Actual source code: zoom.c

  1: /*$Id: zoom.c,v 1.20 2001/03/23 23:20:24 balay Exp $*/

 3:  #include petscdraw.h

  5: /*@C
  6:     PetscDrawZoom - Allows one to create a graphic that users may zoom into.

  8:     Collective on PetscDraw

 10:     Input Parameters:
 11: +   draw - the window where the graph will be made.
 12: .   func - users function that draws the graphic
 13: -   ctx - pointer to any user required data

 15:   Level: advanced

 17:   Concepts: graphics^zooming
 18:   Concepts: drawing^zooming
 19:   Concepts: zooming^in graphics

 21: .seealso:  
 22: @*/
 23: int PetscDrawZoom(PetscDraw draw,int (*func)(PetscDraw,void *),void *ctx)
 24: {
 25:   int        ierr,pause;
 26:   PetscDrawButton button;
 27:   PetscReal  xc,yc,scale = 1.0,w,h,xr,xl,yr,yl,xmin,xmax,ymin,ymax;
 28:   PetscTruth isnull;

 31:   PetscDrawIsNull(draw,&isnull);
 32:   if (isnull) return(0);

 34:   PetscDrawSynchronizedClear(draw);
 35:   (*func)(draw,ctx);
 36:   PetscDrawSynchronizedFlush(draw);

 38:   PetscDrawGetPause(draw,&pause);
 39:   if (pause >= 0) {
 40:     PetscSleep(pause);
 41:     return(0);
 42:   }

 44:   PetscDrawCheckResizedWindow(draw);
 45:   PetscDrawSynchronizedGetMouseButton(draw,&button,&xc,&yc,0,0);
 46:   PetscDrawGetCoordinates(draw,&xl,&yl,&xr,&yr);
 47:   w    = xr - xl; xmin = xl; ymin = yl; xmax = xr; ymax = yr;
 48:   h    = yr - yl;

 50:   if (button != BUTTON_NONE) {
 51:     while (button != BUTTON_RIGHT) {

 53:       PetscDrawSynchronizedClear(draw);
 54:       if (button == BUTTON_LEFT)        scale = .5;
 55:       else if (button == BUTTON_CENTER) scale = 2.;
 56:       xl = scale*(xl + w - xc) + xc - w*scale;
 57:       xr = scale*(xr - w - xc) + xc + w*scale;
 58:       yl = scale*(yl + h - yc) + yc - h*scale;
 59:       yr = scale*(yr - h - yc) + yc + h*scale;
 60:       w *= scale; h *= scale;
 61:       PetscDrawSetCoordinates(draw,xl,yl,xr,yr);

 63:       (*func)(draw,ctx);
 64:       PetscDrawCheckResizedWindow(draw);
 65:       PetscDrawSynchronizedGetMouseButton(draw,&button,&xc,&yc,0,0);
 66:     }
 67:   }

 69:   PetscDrawSetCoordinates(draw,xmin,ymin,xmax,ymax);

 71:   return(0);
 72: }