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Adding gmistHittestPoly()

remotes/origin_old/ugfx_release_2.7
Joel Bodenmann 5 years ago
parent
commit
7d17a34111
  1. 1
      docs/releases.txt
  2. 1
      gfxconf.example.h
  3. 19
      src/gmisc/gmisc.h
  4. 3
      src/gmisc/gmisc.mk
  5. 117
      src/gmisc/gmisc_hittest.c
  6. 1
      src/gmisc/gmisc_mk.c
  7. 7
      src/gmisc/gmisc_options.h

1
docs/releases.txt

@ -22,6 +22,7 @@ FIX: Fixed an issue in the filled polygon drawing function which caused irregul
FEATURE: Added high-level functions to modify image color palettes
FIX: Improving gdispDrawThickLine()
FEATURE: Added gdispAddFont() for adding a dynamic font to the permanent font list
FEATURE: Added gmiscHittestPoly() for checking whether a point is inside of a polygon
*** Release 2.6 ***

1
gfxconf.example.h

@ -335,5 +335,6 @@
// #define GMISC_INVSQRT_REAL_SLOW FALSE
//#define GMISC_NEED_MATRIXFLOAT2D FALSE
//#define GMISC_NEED_MATRIXFIXED2D FALSE
//#define GMISC_NEED_HITTEST_POLY FALSE
#endif /* _GFXCONF_H */

19
src/gmisc/gmisc.h

@ -464,6 +464,25 @@ extern "C" {
#endif
#endif
#if GMISC_NEED_HITTEST_POLY || defined(__DOXYGEN__)
/**
* @brief Check whether a point is inside or on the edge of a polygon
* @pre Requires GFX_USE_GMISC and GMISC_NEED_HITTEST_POLY
*
* @note This function works both with convex and concave polygons
*
* @param[in] pntarray The array of points that form the polygon
* @param[in] cnt The number of points in the point array @pntarray
* @param[in] p The point to test
*
* @return @p TRUE if the point @p p is inside or on the edge of the polygon @p pntarray, @p FALSE otherwise.
*
* @api
*/
bool_t gmiscHittestPoly(const point *pntarray, unsigned cnt, const point *p);
#endif // GMISC_NEED_HITTEST_POLY
#ifdef __cplusplus
}
#endif

3
src/gmisc/gmisc.mk

@ -6,4 +6,5 @@
GFXSRC += $(GFXLIB)/src/gmisc/gmisc.c \
$(GFXLIB)/src/gmisc/gmisc_arrayops.c \
$(GFXLIB)/src/gmisc/gmisc_matrix2d.c \
$(GFXLIB)/src/gmisc/gmisc_trig.c
$(GFXLIB)/src/gmisc/gmisc_trig.c \
$(GFXLIB)/src/gmisc/gmisc_hittest.c

117
src/gmisc/gmisc_hittest.c

@ -0,0 +1,117 @@
/*
* This file is subject to the terms of the GFX License. If a copy of
* the license was not distributed with this file, you can obtain one at:
*
* http://ugfx.org/license.html
*/
#include "../../gfx.h"
#if GFX_USE_GMISC
#if GMISC_NEED_HITTEST_POLY
/* This function is used by gmiscHittestPoly()
*
* This function projects the point c on an horizontal line to the right.
* If the projection cuts the segment formed by the points a and b,
* the function returns 1. If the point c is on the segment, the function
* returns 0. If they don't intersect, it returns 2.
*/
static char _pointCrossingSegment(const point *a, const point *b, const point *c) {
/* If both points are left from our point, it won't intersect */
if (a->x < c->x && b->x < c->x) {
return -1;
}
/* Check if there is a point above and a point below, else
* it won't intersect.
*/
if (c->y <= a->y && c->y >= b->y) {
coord_t crossProduct;
/* If the line is parallel */
if (a->y == b->y) {
/* Point on the segment */
if ((c->x >= a->x && c->x <= b->x) || (c->x <= a->x && c->x >= b->x)) {
return 0;
} else {
return -1;
}
}
/* If the point is on the same horizontal line as one of the segment point,
* allow to add the intersection once
*/
if (c->y == b->y) {
return -1;
}
/* Matrix cross product to find if the point is left or right from the segment*/
crossProduct = (b->x - a->x) * (c->y - a->y) - (b->y - a->y) * (c->x - a->x);
/* Point left of the segment */
if (crossProduct < 0) {
return 1;
}
/* Point on the segment */
if (crossProduct == 0) {
return 0;
}
}
return -1;
}
bool_t gmiscHittestPoly(const point *pntarray, unsigned cnt, const point *p) {
unsigned i = 0;
uint8_t nbrIntersection = 0;
int8_t crossResult;
// For each pair of points
for (i = 0; i < cnt-1; i++) {
/* Order the two points from top to bottom to simplify the function */
if (pntarray[i].y >= pntarray[i+1].y) {
crossResult = _pointCrossingSegment(&pntarray[i], &pntarray[i+1], p);
} else {
crossResult = _pointCrossingSegment(&pntarray[i+1], &pntarray[i], p);
}
/* Point on the edge of the polygon */
if (crossResult == 0) {
return TRUE;
}
/* Point crossing the polygon */
else if(crossResult == 1) {
nbrIntersection++;
}
}
/* Last pair of points, can't be done in the loops
* Same as before
*/
if (pntarray[cnt-1].y >= pntarray[0].y) {
crossResult = _pointCrossingSegment(&pntarray[cnt-1], &pntarray[0], p);
} else {
crossResult = _pointCrossingSegment(&pntarray[0], &pntarray[cnt-1], p);
}
if (crossResult == 0) {
return TRUE;
} else if(crossResult == 1) {
nbrIntersection++;
}
/* If we cross an even pair of segments, we are outside */
if (nbrIntersection % 2 == 0) {
return FALSE;
}
/* Else we are inside the polygon */
return TRUE;
}
#endif // GMISC_NEED_HITTEST_POLY
#endif // GFX_USE_GMISC

1
src/gmisc/gmisc_mk.c

@ -9,3 +9,4 @@
#include "gmisc_arrayops.c"
#include "gmisc_matrix2d.c"
#include "gmisc_trig.c"
#include "gmisc_hittest.c"

7
src/gmisc/gmisc_options.h

@ -48,6 +48,13 @@
#ifndef GMISC_NEED_INVSQRT
#define GMISC_NEED_INVSQRT FALSE
#endif
/**
* @brief Include polygon hit test functions
* @details Defaults to FALSE
*/
#ifndef GMISC_NEED_HITTEST_POLY
#define GMISC_NEED_HITTEST_POLY FALSE
#endif
/**
* @}
*

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