BCB database Image Storage Technology

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BCB database Image Storage Technology
Add the header file # include <jpeg. HPP>
1
Void _ fastcall tform1: speedbutton1click (tobject * sender)
{
Opendialog2-> filename = "";
If (opendialog2-> execute ())
{
String F = opendialog2-> filename;
If (fileexists (f ))
{
String ext = extractfileext (f). lowercase ();
If (EXT = ". BMP" | ext = ". jpg" | ext = ". jpeg ")
{
String JPG = changefileext (extractfilename (F), ". jpg ");
Tsung image * j = new Tsung image;
If (EXT = ". BMP ")
{
Graphics: tbitmap * B = new graphics: tbitmap;
B-> loadfromfile (f );
J-> assign (B );
J-> compressionquality = 90;
J-> compress ();
Delete B;
}
Else
{
Tfilestream * FS = new tfilestream (F, fmopenread );
J-> loadfromstream (FS );
Delete FS;
}
Datamodule1-> adodataset1-> edit ();
Dbedit2-> text = JPG;
Tstream * BS = datamodule1-> adodataset1-> createblobstream (
Datamodule1-> adodataset1-> fieldbyname ("photo image"), bmreadwrite );
BS-> position = 0;
J-> savetostream (BS );
Delete J;
Delete BS;
Dispjpg ();
}
}
}
}

2
Remember to delete the tadoblobstream object before post.
// Read
Tblobfield * pfield = (tblobfield *) pquery-> fieldbyname ("image ");
Tadoblobstream * pmem = new tadoblobstream (pfield, bmread );
Pmem-> seek (0, sofrombeginning );
Graphics: tbitmap * pbitmap = new graphics: tbitmap ();
Pbitmap-> loadfromstream (pmem );
Image1-> picture-> assign (pbitmap );
Delete pbitmap;
Delete pmem;
// Write
Pquery-> edit ();
Tblobfield * pfield = (tblobfield *) pquery-> fieldbyname ("image ");
Tadoblobstream * pmem = new tadoblobstream (pfield, bmwrite );
Pmem-> seek (0, sofrombeginning );
Graphics: tbitmap * pbitmap = new graphics: tbitmap ();
Pbitmap-> assign (image1-> picture-> graphic );
Pbitmap-> savetostream (pmem );
Delete pbitmap;
Delete pmem;
Pquery-> post ();

If you use a fixed field in tTable, it is simpler. The following adotable1pic field is
Read BLOB data in access
Tmemorystream * s = new tmemorystream ();
Adotable1pic-> savetostream (s );
S-> position = 0; // ***** the first position of the stream must be zero ***
Tsung image * JP = new Tsung image ();
JP-> loadfromstream (s );
Image1-> picture-> Bitmap-> assign (JP );
Delete JP;
Delete S;
Blob field for writing data to access
If (opendialog1-> execute ())
{Adotable1-> disablecontrols ();
Adotable1-> append ();
Adotable1pic-> loadfromfile (opendialog1-> filename );
Adotable1name-> value = opendialog1-> filename;
Adotable1-> post ();
Adotable1-> enablecontrols ();
}

3
Void _ fastcall tform2: dbimage2click (tobject * sender)
{
Try
{
If (openpicturedialog1-> execute ());
{
Ansistring myfilesextension = uppercase (extractfileext (openpicturedialog1-> filename ));
If (myfilesextension = ". jpg ")
{
Tsung image * JPG = new Tsung image ();
Jpg-> loadfromfile (openpicturedialog1-> filename );
Clipboard ()-> assign (JPG );
Dbimage1-> datasource-> dataset-> edit ();
Dbimage1-> pastefromclipboard ();
Dbimage1-> datasource-> dataset-> post ();
Delete JPG;
}
If (myfilesextension = ". BMP ")
{
Editdatasource1-> dataset-> edit ();
Datamodule1-> findadodatasetdsdesigner7-> loadfromfile (openpicturedialog1-> filename );
}
}
}
Catch (...)
{
Statusbar1-> panels-> items [1]-> text = "An exception occurred while saving the image ";
}
}

4
In BCB, the following method is used to store images. However, the display code does not need to be written, and dbimage is automatically displayed.

If (openpicturedialog1-> execute ());
{
Ansistring myfilesextension = uppercase (extractfileext (openpicturedialog1-> filename ));
If (myfilesextension = ". jpg ")
{
Tsung image * JPG = new Tsung image ();
Jpg-> loadfromfile (openpicturedialog1-> filename );
Clipboard ()-> assign (JPG );
Dbimage1-> datasource-> dataset-> edit ();
Dbimage1-> pastefromclipboard ();
Dbimage1-> datasource-> dataset-> post ();
Delete JPG;
}

The data type must be image.
Save jpeg to SQL database:
If (openpicturedialog1-> execute ())
{
Adoquery1-> edit ();
Tblobfield * field = (tblobfield *) adoquery1-> fieldbyname ("photo ");
Field-> loadfromfile (openpicturedialog1-> filename );
Adoquery1-> post ();
}

// Read jpeg from the database and display it in the tdbimage control.
# Include <clipbrd. HPP>

Tstream * stream1;
Tsung image * pjp;

Pjp = new tsf-image ();

Adoquery1-> open ();
Try
{
Stream1 = adoquery1-> createblobstream (adoquery1-> fieldbyname ("treenodes"), bmread); // treenodes is the field that stores JPEG content, and its type must be Image
Pjp-> loadfromstream (stream1 );
// Image2 is the tdbimage component. Its datesource and fieldname attributes must be empty.
Image2-> picture-> Bitmap-> assign (pjp );
Delete stream1;
}
_ Finally
{
Adoquery1-> close ();
Delete pjp;
}

The following is a better way for others to store various images
The following is a program for generating various types of video clips. It supports ado, BDE, or tclientdataset.
# Define picture_map _ (Tbit) {Tbit * Pg = new Tbit ();/
Try {PG-> loadfromstream (tmpstream );/
PIC-> assign (PG );/
}/
Catch (...)/
{Delete PG ;/
Return false ;/
}/
Delete PG ;/
}
//----------------------------------------------------------------
// The template uses the Assign Method to convert the image (GIF or JPG) in the binary field to tpicture, tbitmap, and so on.
Template <class T>
Bool loadphotofromfield (tfield * f_photo, const ansistring format, T * pic)
{If (! F_photo-> dataset-> active) return false;
If (f_photo-> isnull) return false;
Else
{Tstream * tmpstream = f_photo-> dataset-> createblobstream (f_photo, bmread );
If (format = ". jpg" | format = ". jpeg") picture_map _ (t1_image)
Else if (format = ". BMP") picture_map _ (graphics: tbitmap)
// Else if (format = ". GIF") picture_map _ (tgifimage)
Else if (format = ". ICO") picture_map _ (ticon)
Else if (format = ". WMF" | format = ". EMF") picture_map _ (tmetafile)
Else return false;
}
Return true;
}
# UNDEF picture_map _ (Tbit)
// If You Want To support GIF, you need to install the VCL type that supports GIF.

 

Supports multiple formats
Deposit:
If (openpicturedialog1-> execute ())
{Dataset-> edit ();
Tblobfield * field = (tblobfield *) dataset-> fieldbyname ("photo ");
Field-> loadfromfile (openpicturedialog1-> filename );
Dataset-> fieldbyname ("photoformat")-> asstring =
Extractfileext (openpicturedialog1-> filename). uppercase ();
Dataset-> post ();
}