Re: Can't see PNG images !

Tech-Archive recommends: Fix windows errors by optimizing your registry

"Thomas D Scotland" <ThomasDScotland@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:CD5FCA2F-4DE3-43AA-A1CC-A3E9BE5DC2B9@xxxxxxxxxxxxxxxx
> Robert,
>
> Here goes with today's investigation.... Todays comments are in following
> {{.. ..}}
>
> {{Tried MIME sniffing switch but no change. After changing these settings I
> shut down IE & restarted then shut the machine down and rebooted and still no
> change. Now the reference to MIME settings has set me thinking... It
> shouldn't be necessary to remove any application.

Agreed. I was just thinking that whatever state removing it might restore
might be more stable. I don't know if those apps can affect MIME rendering
or not. Without any explicit knowledge to the contrary it seemed useful to
test what removing the current owner of the local file default would do.


> I have changed file
> extension to application associations many many times over the years on both
> my workstation and laptop without any effect on the IE rendering. I am
> convinced the application association issue is a diversion. The assoc &
> ftype configurations for both .gif and .png filetypes are exactly the same...

....

> ... and they are the same for jpg filetype. I can view the TIF cache of
> either .gif, jpg or .png in any image viewing application without any
> problem.

That reminds me of another test we could try which would avoid
the issue of ownership of the local file default--drag the web file
from the TIF to the application window.

Ha! Here's another one. I used F3 on the TIF viewer to search for
cached .png files and discovered serendipitously that its View was set
for Thumbnails. So I have thumbnails of the graphs that I can drag to
an IE window! Actually dragging thumbnails is somehow less impressive
than dragging a normal icon and watching IE render it. <eg>


> The issue is clearly that when IE requires the viewer to render a
> .gif or jpg it can execute the request but when IE requires the viewer to
> render a .png it cannot excecute this command.

I'm not sure that it does. I'd like to see some accesses from some
"viewer" .dlls but I'm not seeing them. I'm not even seeing Ramesh's
imgutil.dll accessed. This is with using just RegMon and FileMon.
If it is already loaded we may need a finer trace tool to be able to detect
calls being made within it.

FWIW here are some of the modules which RegMon referred to
when I did the above drag operation.
shimgvw.dll
shell32.dll
shdocvw.dll
but the only ones which FileMon reported being accessed were
shell32.dll
mshtmler.dll

Of these I know for a fact that the first three have entry points for
both DllInstall and DllRegisterServer. DependencyWalker
reports neither in mshtmler.dll. Therefore the following 3 regsvr32
commands might prove helpful (at least for the case of dragging
thumbnails <eg>):

regsvr32 /i shimgvw.dll
regsvr32 /i shell32.dll
regsvr32 /i shdocvw.dll


> Somewhere the
> command/execution 'chain' for an IE .png rendering request is 'broken' and my
> guess is this problem must lie somewhere within the registry.

Yup.


> Now I have
> noticed your references to MIME encoding/decoding so I did some searching
> within the registry. Working on the premise that as .gif & .jpg are rendered
> but NOT .png I am searching for common patterns between .gif & .jpg but
> differences with .png. If I look into the '\MIME\Database\Content Type' tree
> I find entries for image/gif, image/jpg & image/png. What is significant is
> that the .png entry is the oddball. I have exported the relevant sections
> and included them below...

....

> Key Name: HKEY_CLASSES_ROOT\MIME\Database\Content Type\image/png
> Class Name: <NO CLASS>
> Last Write Time: 22/07/2005 - 09:16 AM


Would this be when you did a regsvr32 pngfilt.dll ?
We could actually use RegMon to trace the SetValue that it does
when you do that.

Hmm... I was just looking at pngfilt.dll with DependencyWalker.
Apparently there is a delay-load dependency for msjava.dll
which I no longer have. Do either of your systems still use msjava?


> Value 0
> Name: Extension
> Type: REG_SZ
> Data: .png
>
> Value 1
> Name: Image Filter CLSID
> Type: REG_SZ
> Data: {A3CCEDF7-2DE2-11D0-86F4-00A0C913F750}

Just to make sure that we are both seeing the same thing,
try finding that CLSID and verify its registry values:

<example>
Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\CLSID\{A3CCEDF7-2DE2-11D0-86F4-00A0C913F750}]
@="CoPNGFilter Class"

[HKEY_CLASSES_ROOT\CLSID\{A3CCEDF7-2DE2-11D0-86F4-00A0C913F750}\InProcServer32]
@=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,6f,00,74,00,25,\
00,5c,00,53,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00,70,00,6e,00,\
67,00,66,00,69,00,6c,00,74,00,2e,00,64,00,6c,00,6c,00,00,00
"ThreadingModel"="Both"

[HKEY_CLASSES_ROOT\CLSID\{A3CCEDF7-2DE2-11D0-86F4-00A0C913F750}\ProgID]
@="PNGFilter.CoPNGFilter.1"

</example>


>
>
> Key Name: HKEY_CLASSES_ROOT\MIME\Database\Content Type\image/png\Bits
> Class Name: <NO CLASS>
> Last Write Time: 22/07/2005 - 09:16 AM
> Value 0
> Name: 0
> Type: REG_BINARY
> Data:
> 00000000 08 00 00 00 ff ff ff ff - ff ff ff ff 89 50 4e 47 ....ÿÿÿÿÿÿÿÿ.PNG
> 00000010 0d 0a 1a 0a ....
>
>
> ... Note that when comparing .gif & .jpg to .png there are two 'Value'
> enties 'missing' from the .png section! They are 'CLSID' &
> 'AutoplayContentTypeHandler'. I am only guessing here but I would not expect
> .png images to be handled in a different way to .gif or .jpg? I have tried
> to check all !!! occurances of .gif, .jpg & .png entries and compare them for
> similarities v. differencies and it is the above MIME entries that are the
> most striking. Food for thought??

Good thinking but that is exactly what I have there too.


> Unfortunately I am away from home
> otherwise I would have immediately compared these enties on this laptop with
> my workstation which works correctly with gif, jpg & pngs.}}
>


HTH

Robert
---


.

Relevant Pages

  • Re: Cant see PNG images !
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