[webkit-dev] SupportImage[Resource]MIMEType

Rudi Sherry rsherry at adobe.com
Wed Jul 12 17:41:59 PDT 2006

I'm looking into a problem where embedded PDFs don't invoke a WebKit  

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  


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