<AWT Dev> [OpenJDK 2D-Dev] [9] Review request for 8076545 Text size is twice bigger under Windows L&F on Win 8.1 with HiDPI display

[Alexandr Scherbatiy]

  Could you review the updated fix:
   http://cr.openjdk.java.net/~alexsch/8076545/webrev.03

  - LOGPIXELSX is changed to  LOGPIXELSY

On 11/16/2015 1:43 PM, Jim Graham wrote:
> Note that LOGPIXELSY is global and static between reboots so it 
> doesn't really matter which monitor is used to get the value.
>
> Also, the issue is that the measurements are in pixels, so if we 
> convert them into a resolution independent measurement then the rest 
> of the scaling in the AWT/2D will be correct regardless of any given 
> monitor's resolution.  We just have to make sure the "de-pixelization" 
> of the measurement is an apples-to-apples calculation.
>
> The question in my mind is whether the values they get from 
> GetTheme*() and SPI_GETNONCLIENTMETRICS are relative to LOGPIXELSY, or 
> the more recent Per-Monitor aware DPI APIs, or ...?  It would be 
> interesting to see what happens to those values when you change the 
> DPI settings on Windows 8.1 and not reboot. If they stay constant 
> until you reboot then LOGPIXELSY on the main screen would be the value 
> to use to de-scale them...

    I tried to use the "Change the size of all items" slider on Windows 
8.1 without rebooting.
    GetDpiForMonitor() returns the updated DPI values: 192, 144, 96
    LOGPIXELSY returns unchanged values:  192, 192, 192
    SystemParametersInfo(SPI_GETNONCLIENTMETRICS,...) returns unchanged 
NONCLIENTMETRICS
    GetThemePartSize() returns unchanged theme part sizes

    It seems that theme part sizes behave in the same way as the 
LOGPIXELSY in this case.

    Thanks,
    Alexandr.

>
>             ...jim
>
> On 11/16/2015 12:51 PM, Phil Race wrote:
>> That seems better. But one more question to get a point clarified.
>> You are using getDesktopWindow() which is for the primary monitor.
>> I assume that the 'inversion' results in the value being used to be
>> independent
>> of the monitor in a multi-mon situation and so when we move to a 2nd
>> monitor
>> that inverted size remains valid ?
>>
>> If so looks good to me.
>>
>> -phil.
>>
>> On 11/16/2015 06:07 AM, Alexander Scherbatiy wrote:
>>>
>>>   Hello,
>>>
>>>   Could you review the updated fix:
>>>     http://cr.openjdk.java.net/~alexsch/8076545/webrev.02
>>>
>>>   - round is used instead of ceil
>>>   - inverted scales are used
>>>
>>>   Thanks,
>>>   Alexandr.
>>>
>>>
>>> On 10/30/2015 10:40 PM, Jim Graham wrote:
>>>> In this case round may be better. ceil() is more for cases where you
>>>> needed "at least X amount of room", but I don't think a font size is
>>>> an "at least this much" kind of case.
>>>>
>>>> Also, I've been toying with the idea that use of ceil() and floor()
>>>> in any DPI-adjustment equations should really be "ceil(val -
>>>> epsilon)" or "floor(ceil + epsilon)" for some small value of epsilon
>>>> chosen just large enough to prevent various round-off errors from
>>>> affecting the outcome.  One idea is for 1/256 as the value of epsilon
>>>> since that could equate to the smallest measurable difference in
>>>> terms of alpha or interpolation results (or 1/512 for "half the
>>>> smallest quantum")...
>>>>
>>>>             ...jim
>>>>
>>>> On 10/29/15 1:36 PM, Phil Race wrote:
>>>>> size->cx = (int)ceil(size->cx / scale);
>>>>>
>>>>>
>>>>> So if size->cx / scale works out to be 12.0001 you will round it up
>>>>> to 13?
>>>>>
>>>>> Can you check what pixel size windows gives you in such a case ?
>>>>> I'd be a little surprised if they did that rather than round.
>>>>>
>>>>> Is the SetFontProperty that does not accept a scale parameter still
>>>>> used
>>>>> somewhere ?
>>>>>
>>>>> -phil.
>>>>>
>>>>> On 10/29/2015 04:53 AM, Sergey Bylokhov wrote:
>>>>>> On 17.07.15 16:27, Alexander Scherbatiy wrote:
>>>>>>>>
>>>>>>>> - Sergey's point about multi-mon should be checked out.
>>>>>>>      Windows 8.1 has option "Let me choose one scaling level for
>>>>>>> all my
>>>>>>> displays".
>>>>>>>      If I unset it I am able to change the size of all items.
>>>>>>> However,
>>>>>>> the DPI which returns GetDPIForMonitor is still 2 on HiDPI 
>>>>>>> displays.
>>>>>>
>>>>>> This version looks fine, but I am sure it can be double checked on
>>>>>> windows 10 at some moment as well.
>>>>>>
>>>>>>
>>>>>
>>>
>>