Actual source code: ximage.c

  1: /*
  2:     Code for getting raster images out of a X image or pixmap
  3: */

  5: #include <../src/sys/classes/draw/impls/x/ximpl.h>

  7: PETSC_INTERN PetscErrorCode PetscDrawGetImage_X(PetscDraw,unsigned char[PETSC_DRAW_MAXCOLOR][3],unsigned int*,unsigned int*,unsigned char*[]);

  9: PETSC_STATIC_INLINE PetscErrorCode PetscArgSortPixVal(const PetscDrawXiPixVal v[PETSC_DRAW_MAXCOLOR],int idx[],int right)
 10: {
 11:   PetscDrawXiPixVal vl;
 12:   int               i,last,tmp;
 13:   PetscErrorCode    ierr;
 14: # define            SWAP(a,b) {tmp=a;a=b;b=tmp;}
 16:   if (right <= 1) {
 17:     if (right == 1) {
 18:       if (v[idx[0]] > v[idx[1]]) SWAP(idx[0],idx[1]);
 19:     }
 20:     return(0);
 21:   }
 22:   SWAP(idx[0],idx[right/2]);
 23:   vl = v[idx[0]]; last = 0;
 24:   for (i=1; i<=right; i++)
 25:     if (v[idx[i]] < vl) {last++; SWAP(idx[last],idx[i]);}
 26:   SWAP(idx[0],idx[last]);
 27:   PetscArgSortPixVal(v,idx,last-1);
 28:   PetscArgSortPixVal(v,idx+last+1,right-(last+1));
 29: # undef SWAP
 30:   return(0);
 31: }

 33: /*
 34:    Map a pixel value to PETSc color value (index in the colormap)
 35: */
 36: PETSC_STATIC_INLINE int PetscDrawXiPixelToColor(PetscDraw_X *Xwin,const int arg[PETSC_DRAW_MAXCOLOR],PetscDrawXiPixVal pix)
 37: {
 38:   const PetscDrawXiPixVal *cmap = Xwin->cmapping;
 39:   int                     lo, mid, hi = PETSC_DRAW_MAXCOLOR;
 40:   /* linear search the first few entries */
 41:   for (lo=0; lo<8; lo++)
 42:     if (pix == cmap[lo])
 43:       return lo;
 44:   /* binary search the remaining entries */
 45:   while (hi - lo > 1) {
 46:     mid = lo + (hi - lo)/2;
 47:     if (pix < cmap[arg[mid]]) hi = mid;
 48:     else                      lo = mid;
 49:   }
 50:   return arg[lo];
 51: }

 53: PetscErrorCode PetscDrawGetImage_X(PetscDraw draw,unsigned char palette[PETSC_DRAW_MAXCOLOR][3],unsigned int *out_w,unsigned int *out_h,unsigned char *out_pixels[])
 54: {
 55:   PetscDraw_X      *Xwin = (PetscDraw_X*)draw->data;
 56:   PetscMPIInt      rank;
 57:   PetscErrorCode   ierr;

 60:   if (out_w)      *out_w      = 0;
 61:   if (out_h)      *out_h      = 0;
 62:   if (out_pixels) *out_pixels = NULL;
 63:   MPI_Comm_rank(PetscObjectComm((PetscObject)draw),&rank);

 65:   /* make sure the X server processed requests from all processes */
 66:   PetscDrawCollectiveBegin(draw);
 67:   XSync(Xwin->disp,True);
 68:   PetscDrawCollectiveEnd(draw);
 69:   MPI_Barrier(PetscObjectComm((PetscObject)draw));

 71:   /* only the first process return image data */
 72:   PetscDrawCollectiveBegin(draw);
 73:   if (rank == 0) {
 74:     Window        root;
 75:     XImage        *ximage;
 76:     int           pmap[PETSC_DRAW_MAXCOLOR];
 77:     unsigned char *pixels = NULL;
 78:     unsigned int  w,h,dummy;
 79:     int           x,y,p;
 80:     /* copy colormap palette to the caller */
 81:     PetscMemcpy(palette,Xwin->cpalette,sizeof(Xwin->cpalette));
 82:     /* get image out of the drawable */
 83:     XGetGeometry(Xwin->disp,PetscDrawXiDrawable(Xwin),&root,&x,&y,&w,&h,&dummy,&dummy);
 84:     ximage = XGetImage(Xwin->disp,PetscDrawXiDrawable(Xwin),0,0,w,h,AllPlanes,ZPixmap);
 85:     if (!ximage) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Cannot XGetImage()");
 86:     /* build indirect sort permutation (a.k.a argsort) of the color -> pixel mapping */
 87:     for (p=0; p<PETSC_DRAW_MAXCOLOR; p++) pmap[p] = p; /* identity permutation */
 88:     PetscArgSortPixVal(Xwin->cmapping,pmap,255);
 89:     /* extract pixel values out of the image and map them to color indices */
 90:     PetscMalloc1(w*h,&pixels);
 91:     for (p=0,y=0; y<(int)h; y++)
 92:       for (x=0; x<(int)w; x++) {
 93:         PetscDrawXiPixVal pix = XGetPixel(ximage,x,y);
 94:         pixels[p++] = (unsigned char)PetscDrawXiPixelToColor(Xwin,pmap,pix);
 95:       }
 96:     XDestroyImage(ximage);
 97:     *out_w      = w;
 98:     *out_h      = h;
 99:     *out_pixels = pixels;
100:   }
101:   PetscDrawCollectiveEnd(draw);
102:   return(0);
103: }