[OpenJDK 2D-Dev] RFR: 8132890 Text overlapping on dot matrix printers.

[Jennifer Godinez]

Approved.

- Jennifer

On 10/20/2015 01:47 PM, Phil Race wrote:
> On 10/20/2015 12:32 PM, Jennifer Godinez wrote:
>> Hi Phil,
>>
>> I assume you've run all the manual regression tests on text?
>
> I would not say all. But I have run the ones that relate
> to text size/position/transform.
>
>> The copyright year in the regression test needs updating.
>
> We don't need to do that as there will be a script run to
> update all files touched in 2015.
>
> -phil.
>
>> Otherwise, looks good.
>>
>> Jennifer
>>
>> On 10/16/2015 04:16 PM, Phil Race wrote:
>>> https://bugs.openjdk.java.net/browse/JDK-8132890
>>> http://cr.openjdk.java.net/~prr/8132890/
>>>
>>> The notable thing about this case is that the printer has different 
>>> dpi in x and y.
>>>
>>> In GDI printing we detect when the transform under which the font is
>>> rendered is non-uniform as in that case we want to tell GDI to create
>>> a stretched font as that is better than trying to draw the text as a 
>>> filled path.
>>> What happens here is that the *device resolution* is not uniform.
>>>
>>> It is a scale of (3.33, 2.0) - ie 240x144 dpi so x=1.66*y
>>>
>>> This device resolution then gets combined with any graphics transform
>>> and the font transform and we have lost sight of the fact that the
>>> non-uniform part came from the device rather than the application
>>> specifying an additional x-scale factor to be applied.
>>> GDI is already accounting for the real device resolution and we cause
>>> it to be applied twice.
>>>
>>> So we need to divide this out as part of the calculation.
>>> This needs access to the real device dpi to be passed in/made 
>>> available.
>>>
>>> But there is another issue.  JDK puts the printer job into portrait 
>>> mode
>>> even in landscape printing and takes care of the transforms itself.
>>> So the size used to set the font for GDI needs to use GDI's idea of 
>>> the orientation.
>>>
>>> I augmented a text printing test used to verify this with some 
>>> additional scenarios.
>>> It is now a pretty comprehensive test of many different scenarios.
>>> It has been tested on an HP LaserJet, the Oki dot matrix printer and 
>>> the XPS driver.
>>>
>>> There is also a not completely necessary tweak here to adjust the 
>>> error we
>>> allow in gdi vs jdk advances from 0.2% to 1%. This made for about a 25%
>>> reduction in the overall spool file size for my test with no 
>>> noticeable consequences.
>>>
>>> -phil.
>>>
>>
>

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