Images & Pictures in Delphi (TImage & TDBImage)

In Delphi loading, saving and deleting images in application is very easy. Delphi provides lots of classes and members to manage images in application. We can use useful component like TImage and TDBImage to load and save an Images. TImage is used to save or load an Image to or from a file. And TDBImage is used to save or load an Image to or from a database. Lets check in detail.

Timage

TImage control to display an image from files that ends in extensions including ICO, BMP, WMF, WMF, GIF and JPG. The Picture property specifies the image that appears in the TImage control. Delphi supports several different methods for assigning an image for the TImage component: a TPicture's method LoadFromFile reads graphics from disk or the Assign method obtains the image from Clipboard.

Properties

Center	Sets image in center
Stretch	Shows image in stretch mode
Transparet	Sets Transparent background
Proportional	Indicates weather the image should be changed, without distortion.
Picture	To load, save picture to Timage control

Events

onClick	When user clicks on image
onProgress	When image is about to process or clear. This can be used to show percentages in case of slow process.

                         

Methods

Picture.LoadFromFile	Loads an image from file
Picture.SaveToFile	Saves an image to a file

Lets check with an example

First I put a Timage control on form to load and save images. Here I have also used OpenPicturedialog and SavePicturedialog component to show open and save dialog to select files.

Load image from file to Timage

procedure TForm1.btnLoadImgClick(Sender: TObject);

begin

  if OpenPictureDialog1.Execute then

  begin

    if OpenPictureDialog1.FileName<>'' then

    begin

      Image1.Picture.LoadFromFile(OpenPictureDialog1.FileName);

    end;

  end;

end;

Clear image from Timage

procedure TForm1.btnDelImgClick(Sender: TObject);

begin

  Image1.Picture := Nil;

  //Or//

  Image1.Picture.Assign(Nil);

end;

Save image from Timage to a file

procedure TForm1.btnSaveImgClick(Sender: TObject);

begin

  if SavePictureDialog1.Execute then

  begin

    if SavePictureDialog1.FileName<>'' then

    begin

      Image1.Picture.SaveToFile(SavePictureDialog1.FileName);

    end;

  end;

end;

TDBimage
TDBImage control to display an image that stored in a database. By using TDBImage we can save and retrieve an Image to and from database. The Datasource and DataField property specifies the database field that stores the image and which will display in TDBImage control.

Properties

Center	Sets image in center
Stretch	Shows image in stretch mode
Transparent	Sets Transparent background
Proportional	Indicates weather the image should be changed, without distortion.
DataSource	Sets datasource link
DataField	Actual database field that stores image data

Events

onClick	When user clicks on image
onDblClick	When user double clicks

Methods

Picture.LoadFromFile	Loads an image from file
Picture.SaveToFile	Saves an image to a file

Lets check with an example

First I put a TDBImage control on form and set datasource, datafield properties. Then I used OpenPicturedialog and SavePicturedialog component to show open and save dialog to select files.

Load image from file to AdoTable image field and then store in DB.

procedure TForm1.btnLoadImgClick(Sender: TObject);
begin
  if OpenPictureDialog1.Execute then
  begin
    if OpenPictureDialog1.FileName<>'' then
    begin
         ADOTable1.Edit;         
         TBlobField(ADOTable1.FieldByName('IMAGE1')).
                                     LoadFromFile(OpenPictureDialog1.FileName);
         ADOTable1.Post;  //will store the image in DB field//
    end;
  end;
end;

Clear image from  AdoTable image field.

procedure TForm1.btnDelImgClick(Sender: TObject);
begin
    ADOTable1.Edit;
    TBlobField(ADOTable1.FieldByName('IMAGE1')).Clear;
//or//
    TBlobField(ADOTable1.FieldByName('IMAGE1')).Assign(Nil);
    ADOTable1.Post;  //will clear the image from DB field//
end;

Save image from AdoTable image field to a file

procedure TForm1.btnSaveImgClick(Sender: TObject);
begin
  if SavePictureDialog1.Execute then
  begin
    if SavePictureDialog1.FileName<>'' then
    begin
       TBlobField(ADOTable1.FieldByName('IMAGE1')).
                                      SaveToFile(SavePictureDialog1.FileName);
    end;
  end;
end;