bezier.c

nucleus 文件系统,内核和彩色图形系统,在小系统上非常好用

#define byte unsigned char
#define word unsigned short
#include <stdlib.h>
#include <stdio.h>
#include "metawndo.h"      /* master MetaWINDOW include file */

/* special stack size declaration if using Turbo or Borland C++ */
#ifdef      TurboC
extern unsigned _stklen = 14336U;  /* stack size 14K */
#endif


void DrawBezier( point *bez, int count );
void DrawHandle( point *bez, int count, int control );
void Waiting(int a);

#define HANDLESIZE 10      // size of 'handle' bounding boxes
#define NUMPOINTS  16      // number of points in our sample array

void bezier( )
{
#ifdef _MNT_
	void QueryMousePosition(int *x, int *y, int *level, int *button);
#endif
	void quit(void);
   int      GrafixCard = 2;
   rect     scrnR, tR;
   point    mousePt, bz[NUMPOINTS];
   mwEvent  myevent;
   int i, x, y, l, buttons;

    /* init the system */
//   i = InitGraphics( GrafixCard );

//   SetDisplay( GrafPg0 ); 

   /* set a virtual coordinate system of 500x500 */
   SetRect( &scrnR, 0, 0, 500, 500 );
   VirtualRect( &scrnR );

   // Init the bezier control points
   bz[0].X=25;    bz[0].Y=475;
   bz[3].X=125;   bz[3].Y=25;
   bz[6].X=250;   bz[6].Y=450;
   bz[9].X=375;   bz[9].Y=25;
   bz[12].X=475;  bz[12].Y=475;
   bz[15].X=33;   bz[15].Y=475;

   // Init bezier handles
   bz[1].X=13;    bz[1].Y=425;   // handle from point 0
   bz[2].X=75;    bz[2].Y=25;    // handle to   point 3
   bz[4].X=225;   bz[4].Y=45;    // handle from point 3
   bz[5].X=150;   bz[5].Y=450;   // handle to   point 6
   bz[7].X=350;   bz[7].Y=425;   // handle from point 6
   bz[8].X=275;   bz[8].Y=5;    // handle to   point 9
   bz[10].X=425;  bz[10].Y=25;   // handle from point 9
   bz[11].X=485;  bz[11].Y=425;  // handle to   point 12
   bz[13].X=463;  bz[13].Y=488;  // handle from point 12
   bz[14].X=38;   bz[14].Y=488;  // handle to   point 15


   DrawBezier( bz, NUMPOINTS );

   // let them move the points around

   TrackCursor( 1 ); 

#ifndef CYCLE
   // until a key is pressed
   while( 1 ) {

		MoveTo( (scrnR.Xmax >> 1),scrnR.Ymax - 30 );
		DrawString( "Use mouse to move control points" );
		MoveTo( (scrnR.Xmax >> 1),scrnR.Ymax - 20 );
		DrawString( "Or press 'x' to exit" );
		MoveTo( (scrnR.Xmax >> 1),scrnR.Ymax - 10 );
		DrawString( "any other key to continue" );

      KeyEvent( 1, &myevent );

      /* key press is exit */
      if( myevent.eventType == evntKEYDN )
         break;

      /* we only care about mouse button press events */ 
      if( myevent.eventType != evntPRESS ) 
         continue;

      // is press on a bezier point ?
	  mousePt.X = myevent.eventX;
	  mousePt.Y = myevent.eventY;
	  Gbl2VirPt(&mousePt);
      for( i = 0 ; i < NUMPOINTS; i++ ) {

         CenterRect( &bz[i], HANDLESIZE, HANDLESIZE, &tR );
         if( PtInRoundRect( &mousePt, &tR, 2, 2, 2, 2 ) )
            break;
      }

      // not on any of our points, keep trying
      if( i >= NUMPOINTS )
         continue;

      // drag a bezier point
      buttons = myevent.eventButtons;
      while( buttons ) {

         // wait for a movement
#ifdef _MNT_
   QueryMousePosition(&x,&y,&l,&buttons);
#else
   /* This is a raw Metagraphics function */
   QueryCursor(&x,&y,&l,&buttons); 
#endif
         if( x == myevent.eventX && y == myevent.eventY )
            continue;

         // record new position
         myevent.eventX = x; myevent.eventY = y;
         
         // first undraw it
         DrawHandle( bz, NUMPOINTS, i );

         // change the point
         bz[i].X = x;
         bz[i].Y = y;
		Gbl2VirPt(&bz[i]);

         // re-draw it
         DrawHandle( bz, NUMPOINTS, i );

      }  // end of while(buttons)

      // redraw the updated curve
      DrawBezier( bz, NUMPOINTS );

   }  // end of while( 1 )
   
   if((myevent.eventChar == 'x') || (myevent.eventChar == 'X')) quit();
#else
#ifdef _MNT_
	  KeyEvent(0, &myevent);
	  if((myevent.eventChar == 'x') || (myevent.eventChar == 'X')) quit();
#endif
   Waiting(150);

#endif

   SetLocal();
   return;
}

// update the display to show the Bezier curve with indicators
void DrawBezier( point *bez, int count )
{

   int   i;
   rect  scrnR;

   HideCursor();

   ScreenRect( &scrnR );

   BackColor( LtBlue );
   EraseRect( &scrnR );

   PenColor( Green );
   PaintBezier( bez, count );

   PenColor( Red );
   PolyBezier( bez, count );
   PenSize(4,4);
   PenShape(shapeOval);
 FrameBezier( bez, count );
 PenNormal();

  // show all the points and handles
  for( i = 0 ; i < count; i += 3 ) 
     DrawHandle( bez, count, i );

  ShowCursor();

}


// givin a bezier point, draw indicators for its associated control and
// handle points
void DrawHandle( point *bez, int count, int pointndx )
{
   int control;
   rect tR;

   HideCursor();

   // draw in invert
   PenColor( -1 );
   RasterOp( zXORz );

   // compute the control point index (second of each three points)
   control = (pointndx + 1) / 3 * 3;


   // center a rectangle on the bezier control point
   CenterRect( &bez[control], HANDLESIZE, HANDLESIZE, &tR );
   // draw an oval for the first point
/*   FrameOval( &tR ); */
   MarkerSize(HANDLESIZE, HANDLESIZE);
   MarkerAngle((control << 8));
   MarkerType((short) control);
   PolyMarker(1, &bez[control]);
 
   // draw on the preceeding handle (if any)
   if( control != 0 ) {
      CenterRect( &bez[control-1], HANDLESIZE, HANDLESIZE, &tR );
      FrameRect( &tR );
      MoveTo( bez[control].X, bez[control].Y );
      LineTo( bez[control-1].X, bez[control-1].Y );
   }

   // center a rectangle on the postceeding handle (if any)
   if( control < (count - 1) ) {
      CenterRect( &bez[control+1], HANDLESIZE, HANDLESIZE, &tR );
      FrameRect( &tR );
      MoveTo( bez[control].X, bez[control].Y );
      LineTo( bez[control+1].X, bez[control+1].Y );
   }

   RasterOp( zREPz );

   ShowCursor();

}