%% STEP 1: INHERIT FROM ADAPTER CLASS
classdef My3DTIFFAdapter < images.blocked.Adapter
    
    properties
        File (1,1) string
        Info (1,1) struct
    end    
    
%% STEP 2: DEFINE REQUIRED METHODS
    methods
        
        % Define the openToRead method
        function openToRead(obj,source)
            obj.File = source;
        end

        % Define the getInfo method      
        function info = getInfo(obj)
            % Read raw file info
            finfo = imfinfo(obj.File);
            
            % Make sure all slices are the same size.
            assert(all(finfo(1).Width==[finfo.Width]), ...
                'All slices do not have the same width.');
            assert(all(finfo(1).Height==[finfo.Height]), ...
                'All slices do not have the same height.');
            obj.Info.Size = [finfo(1).Height, finfo(1).Width, numel(finfo)];
            
            % The first two dims of the smallest unit of data that can be
            % read depends on the type of TIFF file - stripped or tiled.
            % The third dim is always 1 - indicating that the smallest unit
            % that can be read in the third dimensions is 1 (one slice).
            if isempty(finfo(1).TileWidth)
                % This is a stripped TIFF file
                obj.Info.IOBlockSize = [finfo(1).RowsPerStrip, finfo(1).Width, 1];
            else
                % This is a tiled TIFF file
                obj.Info.IOBlockSize = [finfo(1).TileLength, finfo(1).TileWidth, 1];
            end
            
            % This is usually the same for a data set and can be hardcoded.
            assert(finfo(1).BitsPerSample==8 && finfo(1).BitDepth==8)
            obj.Info.Datatype = "uint8";
            obj.Info.InitialValue = cast(0,obj.Info.Datatype);
            info = obj.Info;
        end
        
        % Define the getIOBlock method
        function block = getIOBlock(obj,ioblockSub,level)
            assert(level==1)
            
            % Convert ioblockSub (which is in terms of IOBlockSize) into a
            % 'PixelRegion' coordinate.
            regionStart = (ioblockSub-1).*obj.Info.IOBlockSize + 1;
            regionEnd = (ioblockSub).*obj.Info.IOBlockSize;
            rows = [regionStart(1), regionEnd(1)];
            cols = [regionStart(2), regionEnd(2)];
            slices = [regionStart(3), regionEnd(3)];
            
            block = tiffreadVolume(obj.File, ...
                'PixelRegion',{rows,cols,slices});
        end

    end
end