g_uint_t v1) +{ + /* surprisingly the macro leads to larger code */ + /* return U8G_IS_INTERSECTION_MACRO(a0,a1,v0,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; + } + } +} + + +uint8_t u8g_IsBBXIntersection(u8g_t *u8g, u8g_uint_t x, u8g_uint_t y, u8g_uint_t w, u8g_uint_t h) +{ + register u8g_uint_t tmp; + tmp = y; + tmp += h; + tmp--; + if ( u8g_is_intersection_decision_tree(u8g->current_page.y0, u8g->current_page.y1, y, tmp) == 0 ) + return 0; + + tmp = x; + tmp += w; + tmp--; + return u8g_is_intersection_decision_tree(u8g->current_page.x0, u8g->current_page.x1, x, tmp); +} + + |