[webkit-dev] SupportImage[Resource]MIMEType

David D. Kilzer ddkilzer at kilzer.net
Wed Jul 12 20:54:08 PDT 2006

I would suggest filing two bugs:  one for the <object> tag (mis) 
behavior, and a second for the WebKitOmitPDFSupport not omitting  
support for embedded objects.



On Jul 12, 2006, at 7:41 PM, Rudi Sherry wrote:

> I'm looking into a problem where embedded PDFs don't invoke a  
> WebKit plugin.
> I found that
>    <object data="url-to-pdf" ... >
> with a "type" property works fine (invokes the PDF plugin), but
>    <object data="url-to-pdf" type="application/pdf" ... >
> simply shows the first page of the PDF in the embedding location as  
> an image.
> I tracked it down to the fact that HTMLObjectEelement::isImageType 
> () is returning 'true' for "application/pdf"; this happens because  
> Image::supportsType() looks at all the types that could be an  
> image.  Since it returns TRUE, this becomes a CachedImage and it  
> never goes out to WebKit to check if any plug-ins support this type.
> Image::supportsType() calls +[WebCoreFrameBridge  
> supportedImageResourceMIMETypes] to get the list.  There is also + 
> [WebCoreFrameBridge supportedImageMIMETypes], which is the same  
> list except specifically excluding the hard-coded strings  
> "application/pdf" and "application/postscript".
> Does anyone know why are there two different methods for returning  
> the image mime types -- whose only difference are the pdf/ 
> postscript types?  Neither are called from within WebCore itself.
> Another tantalizing tidbit is that there is a hidden preference  
> "WebKitOmitPDFSupport", used by WebKit (but not WebCore), that will  
> remove some built-in PDF support from numerous places... but not,  
> unfortunately, from embedded objects as they're being parsed.
> Does anyone on this list know more about the history or design of  
> all this?
> Thanks,
> Rudi

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