<Swing Dev> [8] Review request for 8016833: Underlines and strikethrough not rendering correctly

[Alexander Scherbatiy]

On 6/20/2013 2:41 PM, anton nashatyrev wrote:
> Hello,
>     could you please review the following fix:
>
> fix: http://cr.openjdk.java.net/~vkarnauk/8016833/jdk8/webrev.00/ 
> <http://cr.openjdk.java.net/%7Evkarnauk/8016833/jdk8/webrev.00/>
> bug: http://bugs.sun.com/view_bug.do?bug_id=8016833
>
     It seem that there is the same problem with the background color:
         Style style = comp.addStyle("underlined superscript", null);
         StyleConstants.setBackground(style, Color.BLUE);
         ...
             doc.insertString(doc.getLength(), "hello", style);

     because paint(Graphics g, Shape a) method in GlyphView uses the 
alloc.height in the same way.


   Could invoke all Swing methods on EDT and remove the comments from 
the test:

  266 //        bug8016833 b = new bug8016833();
  267 //        b.demo();

Thanks,
    Alexandr.

> The reason of such behavior is that the superscripted GlyphView requested
> increased vertical span, since the alignment of value 1.0
> (GlyphView.getAligment(View.Y_AXIS) returns 1.0) isn't enough to paint 
> it as
> high as required.
> (BTW, for subscripted text setting the alignment is enough)
>
> GlyphView.paintTextUsingColor() calculates the Y position of the 
> underscore
> as following:
>
>   int y = alloc.y + alloc.height - (int) painter.getDescent(this);
>
> but here alloc.height means the space _reserved_ for glyphs and not the
> actual boundary of the painted text. To fix that we need to substitute
> alloc.height with painter.getHeight(this).
>
> The fix looks safe since the GlyphView preferred vertical span is 
> initially
> requested from the GlyphPainter.
>
> Thanks!
> Anton.