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Problem of exporting image in HTML format using HtmlFormatProvider

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answered on 23 Nov 2011, 12:44 PM

Hello Guy,

Could you attach the image that is causing the issue and elaborate a bit more on your scenario and the issue itself.
1. How are you exporting the document (a code-snippet will be appreciated if you are not using RadRichTextBoxRibbonUI to trigger the saving of the document).
2. Are you creating the document in the rich text box or building it in code-behind? If you are not creating the document in the editor, a code-snippet for that may also be helpful.
3. What exactly is the problem with the export?
3.1 An exception occurs - in that case, please copy the stacktrace to give us an idea of what may be wrong.
3.2 The image is not visible in the exported HTML - we can test that once you attach the image.
4. To make sure I understand you correctly, you are observing the issue when exporting the image from a PC using Windows 7 and IE 8, while the export works correctly on other machines?
Looking forward to your reply. If you have a sample demo illustrating the problem, please attach it, so that we can reproduce the issue more easily.

Regards,
Iva Toteva
the Telerik team

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answered on 23 Nov 2011, 03:56 PM

Result.png

Hello Iva,
Thank you for your quick reply. Here is the code snippet i used to create the RadDocument containing an image from a RadChart:

public RadDocument CreateDocumentFromRadChartForHTML(RadChart chart)

{

RadDocument document = new RadDocument();

document.LayoutMode = DocumentLayoutMode.Paged;

try

{

//

// Create here sections conatining some information i want to export....

//

// Export image in the memory

MemoryStream memoryStream = new MemoryStream();

chart.ExportToImage(memoryStream);

//create image section

Section imageSection = new Section();

Paragraph imgParagraph = new Paragraph();

int width = 700;

int height = 380;

Size sizeImg = new Size(width, height);

ImageInline img = new ImageInline(memoryStream, sizeImg, "PNG");

imgParagraph.Inlines.Add(img);

imageSection.Children.Add(imgParagraph);

document.Sections.Add(imageSection);

}

catch (Exception ex)

{

}

return document;

}

After creating the document i export it in HTML format using HtmlFormatProvider. As I said in the previous message, on some PC the HTML file contains all information i inserted including the image while others can not display the image in the exported HTML file. But both machines use Windows 7 and IE8. I attached the picture when the image doesn' t display properly.
Thank you for your precious help

answered on 18 Sep 2012, 03:47 PM

Hello Guy,

We've made further research on the subject and it seems that there are some limitations in MS Word and IE 8.

The limitation of IE 8 is the length of the embedded data which it can read. For this reason we have prepared a workaround - if the image is larger than the limitation, we split it in many smaller images placed in a table so it can look the same as the original. In order to use this fix you need to set the "ImageExportMode" to "Base64EncodedSplit". We also reduced even more our internal check for this length limitation just to make sure there is no problematic images. This additional fix will be available with the next LIB. Setting the export mode of images and other HTML export/import customizations are described here.

When it comes to MS Word and Excel, they do not support base64 embedded data. A possible workaround for you can be to attach a handler to the ImageExporting event of HtmlExportSettings and have the ImageExportMode of the settings specified to be ImageExportingEvent. In the handler, you can save the image on a server with permissive cross-domain policy and have the source of the images replaced with the new URI.

Another workaround for this problem would be to use the default HTML export settings and convert the HTML file to MHT format using some tool. According to MS Word documentation there shouldn't be any problems with MHT format.

Depending on your application you can use DocxFormatProvider or RtfFormatProvider to export documents to MS Word.

When it comes to the image you have attached in ticket 495110, the export to HTML with Base64EncodedSplit option now works correctly in IE 8.

All the best,
Mihail
the Telerik team

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