<Swing Dev> [10] RFR JDK-8187957:Tab Size does not work correctly in JTextArea

[Sergey Bylokhov]

On 08/11/2017 11:38, Semyon Sadetsky wrote:
>> Yes "(int)+1" is also can be used for positive values, but the 
>> "ceil()" is better since this purpose of this method, and in general 
>> it works for negative values as well.
> There may not be negative values here, so Math.ceil() is redundant.

I do not see a reason why standard function can be redundant, and why 
manual implementation is better. Since even in the first version of the 
fix there is an issues in manual implementation.

> 
> --Semyon
>>
>>>
>>>
>>> On 11/08/2017 10:24 AM, Sergey Bylokhov wrote:
>>>> Hi, Prasanta.
>>>> Is it possible that dropping the float part of "tabSize" and "x" 
>>>> will cause Off-by-one error? For example:
>>>>     float tabSize=3.99f;
>>>>     float x=21.9f;
>>>>     int tabBase=0;
>>>>  649         int ntabs = ((int) x - tabBase) / (int)tabSize;
>>>>  650         return tabBase + ((ntabs + 1) * tabSize);
>>>>
>>>> The result is: ntabs=7 -> 31.92 which is not correct.
>>>>
>>>> I guess you will need something like this:
>>>>     int ntabs = (int) Math.ceil((x - tabBase) / tabSize);
>>>>     return tabBase + ntabs * tabSize;
>>>> The result is: ntabs=6 -> 23.94
>>>>
>>>>
>>>> On 08/11/2017 03:25, Prasanta Sadhukhan wrote:
>>>>> Hi All,
>>>>>
>>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8187957
>>>>> webrev: http://cr.openjdk.java.net/~psadhukhan/8187957/webrev.00/
>>>>>
>>>>> Please review a fix for an issue where it is seen string with "tab" 
>>>>> in them are not aligned properly.
>>>>> This is because while calculating tab stop postion, it is 
>>>>> calculating number of tabs in float value (an aftereffect of 
>>>>> JDK-8156217 <https://bugs.openjdk.java.net/browse/JDK-8156217>)
>>>>> so next tab stop location is coming out wrong.
>>>>> Fix is to use "number of tabs" as an integer value in order to 
>>>>> calculate the tab position correctly.
>>>>>
>>>>> Regards
>>>>> Prasanta
>>>>
>>>>
>>>
>>
>>
> 


-- 
Best regards, Sergey.