This interface is very similar to the 'ImgData' one. It differs only by /// the fact that it handles multiple resolutions.
/// ///Resolution levels are counted from 0 to L. Resolution level 0 is the /// lower resolution, while L is the maximum resolution level, or full /// resolution, which is returned by 'getMaxResLvl()'. Note that there are L+1 /// resolution levels available.
/// ///As in the 'ImgData' interface a multi-resolution image lies on top of a /// canvas. The canvas coordinates are mapped from the full resolution /// reference grid (i.e. resolution level 'L' reference grid) to a resolution /// level 'l' reference grid by '(x_l,y_l) = /// (ceil(x_l/2^(L-l)),ceil(y_l/2^(L-l)))', where '(x,y)' are the full /// resolution reference grid coordinates and '(x_l,y_l)' are the level 'l' /// reference grid coordinates.
/// ///For details on the canvas system and its implications consult the /// 'ImgData' interface.
/// ///Note that tile sizes may not be obtained by simply dividing the tile /// size in the reference grid by the subsampling factor.
/// ///