<Swing Dev> [9] Review request for 8132119 Provide public API for text related methods in SwingUtilities2

[Alexander Scherbatiy]

   Hello,

   Could you review the updated fix:
     http://cr.openjdk.java.net/~alexsch/8132119/webrev.01/

   I tried to use Utilities.drawStringUnderlineCharAt(...) with chars 
that have
   - 1 character:2 glyphs mapping (U+00E1) and ligature (U+FB01)
     The whole glyph  is underlined.
   - 2 characters: 1 glyph mapping (supplementary char U+10400)

   The char value specified the the underlined index should point to the 
high-surrogate range of a supplementary character.
   I updated the javadoc for the 
Utilities.drawStringUnderlineCharAt(...) method to:
-----------------------------
     /**
      * Draws the given string at the specified location underlining
      * the specified character.
      * <p>
      * The underlined index refers to char values (Unicode code units).
      * If the char value specified at the given underlined index is in
      * the high-surrogate range and the char value at the following 
index is in
      * the low-surrogate range then the supplementary character 
corresponding
      * to this surrogate pair is underlined.
      * <p>
      * Nothing is drawn for null string. No character is underlined for the
      * index {@code < 0}, {@code >=} than the string width or if the 
char value
      * specified at the given index is in the low-surrogate range.
-----------------------------

Thanks,
Alexandr.

On 9/7/2015 12:27 PM, Alexander Scherbatiy wrote:
> On 9/2/2015 8:09 PM, Phil Race wrote:
>> I don't remember or know how Swing resolves this but the measurement 
>> ones
>> are not reliable since they do not take a Graphics context, so you 
>> cannot
>> measure the string properly. You need a FontRenderContext to measure.
>
>    The provided methods use 
> SwingUtilities2.getFontRenderContext(JComponent) method which returns 
> the FontRenderContext associated with the component.
>
>>
>> So as it stands these APIs do not appear suitable to be made public 
>> as they
>> are not reliable.
>>
>> Whilst I could look at the code, if I instead just look at the API, I 
>> am scratching my
>> head over :-
>>
>> public static void drawString(JComponent c, Graphics g, String 
>> text,   int x, int y)
>>
>> Here you provide the Graphics *and* the Component.
>> And it says the JComponent may be null.
>> So I am supposing that there is optional information that may be 
>> pulled from the
>> JComponent regarding rendering mode ?
>
>    The optional information provided by the component is:
>      - java.awt.font.NumericShaper
>      - java.awt.font.FontRenderContext
>      - antialiasing hints
>
>>
>> drawStringUnderlineCharAt(..) probably needs to explain if the index 
>> is code point
>> or UTF16 char index and what happens if there is not 1:1 code 
>> point:glyph mapping.
>     I will update this.
>>
>> Are we sure that (any of) these really ought/need to be public - 
>> particularly given the
>> resolution of https://bugs.openjdk.java.net/browse/JDK-6302464
>
>    These methods are used by JDK L&Fs to draw text.  The initial 
> request was to provide public methods that can be used by a custom L&F 
> to draw strings consistently with other L&Fs.
>
>    They are also designed to properly render text for printing. To do 
> that they use call to internal ProxyPrintGraphics class to obtain the 
> print graphics context.
>
>    Even if printing staff will be public, these methods are just 
> utility methods (in the same way as other text methods in the 
> javax.swing.text.Utilities class) that help easily to draw and print 
> text in the same way as JDK L&Fs do that.
>
>   Thanks,
>   Alexandr.
>
>>
>> -phil.
>>
>> On 09/02/2015 08:28 AM, Alexander Scherbatiy wrote:
>>>
>>> Hello,
>>>
>>> Could you review the fix:
>>>   bug: https://bugs.openjdk.java.net/browse/JDK-8132119
>>>   webrev: http://cr.openjdk.java.net/~alexsch/8132119/webrev.00
>>>
>>>   The suggested drawString, drawStringUnderlineCharAt, 
>>> clipStringIfNecessary, and stringWidth methods are
>>>   added to the javax.swing.text.Utilities class.
>>>
>>> Thanks,
>>> Alexandr.
>>>
>>
>