colorspace.zip

function s = iccread(filename) %ICCREAD Read ICC color profile. % P = ICCREAD(FILENAME) reads the International Color Consortium (ICC) % color profile data from the file specified by FILENAME. The file can % be either an ICC profile file or a TIFF file containing an embedded % ICC profile. ICCREAD returns the profile information in the % structure P, which can be used by MAKECFORM and APPLYCFORM to compute % color space transformations. P can also be written to a new % ICC profile file by ICCWRITE. Both Version 2 and Version 4 % of the ICC specification are supported. % % The reference page for ICCREAD has additional information about the % fields of the structure P. For complete details, see the % specifications ICC.1:2001-04 for Version 2 and ICC.1:2001-12 % for Version 4.0 or ICC.1:2004-10 for Version 4.2.0.0 (available % at www.color.org). % % Example % ------- % Read in the sRGB profile. % % P = iccread('sRGB.icm'); % % See also ISICC, ICCWRITE, MAKECFORM, APPLYCFORM. % Copyright 2002-2015 The MathWorks, Inc. % Check input argument validateattributes(filename,{'char'},{'nonempty'},'iccread','FILENAME',1); % Check to see that FILENAME is actually a file that exists if exist(filename,'file') ~= 2 % Look in the system's ICC profile repository. try repository = iccroot; catch repository = ''; end if (exist(fullfile(repository, filename), 'file')) filename = fullfile(iccroot, filename); else error(message('images:iccread:fileNotFound')) end end if istif(filename) info = imfinfo(filename); if ~isfield(info,'ICCProfileOffset') error(message('images:iccread:noProfileInTiffFile')) end start = info.ICCProfileOffset; elseif isiccprof(filename) start = 0; else error(message('images:iccread:unrecognizedFileType')) end % "All profile data must be encoded as big-endian." Clause 6 [fid,msg] = fopen(filename,'r','b'); if (fid < 0) error(message('images:iccread:errorOpeningProfile', filename, msg)); end s = iccread_embedded(fid, start); fclose(fid); s.Filename = filename; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% function tf = isiccprof(filename) tf = false; fid = fopen(filename, 'r', 'b'); if (fid < 0) fclose(fid); return; end [~, count] = fread(fid, 3, 'uint32'); if count ~= 3 fclose(fid); return; end [device_class_code, count] = fread(fid, 4, 'uchar'); if count ~= 4 fclose(fid); return; end valid_device_classes = get_device_classes; if any(strcmp(char(device_class_code'), valid_device_classes(:, 1))) tf = true; end fclose(fid); %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% function tf = istif(filename) fid = fopen(filename, 'r', 'ieee-le'); if (fid < 0) tf = false; else sig = fread(fid, 4, 'uint8'); fclose(fid); tf = isequal(sig, [73; 73; 42; 0]) | isequal(sig, [77; 77; 0; 42]); end %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% function s = iccread_embedded(fid, start) % ICCREAD_EMBEDDED(FID, START) reads ICC profile data using the file % identifier FID, starting at byte offset location START, as measured % from the beginning of the file. fseek_check(fid, start, 'bof'); s.Header = read_header(fid); version = sscanf(s.Header.Version(1), '%d%'); % Skip past header -- 128 bytes (Clause 6.1) fseek_check(fid, start + 128, 'bof'); % Use fixed length of header % Read the Tag Table tag_count = fread_check(fid, 1, 'uint32'); tag_table = cell(tag_count,3); for k = 1:tag_count tag_table{k,1} = char(fread_check(fid, 4, '*uint8'))'; tag_table{k,2} = fread_check(fid, 1, 'uint32'); tag_table{k,3} = fread_check(fid, 1, 'uint32'); end s.TagTable = tag_table; % Build up a list of defined public tags public_tagnames = get_public_tagnames(version); mattrc_tagnames = get_mattrc_tagnames(version); private_tags = cell(0,0); has_mattrc = false; % Go through each tag in the tag table for k = 1:size(s.TagTable,1) signature = deblank(s.TagTable{k,1}); offset = s.TagTable{k,2}; data_size = s.TagTable{k,3}; pub_idx = strmatch(signature,public_tagnames,'exact'); mattrc_idx = strmatch(signature,mattrc_tagnames,'exact'); % Check to see if the tag is public, a mattrc tag, or private if ~isempty(pub_idx) % A public tag is found tagname = public_tagnames{pub_idx, 2}; s.(tagname) = get_public_tag(fid, signature, offset + start, ... data_size, version, s.Header.ConnectionSpace, tagname); elseif ~isempty(mattrc_idx) % A Mattrc element is found... and the MatTRC struct will % now be generated or appended. has_mattrc = true; tagname = mattrc_tagnames{mattrc_idx, 2}; MatTRC.(tagname) = get_public_tag(fid, signature, offset + start, ... data_size, version, s.Header.ConnectionSpace, tagname); else % The tag is a private tag data = get_private_tag(fid,offset+start,data_size); current_row = size(private_tags,1)+1; private_tags{current_row,1} = signature; private_tags{current_row,2} = data; end end % Generate the MatTRC field if has_mattrc s.MatTRC = MatTRC; end % Populate the private tags s.PrivateTags = private_tags; % Verify the checksum if present and nonzero. if isfield(s.Header, 'ProfileID') && any(s.Header.ProfileID) fseek_check(fid, start, 'bof'); bytes = fread_check(fid, s.Header.Size, '*uint8'); % See clause 6.1.13. The checksum is computed after setting bytes % 44-47 (indexed from 0), 64-67, and 84-99 to 0. bytes([45:48 65:68 85:100]) = 0; digest = compute_md5(bytes); if ~isequal(digest, s.Header.ProfileID) warning(message('images:iccread:badChecksum')); end end %------------------------------------------ function header = read_header(fid) % Clause 6.1.1 - Profile size header.Size = fread_check(fid, 1, 'uint32'); % Clause 6.1.2 - CMM Type header.CMMType = char(fread_check(fid, 4, 'uint8'))'; % Clause 6.1.3 - Profile Version % Byte 0: Major Revision in BCD % Byte 1: Minor Revision & Bug Fix Revision in each nibble in BCD % Byte 2: Reserved; expected to be 0 % Byte 3: Reserved; expected to be 0 version_bytes = fread_check(fid, 4, 'uint8'); major_version = version_bytes(1); % Minor version and bug fix version are in the two nibbles % of the second version byte. minor_version = bitshift(version_bytes(2), -4); bugfix_version = bitand(version_bytes(2), 15); header.Version = sprintf('%d.%d.%d', major_version, minor_version, ... bugfix_version); % Clause 6.1.4 - Profile/Device Class signature % Profile/Device Class Signature % ------------ --------- % Input Device profile 'scnr' % Display Device profile 'mntr' % Output Device profile 'prtr' % DeviceLink profile 'link' % ColorSpace Conversion profile 'spac' % Abstract profile 'abst' % Named Color profile 'nmcl' device_classes = get_device_classes(major_version); device_class_char = char(fread_check(fid, 4, '*uint8'))'; idx = strmatch(device_class_char, device_classes(:, 1), 'exact'); if isempty(idx) fclose(fid); error(message('images:iccread:invalidProfileClass')) end header.DeviceClass = device_classes{idx, 2}; % Clause 6.1.5 - Color Space signature % Four-byte string, although some signatures have a blank % space at the end. Translate into more readable string. colorspaces = get_colorspaces(major_version); signature = char(fread_check(fid, 4, '*uint8'))'; idx = strmatch(signature, colorspaces(:, 1), 'exact'); if isempty(idx) fclose(fid); error(message('images:iccread:invalidColorSpaceSignature')); else header.ColorSpace = colorspaces{idx, 2}; end % Clause 6.1.6 - Profile connection space signature % E