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

[Jim Graham]

Hi Alexandr,

Thanks for investigating the behaviors.

With respect to using LOGPIXELSX or Y, these methods are used to scale 
both horizontal and vertical measurements so we really should have 2 
scale values and rescale methods, one for horizontal use and one for 
vertical...

			...jim

On 1/29/2016 10:41 AM, Alexandr Scherbatiy wrote:
>   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.
>>>>>>>
>>>>>>>
>>>>>>
>>>>
>>>
>