#tdf51510: Change the DPI to get better resolution, but failed the unit test

[Lodev]

Hi,

Following sos' suggestion, we tried to get Image Preferred DPI from file 
properties.  We thought to use this value directly to draw bitmap.  
After asking the last question we found a sample in 
sfx2/source/dialog/dinfdlg.cxx to get this property value.  So we added 
the following code to get the DPI:


/* get Image Preferred DPI from File/Properties.  User can specify DPI 
they wanted
             * to exported. */
            SfxObjectShell* pDocSh = SfxObjectShell::Current();
            sal_Int32 nImagePreferredDPI = 0;
if(pDocSh)
            {
try
                    {
                            uno::Reference< lang::XMultiServiceFactory > 
xFac( pDocSh->GetModel(), uno::
UNO_QUERY_THROW );
                            uno::Reference< beans::XPropertySet > 
xProps( xFac->createInstance("com.sun.
star.document.Settings"), uno::UNO_QUERY_THROW );
                            xProps->getPropertyValue("ImagePreferredDPI") >>= nImagePreferredDPI;
                    }
catch( uno::Exception& )
                    {
                    }
            }

then sent the nImagePreferredDPI to generate the bitmap.  It worked!  At 
least we can use designated DPI to get a better bitmap quality.

Then when we tried to patch it to latest libreoffice.core and compile 
it, it failed to link:

/usr/bin/ld: 
/home/lodev/git/libreoffice.core/workdir/CxxObject/vcl/source/gdi/vectorgraphicdata.o: 
in function 
`convertPrimitive2DSequenceToBitmapEx(std::deque<com::sun::star::uno::Reference<com::sun::star::graphic::XPrimitive2D>, 
std::allocator<com::sun::star::uno::Reference<com::sun::star::graphic::XPrimitive2D> 
 > > const&, basegfx::B2DRange const&, unsigned int, o3tl::Length, 
std::optional<Size> const&)':
vectorgraphicdata.cxx:(.text+0x226d): undefined reference to 
`SfxObjectShell::Current()'
/usr/bin/ld: vectorgraphicdata.cxx:(.text+0x228f): undefined reference 
to `SfxObjectShell::GetModel() const'
collect2: error: ld returned 1 exit status
make[1]: *** 
[/home/lodev/git/libreoffice.core/vcl/Library_vcl.mk:20：/home/lodev/git/libreoffice.core/instdir/program/libvcllo.so] 
錯誤 1

We thought that the time we succeeded should be because the related 
objects (sfx2) had been there when we tried, so it could compiled and 
linked successfully.  This time we did it from starting so it failed 
because the object files were no longer there, and we have no idea how 
to make sfx objects compile first.

So again we're stuck.  We did prove the idea, using Image Preferred DPI 
to generate better bitmap, works.  User can specify a bigger DPI there 
to get better bitmap resolutions after exporting to OOXML.  Just that 
maybe we shouldn't use sfx object to get the property.  But we have no 
idea how to get the property value since we're not very familiar with 
the reference things.

Would anyone please give a little help and hints here?


Thanks, Dev


Lodev 於 2023/9/11 21:32 寫道:
> Hi,
>
> sos 於 2023/8/31 17:53 寫道:
>>
>> Sorry to come back to this: every document has a property called 
>> "Image Preferred DPI" that can be used to represent the printing 
>> intentions of that document.
>>
>> Apparent dimensions are a result of deviding the available pixels in 
>> the Image by the print intentions .
>> if the user like to send the document to a professional printing 
>> house then all  images need to have a DPI of minimal 254, laser 
>> printers need 150 DPI  and on screen presentations 96 DPI
>>
>> Tomaz has this implemented a feature called "Image Preferred DPI" so  
>> the dimensions of an image in the document can been 
>> checked/controled  by the number of pixels in the image and the print 
>> intentions off a document.
>>
>> With a Preferred DPI of 254 and 2450 pixels in the image, the image 
>> can be displayed at a maximum size of 10 inches. If the image is 
>> smaller, then fewer than 2450 pixels are needed.
>> So the "Image Preferred DPI" can be used to determine the "Print 
>> Intentions" for a Document, and it can easily calculate how many DPI 
>> or pixels an image needs.
>> grtz
>> Fernand
>>
>
> Sorry for disturbing again, but we're not experienced enough.
>
> Following your instruction, we thought about getting the "Image 
> Preferred DPI" property and used it as aDPI when creating bitmaps.  
> That way, at least user could try to assign a large DPI to get better 
> resolution.  However we failed to find out how to get it.  We know it 
> is in File-Properties and we know it is set in 
> sfx2/source/dialog/dinfdlg.cxx,
>
>                 xProps->setPropertyValue("ImagePreferredDPI", 
> uno::Any(nImagePreferredDPI));
>
> But we couldn't find out how to get this "ImagePreferredDPI" property 
> value and use it in vcl/source/gdi/vectorgraphicdata.cxx.  A little 
> more help here please?
>
>
> Dev
>
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