/***********************************************************************************************************                                                uC/GUI*                        Universal graphic software for embedded applications**                       (c) Copyright 2002, Micrium Inc., Weston, FL*                       (c) Copyright 2002, SEGGER Microcontroller Systeme GmbH**              礐/GUI is protected by international copyright laws. Knowledge of the*              source code may not be used to write a similar product. This file may*              only be used in accordance with a license and should not be redistributed*              in any way. We appreciate your understanding and fairness.*----------------------------------------------------------------------File        : GUICirc.CPurpose     : Circle and ellipse drawing functions----------------------------------------------------------------------Version-Date---Author-Explanation----------------------------------------------------------------------1.00.02 011115 JE     a) GL_FillEllipse, GL_FillCircle, GL_DrawCircle changed1.00.01 011113 JE     a) GL_DrawEllipse changed1.00.00 991206 RS     First release----------------------------------------------------------------------Known problems or limitations with current version----------------------------------------------------------------------None.----------------------------------------------------------------------Open issues----------------------------------------------------------------------None---------------------------END-OF-HEADER------------------------------*/#include <stddef.h>           /* needed for definition of NULL */#include "GUI_Private.H"/*      *************************************************      *                                               *      *            Draw Circle                        *      *                                               *      **************************************************/static  void Draw8Point(int x0,int y0, int xoff, int yoff) {  LCD_HL_DrawPixel(x0+xoff,y0+yoff);  LCD_HL_DrawPixel(x0-xoff,y0+yoff);  LCD_HL_DrawPixel(x0+yoff,y0+xoff);  LCD_HL_DrawPixel(x0+yoff,y0-xoff);  if (yoff) {    LCD_HL_DrawPixel(x0+xoff,y0-yoff);    LCD_HL_DrawPixel(x0-xoff,y0-yoff);    LCD_HL_DrawPixel(x0-yoff,y0+xoff);    LCD_HL_DrawPixel(x0-yoff,y0-xoff);  }}void GL_DrawCircle(int x0, int y0, int r) {  I32 i;  int imax = ((I32)((I32)r*707))/1000+1;  I32 sqmax = (I32)r*(I32)r+(I32)r/2;  I32 y=r;  Draw8Point(x0,y0,r,0);  for (i=1; i<= imax; i++) {    if ((i*i+y*y) >sqmax) {      Draw8Point(x0,y0,i,y);      y--;    }    Draw8Point(x0,y0,i,y);  }}void GUI_DrawCircle       (int x0, int y0, int r) {  #if (GUI_WINSUPPORT)    GUI_RECT Rect;  #endif  GUI_LOCK();  #if (GUI_WINSUPPORT)    WM_ADDORG(x0,y0);    Rect.x0 = x0-r;    Rect.x1 = x0+r;    Rect.y0 = y0-r;    Rect.y1 = y0+r;    WM_ITERATE_START(&Rect); {  #endif    GL_DrawCircle( x0, y0, r);  #if (GUI_WINSUPPORT)    } WM_ITERATE_END();  #endif  GUI_UNLOCK();}/*      *************************************************      *                                               *      *            Fill Circle                        *      *                                               *      **************************************************/void GL_FillCircle       (int x0, int y0, int r) {  I32 i;  int imax = ((I32)((I32)r*707))/1000+1;  I32 sqmax = (I32)r*(I32)r+(I32)r/2;  I32 x=r;  LCD_HL_DrawHLine(x0-r,y0,x0+r);  for (i=1; i<= imax; i++) {    if ((i*i+x*x) >sqmax) {      /* draw lines from outside */      if (x>imax) {        LCD_HL_DrawHLine (x0-i+1,y0+x, x0+i-1);        LCD_HL_DrawHLine (x0-i+1,y0-x, x0+i-1);      }      x--;    }    /* draw lines from inside (center) */    LCD_HL_DrawHLine(x0-x,y0+i, x0+x);    LCD_HL_DrawHLine(x0-x,y0-i, x0+x);  }}void GUI_FillCircle       (int x0, int y0, int r) {  GUI_LOCK();  #if (GUI_WINSUPPORT)    WM_ADDORG(x0,y0);    WM_ITERATE_START(NULL); {  #endif  GL_FillCircle(x0,y0,r);  #if (GUI_WINSUPPORT)    } WM_ITERATE_END();  #endif  GUI_UNLOCK();}/*        *********************************************************        *                                                       *        *               Ellipse drawing / filling               *        *                                                       *        *********************************************************The most efficient way to calculate the ellipse positionsis using the knowledge that the ellipse is just circle which hascompressed (or stretched) in one direction. For a circle, thefollowing equation holds true for all points located on the border ofit:               x^2 + y(x)^2 = r^2 = constTherefor, for an ellipse we can make use of the following equation:               (ry*x)^2 + (rx*y(x))^2 = (ry*rx)^2 = const*/void GL_FillEllipse      (int x0, int y0, int rx, int ry) {  I32 OutConst, Sum, SumY;  int x,y;  U32 _rx = rx;  U32 _ry = ry;  OutConst = _rx*_rx*_ry*_ry  /* Constant as explaint above */            +(_rx*_rx*_ry>>1); /* To compensate for rounding */  x = rx;  for (y=0; y<=ry; y++) {    SumY =((I32)(rx*rx))*((I32)(y*y)); /* Does not change in loop */    while (Sum = SumY + ((I32)(ry*ry))*((I32)(x*x)),           (x>0) && (Sum>OutConst))    {      x--;    }    LCD_HL_DrawHLine(x0-x, y0+y, x0+x);    if (y)      LCD_HL_DrawHLine(x0-x, y0-y, x0+x);  }}void GUI_FillEllipse      (int x0, int y0, int rx, int ry) {  #if (GUI_WINSUPPORT)    GUI_RECT r;  #endif  GUI_LOCK();  #if (GUI_WINSUPPORT)    WM_ADDORG(x0,y0);    /* Calc rectangle in order to avoid unnecessary drawing ops. */    r.x0 = x0-rx; r.x1 = x0+rx; r.y0 = y0-ry; r.y1 = y0+ry;    WM_ITERATE_START(&r); {  #endif  GL_FillEllipse (x0,y0, rx, ry);  #if (GUI_WINSUPPORT)    } WM_ITERATE_END();  #endif  GUI_UNLOCK();}void GL_DrawEllipse      (int x0, int y0, int rx, int ry) {  I32 OutConst, Sum, SumY;  int x,y;  int xOld;  U32 _rx = rx;  U32 _ry = ry;  OutConst = _rx*_rx*_ry*_ry  /* Constant as explaint above */            +(_rx*_rx*_ry>>1); /* To compensate for rounding */  xOld = x = rx;  for (y=0; y<=ry; y++) {    if (y==ry) {      x=0;    } else {      SumY =((I32)(rx*rx))*((I32)(y*y)); /* Does not change in loop */      while (Sum = SumY + ((I32)(ry*ry))*((I32)(x*x)),             (x>0) && (Sum>OutConst)) x--;    }/* Since we draw lines, we can not draw on the first    iteration*/    if (y) {      GL_DrawLine1(x0-xOld,y0-y+1,x0-x,y0-y);      GL_DrawLine1(x0-xOld,y0+y-1,x0-x,y0+y);      GL_DrawLine1(x0+xOld,y0-y+1,x0+x,y0-y);      GL_DrawLine1(x0+xOld,y0+y-1,x0+x,y0+y);    }    xOld = x;  }}void GUI_DrawEllipse      (int x0, int y0, int rx, int ry) {  #if (GUI_WINSUPPORT)    GUI_RECT r;  #endif  GUI_LOCK();  #if (GUI_WINSUPPORT)    WM_ADDORG(x0,y0);  /* Calc rectangle in order to avoid unnecessary drawing ops. */    r.x0 = x0-rx; r.x1 = x0+rx; r.y0 = y0-ry; r.y1 = y0+ry;    WM_ITERATE_START(&r); {  #endif  GL_DrawEllipse(x0, y0, rx, ry);  #if (GUI_WINSUPPORT)    } WM_ITERATE_END();  #endif  GUI_UNLOCK();}