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[][3],unsigned int*,unsigned int*,unsigned char*[]);


 12: PETSC_STATIC_INLINE PetscErrorCode PetscArgSortPixVal(const PetscDrawXiPixVal v[256],int idx[],int right)
 13: {
 14:   PetscDrawXiPixVal vl;
 15:   int               i,last,tmp;
 16:   PetscErrorCode    ierr;
 17: # define            SWAP(a,b) {tmp=a;a=b;b=tmp;}
 19:   if (right <= 1) {
 20:     if (right == 1) {
 21:       if (v[idx[0]] > v[idx[1]]) SWAP(idx[0],idx[1]);
 22:     }
 23:     return(0);
 24:   }
 25:   SWAP(idx[0],idx[right/2]);
 26:   vl = v[idx[0]]; last = 0;
 27:   for (i=1; i<=right; i++)
 28:     if (v[idx[i]] < vl) {last++; SWAP(idx[last],idx[i]);}
 29:   SWAP(idx[0],idx[last]);
 30:   PetscArgSortPixVal(v,idx,last-1);
 31:   PetscArgSortPixVal(v,idx+last+1,right-(last+1));
 32: # undef SWAP
 33:   return(0);
 34: }

 36: /*
 37:    Map a pixel value to PETSc color value (index in the colormap)
 38: */
 41: PETSC_STATIC_INLINE int PetscDrawXiPixelToColor(PetscDraw_X *Xwin,const int arg[256],PetscDrawXiPixVal pix)
 42: {
 43:   const PetscDrawXiPixVal *cmap = Xwin->cmapping;
 44:   int                     lo, mid, hi = 256;
 45:   /* linear search the first few entries */
 46:   for (lo=0; lo<8; lo++)
 47:     if (pix == cmap[lo])
 48:       return lo;
 49:   /* binary search the remaining entries */
 50:   while (hi - lo > 1) {
 51:     mid = lo + (hi - lo)/2;
 52:     if (pix < cmap[arg[mid]]) hi = mid;
 53:     else                      lo = mid;
 54:   }
 55:   return arg[lo];
 56: }

 60: PetscErrorCode PetscDrawGetImage_X(PetscDraw draw,unsigned char palette[256][3],unsigned int *out_w,unsigned int *out_h,unsigned char *out_pixels[])
 61: {
 62:   PetscDraw_X      *Xwin = (PetscDraw_X*)draw->data;
 63:   PetscMPIInt      rank;
 64:   PetscErrorCode   ierr;

 67:   if (out_w)      *out_w      = 0;
 68:   if (out_h)      *out_h      = 0;
 69:   if (out_pixels) *out_pixels = NULL;
 70:   MPI_Comm_rank(PetscObjectComm((PetscObject)draw),&rank);

 72:   /* make sure the X server processed requests from all processes */
 73:   PetscDrawCollectiveBegin(draw);
 74:   XSync(Xwin->disp,True);
 75:   PetscDrawCollectiveEnd(draw);
 76:   MPI_Barrier(PetscObjectComm((PetscObject)draw));

 78:   /* only the first process return image data */
 79:   PetscDrawCollectiveBegin(draw);
 80:   if (!rank) {
 81:     Window        root;
 82:     XImage        *ximage;
 83:     int           pmap[256];
 84:     unsigned char *pixels = NULL;
 85:     unsigned int  w,h,dummy;
 86:     int           x,y,p;
 87:     /* copy colormap palette to the caller */
 88:     PetscMemcpy(palette,Xwin->cpalette,sizeof(Xwin->cpalette));
 89:     /* get image out of the drawable */
 90:     XGetGeometry(Xwin->disp,PetscDrawXiDrawable(Xwin),&root,&x,&y,&w,&h,&dummy,&dummy);
 91:     ximage = XGetImage(Xwin->disp,PetscDrawXiDrawable(Xwin),0,0,w,h,AllPlanes,ZPixmap);
 92:     if (!ximage) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Cannot XGetImage()");
 93:     /* build indirect sort permutation (a.k.a argsort) of the color -> pixel mapping */
 94:     for (p=0; p<256; p++) pmap[p] = p; /* identity permutation */
 95:     PetscArgSortPixVal(Xwin->cmapping,pmap,255);
 96:     /* extract pixel values out of the image and map them to color indices */
 97:     PetscMalloc1(w*h,&pixels);
 98:     for (p=0,y=0; y<(int)h; y++)
 99:       for (x=0; x<(int)w; x++) {
100:         PetscDrawXiPixVal pix = XGetPixel(ximage,x,y);
101:         pixels[p++] = (unsigned char)PetscDrawXiPixelToColor(Xwin,pmap,pix);
102:       }
103:     XDestroyImage(ximage);
104:     *out_w      = w;
105:     *out_h      = h;
106:     *out_pixels = pixels;
107:   }
108:   PetscDrawCollectiveEnd(draw);
109:   return(0);
110: }