guipolye.c

来自「uCGUI」· C语言 代码 · 共 113 行

/*************************************************************************************************************
                                                   uC/GUI
                                               嵌入式通用图形软件
File        : GUIPolyE.c
Purpose     : Polygon enlarge
*************************************************************************************************************/
#include <math.h>
#include "GUI.H"
#include "GUIDebug.H"


typedef struct 
{
  float x,y;
} tfPoint;

static int fround ( float f) 
{
  if (f>0)
    return f+0.5;
  return f-0.5;
}

static void Normalize(tfPoint* pfPoint) 
{
  float fx = pfPoint->x;
  float fy = pfPoint->y;
  float r = sqrt(fx*fx + fy*fy);
  if (r > 0) {
    pfPoint->x = fx/r;
    pfPoint->y = fy/r;
  }
}

static void ReverseLen(tfPoint *pfPoint) 
{
  float fx = pfPoint->x;
  float fy = pfPoint->y;
  float r = sqrt(fx*fx/2 + fy*fy/2);
  if (r > 0) {
    pfPoint->x = fx/r/r;
    pfPoint->y = fy/r/r;
  }
}

static void GetVect(tfPoint *pfPoint, const GUI_POINT *pSrc, int NumPoints, int Index) 
{
  int Off0 = (Index + NumPoints-1) % NumPoints;
  int Off1 = Index % NumPoints;
  pfPoint->x = pSrc[Off1].x - pSrc[Off0].x; 
  pfPoint->y = pSrc[Off1].y - pSrc[Off0].y; 
}

/*************************************************************************************************************
                  GUI_EnlargePolygon
*************************************************************************************************************/
#if 0
void GUI_EnlargePolygon(GUI_POINT *pDest, const GUI_POINT *pSrc, int NumPoints, int Len) 
{
  int j;
  /* Calc destination points */
  for (j=0; j<NumPoints; j++) 
  {
    int x, y;
    tfPoint aVect[2];
    /* Get the vectors */
    GetVect(&aVect[0], pSrc, NumPoints, j);
    GetVect(&aVect[1], pSrc, NumPoints, j+1);
    /* Normalize the vectors and add vectors */
    Normalize(&aVect[0]);
    Normalize(&aVect[1]);
    aVect[0].x += aVect[1].x;
    aVect[0].y += aVect[1].y;
    /* Resulting vector needs to be normalized again */
    Normalize(&aVect[0]);
    x =  fround(aVect[0].y * Len);
    y = -fround(aVect[0].x * Len);
    /* Store destination */
    (pDest+j)->x = (pSrc+j)->x + x;
    (pDest+j)->y = (pSrc+j)->y + y;
  }
}

#else

void GUI_EnlargePolygon(GUI_POINT *pDest, const GUI_POINT *pSrc, int NumPoints, int Len) 
{
  int j;
  /* Calc destination points */
  for (j=0; j<NumPoints; j++) 
  {
    int x, y;
    tfPoint aVect[2];
    /* Get the vectors */
    GetVect(&aVect[0], pSrc, NumPoints, j);
    GetVect(&aVect[1], pSrc, NumPoints, j+1);
    /* Normalize the vectors and add vectors */
    Normalize(&aVect[0]);
    Normalize(&aVect[1]);
    aVect[0].x += aVect[1].x;
    aVect[0].y += aVect[1].y;
    /* Resulting vector needs to be normalized again */
    ReverseLen(&aVect[0]);
    x =  fround(aVect[0].y * Len);
    y = -fround(aVect[0].x * Len);
    /* Store destination */
    (pDest+j)->x = (pSrc+j)->x + x;
    (pDest+j)->y = (pSrc+j)->y + y;
  }
}
#endif