2: #include <petscdraw.h>     /*I "petscdraw.h"  I*/

  4: #if defined(PETSC_HAVE_SETJMP_H) && defined(PETSC_HAVE_X)
  5: #include <X11/Xlib.h>
  6: #include <X11/Xutil.h>
  7: #include <setjmp.h>
  8: static jmp_buf PetscXIOErrorJumpBuf;
  9: static void PetscXIOHandler(Display *dpy)
 10: {
 11:   longjmp(PetscXIOErrorJumpBuf, 1);
 12: }
 13: #endif

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

 20:     Collective on PetscDraw

 22:     Input Parameters:
 23: +   draw - the window where the graph will be made.
 24: .   func - users function that draws the graphic
 25: -   ctx - pointer to any user required data

 27:   Level: advanced

 29:   Concepts: graphics^zooming
 30:   Concepts: drawing^zooming
 31:   Concepts: zooming^in graphics

 33: .seealso:
 34: @*/
 35: PetscErrorCode  PetscDrawZoom(PetscDraw draw,PetscErrorCode (*func)(PetscDraw,void*),void *ctx)
 36: {
 37:   PetscErrorCode  ierr;
 38:   PetscDrawButton button;
 39:   PetscReal       dpause,xc,yc,scale = 1.0,w,h,xr,xl,yr,yl,xmin,xmax,ymin,ymax;
 40:   PetscBool       isnull;

 43:   PetscDrawIsNull(draw,&isnull);
 44:   if (isnull) return(0);

 46: #if defined(PETSC_HAVE_SETJMP_H) && defined(PETSC_HAVE_X)
 47:   if (!setjmp(PetscXIOErrorJumpBuf)) XSetIOErrorHandler((XIOErrorHandler)PetscXIOHandler);
 48:   else {
 49:     XSetIOErrorHandler(NULL);
 50:     PetscDrawSetType(draw,PETSC_DRAW_NULL);
 51:     return(0);
 52:   }
 53: #endif

 55:   PetscDrawCheckResizedWindow(draw);
 56:   PetscDrawSynchronizedClear(draw);
 57:   (*func)(draw,ctx);
 58:   PetscDrawSynchronizedFlush(draw);

 60:   PetscDrawGetPause(draw,&dpause);
 61:   if (dpause >= 0) {
 62:     PetscSleep(dpause);
 63:     goto theend;
 64:   }
 65:   if (dpause != -1) goto theend;

 67:   PetscDrawCheckResizedWindow(draw);
 68:   PetscDrawSynchronizedGetMouseButton(draw,&button,&xc,&yc,0,0);
 69:   PetscDrawGetCoordinates(draw,&xl,&yl,&xr,&yr);
 70:   w    = xr - xl; xmin = xl; ymin = yl; xmax = xr; ymax = yr;
 71:   h    = yr - yl;

 73:   if (button != PETSC_BUTTON_NONE) {
 74:     while (button != PETSC_BUTTON_RIGHT) {

 76:       PetscDrawSynchronizedClear(draw);
 77:       if (button == PETSC_BUTTON_LEFT)        scale = .5;
 78:       else if (button == PETSC_BUTTON_CENTER) scale = 2.;
 79:       xl   = scale*(xl + w - xc) + xc - w*scale;
 80:       xr   = scale*(xr - w - xc) + xc + w*scale;
 81:       yl   = scale*(yl + h - yc) + yc - h*scale;
 82:       yr   = scale*(yr - h - yc) + yc + h*scale;
 83:       w   *= scale; h *= scale;
 84:       PetscDrawSetCoordinates(draw,xl,yl,xr,yr);

 86:       (*func)(draw,ctx);
 87:       PetscDrawSynchronizedFlush(draw);
 88:       PetscDrawCheckResizedWindow(draw);
 89:       PetscDrawSynchronizedGetMouseButton(draw,&button,&xc,&yc,0,0);
 90:     }
 91:   }
 92:   PetscDrawSetCoordinates(draw,xmin,ymin,xmax,ymax);
 93: theend:
 94: #if defined(PETSC_HAVE_SETJMP_H) && defined(PETSC_HAVE_X)
 95:   XSetIOErrorHandler(NULL);
 96: #endif
 97:   return(0);
 98: }