TdxCustomSmartImage.ImageCodec Property

Specifies the active image format codec.

Declaration

property ImageCodec: TdxSmartImageCodecClass read; write;

Property Value

Type	Description
TdxSmartImageCodecClass	The reference to the active image format codec. Refer to the following section for the full list of image codecs shipped with DevExpress VCL products: Property Values.

Remarks

Use the ImageCodec property to identify the current image format or convert the stored image to a different format. All supported formats are implemented as codec classes derived from the TdxSmartImageCodec class. All image format implementations (except for SVG available in DevExpress VCL products rely on the native image format encoder functionality of the Windows Imaging Component (WIC).

Property Values

DevExpress VCL products ship with the following image codec classes registered in the Smart Image codec repository:

Value	Image Format	File Name Extensions[1]	MimeType[2]
TdxGPImageCodecBMP	Device-Independent Bitmap (BMP/DIB)	'*.bmp;'	'image/bmp'
TdxGPImageCodecEMF	Enhanced Windows Metafile (EMF)	'*.emf;'	'image/emf'
TdxGPImageCodecGIF	Graphics Interchange Format (GIF)	'*.gif;'	'image/gif'
TdxGPImageCodecJPEG	Joint Photographic Experts Group (JPEG)	*.jpeg;*jpg;	'image/jpg'
TdxGPImageCodecPNG	Portable Network Graphics (PNG)	'*.png;'	'image/png'
TdxGPImageCodecTIFF	Tagged Image File Format (TIFF)	'*.tiff;*.tif;'	'image/tiff'
TdxGPImageCodecWMF	Windows Metafile (WMF)	'*wmf'	'image/wmf'
TdxSVGImageCodec	Scalable Vector Graphics (SVG)	'*.svg;'	'image/svg+xml'

Code Example: Check the Current Image Format

The code example below allows users to select an image in any format and insert the image at the end of a document opened in a TdxRichEditControl. Since inline and floating document images do not support vector images, the code example uses the ImageCodec property to check if the source image is an SVG.

Delphi

uses
..., dxSVGImage;  // This unit contains the TdxSVGImageCodec class declaration
//...
procedure TMyForm.cxButton1Click(Sender: TObject);
var
  ADocument: IdxRichEditDocument;
  AImageContainer: TdxSmartImage;
  AFileName: string;
begin
  ADocument := dxRichEditControl1.Document;
  dxOpenPictureDialog1.Execute(Handle);  // Invokes the "Open" dialog for image file selection
  AFileName := dxOpenPictureDialog1.FileName;
  if (AFileName = '') then Exit;  // Exits the procedure if a user selects no image
  AImageContainer := TdxSmartImage.Create;  // Creates a Smart Image container
  try
    AImageContainer.LoadFromFile(AFileName);
    if (AImageContainer.ImageCodec = TdxSVGImageCodec) then  // If the container stores an SVG image
      AImageContainer.ConvertToBitmap;  // Rasterizes the vector image
    ADocument.Images.Append(AImageContainer);  // Creates a new inline image from the stored bitmap
  finally
    AImageContainer.Free;  // Destroys the Smart Image container to prevent memory leaks
  end;
end;

C++

#include "dxSVGImage.hpp"  // This header contains the TdxSVGImageCodec class declaration
//...
void __fastcall TMyForm::cxButton1Click(Sender: TObject)
{
  _di_IdxRichEditDocument ADocument;
  TdxSmartImage *AImageContainer;
  UnicodeString AFileName;
  // ...
  ADocument = dxRichEditControl1->Document;
  dxOpenPictureDialog1->Execute(Handle);  // Invokes the "Open" dialog for image file selection
  AFileName = dxOpenPictureDialog1->FileName;
  if (AFileName == "") { return; }  // Exits the routine if a user selects no image
  AImageContainer = new TdxSmartImage();  // Creates a Smart Image container
  try
  {
    AImageContainer->LoadFromFile(AFileName);
    if (AImageContainer->ImageCodec == __classid(TdxSVGImageCodec))  // If the container stores an SVG image
      AImageContainer->ConvertToBitmap();  // Rasterizes the vector image
    ADocument->Images->Append(AImageContainer);  // Creates a new inline image from the stored bitmap
  }
  __finally
  {
    delete AImageContainer;  // Destroys the Smart Image container to prevent memory leaks
  }
}

Smart Image Codec Repository

The TdxSmartImageCodecsRepository class implements a repository that manages references to all TdxSmartImageCodec class descendants and allows DevExpress components to work with images in all supported formats in a uniform manner.

Limitations

You can assign a reference to any supported bitmap codec class to the ImageCodec to convert a stored bitmap or vector image to a different bitmap format. However, vector image rasterization is irreversible. You cannot assign TdxSVGImageCodec to the ImageCodec property to vectorize the stored bitmap image.

Footnotes

1. This column lists strings of file name extensions associated with corresponding image formats.

   The TdxSmartImageCodec.Extensions class function returns these strings for corresponding TdxSmartImageCodec class descendants listed in the first column.

2. This column lists multi-purpose internet mail extension (MIME) content types associated with corresponding image formats.

   The TdxSmartImageCodec.MimeType class function returns these strings for corresponding TdxSmartImageCodec class descendants listed in the first column.