JpgSaver

class io.savers.JpgSaver

Bases: io.savers.BaseSaver

JPGSAVER - Saver for JPEG output - one file per Z-slice (always a 2-D sequence).

JPEG is a lossy format suitable for display purposes; it is NOT recommended for quantitative analysis. uint16 multichannel data cannot be saved as JPEG (MATLAB limitation); use uint8 RGB only.

Handled format string: ‘Joint Photographic Experts Group (*.jpg)’

DATA DIMENSIONS Input data : [H, W, D, C, T] imwrite call: [H, W, C] per 2-D slice (C ≤ 3, class == uint8)

NOTES * options.Quality (0-100, default 90): JPEG quality factor. * options.Compression (‘lossy’|’lossless’, default ‘lossy’). * JPEG does not support indexed colourmaps; ‘indexed’ colour images will be saved using the raw index values as greyscale.

USAGE EXAMPLES

%% 1. Direct saver use
saver = io.SaverFactory.create('Joint Photographic Experts Group (``*.jpg``)');

opts.Format      = 'Joint Photographic Experts Group (``*.jpg``)';
opts.Quality     = 90;
opts.Compression = 'lossy';
opts.showWaitbar = false;
opts.silent      = true;
opts.overwrite   = true;
opts.FilenameGenerator = 'Use sequential filename';

meta.filename         = 'source.tif';
meta.colorType        = 'multichannel';
meta.lutColors        = eye(3);
meta.dataClass        = 'uint8';
meta.maxInt           = 255;
meta.sliceName        = {};
meta.imageDescription = '';

data = uint8(rand(256,256,10,3,1)*255);   % [H W D C T], RGB
fnOut = saver.save(data, meta, '/output/slice.jpg', opts);
% Generates /output/slice_01.jpg … /output/slice_10.jpg

%% 2. Via MibModel with quality control
BatchOpt.LayerType       = {'image'};
BatchOpt.Format          = {'Joint Photographic Experts Group (``*.jpg``)'};
BatchOpt.Quality         = '90';
BatchOpt.Compression     = 'lossy';
BatchOpt.OutputDirectoryPolicy = {'Full path'};
BatchOpt.DestinationDirectory  = '/output';
BatchOpt.FilenamePolicy  = {'Use existing name'};
BatchOpt.showWaitbar     = false;
BatchOpt.mibBatchTooltip.LayerType = '';
model.save('image', [], BatchOpt);

SEE ALSO io.SaverFactory, io.savers.BaseSaver, io.savers.PngSaver

Constructor Summary
JpgSaver(options)

JPGSAVER - Constructor for JpgSaver class.

Syntax:
saver = io.savers.JpgSaver(options)
Input Arguments:

  • options - (optional) struct, saver-level options (usually empty; per-save options are passed to save() instead)

Output Arguments:

  • obj - instance of the JpgSaver class

Method Summary
getSupportedFormats(~)

GETSUPPORTEDFORMATS - Return format strings handled by JpgSaver.

Syntax:
formats = obj.getSupportedFormats()
Input Arguments:

(none)

Output Arguments:

  • formats - cell array of format strings for JPEG output

save(data, metadata, filename, options)

SAVE - Write JPEG 2-D sequence (one file per Z-slice × time point).

Syntax:
fnOut = obj.save(data, metadata, filename, options)
Input Arguments:

  • data - [H, W, D, C, T] uint8 (or uint16 greyscale)

  • metadata - struct with fields:

    • colorType - data type (multichannel RGB must be uint8)

    • sliceName - (optional) per-slice source filenames

    • imageDescription - (optional) JPEG Comment tag

  • filename - full path template, e.g. '/out/frame.jpg'

  • options - struct with fields:

    • Quality - [double] 0-100; default: 90

    • Compression - [char] 'lossy' | 'lossless'; default: 'lossy'

    • showWaitbar - logical; default: true

    • silent - logical, suppress dialogs; default: false

    • overwrite - logical; default: true

    • FilenameGenerator - [char] filename generation mode

Output Arguments:

  • fnOut - cell of char with all saved paths, or single char if only one slice

JPEG is inherently per-slice, so save is a thin wrapper over the streaming primitive saveStream (single code path).

saveStream(provider, metadata, filename, options)

SAVESTREAM - Write a JPEG 2-D sequence one slice at a time from a SliceProvider. See io.savers.BaseSaver.saveStream.

Example - stream a level to a JPEG sequence (quality 90):

provider = io.savers.MibImageSliceProvider(img, 'image', 2, [], numZ, 1, zScale);
saver    = io.savers.JpgSaver(struct());
meta.colorType = 'grayscale';
saver.saveStream(provider, meta, 'C:\out\frame.jpg', ...
    struct('silent',true,'showWaitbar',false,'Quality',90,'Compression','lossy', ...
           'FilenameGenerator','Use sequential filename'));