Contents
ABOUT THE COMPONENT LIBRARY

INSTALLATION INSTRUCTIONS

USING THE JPEG DEMO APPLICATION

CLASSES AND UNITS

PRICING INFORMATION

HOW TO REGISTER

SECURE REGISTRATION

SHAREWARE LICENCE


ABOUT THE COMPONENT LIBRARY

The JPEG Component Library provides two additional non-visual components for use under either Delphi 1.0 or Delphi 2.0. These are TJPEGFileCompressor and TJPEGFileDecompressor. These support compression of images to JPEG Format and decompression respectively.  This, the shareware version comes with a licence to evaluate for 30 days, after which you must register (see below) in order to continue to use the software. The shareware version will only operate while the Delphi IDE is active.

Simply installing these components JPEG enables the Delphi IDE. The components register themselves as supporting .jpg files and the JPEG compression format and, when you come to load an image into a TImage Picture, the JPEG format will be found amongst the list of supported file formats. An image loaded from a JPEG source can also be saved back to JPEG. These components support the JPEG File Interchange Format (JFIF).

These two components also support TImage at run-time too. As at design time, if TJPEGFileDecompressor is included in your project, then calling TImage.Picture.LoadFromFile when the file extension is .jpg will automatically invoke the JPEG decompressor. You can also explicitly call TJPEGFileDecompressor to load a JPEG image from any file.

This software uses original software for JPEG developed by the Independent JPEG Group (see ftp://ftp.uu.net/graphics/jpeg). The IDG have made available a library of generic 'C' code supporting JPEG compression and decompression and have permitted its free use provided the source is acknowledged. The IDG code has been modified for use with Delphi and MS Windows and is provided as a separate .dll (mwjpeg.dll for the 16-bit version and mwjpeg32.dll for the 32-bit version). This dll may be freely distributed.

An interface to this .dll is provided by the unit jpeglib.pas. This is encapsulated as a set of Delphi components in the unit jpeg.pas, which also supports the mapping of the environment independent image format expected by the IJG code into MS Windows bitmap and metafile formats.

When you purchase a licence to this product, you purchase a licence for the source code to the jpeg and jpeglib units and the right to include binaries derived from them in your own products without having to pay additional royalties. You also have a right to freely distribute the mwjpeg and mwjpeg32 dlls, and copies of the modified 'C' source is also included in the registered version. Support is also provided by EMail albeit without a guaranteed response time.


INSTALLATION INSTRUCTIONS

Installation is straightforward. The JPEG Component Library is distributed in a .zip archive, with one version for use with Delphi 1.0 and the other for Delphi 2.0. Make sure you have the correct version and then:

1.	Copy the jpeg .dll to your windows directory. This will be mwjpeg.dll for Delphi 1.0 and mwjpeg32.dll for Delphi 2.0.

2.	Create a new sub-directory in your delphi directory (the actual name is unimportant - call it jpeg if you can't think of anything better) and copy the remaining files contained in the .zip file into this new subdirectory.

3.	Start the Delphi IDE and choose then Options|Install Components (Delphi 1.0) or Component|Install (Delphi 2.0) menu option. Click on the "Add" button and browse for the jpeg-reg.pas file you just copied to the new subdirectory. Click on OK. (Note that this file contains the registration information for the JPEG components. By default these are placed on the "Additional" tab. You can edit this file to locate them elsewhere).

The components are now installed. Use the demo application to learn how they are used.


Units

The MWA JPEG Component Library consists of three units:

JPEG	This unit encapsulates the JPEG Compression/Decompression library and defines the two Delphi Components exported by the library.
JPEGLIB	This is the interface unit to the JPEG Compression/Decompression library
JPEG_REG	This unit contains the Register procedure used to install the components. It may be modified in order to change the palette on which the components are installed. By default, this is the Additional palette.


USING THE JPEG DEMO APPLICATION

The JPEG Demo application may be found in the subdirectory created above. To activate, load the jpegdemo.dpr file into the IDE using the File|Open Project (Delphi 1.0) or the File|Open (Delphi 2.0) menu item. This provides a simple application that can open and save .jpg (JPEG), .bmp (Windows Bitmap) and .wmf (Windows metfaile) files, and copy and paste bitmaps and metafiles to and from the clipboard. To test out, simply compile and run the application.

To load and view a JPEG file, click on the open button and load the test.jpg file contained in the subdirectory created above. You can also try saving it to another file name (you can save it as either a JPEG or a bitmap). You can also use the demo application to convert windows bitmaps and metafiles to jpegs simply by opening the file containing them (or pasting from the clipboard) and saving them as jpegs.

You can also use the Object Inspector to see the properties published by the two JPEG components.


Comment Property
Comment: string

Class: TJPEGFileCompressor

This comment is included in the compressed JPEG image. A typical use is to include a copyright message.


DCTMethod Property
DCTMethod: J_DCT_METHOD;

Classes: TJPEGFileDecompressor and  TJPEGFileCompressor

Selects the algorithm used for the DCT quantisation step.  Choices are:

JDCT_ISLOW:	slow but accurate integer algorithm
JDCT_IFAST:	faster, less accurate integer method
JDCT_FLOAT:	floating-point method.
The FLOAT method is very slightly more accurate than the ISLOW method, but may give different results on different machines due to varying roundoff behaviour.  The integer methods should give the same results on all machines.  On machines with sufficiently fast FP hardware, the floating-point method may also be the fastest.  The IFAST method is considerably less accurate than the other two; its use is not recommended if high quality is a concern.


DensityUnit Property
DensityUnit: UINT8; X_Density: UNIT16; Y_Density: UNIT16;

Class: TJPEGFileCompressor

The resolution information to be written into the JFIF marker; not used otherwise.  density_unit may be 0 for unknown, 1 for dots/inch, or 2 for dots/cm.  The default values are 0,1,1 indicating square pixels of unknown size.


GrayscaleOutput Property
GrayscaleOutput: boolean;

Classes: TJPEGFileDecompressor and  TJPEGFileCompressor

If true then the image is converted to a grayscale image.


OptimizeCoding Property
OptimizeCoding: boolean;

Class: TJPEGFileCompressor

TRUE causes the compressor to compute optimal Huffman coding tables for the image.  This requires an extra pass over the data and therefore costs a good deal of space and time.  The default is FALSE, which tells the compressor to use the supplied or default Huffman tables.  In most cases optimal tables save only a few percent of file size compared to the default tables.


ProgressiveJPEG Property
ProgressiveJPEG: boolean;

Class: TJPEGFileCompressor

Progressive JPEG rearranges the stored data into a series of scans of increasing quality.  In situations where a JPEG file is transmitted across a slow communications link, a decoder can generate a low-quality image very quickly from the first scan, then gradually improve the displayed quality as more scans are received.  The final image after all scans are complete is identical to that of a regular (sequential) JPEG file of the same quality setting.  Progressive JPEG files are often slightly smaller than equivalent sequential JPEG files, but the possibility of incremental display is the main reason for using progressive JPEG.

When this property is set to true a progressive JPEG file is generated using a default scan script generated by the JPEG library.


Quality Property
Quality: int;

Class: TJPEGFileCompressor

JPEG quantisation tables appropriate for the indicated quality setting are generated.  The quality value is expressed on a 0..100 scale.


RestartInterval Property
RestartInterval: Cardinal; RestartInRows: int;

Class: TJPEGFileCompressor

To emit restart markers in the JPEG file, set one of these nonzero. Set RestartInterval to specify the exact interval in MCU blocks. Set RestartInRows to specify the interval in MCU rows.  (If RestartInRows is not 0, then RestartInterval is set after the image width in MCUs is computed.)  Defaults are zero (no restarts).


SmoothingFactor Property
SmoothingFactor: int;

Class: TJPEGFileCompressor

If non-zero, the input image is smoothed; the value should be 1 for minimal smoothing to 100 for maximum smoothing.  The default is zero.


Trace_Level Property
Trace_Level: int;

Classes: TJPEGFileDecompressor and  TJPEGFileCompressor

Controls the level of trace information reported. (set >= 3 to see more than the first warning message).


WriteAllTables Property
WriteAllTables: boolean;

Class: TJPEGFileCompressor

Set to True (default) to ensure that a proper JPEG Interchange stream is written. If false, then the quantisation and Huffman tables are not written to the JPEG file. This makes for a smaller file but creates difficulties for the decompressor unless some other way is found to transfer these tables.


WriteJFIFHeader Property
WriteJFIFHeader: boolean;

Class: TJPEGFileCompressor

If true (default) then a JFIF APP0 marker is emitted. The decompressor will then recognise it as a JFIF compatible stream.


SavePictureToFile Property
procedure SavePictureToFile(Picture: TPicture; const FileName: string);

Class: TJPEGFileCompressor

Provided that the Picture holds a Bitmap or a Metafile image, it will be compressed to a JPEG and written out to the file "FileName".


SavePictureToStream Property
procedure SavePictureToStream(Picture: TPicture; Stream: TStream);

Class: TJPEGFileCompressor

Provided that the Picture holds a Bitmap or a Metafile image, it will be compressed to a JPEG and written out to the provided stream.


SaveBitMapToStream Property
procedure SaveBitMapToStream(bitmap: TBitmap; Stream: TStream);

Class: TJPEGFileCompressor

The bitmap is compressed to a JPEG and written out to the provided stream.


SaveDIBitmapToStream Property
procedure SaveDIBitmapToStream(Stream: TStream; const BitmapInfo: TBitmapInfo;bits: PChar);

Class: TJPEGFileCompressor

The device independent bitmap held in the memory block given by "bits", is compressed to a JPEG and written out to the provided stream. Note that the BitmapInfo structure is defined by the Windows API and defines the size and resolution of the bitmap and may also contain a colour map.


SaveMetaFileToStream Property
procedure SaveMetaFileToStream(metafile: TMetafile; Stream: TStream; width, height: longint);

Class: TJPEGFileCompressor

The metafile is compressed to a JPEG and written out to the provided stream. Note that the height and width of the required image (in pixels) must also be provided.


WriteMarker Property
procedure WriteMarker(Marker: int; const buf; Count: uint);

Class: TJPEGFileCompressor

This method may be called from the event "OnWriteMarkers" to write out data with a JPEG APPn marker. The actual marker is identified by the Marker parameter (e.g. to write out an APP1 marker, set Marker to one). The value data written out is contained in buf and contains Count bytes.


OnProgessReport Property
OnProgessReport: TNotifyEvent

Classes: TJPEGFileDecompressor and  TJPEGFileCompressor

Called regularly during compression/decompression to enable a progress report to be maintained. The PercentDone integer property (read only) may be consulted to find out the percentage so far processed.


OnWriteMarkers Property
OnWriteMarkers: TNotifyEvent

Class: TJPEGFileCompressor

This event occurs when it is permissible to output application specific markers to the JPEG data stream. See discussion of WriteMarker Method for details on how to do this.


DitherMode Property
DitherMode: J_DITHER_MODE

Class: TJPEGFileDecompressor

Selects color dithering method.  Supported values are:

JDITHER_NONE	no dithering: fast, very low quality
JDITHER_ORDERED	ordered dither: moderate speed and quality
JDITHER_FS	Floyd-Steinberg dither: slow, high quality
Default is JDITHER_FS.  (At present, ordered dither is implemented only in the single-pass, standard-colormap case.  If you ask for ordered dither when two_pass_quantize is TRUE or when you supply an external color map, you'll get F-S dithering.)


DoBlockSmoothing Property
DoBlockSmoothing: boolean

Class: TJPEGFileDecompressor

If TRUE, interblock smoothing is applied in early stages of decoding progressive JPEG files; if FALSE, not.  Default is TRUE.  Early progression stages look "fuzzy" with smoothing, "blocky" without.


DoFancyUpSampling Property
DoFancyUpSampling: boolean

Class: TJPEGFileDecompressor

If TRUE, do careful upsampling of chroma components.  If FALSE, a faster but sloppier method is used.  Default is TRUE.  The visual impact of the sloppier method is often very small.


TwoPassQuantize Property
TwoPassQuantize: boolean

Class: TJPEGFileDecompressor

If TRUE, an extra pass over the image is made to select a custom colour map for the image.  This usually looks a lot better than the one-size-fits-all colourmap that is used otherwise.  Default is TRUE.  Ignored when the application supplies its own colour map.


LoadPictureFromFile Property
procedure LoadPictureFromFile(Picture: TPicture; const FileName: string);

Class: TJPEGFileDecompressor

Opens the file identified by FileName which is assumed to contain a JPEG image in the JFIF format. This is decoded into a windows bitmap and loaded into the supplied Picture object.


ConvertToDIB Property
procedure ConvertToDIB(Source, Destination: TStream; OutputType: TJPEGOutputType);

Class: TJPEGFileDecompressor

Converts a JPEG compressed image Windows Device Independent bitmap contained in the Source stream to a Windows Device Independent bitmap written to the destination stream.

The format of the DIB is determined by the setting of OutputType.


TJPEGOutputType  Property
TJPEGOutputType =

(jp24bit,	{24 bit bitmap}
jp8bit,	{56 colour bitmap}
jp4bit,	{6 colour bitmap}
jpGrayscale);	{Gyscale}
Determines the bitmap resolution.


LoadPictureFromStream Property
procedure LoadPictureFromStream(Picture: TPicture; Stream: TStream);

Class: TJPEGFileDecompressor

The source stream is assumed to contain a JPEG image in the JFIF format. This is decoded into a windows bitmap and loaded into the supplied Picture object.


ReadBitMapFromStream Property
function ReadBitMapFromStream(Stream: TStream): TBitmap;

Class: TJPEGFileDecompressor

The source stream is assumed to contain a JPEG image in the JFIF format. This is decoded into a windows bitmap and returned as a TBitmap object.


ReadDIBitmapFromStream Property
procedure ReadDIBitmapFromStream(Stream: TStream;
var BitMapInfo: TBitMapInfo;
OutputType: TJPEGOutputType;
var bits: THandle);

Class: TJPEGFileDecompressor

The source stream is assumed to contain a JPEG image in the JFIF format. This is decoded into a windows device independent bitmap and returned in the memory block given by bits. The output type is determined as above and the information describing the bitmap size, resolution and colour map is returned in the Windows APS BitMapInfo structure.


OnJPEGComment Property
OnJPEGComment: TJPEGCommentEvent

  TJPEGCommentEvent = procedure(sender: TJPEGBase; comment: PChar) of object;

Class: TJPEGFileDecompressor

This event occurs when a comment is found in the JPEG compressed image. The comment is extracted and provided as a parameter to the event handler.


OnJPEGMarker Property
OnJPEGMarker: TJPEGMarkerEvent

  TJPEGMarkerEvent = procedure(sender: TJPEGBase; Marker: int; var Done: boolean) of object;

Class: TJPEGFileDecompressor

This event occurs when any other JPEG marker is found in the JPEG image (except for APP1 the JFIF marker). The marker is identified by the Marker parameter (range 1..13), and the response method may read successive bytes from the stream after the marker by calling the GetByte method (this is a parameterless function that returns a single byte value). Note that marker processing is application specific.

If the marker is not processed, then the response method should return with Done set to false. The marker text will then be skipped, otherwise, Done should be set to true to indicate that the response method has handled the marker itself.


Abort
procedure Abort; virtual;

Classes: TJPEGFileDecompressor and  TJPEGFileCompressor

The Abort method may be called to abandon a compression or decompression operation. It must be called from the same thread as the compression or decompression operation. Practically, this limits its use to an event handler (e.g. OnProgressReport), when it may be used to abort the operation, perhaps in response to a user cancellation request.


Shareware Licence Agreement
Shareware Licence

LICENCE AGREEMENT

© 1997 McCallum Whyman Associates Limited trading as MWA Software

The copyright in the shareware version of this software ("the Software") is owned by McCallum Whyman Associates Limited trading as MWA Software ("the Owner").  You may not load the Software into any computer or copy it without the licence of the Owner.  The Owner offers you a nonexclusive licence on the terms of this Agreement.

Licence

You are permitted during the Term to:

(1)	load the Software and use it only on a single computer (with a single input terminal) which is under your control;

(2)	transfer the Software from one computer to another provided it is used on only one computer at a time;

(3)	make copies of the Software.  The copies must reproduce and include the Owner's copyright notice;

(4)	transfer a copy of the Software (complete with all its associated documentation and this licence) to another person provided that the Software is not modified in any way and includes all files as originally supplied and that no charge is made for the transfer.  If any transferee does not accept such terms then this licence shall automatically terminate.  The transferor does not retain any rights under this Agreement in respect of the transferred Software or licence.

You are not permitted:

(a)	to rent, lease, sublicence, loan, copy (except as expressly provided in this Agreement), modify, adapt, merge, translate, reverse engineer, decompile, disassemble or create derivative works based on the whole or any part of the Software or its associated documentation;

(b)	except as expressly provided in this Agreement, to use, reproduce or deal in the Software in any way.

Acceptance

You shall be deemed to have accepted the terms of this Agreement by loading the Software into any computer.

Term

Subject as set out below this licence is effective for a period of 30 days from the date of first use by you.   This Licence will terminate if you fail to abide by its terms.  Upon termination you agree to destroy all copies of the Software and its documentation including any Software stored on the hard disk of any computer under your control.

Registration

If you wish to licence the Software beyond the period of 30 days aforesaid then please return the enclosed Licence Registration Form to the Owner within such period.

Ownership

The Owner shall at all times retain ownership of the Software as recorded in the original file set or diskette and all subsequent copies thereof regardless of form.  If the Software was supplied on diskette, you own only the diskette on which the Software is recorded.  You may retain the diskette on termination provided the Software has been erased.  This Agreement applies to the grant of the licence only and not to the contract of sale of the diskette.

Warranties

(1)	The express terms of this Agreement are in lieu of all warranties, conditions, undertakings, terms and obligations implied by statute, common law, trade usage, course of dealing or otherwise all of which are hereby excluded to the fullest extent permitted by law.

(2)	The Owner does not warrant that the Software will meet your requirements or that the operation of the Software will be uninterrupted or errorfree or that defects in the Software will be corrected.  You shall load and use the Software at your own risk and in no event will the Owner be liable to you for any loss or damage of any kind (except personal injury or death resulting from the Owner's negligence) including lost profits or consequential loss arising from your use of or inability to use the Software or from errors or deficiencies in it whether caused by negligence or otherwise.

(3)	Any liability of the Owner pursuant to this licence shall be limited to the purchase price or registration fee paid.

Law

This Agreement shall be governed by English law.

If you have any questions concerning this Agreement please write to McCallum Whyman Associates Limited trading as MWA Software at PO Box 37, Alresford, Hampshire, SO24 9ZF, England.


PRICING INFORMATION

JPEG Component Library Source Licence	12 pounds sterling (US$20)

US dollar prices are for indicative pricing only and assume an exchange rate of one pound = $1.66.  All prices are VAT exclusive. UK VAT (currently 17.5%) will be

charged for all UK residents and EC residents that are not VAT registered or do provide a VAT number as proof of registration.

How To Register


HOW TO REGISTER

See Also - Secure Registration

Registration may be made by FAX, Letter Post or EMail. For FAX and Letter Post registrations, a Registration Form is provided in the File "regform.txt" for you to EMail or print out (FAX or letter post), complete, and send to MWA Software. You may also register via Compuserve's Shareware Registration facility (GO SWREG) - Registration ID 15235. The software is registered under the name "MWA JPEG Component Library".

Visa, Mastercard, Eurocard and JCB are accepted as payment mechanisms. International money orders in pounds sterling and cheques drawn on UK Bank Accounts are also accepted. US Dollar denominated checks are also acceptable provided that an additional 10% is added to the purchase price to allow for the additional Bank Charge. Please make cheques payable to McCallum Whyman Associates Ltd.

EMail registrations should be sent to:   Internet:	sales@mwassocs.demon.co.uk, or   Compuserve:	100041,315

FAX:   UK: 01962 735581   Int: +44 1962 735581

MWA Software, P.O.Box 37, Alresford, Hants, SO24 9ZF, ENGLAND

All registrations are accepted on the basis that the registered user will be deemed to have accepted and be bound by the licence conditions for the registered versions of JPEG component library as recorded in the file reg-lnce.txt supplied with the evaluation version of the software.


Secure Registration by EMail

There are two routes by which you can EMail your credit card details to MWA Software without incurring the risk of sending a credit card number in clear across the Internet. One route is to use the encryption mechanism provided by pkzip. The other is to use PGP.

pkzip encryption will generally be good enough to avoid detection by the so called "sniffer" programs that are understood to monitor EMail communications, looking for numbers that look like credit cards. However, it is not believe to be good enough to resist a determined attack by someone who has access to the necessary skills in cryptography and a powerful enough computer. On the other hand PGP is understood to offer a very strong level of protection. MWA Software makes no recommendations as to which is the better approach. It is for you to decide based on your own location and concerns.


Secure Transmission using pkzip.

pkzip can encrypt files in a .zip archive using a simple password. To register for the JPEG Component Library by EMail when using pkzip as your encryption engine:

1.	Using the file "regform.txt" as a template, complete a registration form for the JPEG Component Library. Remember to include your credit card details, billing address and your name as it appears on your credit card.

2.	Choose a password. Opening a dictionary at some random page is often a good way to do this. For example, let's assume that you choose NERVOUS as your password.

3.	Compress and encrypt the modified regform.txt using pkzip and the -s option to encrypt. For example, with NERVOUS as your password, use the command line:

pkzip -sNERVOUS regform regform.txt

This will create regform.zip containing your compressed and encryted registration details.

4.	EMail regform.zip to MWA Software. Your own EMail utility will usually have a way to send binary attachments to an EMail message. If you do not have such a capability then you can use the J-Write Text Editor (also available from MWA Software) to uuencode a binary file into a text form suitable for attaching to an EMAil message. This feature is available from the File|Merge menu item. The MWA Software EMail address is sales@mwassocs.demon.co.uk. Set the subject to "JPEG Registration"

5.	Send the password you choose at step 2 in a separate EMail to MWA Software. For best protection, use our Compuserve EMail address:

6.	100041.315@compuserve.com

Set the subject to "re: JPEG Registration"


Secure Transmission using PGP

PGP is a powerful data encryption tool that has been made publicly available by its author "Phillip Zimmermann". It is sufficiently good to attract the attentions of various governments' agencies and you should be aware that in certain countries the use of such encryption software is a criminal offence. MWA Software only uses PGP to decrypt registrations and does not send encrypted EMail. Having said that, the international version of PGP can be obtained from:

http://www.ifi.uio.no/pgp/

The following URL is also a good source of information about PGP, including information on how to get the more limited US version.

http://www.arc.unm.edu/~drosoff/pgp/pgp.html

To encrypt a registration using PGP, do the following:

1.	Using the file "regform.txt" as a template, complete a registration form for the JPEG Component Library. Remember to include your credit card details, billing address and your name as it appears on your credit card.

2.	Encrypt regform.txt using PGP and the MWA public key. This is provided in the file "mwakey.asc", which should be in the same archive as this file. This will typically be performed by the following commands (the ; indicates the start of a comment):

pgp -ka mwakey.asc	;add MWA key to your public keyring
pgp -ea regform.txt "MWA Software"	;encrypt and encode for EMail
pgp -kr "MWA Software"	;remove the MWA key from your keyring
The above will have created the encrypted file "regform.pgp". This is a text file and may be sent as part of a normal EMail to MWA Software:

sales@mwassocs.demon.co.uk

Set the subject to "JPEG Registration"

If you have any reason to doubt the validity of the MWA key, request an up-to-date version by EMail to the above address, with a subject of "Key Verification Request".

Thank you for registering for the JPEG Component Library.


Classes

The JPEG Component Library defines the following classes:

TJPEGFileCompressor

TJPEGFileDecompressor


TJPEGFileCompressorProperties
Properties

Comment	DCTMethod	DensityUnit
GrayscaleOutput	OptimizeCoding	ProgressiveJPEG
Quality	RestartInterval	SmoothingFactor
Trace_Level	WriteAllTables	WriteJFIFHeader


TJPEGFileCompressorMethods
Methods

SavePictureToFile	SavePictureToStream	WriteMarker
SaveDIBitmapToStream	SaveMetaFileToStream
SaveBitMapToStream	Abort


TJPEGFileCompressorEvents
Events

OnProgessReport	OnWriteMarkers


TJPEGFileCompressor Class

Properties	Methods	Events	Classes
Unit:	JPEG

TJPEGFileCompressor can be used to save a TImage.Picture in JPEG format, and can handle pictures that are either bitmaps or metafiles. It can also compress a device independent bitmap.


TJPEGFileDecompressorProperties
Properties

DCTMethod	DitherMode	DoBlockSmoothing
DoFancyUpSampling	GrayScaleOutput	TwoPassQuantize
TraceLevel


TJPEGFileDecompressorMethods
Methods

LoadPictureFromFile	LoadPictureFromStream
ReadBitMapFromStream	ReadDIBitmapFromStream
ConvertToDIB	Abort


TJPEGFileDecompressorEvents
Events

OnJPEGComment	OnJPEGMarker	OnProgessReport


TJPEGFileDecompressor Class

Properties	Methods	Events	Classes
Unit:	JPEG

If TJPEGFileDecompressor is included in your project, then calling TImage.Picture.LoadFromFile when the file extension is .jpg will automatically invoke the JPEG decompressor. You can also explicitly call TJPEGFileDecompressor to load a JPEG image from any file.