vcl-dxchartcontrol-dot-tdxcustomchartcontrol-dot-exporttoimage-x28-system-dot-classes-dot-tstream-dxsmartimage-dot-tdxsmartimagecodecclass-system-dot-integer-system-dot-integer-x29.md
Exports content to a stream in any supported image format.
procedure ExportToImage(const AStream: TStream; ACodecClass: TdxSmartImageCodecClass = nil; AImageWidth: Integer = 0; AImageHeight: Integer = 0); overload;
| Name | Type | Description |
|---|---|---|
| AStream | TStream |
The target stream.
| | ACodecClass | TdxSmartImageCodecClass |
Optional. The image codec class that corresponds to the required image format. Refer to the following section for the full list of available image formats: Supported Target Formats.
If this parameter is omitted, the procedure exports chart content in SVG format.
| | AImageWidth | Integer |
Optional. The exported image width, in pixels. If this parameter is omitted, the target image width matches the current pixel width of the Chart control client area on the parent form.
The export procedure stretches or shrinks the Chart control layout horizontally to fit the resulting image into the target width.
All font sizes remain unchanged. If title or label text does not fit into the corresponding visual Chart element, the Chart control crops the text and ends it with an ellipsis in the exported layout.
| | AImageHeight | Integer |
Optional. The exported image height, in pixels. If this parameter is omitted, the target image height matches the current pixel height of the Chart control client area on the parent form.
The export procedure stretches or shrinks the Chart control layout vertically to fit the resulting image into the target height.
All font sizes remain unchanged. If title or label text does not fit into the corresponding visual Chart element, the Chart control crops the text and ends it with an ellipsis in the exported layout.
|
Call the ExportToImage procedure to export content of the Chart control client area to a stream in any supported format. The resulting image size matches the actual pixel dimensions of the Chart control client area on a form.
You can use the optional ACodecClass parameter to specify the required format of the resulting image. The following table lists all possible ACodecClass parameter values:
| ACodecClass Parameter Value | Image Format | File Name Extensions[1] | MimeType[2] |
|---|---|---|---|
nil (in Delphi) or nullptr (in C++Builder)[3] | The default image format (SVG). | – | – |
| TdxGPImageCodecBMP | Device-Independent Bitmap (BMP/DIB) | '*.bmp;' | 'image/bmp' |
| TdxGPImageCodecEMF[4] | 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[4] | Windows Metafile (WMF) | '*wmf' | 'image/wmf' |
| TdxSVGImageCodec | Scalable Vector Graphics (SVG) | '*.svg;' | 'image/svg+xml' |
You can pass required target pixel dimensions for the resulting image as optional AImageWidth and AImageHeight parameters. In this case, the ExportToImage procedure resizes all visible diagrams to fit into the target dimensions. All font sizes remain unchanged.
The following code example exports shrunk content of the Chart control client area (original dimensions on the parent form are 600 by 700 pixels).
var
AStream: TMemoryStream;
begin
dxSavePictureDialog1.Execute(Handle);
if dxSavePictureDialog1.FileName = '' then Exit;
AStream := TMemoryStream.Create;
try
// Exports chart content to a stream in PNG format
dxChartControl1.ExportToImage(AStream, TdxGPImageCodecPNG, 400, 500);
AStream.SaveToFile(dxSavePictureDialog1.FileName);
finally
AStream.Free;
end;
end;
TMemoryStream *AStream = nullptr;
// ...
dxSavePictureDialog1->Execute(Handle);
if(dxSavePictureDialog1->FileName == "") { return; }
AStream = new TMemoryStream();
try
{
// Exports chart content to a stream in PNG format
dxChartControl1->ExportToImage(AStream, __classid(TdxGPImageCodecPNG), 400, 500);
AStream->SaveToFile(dxSavePictureDialog1->FileName);
}
__finally
{
delete AStream;
}
To see the export to BMP functionality in action, run the Chart Control demo in the VCL Demo Center installed with compiled DevExpress VCL demos. Click Export and choose the Export to Image option to export chart content in any supported image format.
Tip
Compiled DevExpress demos ship with source code installed in the Public Documents folder (%Public%) for all users ( default ). You can find all project and source code files for the Chart control in the following folder:
_%Public%\Documents\DevExpress VCL Demos\MegaDemos\Product Demos\ExpressChart_
You can call the following procedures to export chart content to a file or stream in other formats:
ExportToBMP | ExportToGIF | ExportToJPEG | ExportToPNG | ExportToSVG | ExportToTIFFExport the current state of the Chart control client area as an individual image in corresponding formats.ExportToDOCX | ExportToXLSXExport the current state of the Chart control client area as an inline or floating image in the resulting DOCX or XLSX document.ExportToEMF | ExportToWMFExport the current state of the Chart control client area as an individual image in Windows Metafile (EMF and WMF) formats.
Footnotes
This column lists strings of file name extensions associated with corresponding image formats.
This column lists multipurpose internet mail extension (MIME) content types associated with corresponding image formats.
The default ACodecClass parameter value that corresponds to the SVG image format.
An exported image and its actual dimensions may vary significantly depending on the target operating system and its GDI+ library version because Windows Metafile and Enhanced Windows Metafile format implementations rely on the functionality of the native Windows Metafile encoder from the Windows Imaging Component (WIC).
See Also