RFB_PIX_PER_CELL
xcells = howmany(gci->width, RFB_PIX_PER_CELL);
ycells = howmany(gci->height, RFB_PIX_PER_CELL);
rem_y = RFB_PIX_PER_CELL;
cellwidth = RFB_PIX_PER_CELL;
for (y = 0; y < gci->height; y += RFB_PIX_PER_CELL) {
cellwidth = RFB_PIX_PER_CELL;
x * RFB_PIX_PER_CELL, celly * RFB_PIX_PER_CELL,
cellwidth, y + RFB_PIX_PER_CELL >= gci->height ?
rem_y : RFB_PIX_PER_CELL)) {
c->rc_cells = howmany(RFB_MAX_WIDTH * RFB_MAX_HEIGHT, RFB_PIX_PER_CELL);