xref: /petsc/src/sys/classes/draw/impls/x/xops.c (revision 82f73ecaae2ba6158892468c437f14f4e82707f0)
1 /*
2     Defines the operations for the X PetscDraw implementation.
3 */
4 
5 #include <../src/sys/classes/draw/impls/x/ximpl.h>         /*I  "petscsys.h" I*/
6 
7 /*
8      These macros transform from the users coordinates to the  X-window pixel coordinates.
9 */
10 #define XTRANS(draw,xwin,x)  (int)(((xwin)->w)*((draw)->port_xl + (((x - (draw)->coor_xl)*((draw)->port_xr - (draw)->port_xl))/((draw)->coor_xr - (draw)->coor_xl))))
11 #define YTRANS(draw,xwin,y)  (int)(((xwin)->h)*(1 - (draw)->port_yl - (((y - (draw)->coor_yl)*((draw)->port_yr - (draw)->port_yl))/((draw)->coor_yr - (draw)->coor_yl))))
12 
13 #define ITRANS(draw,xwin,i)  (draw)->coor_xl + (i*((draw)->coor_xr - (draw)->coor_xl)/((xwin)->w) - (draw)->port_xl)/((draw)->port_xr - (draw)->port_xl)
14 #define JTRANS(draw,xwin,j)  draw->coor_yl + (((PetscReal)j)/xwin->h + draw->port_yl - 1)*(draw->coor_yr - draw->coor_yl)/(draw->port_yl - draw->port_yr)
15 
16 #undef __FUNCT__
17 #define __FUNCT__ "PetscDrawSetViewport_X"
18 static PetscErrorCode PetscDrawSetViewport_X(PetscDraw draw,PetscReal xl,PetscReal yl,PetscReal xr,PetscReal yr)
19 {
20   PetscDraw_X    *XiWin = (PetscDraw_X*)draw->data;
21   XRectangle     box;
22   PetscErrorCode ierr;
23 
24   PetscFunctionBegin;
25   ierr = PetscDrawCollectiveBegin(draw);CHKERRQ(ierr);
26   box.x = (short)(xl*XiWin->w);
27   box.y = (short)((1-yr)*XiWin->h);
28   box.width  = (unsigned short)((xr-xl)*XiWin->w);
29   box.height = (unsigned short)((yr-yl)*XiWin->h);
30   XSetClipRectangles(XiWin->disp,XiWin->gc.set,0,0,&box,1,Unsorted);
31   ierr = PetscDrawCollectiveEnd(draw);CHKERRQ(ierr);
32   PetscFunctionReturn(0);
33 }
34 
35 #undef __FUNCT__
36 #define __FUNCT__ "PetscDrawCoordinateToPixel_X"
37 static PetscErrorCode PetscDrawCoordinateToPixel_X(PetscDraw draw,PetscReal x,PetscReal y,PetscInt *i,PetscInt *j)
38 {
39   PetscDraw_X *XiWin = (PetscDraw_X*)draw->data;
40 
41   PetscFunctionBegin;
42   *i = XTRANS(draw,XiWin,x);
43   *j = YTRANS(draw,XiWin,y);
44   PetscFunctionReturn(0);
45 }
46 
47 #undef __FUNCT__
48 #define __FUNCT__ "PetscDrawPixelToCoordinate_X"
49 static PetscErrorCode PetscDrawPixelToCoordinate_X(PetscDraw draw,PetscInt i,PetscInt j,PetscReal *x,PetscReal *y)
50 {
51   PetscDraw_X *XiWin = (PetscDraw_X*)draw->data;
52 
53   PetscFunctionBegin;
54   *x = ITRANS(draw,XiWin,i);
55   *y = JTRANS(draw,XiWin,j);
56   PetscFunctionReturn(0);
57 }
58 
59 #undef __FUNCT__
60 #define __FUNCT__ "PetscDrawPoint_X"
61 static PetscErrorCode PetscDrawPoint_X(PetscDraw draw,PetscReal x,PetscReal y,int c)
62 {
63   PetscDraw_X *XiWin = (PetscDraw_X*)draw->data;
64   int         xx,yy,i,j;
65 
66   PetscFunctionBegin;
67   xx = XTRANS(draw,XiWin,x);  yy = YTRANS(draw,XiWin,y);
68   PetscDrawXiSetColor(XiWin,c);
69   for (i=-1; i<2; i++) {
70     for (j=-1; j<2; j++) {
71       XDrawPoint(XiWin->disp,PetscDrawXiDrawable(XiWin),XiWin->gc.set,xx+i,yy+j);
72     }
73   }
74   PetscFunctionReturn(0);
75 }
76 
77 #undef __FUNCT__
78 #define __FUNCT__ "PetscDrawPointPixel_X"
79 static PetscErrorCode PetscDrawPointPixel_X(PetscDraw draw,PetscInt x,PetscInt y,int c)
80 {
81   PetscDraw_X *XiWin = (PetscDraw_X*)draw->data;
82 
83   PetscFunctionBegin;
84   PetscDrawXiSetColor(XiWin,c);
85   XDrawPoint(XiWin->disp,PetscDrawXiDrawable(XiWin),XiWin->gc.set,x,y);
86   PetscFunctionReturn(0);
87 }
88 
89 #undef __FUNCT__
90 #define __FUNCT__ "PetscDrawLine_X"
91 static PetscErrorCode PetscDrawLine_X(PetscDraw draw,PetscReal xl,PetscReal yl,PetscReal xr,PetscReal yr,int cl)
92 {
93   PetscDraw_X *XiWin = (PetscDraw_X*)draw->data;
94   int         x1,y_1,x2,y2;
95 
96   PetscFunctionBegin;
97   PetscDrawXiSetColor(XiWin,cl);
98   x1  = XTRANS(draw,XiWin,xl);   x2  = XTRANS(draw,XiWin,xr);
99   y_1 = YTRANS(draw,XiWin,yl);   y2  = YTRANS(draw,XiWin,yr);
100   if (x1 == x2 && y_1 == y2) PetscFunctionReturn(0);
101   XDrawLine(XiWin->disp,PetscDrawXiDrawable(XiWin),XiWin->gc.set,x1,y_1,x2,y2);
102   PetscFunctionReturn(0);
103 }
104 
105 #undef __FUNCT__
106 #define __FUNCT__ "PetscDrawArrow_X"
107 static PetscErrorCode PetscDrawArrow_X(PetscDraw draw,PetscReal xl,PetscReal yl,PetscReal xr,PetscReal yr,int cl)
108 {
109   PetscDraw_X *XiWin = (PetscDraw_X*)draw->data;
110   int         x1,y_1,x2,y2;
111 
112   PetscFunctionBegin;
113   PetscDrawXiSetColor(XiWin,cl);
114   x1  = XTRANS(draw,XiWin,xl);   x2  = XTRANS(draw,XiWin,xr);
115   y_1 = YTRANS(draw,XiWin,yl);   y2  = YTRANS(draw,XiWin,yr);
116   if (x1 == x2 && y_1 == y2) PetscFunctionReturn(0);
117   XDrawLine(XiWin->disp,PetscDrawXiDrawable(XiWin),XiWin->gc.set,x1,y_1,x2,y2);
118   if (x1 == x2 && PetscAbs(y_1 - y2) > 7) {
119     if (y2 > y_1) {
120       XDrawLine(XiWin->disp,PetscDrawXiDrawable(XiWin),XiWin->gc.set,x2,y2,x2-3,y2-3);
121       XDrawLine(XiWin->disp,PetscDrawXiDrawable(XiWin),XiWin->gc.set,x2,y2,x2+3,y2-3);
122     } else {
123       XDrawLine(XiWin->disp,PetscDrawXiDrawable(XiWin),XiWin->gc.set,x2,y2,x2-3,y2+3);
124       XDrawLine(XiWin->disp,PetscDrawXiDrawable(XiWin),XiWin->gc.set,x2,y2,x2+3,y2+3);
125     }
126   }
127   PetscFunctionReturn(0);
128 }
129 
130 #undef __FUNCT__
131 #define __FUNCT__ "PetscDrawRectangle_X"
132 static PetscErrorCode PetscDrawRectangle_X(PetscDraw draw,PetscReal xl,PetscReal yl,PetscReal xr,PetscReal yr,int c1,int c2,int c3,int c4)
133 {
134   PetscDraw_X *XiWin = (PetscDraw_X*)draw->data;
135   int         x1,y_1,w,h,c = (c1 + c2 + c3 + c4)/4;
136 
137   PetscFunctionBegin;
138   PetscDrawXiSetColor(XiWin,c);
139   x1  = XTRANS(draw,XiWin,xl);   w  = XTRANS(draw,XiWin,xr) - x1;
140   y_1 = YTRANS(draw,XiWin,yr);   h  = YTRANS(draw,XiWin,yl) - y_1;
141   if (w <= 0) w = 1;
142   if (h <= 0) h = 1;
143   XFillRectangle(XiWin->disp,PetscDrawXiDrawable(XiWin),XiWin->gc.set,x1,y_1,w,h);
144   PetscFunctionReturn(0);
145 }
146 
147 #undef __FUNCT__
148 #define __FUNCT__ "PetscDrawEllipse_X"
149 static PetscErrorCode PetscDrawEllipse_X(PetscDraw Win,PetscReal x,PetscReal y,PetscReal a,PetscReal b,int c)
150 {
151   PetscDraw_X *XiWin = (PetscDraw_X*) Win->data;
152   int         xA,yA,w,h;
153 
154   PetscFunctionBegin;
155   PetscDrawXiSetColor(XiWin, c);
156   xA = XTRANS(Win, XiWin, x - a/2.0); w = XTRANS(Win, XiWin, x + a/2.0) - xA;
157   yA = YTRANS(Win, XiWin, y + b/2.0); h = PetscAbs(YTRANS(Win, XiWin, y - b/2.0) - yA);
158   XFillArc(XiWin->disp, PetscDrawXiDrawable(XiWin), XiWin->gc.set, xA, yA, w, h, 0, 23040);
159   PetscFunctionReturn(0);
160 }
161 
162 PETSC_INTERN PetscErrorCode PetscDrawInterpolatedTriangle_X(PetscDraw_X*,int,int,int,int,int,int,int,int,int);
163 
164 #undef __FUNCT__
165 #define __FUNCT__ "PetscDrawTriangle_X"
166 static PetscErrorCode PetscDrawTriangle_X(PetscDraw draw,PetscReal X1,PetscReal Y_1,PetscReal X2,PetscReal Y2,PetscReal X3,PetscReal Y3,int c1,int c2,int c3)
167 {
168   PetscDraw_X    *XiWin = (PetscDraw_X*)draw->data;
169   PetscErrorCode ierr;
170 
171   PetscFunctionBegin;
172   if (c1 == c2 && c2 == c3) {
173     XPoint pt[3];
174     PetscDrawXiSetColor(XiWin,c1);
175     pt[0].x = XTRANS(draw,XiWin,X1);
176     pt[0].y = YTRANS(draw,XiWin,Y_1);
177     pt[1].x = XTRANS(draw,XiWin,X2);
178     pt[1].y = YTRANS(draw,XiWin,Y2);
179     pt[2].x = XTRANS(draw,XiWin,X3);
180     pt[2].y = YTRANS(draw,XiWin,Y3);
181     XFillPolygon(XiWin->disp,PetscDrawXiDrawable(XiWin),XiWin->gc.set,pt,3,Convex,CoordModeOrigin);
182   } else {
183     int x1,y_1,x2,y2,x3,y3;
184     x1   = XTRANS(draw,XiWin,X1);
185     y_1  = YTRANS(draw,XiWin,Y_1);
186     x2   = XTRANS(draw,XiWin,X2);
187     y2   = YTRANS(draw,XiWin,Y2);
188     x3   = XTRANS(draw,XiWin,X3);
189     y3   = YTRANS(draw,XiWin,Y3);
190     ierr = PetscDrawInterpolatedTriangle_X(XiWin,x1,y_1,c1,x2,y2,c2,x3,y3,c3);CHKERRQ(ierr);
191   }
192   PetscFunctionReturn(0);
193 }
194 
195 #undef __FUNCT__
196 #define __FUNCT__ "PetscDrawStringSetSize_X"
197 static PetscErrorCode PetscDrawStringSetSize_X(PetscDraw draw,PetscReal x,PetscReal y)
198 {
199   PetscDraw_X    *XiWin = (PetscDraw_X*)draw->data;
200   int            w,h;
201   PetscErrorCode ierr;
202 
203   PetscFunctionBegin;
204   w    = (int)((XiWin->w)*x*(draw->port_xr - draw->port_xl)/(draw->coor_xr - draw->coor_xl));
205   h    = (int)((XiWin->h)*y*(draw->port_yr - draw->port_yl)/(draw->coor_yr - draw->coor_yl));
206   ierr = PetscFree(XiWin->font);CHKERRQ(ierr);
207   ierr = PetscDrawXiFontFixed(XiWin,w,h,&XiWin->font);CHKERRQ(ierr);
208   PetscFunctionReturn(0);
209 }
210 
211 #undef __FUNCT__
212 #define __FUNCT__ "PetscDrawStringGetSize_X"
213 static PetscErrorCode PetscDrawStringGetSize_X(PetscDraw draw,PetscReal *x,PetscReal  *y)
214 {
215   PetscDraw_X *XiWin = (PetscDraw_X*)draw->data;
216   PetscReal   w,h;
217 
218   PetscFunctionBegin;
219   w = XiWin->font->font_w; h = XiWin->font->font_h;
220   if (x) *x = w*(draw->coor_xr - draw->coor_xl)/((XiWin->w)*(draw->port_xr - draw->port_xl));
221   if (y) *y = h*(draw->coor_yr - draw->coor_yl)/((XiWin->h)*(draw->port_yr - draw->port_yl));
222   PetscFunctionReturn(0);
223 }
224 
225 #undef __FUNCT__
226 #define __FUNCT__ "PetscDrawString_X"
227 static PetscErrorCode PetscDrawString_X(PetscDraw draw,PetscReal x,PetscReal y,int c,const char chrs[])
228 {
229   PetscDraw_X    *XiWin = (PetscDraw_X*)draw->data;
230   int            xx,yy;
231   size_t         len;
232   char           *substr;
233   PetscToken     token;
234   PetscErrorCode ierr;
235 
236   PetscFunctionBegin;
237   xx = XTRANS(draw,XiWin,x);
238   yy = YTRANS(draw,XiWin,y);
239   PetscDrawXiSetColor(XiWin,c);
240 
241   ierr = PetscTokenCreate(chrs,'\n',&token);CHKERRQ(ierr);
242   ierr = PetscTokenFind(token,&substr);CHKERRQ(ierr);
243   ierr = PetscStrlen(substr,&len);CHKERRQ(ierr);
244   XDrawString(XiWin->disp,PetscDrawXiDrawable(XiWin),XiWin->gc.set,xx,yy - XiWin->font->font_descent,substr,len);
245   ierr = PetscTokenFind(token,&substr);CHKERRQ(ierr);
246   while (substr) {
247     yy  += 4*XiWin->font->font_descent;
248     ierr = PetscStrlen(substr,&len);CHKERRQ(ierr);
249     XDrawString(XiWin->disp,PetscDrawXiDrawable(XiWin),XiWin->gc.set,xx,yy - XiWin->font->font_descent,substr,len);
250     ierr = PetscTokenFind(token,&substr);CHKERRQ(ierr);
251   }
252   ierr = PetscTokenDestroy(&token);CHKERRQ(ierr);
253   PetscFunctionReturn(0);
254 }
255 
256 #undef __FUNCT__
257 #define __FUNCT__ "PetscDrawStringVertical_X"
258 static PetscErrorCode PetscDrawStringVertical_X(PetscDraw draw,PetscReal x,PetscReal y,int c,const char chrs[])
259 {
260   PetscDraw_X    *XiWin = (PetscDraw_X*)draw->data;
261   int            xx,yy;
262   char           tmp[2];
263   PetscReal      tw,th;
264   size_t         i,n;
265   PetscErrorCode ierr;
266 
267   PetscFunctionBegin;
268   ierr   = PetscStrlen(chrs,&n);CHKERRQ(ierr);
269   tmp[1] = 0;
270   PetscDrawXiSetColor(XiWin,c);
271   ierr = PetscDrawStringGetSize_X(draw,&tw,&th);CHKERRQ(ierr);
272   xx   = XTRANS(draw,XiWin,x);
273   for (i=0; i<n; i++) {
274     tmp[0] = chrs[i];
275     yy     = YTRANS(draw,XiWin,y-th*i);
276     XDrawString(XiWin->disp,PetscDrawXiDrawable(XiWin),XiWin->gc.set, xx,yy - XiWin->font->font_descent,tmp,1);
277   }
278   PetscFunctionReturn(0);
279 }
280 
281 #undef __FUNCT__
282 #define __FUNCT__ "PetscDrawFlush_X"
283 static PetscErrorCode PetscDrawFlush_X(PetscDraw draw)
284 {
285   PetscDraw_X    *XiWin = (PetscDraw_X*)draw->data;
286   PetscMPIInt    rank;
287   PetscErrorCode ierr;
288 
289   PetscFunctionBegin;
290 
291   /* make sure the X server processed requests from all processes */
292   ierr = PetscDrawCollectiveBegin(draw);CHKERRQ(ierr);
293   XSync(XiWin->disp,False);
294   ierr = PetscDrawCollectiveEnd(draw);CHKERRQ(ierr);
295   ierr = MPI_Barrier(PetscObjectComm((PetscObject)draw));CHKERRQ(ierr);
296 
297   /* transfer pixmap contents to window (only the first process does this) */
298   if (XiWin->drw && XiWin->win) {
299     ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)draw),&rank);CHKERRQ(ierr);
300     ierr = PetscDrawCollectiveBegin(draw);CHKERRQ(ierr);
301     if (!rank) XCopyArea(XiWin->disp,XiWin->drw,XiWin->win,XiWin->gc.set,0,0,XiWin->w,XiWin->h,0,0);
302     if (!rank) XSync(XiWin->disp,False);
303     ierr = PetscDrawCollectiveEnd(draw);CHKERRQ(ierr);
304     ierr = MPI_Barrier(PetscObjectComm((PetscObject)draw));CHKERRQ(ierr);
305   }
306 
307   if (draw->saveonflush) {ierr = PetscDrawSave(draw);CHKERRQ(ierr);}
308   PetscFunctionReturn(0);
309 }
310 
311 #undef __FUNCT__
312 #define __FUNCT__ "PetscDrawClear_X"
313 static PetscErrorCode PetscDrawClear_X(PetscDraw draw)
314 {
315   PetscDraw_X    *XiWin = (PetscDraw_X*)draw->data;
316   PetscMPIInt    rank;
317   PetscErrorCode ierr;
318 
319   PetscFunctionBegin;
320   if (draw->saveonclear) {ierr = PetscDrawSave(draw);CHKERRQ(ierr);}
321 
322   /* make sure the X server processed requests from all processes */
323   ierr = PetscDrawCollectiveBegin(draw);CHKERRQ(ierr);
324   XSync(XiWin->disp,False);
325   ierr = PetscDrawCollectiveEnd(draw);CHKERRQ(ierr);
326   ierr = MPI_Barrier(PetscObjectComm((PetscObject)draw));CHKERRQ(ierr);
327 
328   /* only the first process handles the clearing business */
329   ierr = PetscDrawCollectiveBegin(draw);CHKERRQ(ierr);
330   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)draw),&rank);CHKERRQ(ierr);
331   if (!rank) {
332     int x = (int)(draw->port_xl*XiWin->w);
333     int y = (int)((1-draw->port_yr)*XiWin->h);
334     int w = (int)((draw->port_xr - draw->port_xl)*XiWin->w);
335     int h = (int)((draw->port_yr - draw->port_yl)*XiWin->h);
336     PetscDrawXiSetPixVal(XiWin,XiWin->background);
337     XFillRectangle(XiWin->disp,PetscDrawXiDrawable(XiWin),XiWin->gc.set,x,y,w,h);
338     XSync(XiWin->disp,False);
339   }
340   ierr = PetscDrawCollectiveEnd(draw);CHKERRQ(ierr);
341   ierr = MPI_Barrier(PetscObjectComm((PetscObject)draw));CHKERRQ(ierr);
342   PetscFunctionReturn(0);
343 }
344 
345 #undef __FUNCT__
346 #define __FUNCT__ "PetscDrawSetDoubleBuffer_X"
347 static PetscErrorCode PetscDrawSetDoubleBuffer_X(PetscDraw draw)
348 {
349   PetscDraw_X    *win = (PetscDraw_X*)draw->data;
350   PetscMPIInt    rank;
351   PetscErrorCode ierr;
352 
353   PetscFunctionBegin;
354   if (win->drw) PetscFunctionReturn(0);
355   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)draw),&rank);CHKERRQ(ierr);
356 
357   ierr = PetscDrawCollectiveBegin(draw);CHKERRQ(ierr);
358   if (!rank) {ierr = PetscDrawXiQuickPixmap(win);CHKERRQ(ierr);}
359   ierr = PetscDrawCollectiveEnd(draw);CHKERRQ(ierr);
360   ierr = MPI_Bcast(&win->drw,1,MPI_UNSIGNED_LONG,0,PetscObjectComm((PetscObject)draw));CHKERRQ(ierr);
361   PetscFunctionReturn(0);
362 }
363 
364 #undef __FUNCT__
365 #define __FUNCT__ "PetscDrawGetPopup_X"
366 static PetscErrorCode PetscDrawGetPopup_X(PetscDraw draw,PetscDraw *popup)
367 {
368   PetscDraw_X    *win = (PetscDraw_X*)draw->data;
369   PetscBool      flg  = PETSC_TRUE;
370   PetscErrorCode ierr;
371 
372   PetscFunctionBegin;
373   ierr = PetscOptionsGetBool(((PetscObject)draw)->options,((PetscObject)draw)->prefix,"-draw_popup",&flg,NULL);CHKERRQ(ierr);
374   if (!flg || !win->win) {*popup = NULL; PetscFunctionReturn(0);}
375 
376   ierr = PetscDrawCreate(PetscObjectComm((PetscObject)draw),draw->display,NULL,win->x,win->y+win->h+36,220,220,popup);CHKERRQ(ierr);
377   ierr = PetscObjectSetOptionsPrefix((PetscObject)*popup,"popup_");CHKERRQ(ierr);
378   ierr = PetscObjectAppendOptionsPrefix((PetscObject)*popup,((PetscObject)draw)->prefix);CHKERRQ(ierr);
379   ierr = PetscDrawSetType(*popup,PETSC_DRAW_X);CHKERRQ(ierr);
380   draw->popup = *popup;
381   PetscFunctionReturn(0);
382 }
383 
384 #undef __FUNCT__
385 #define __FUNCT__ "PetscDrawSetTitle_X"
386 static PetscErrorCode PetscDrawSetTitle_X(PetscDraw draw,const char title[])
387 {
388   PetscDraw_X    *win = (PetscDraw_X*)draw->data;
389   PetscMPIInt    rank;
390   PetscErrorCode ierr;
391 
392   PetscFunctionBegin;
393   if (!win->win) PetscFunctionReturn(0);
394   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)draw),&rank);CHKERRQ(ierr);
395   ierr = PetscDrawCollectiveBegin(draw);CHKERRQ(ierr);
396   if (!rank) {
397     size_t        len;
398     XTextProperty prop;
399     ierr = PetscStrlen(title,&len);CHKERRQ(ierr);
400     XGetWMName(win->disp,win->win,&prop);
401     XFree((void*)prop.value);
402     prop.value  = (unsigned char*)title;
403     prop.nitems = (long)len;
404     XSetWMName(win->disp,win->win,&prop);
405   }
406   ierr = PetscDrawCollectiveEnd(draw);CHKERRQ(ierr);
407   PetscFunctionReturn(0);
408 }
409 
410 #undef __FUNCT__
411 #define __FUNCT__ "PetscDrawCheckResizedWindow_X"
412 static PetscErrorCode PetscDrawCheckResizedWindow_X(PetscDraw draw)
413 {
414   PetscDraw_X    *win = (PetscDraw_X*)draw->data;
415   int            xywh[4];
416   PetscMPIInt    rank;
417   PetscErrorCode ierr;
418 
419   PetscFunctionBegin;
420   if (!win->win) PetscFunctionReturn(0);
421   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)draw),&rank);CHKERRQ(ierr);
422 
423   ierr = PetscDrawCollectiveBegin(draw);CHKERRQ(ierr);
424   if (!rank) {
425     Window       root;
426     int          x,y;
427     unsigned int w,h,border,depth;
428     XGetGeometry(win->disp,win->win,&root,&x,&y,&w,&h,&border,&depth);
429     xywh[0] = x; xywh[1] = y; xywh[2] = (int)w; xywh[3] = (int)h;
430   }
431   ierr = PetscDrawCollectiveEnd(draw);CHKERRQ(ierr);
432 
433   ierr = MPI_Bcast(xywh,4,MPI_INT,0,PetscObjectComm((PetscObject)draw));CHKERRQ(ierr);
434   /* record new window position */
435   draw->x = win->x = xywh[0];
436   draw->y = win->y = xywh[1];
437   if (xywh[2] == win->w && xywh[3] == win->h) PetscFunctionReturn(0);
438   /* record new window sizes */
439   draw->w = win->w = xywh[2];
440   draw->h = win->h = xywh[3];
441 
442   /* recreate pixmap (only first processor does this) */
443   ierr = PetscDrawCollectiveBegin(draw);CHKERRQ(ierr);
444   if (!rank && win->drw) {ierr = PetscDrawXiQuickPixmap(win);CHKERRQ(ierr);}
445   ierr = PetscDrawCollectiveEnd(draw);CHKERRQ(ierr);
446   ierr = MPI_Bcast(&win->drw,1,MPI_UNSIGNED_LONG,0,PetscObjectComm((PetscObject)draw));CHKERRQ(ierr);
447   /* reset the clipping */
448   ierr = PetscDrawSetViewport_X(draw,draw->port_xl,draw->port_yl,draw->port_xr,draw->port_yr);CHKERRQ(ierr);
449   PetscFunctionReturn(0);
450 }
451 
452 #undef __FUNCT__
453 #define __FUNCT__ "PetscDrawResizeWindow_X"
454 static PetscErrorCode PetscDrawResizeWindow_X(PetscDraw draw,int w,int h)
455 {
456   PetscDraw_X    *win = (PetscDraw_X*)draw->data;
457   PetscMPIInt    rank;
458   PetscErrorCode ierr;
459 
460   PetscFunctionBegin;
461   if (w == win->w && h == win->h) PetscFunctionReturn(0);
462   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)draw),&rank);CHKERRQ(ierr);
463 
464   if (win->win) {
465     ierr = PetscDrawCollectiveBegin(draw);CHKERRQ(ierr);
466     if (!rank) XResizeWindow(win->disp,win->win,(unsigned int)w,(unsigned int)h);
467     ierr = PetscDrawCollectiveEnd(draw);CHKERRQ(ierr);
468     ierr = PetscDrawCheckResizedWindow_X(draw);CHKERRQ(ierr);
469   } else if (win->drw) {
470     draw->w = win->w = w; draw->h = win->h = h;
471     /* recreate pixmap (only first processor does this) */
472     ierr = PetscDrawCollectiveBegin(draw);CHKERRQ(ierr);
473     if (!rank) {ierr = PetscDrawXiQuickPixmap(win);CHKERRQ(ierr);}
474     ierr = MPI_Bcast(&win->drw,1,MPI_UNSIGNED_LONG,0,PetscObjectComm((PetscObject)draw));CHKERRQ(ierr);
475     /* reset the clipping */
476     ierr = PetscDrawCollectiveEnd(draw);CHKERRQ(ierr);
477     ierr = PetscDrawSetViewport_X(draw,draw->port_xl,draw->port_yl,draw->port_xr,draw->port_yr);CHKERRQ(ierr);
478   }
479   PetscFunctionReturn(0);
480 }
481 
482 #include <X11/cursorfont.h>
483 
484 #undef __FUNCT__
485 #define __FUNCT__ "PetscDrawGetMouseButton_X"
486 static PetscErrorCode PetscDrawGetMouseButton_X(PetscDraw draw,PetscDrawButton *button,PetscReal *x_user,PetscReal *y_user,PetscReal *x_phys,PetscReal *y_phys)
487 {
488   PetscDraw_X    *win = (PetscDraw_X*)draw->data;
489   Cursor         cursor;
490   XEvent         report;
491   Window         root,child;
492   int            root_x,root_y,px=0,py=0;
493   unsigned int   w,h,border,depth;
494   unsigned int   keys_button;
495   PetscMPIInt    rank;
496   PetscReal      xx,yy;
497   PetscErrorCode ierr;
498 
499   PetscFunctionBegin;
500   *button = PETSC_BUTTON_NONE;
501   if (!win->win) PetscFunctionReturn(0);
502   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)draw),&rank);CHKERRQ(ierr);
503 
504   ierr = PetscDrawCollectiveBegin(draw);CHKERRQ(ierr);
505   if (rank) goto finally;
506 
507   /* change cursor to indicate input */
508   cursor = XCreateFontCursor(win->disp,XC_hand2); if (!cursor) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_LIB,"Unable to create X cursor");
509   XDefineCursor(win->disp,win->win,cursor);
510   /* wait for mouse button events */
511   XSelectInput(win->disp,win->win,ButtonPressMask|ButtonReleaseMask);
512   while (XCheckTypedEvent(win->disp,ButtonPress,&report));
513   XMaskEvent(win->disp,ButtonReleaseMask,&report);
514   /* get mouse pointer coordinates */
515   XQueryPointer(win->disp,report.xmotion.window,&root,&child,&root_x,&root_y,&px,&py,&keys_button);
516   /* the user may resize the window before pressing the mouse button */
517   XGetGeometry(win->disp,win->win,&root,&root_x,&root_y,&w,&h,&border,&depth);
518   /* cleanup input event handler and cursor  */
519   XSelectInput(win->disp,win->win,NoEventMask);
520   XUndefineCursor(win->disp,win->win);
521   XFreeCursor(win->disp, cursor);
522   XSync(win->disp,False);
523 
524   switch (report.xbutton.button) {
525   case Button1: *button = PETSC_BUTTON_LEFT; break;
526   case Button2: *button = PETSC_BUTTON_CENTER; break;
527   case Button3: *button = PETSC_BUTTON_RIGHT; break;
528   case Button4: *button = PETSC_BUTTON_WHEEL_UP; break;
529   case Button5: *button = PETSC_BUTTON_WHEEL_DOWN; break;
530   }
531   if (report.xbutton.state & ShiftMask) {
532     switch (report.xbutton.button) {
533     case Button1: *button = PETSC_BUTTON_LEFT_SHIFT; break;
534     case Button2: *button = PETSC_BUTTON_CENTER_SHIFT; break;
535     case Button3: *button = PETSC_BUTTON_RIGHT_SHIFT; break;
536     }
537   }
538   xx = ((PetscReal)px)/w;
539   yy = 1 - ((PetscReal)py)/h;
540   if (x_user) *x_user = draw->coor_xl + (xx - draw->port_xl)*(draw->coor_xr - draw->coor_xl)/(draw->port_xr - draw->port_xl);
541   if (y_user) *y_user = draw->coor_yl + (yy - draw->port_yl)*(draw->coor_yr - draw->coor_yl)/(draw->port_yr - draw->port_yl);
542   if (x_phys) *x_phys = xx;
543   if (y_phys) *y_phys = yy;
544 
545 finally:
546   ierr = PetscDrawCollectiveEnd(draw);CHKERRQ(ierr);
547   ierr = PetscDrawCheckResizedWindow_X(draw);CHKERRQ(ierr);
548   PetscFunctionReturn(0);
549 }
550 
551 #undef __FUNCT__
552 #define __FUNCT__ "PetscDrawPause_X"
553 static PetscErrorCode PetscDrawPause_X(PetscDraw draw)
554 {
555   PetscDraw_X    *win = (PetscDraw_X*)draw->data;
556   PetscErrorCode ierr;
557 
558   PetscFunctionBegin;
559   if (!win->win) PetscFunctionReturn(0);
560   if (draw->pause > 0) PetscSleep(draw->pause);
561   else if (draw->pause == -1) {
562     PetscDrawButton button = PETSC_BUTTON_NONE;
563     ierr = PetscDrawGetMouseButton(draw,&button,NULL,NULL,NULL,NULL);CHKERRQ(ierr);
564     if (button == PETSC_BUTTON_CENTER) draw->pause = 0;
565   }
566   PetscFunctionReturn(0);
567 }
568 
569 #undef __FUNCT__
570 #define __FUNCT__ "PetscDrawDestroy_X"
571 static PetscErrorCode PetscDrawDestroy_X(PetscDraw draw)
572 {
573   PetscDraw_X    *win = (PetscDraw_X*)draw->data;
574   PetscErrorCode ierr;
575 
576   PetscFunctionBegin;
577   ierr = PetscDrawDestroy(&draw->popup);CHKERRQ(ierr);
578   ierr = PetscDrawXiClose(win);CHKERRQ(ierr);
579   ierr = PetscFree(draw->data);CHKERRQ(ierr);
580   PetscFunctionReturn(0);
581 }
582 
583 static       PetscErrorCode PetscDrawGetSingleton_X(PetscDraw,PetscDraw*);
584 static       PetscErrorCode PetscDrawRestoreSingleton_X(PetscDraw,PetscDraw*);
585 PETSC_INTERN PetscErrorCode PetscDrawSave_X(PetscDraw);
586 PETSC_INTERN PetscErrorCode PetscDrawSetSave_X(PetscDraw,const char[]);
587 
588 static struct _PetscDrawOps DvOps = { PetscDrawSetDoubleBuffer_X,
589                                       PetscDrawFlush_X,
590                                       PetscDrawLine_X,
591                                       0,
592                                       0,
593                                       PetscDrawPoint_X,
594                                       0,
595                                       PetscDrawString_X,
596                                       PetscDrawStringVertical_X,
597                                       PetscDrawStringSetSize_X,
598                                       PetscDrawStringGetSize_X,
599                                       PetscDrawSetViewport_X,
600                                       PetscDrawClear_X,
601                                       PetscDrawRectangle_X,
602                                       PetscDrawTriangle_X,
603                                       PetscDrawEllipse_X,
604                                       PetscDrawGetMouseButton_X,
605                                       PetscDrawPause_X,
606                                       0,
607                                       0,
608                                       PetscDrawGetPopup_X,
609                                       PetscDrawSetTitle_X,
610                                       PetscDrawCheckResizedWindow_X,
611                                       PetscDrawResizeWindow_X,
612                                       PetscDrawDestroy_X,
613                                       0,
614                                       PetscDrawGetSingleton_X,
615                                       PetscDrawRestoreSingleton_X,
616                                       PetscDrawSave_X,
617                                       PetscDrawSetSave_X,
618                                       0,
619                                       PetscDrawArrow_X,
620                                       PetscDrawCoordinateToPixel_X,
621                                       PetscDrawPixelToCoordinate_X,
622                                       PetscDrawPointPixel_X,
623                                       0};
624 
625 
626 #undef __FUNCT__
627 #define __FUNCT__ "PetscDrawGetSingleton_X"
628 static PetscErrorCode PetscDrawGetSingleton_X(PetscDraw draw,PetscDraw *sdraw)
629 {
630   PetscDraw_X    *Xwin = (PetscDraw_X*)draw->data,*sXwin;
631   PetscErrorCode ierr;
632 
633   PetscFunctionBegin;
634   ierr = PetscDrawCreate(PETSC_COMM_SELF,draw->display,draw->title,draw->x,draw->y,draw->w,draw->h,sdraw);CHKERRQ(ierr);
635   ierr = PetscObjectChangeTypeName((PetscObject)*sdraw,PETSC_DRAW_X);CHKERRQ(ierr);
636   ierr = PetscMemcpy((*sdraw)->ops,&DvOps,sizeof(DvOps));CHKERRQ(ierr);
637 
638   if (draw->popup) {
639     PetscBool isnull;
640     ierr = PetscDrawIsNull(draw->popup,&isnull);CHKERRQ(ierr);
641     if (isnull) {ierr = PetscDrawOpenNull(PETSC_COMM_SELF,&(*sdraw)->popup);CHKERRQ(ierr);}
642     else        {ierr = PetscDrawGetSingleton(draw->popup,&(*sdraw)->popup);CHKERRQ(ierr);}
643   }
644 
645   (*sdraw)->pause   = draw->pause;
646   (*sdraw)->coor_xl = draw->coor_xl;
647   (*sdraw)->coor_xr = draw->coor_xr;
648   (*sdraw)->coor_yl = draw->coor_yl;
649   (*sdraw)->coor_yr = draw->coor_yr;
650   (*sdraw)->port_xl = draw->port_xl;
651   (*sdraw)->port_xr = draw->port_xr;
652   (*sdraw)->port_yl = draw->port_yl;
653   (*sdraw)->port_yr = draw->port_yr;
654 
655   /* share drawables (windows and/or pixmap) from the parent draw */
656   ierr = PetscNewLog(*sdraw,&sXwin);CHKERRQ(ierr);
657   (*sdraw)->data = (void*)sXwin;
658   ierr = PetscDrawXiInit(sXwin,draw->display);CHKERRQ(ierr);
659   if (Xwin->win) {
660     ierr = PetscDrawXiQuickWindowFromWindow(sXwin,Xwin->win);CHKERRQ(ierr);
661     sXwin->drw = Xwin->drw; /* XXX If the window is ever resized, this is wrong! */
662   } else if (Xwin->drw) {
663     ierr = PetscDrawXiColormap(sXwin);CHKERRQ(ierr);
664     sXwin->drw = Xwin->drw;
665   }
666   (*sdraw)->x = sXwin->x; (*sdraw)->y = sXwin->y;
667   (*sdraw)->w = sXwin->w; (*sdraw)->h = sXwin->h;
668   PetscFunctionReturn(0);
669 }
670 
671 #undef __FUNCT__
672 #define __FUNCT__ "PetscDrawRestoreSingleton_X"
673 static PetscErrorCode PetscDrawRestoreSingleton_X(PetscDraw draw,PetscDraw *sdraw)
674 {
675   PetscErrorCode ierr;
676 
677   PetscFunctionBegin;
678   if (draw->popup && (*sdraw)->popup) {
679     PetscBool isdrawx;
680     PetscDraw_X *pXwin = (PetscDraw_X*)draw->popup->data;
681     PetscDraw_X *sXwin = (PetscDraw_X*)(*sdraw)->popup->data;
682     ierr = PetscObjectTypeCompare((PetscObject)draw->popup,PETSC_DRAW_X,&isdrawx);CHKERRQ(ierr);
683     if (!isdrawx) goto finally;
684     ierr = PetscObjectTypeCompare((PetscObject)(*sdraw)->popup,PETSC_DRAW_X,&isdrawx);CHKERRQ(ierr);
685     if (!isdrawx) goto finally;
686     if (sXwin->win == pXwin->win) {
687       ierr = PetscDrawRestoreSingleton(draw->popup,&(*sdraw)->popup);CHKERRQ(ierr);
688     }
689   }
690 finally:
691   ierr = PetscDrawDestroy(sdraw);CHKERRQ(ierr);
692   PetscFunctionReturn(0);
693 }
694 
695 #undef __FUNCT__
696 #define __FUNCT__ "PetscDrawXGetDisplaySize_Private"
697 static PetscErrorCode PetscDrawXGetDisplaySize_Private(const char name[],int *width,int *height)
698 {
699   Display *display;
700 
701   PetscFunctionBegin;
702   display = XOpenDisplay(name);
703   if (!display) {
704     *width  = *height = 0;
705     SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Unable to open display on %s\n\
706     Make sure your COMPUTE NODES are authorized to connect\n\
707     to this X server and either your DISPLAY variable\n\
708     is set or you use the -display name option\n",name);
709   }
710   *width  = (int)DisplayWidth(display,DefaultScreen(display));
711   *height = (int)DisplayHeight(display,DefaultScreen(display));
712   XCloseDisplay(display);
713   PetscFunctionReturn(0);
714 }
715 
716 /*MC
717      PETSC_DRAW_X  - PETSc graphics device that uses either X windows or its virtual version Xvfb
718 
719    Options Database Keys:
720 +  -display <display> - sets the display to use
721 .  -x_virtual - forces use of a X virtual display Xvfb that will not display anything but -draw_save will still work.
722                 Xvfb is automatically started up in PetscSetDisplay() with this option
723 .  -draw_size w,h - percentage of screeen (either 1, .5, .3, .25), or size in pixels
724 .  -geometry x,y,w,h - set location and size in pixels
725 .  -draw_virtual - do not open a window (draw on a pixmap), -draw_save will still work
726 -  -draw_double_buffer - avoid window flickering (draw on pixmap and flush to window)
727 
728    Level: beginner
729 
730 .seealso:  PetscDrawOpenX(), PetscDrawSetDisplay(), PetscDrawSetFromOptions()
731 
732 M*/
733 
734 #undef __FUNCT__
735 #define __FUNCT__ "PetscDrawCreate_X"
736 PETSC_EXTERN PetscErrorCode PetscDrawCreate_X(PetscDraw draw)
737 {
738   PetscDraw_X    *Xwin;
739   PetscErrorCode ierr;
740   PetscMPIInt    rank;
741   int            x = draw->x,y = draw->y,w = draw->w,h = draw->h;
742   static int     xavailable = 0,yavailable = 0,ybottom = 0,xmax = 0,ymax = 0;
743   PetscBool      set,dvirtual = PETSC_FALSE,doublebuffer = PETSC_TRUE;
744   PetscInt       xywh[4],osize = 4,nsizes=2;
745   PetscReal      sizes[2] = {.3,.3};
746 
747   PetscFunctionBegin;
748   /* get the display variable */
749   if (!draw->display) {
750     ierr = PetscMalloc1(256,&draw->display);CHKERRQ(ierr);
751     ierr = PetscGetDisplay(draw->display,256);CHKERRQ(ierr);
752   }
753 
754   /* initialize the display size */
755   if (!xmax) {
756     ierr = PetscDrawXGetDisplaySize_Private(draw->display,&xmax,&ymax);
757     /* if some processors fail on this and others succed then this is a problem ! */
758     if (ierr) {
759       (*PetscErrorPrintf)("PETSc unable to use X windows\nproceeding without graphics\n");
760       ierr = PetscDrawSetType(draw,PETSC_DRAW_NULL);CHKERRQ(ierr);
761       PetscFunctionReturn(0);
762     }
763   }
764 
765   /* allow user to set size of drawable */
766   ierr = PetscOptionsGetRealArray(((PetscObject)draw)->options,((PetscObject)draw)->prefix,"-draw_size",sizes,&nsizes,&set);CHKERRQ(ierr);
767   if (set && nsizes == 1 && sizes[0] > 1.0) sizes[1] = sizes[0];
768   if (set) {
769     if (sizes[0] > 1.0)       w = (int)sizes[0];
770     else if (sizes[0] == 1.0) w = PETSC_DRAW_FULL_SIZE;
771     else if (sizes[0] == .5)  w = PETSC_DRAW_HALF_SIZE;
772     else if (sizes[0] == .3)  w = PETSC_DRAW_THIRD_SIZE;
773     else if (sizes[0] == .25) w = PETSC_DRAW_QUARTER_SIZE;
774     if (sizes[1] > 1.0)       h = (int)sizes[1];
775     else if (sizes[1] == 1.0) h = PETSC_DRAW_FULL_SIZE;
776     else if (sizes[1] == .5)  h = PETSC_DRAW_HALF_SIZE;
777     else if (sizes[1] == .3)  h = PETSC_DRAW_THIRD_SIZE;
778     else if (sizes[1] == .25) h = PETSC_DRAW_QUARTER_SIZE;
779   }
780   if (w == PETSC_DECIDE || w == PETSC_DEFAULT) w = draw->w = 300;
781   if (h == PETSC_DECIDE || h == PETSC_DEFAULT) h = draw->h = 300;
782   switch (w) {
783   case PETSC_DRAW_FULL_SIZE:    w = draw->w = (xmax - 10);   break;
784   case PETSC_DRAW_HALF_SIZE:    w = draw->w = (xmax - 20)/2; break;
785   case PETSC_DRAW_THIRD_SIZE:   w = draw->w = (xmax - 30)/3; break;
786   case PETSC_DRAW_QUARTER_SIZE: w = draw->w = (xmax - 40)/4; break;
787   }
788   switch (h) {
789   case PETSC_DRAW_FULL_SIZE:    h = draw->h = (ymax - 10);   break;
790   case PETSC_DRAW_HALF_SIZE:    h = draw->h = (ymax - 20)/2; break;
791   case PETSC_DRAW_THIRD_SIZE:   h = draw->h = (ymax - 30)/3; break;
792   case PETSC_DRAW_QUARTER_SIZE: h = draw->h = (ymax - 40)/4; break;
793   }
794 
795   ierr = PetscOptionsGetBool(((PetscObject)draw)->options,((PetscObject)draw)->prefix,"-draw_virtual",&dvirtual,NULL);CHKERRQ(ierr);
796 
797   if (!dvirtual) {
798 
799     /* allow user to set location and size of window */
800     xywh[0] = x; xywh[1] = y; xywh[2] = w; xywh[3] = h;
801     ierr = PetscOptionsGetIntArray(((PetscObject)draw)->options,((PetscObject)draw)->prefix,"-geometry",xywh,&osize,NULL);CHKERRQ(ierr);
802     x = (int)xywh[0]; y = (int)xywh[1]; w = (int)xywh[2]; h = (int)xywh[3];
803     if (w == PETSC_DECIDE || w == PETSC_DEFAULT) w = 300;
804     if (h == PETSC_DECIDE || h == PETSC_DEFAULT) h = 300;
805     draw->x = x; draw->y = y; draw->w = w; draw->h = h;
806 
807     if (draw->x == PETSC_DECIDE || draw->y == PETSC_DECIDE) {
808       /*
809        PETSc tries to place windows starting in the upper left corner
810         and moving across to the right.
811 
812        0,0+----------------------------------------------+
813        |  Region used so far  +xavailable,yavailable  |
814        |                      |                       |
815        |                      |                       |
816        +--------------------- +ybottom                |
817        |                                              |
818        |                                              |
819        +----------------------------------------------+xmax,ymax
820 
821        */
822       /*  First: can we add it to the right? */
823       if (xavailable+w+10 <= xmax) {
824         x       = xavailable;
825         y       = yavailable;
826         ybottom = PetscMax(ybottom,y + h + 30);
827       } else {
828         /* No, so add it below on the left */
829         x          = 0;
830         xavailable = 0;
831         y          = ybottom;
832         yavailable = ybottom;
833         ybottom    = ybottom + h + 30;
834       }
835     }
836     /* update available region */
837     xavailable = PetscMax(xavailable,x + w + 10);
838     if (xavailable >= xmax) {
839       xavailable = 0;
840       yavailable = yavailable + h + 30;
841       ybottom    = yavailable;
842     }
843     if (yavailable >= ymax) {
844       y          = 0;
845       yavailable = 0;
846       ybottom    = 0;
847     }
848 
849   } /* endif(!dvirtual) */
850 
851   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)draw),&rank);CHKERRQ(ierr);
852   if (!rank && (w <= 0 || h <= 0)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Negative window width or height");
853 
854   ierr = PetscNewLog(draw,&Xwin);CHKERRQ(ierr);
855   ierr = PetscMemcpy(draw->ops,&DvOps,sizeof(DvOps));CHKERRQ(ierr);
856   draw->data = (void*)Xwin;
857 
858   ierr = PetscDrawXiInit(Xwin,draw->display);CHKERRQ(ierr);
859   if (!dvirtual) {
860     Xwin->x = x; Xwin->y = y;
861     Xwin->w = w; Xwin->h = h;
862     if (!rank) {ierr = PetscDrawXiQuickWindow(Xwin,draw->title,x,y,w,h);CHKERRQ(ierr);}
863     ierr = MPI_Bcast(&Xwin->win,1,MPI_UNSIGNED_LONG,0,PetscObjectComm((PetscObject)draw));CHKERRQ(ierr);
864     if (rank) {ierr = PetscDrawXiQuickWindowFromWindow(Xwin,Xwin->win);CHKERRQ(ierr);}
865   } else {
866     Xwin->x = 0; Xwin->y = 0;
867     Xwin->w = w; Xwin->h = h;
868     ierr = PetscDrawXiColormap(Xwin);CHKERRQ(ierr);
869     if (!rank) {ierr = PetscDrawXiQuickPixmap(Xwin);CHKERRQ(ierr);}
870     ierr = MPI_Bcast(&Xwin->drw,1,MPI_UNSIGNED_LONG,0,PetscObjectComm((PetscObject)draw));CHKERRQ(ierr);
871   }
872   draw->x = Xwin->x; draw->y = Xwin->y;
873   draw->w = Xwin->w; draw->h = Xwin->h;
874 
875   ierr = PetscOptionsGetBool(((PetscObject)draw)->options,((PetscObject)draw)->prefix,"-draw_double_buffer",&doublebuffer,NULL);CHKERRQ(ierr);
876   if (doublebuffer) {ierr = PetscDrawSetDoubleBuffer(draw);CHKERRQ(ierr);}
877   PetscFunctionReturn(0);
878 }
879