Actual source code: zoom.c
2: #include <petscdraw.h>
4: /*@C
5: PetscDrawZoom - Allows one to create a graphic that users may zoom into.
7: Collective on PetscDraw
9: Input Parameters:
10: + draw - the window where the graph will be made.
11: . func - users function that draws the graphic
12: - ctx - pointer to any user required data
14: Level: advanced
16: .seealso:
17: @*/
18: PetscErrorCode PetscDrawZoom(PetscDraw draw,PetscErrorCode (*func)(PetscDraw,void*),void *ctx)
19: {
20: PetscDrawButton button;
21: PetscReal dpause,xc,yc,scale = 1.0,w,h,xr,xl,yr,yl,xmin,xmax,ymin,ymax;
22: PetscBool isnull;
25: PetscDrawIsNull(draw,&isnull);
26: if (isnull) return 0;
28: PetscDrawCheckResizedWindow(draw);
29: PetscDrawClear(draw);
30: PetscDrawCollectiveBegin(draw);
31: (*func)(draw,ctx);
32: PetscDrawCollectiveEnd(draw);
33: PetscDrawFlush(draw);
35: PetscDrawGetPause(draw,&dpause);
36: if (dpause >= 0) {
37: PetscSleep(dpause);
38: goto theend;
39: }
40: if (dpause != -1) goto theend;
42: PetscDrawGetMouseButton(draw,&button,&xc,&yc,NULL,NULL);
43: PetscDrawGetCoordinates(draw,&xl,&yl,&xr,&yr);
44: xmin = xl; xmax = xr; w = xr - xl;
45: ymin = yl; ymax = yr; h = yr - yl;
47: while (button != PETSC_BUTTON_NONE && button != PETSC_BUTTON_RIGHT) {
48: switch (button) {
49: case PETSC_BUTTON_LEFT: scale = 0.5; break;
50: case PETSC_BUTTON_CENTER: scale = 2.0; break;
51: case PETSC_BUTTON_WHEEL_UP: scale = 8/10.; break;
52: case PETSC_BUTTON_WHEEL_DOWN: scale = 10/8.; break;
53: default: scale = 1.0;
54: }
55: xl = scale*(xl + w - xc) + xc - w*scale;
56: xr = scale*(xr - w - xc) + xc + w*scale;
57: yl = scale*(yl + h - yc) + yc - h*scale;
58: yr = scale*(yr - h - yc) + yc + h*scale;
59: w *= scale; h *= scale;
60: PetscDrawClear(draw);
61: PetscDrawSetCoordinates(draw,xl,yl,xr,yr);
62: PetscDrawCollectiveBegin(draw);
63: (*func)(draw,ctx);
64: PetscDrawCollectiveEnd(draw);
65: PetscDrawFlush(draw);
66: PetscDrawGetMouseButton(draw,&button,&xc,&yc,NULL,NULL);
67: }
68: PetscDrawSetCoordinates(draw,xmin,ymin,xmax,ymax);
69: theend:
70: return 0;
71: }