<Swing Dev> [13] RFR JDK-8212904:JTextArea line wrapping incorrect when using UI scale

[Prasanta Sadhukhan]

On 23-Mar-19 5:02 AM, Sergey Bylokhov wrote:
> On 21/03/2019 22:34, Prasanta Sadhukhan wrote:
>> Thanks for your review. textarea.getLineCount() returns same number 
>> for both correct and broken wrap so it cannot be used for test 
>> automation...
>
> Then probably it can be checked by the visibility of the horizontal 
> scroll bar?
> If you set the scrollbar policy as HORIZONTAL_SCROLLBAR_AS_NEEDED then 
> you can check is it visible(wrap-off) or is it invisible(wrap-on).
> Or you can check the height of the text area, which is different when 
> wrap on/off.
>
Thanks Sergey for the pointer. But horizontal scrollbar is not visible 
for both correct and broken wrap if scrollbar policy is set to 
HORIZONTAL_SCROLLBAR_AS_NEEDED.
Also, the textArea.getHeight() is same for both 
textArea.setWrapStyleWord( true ) and not. Attached is the automated 
testcase I tried.

Regards
Prasanta
>> Regards
>> Prasanta
>> On 21-Mar-19 4:24 AM, Sergey Bylokhov wrote:
>>> Hi, Prasanta.
>>>
>>> The change looks fine, but probably the test can be automated? I 
>>> guess when "wrap" works properly you should get more lines in the 
>>> text area, than in case of broken "wrap"?
>>>
>>> On 19/03/2019 00:03, Prasanta Sadhukhan wrote:
>>>> Hi All,
>>>>
>>>> Please review a fix for an issue where it is seen that
>>>> line wrapping of JTextArea doen't work correctly if you set 
>>>> wrapStyleWord = true and you use a UI scale (either by setting 
>>>> "sun.java2d.uiScale" or by setting display scale of Windows)
>>>>
>>>> It is a regression of JDK-8132119: Provide public API for text 
>>>> related methods in SwingUtilities2
>>>> where many public text related API was added catering to floating 
>>>> point hidpi scale.
>>>> This issue happened because of that as the public 
>>>> Utilities.getBreakLocation() API, used to determine where to break 
>>>> the given text, is using non-floating point methods.
>>>>
>>>> Proposed fix is to make sure correct getBreakLocation() method is 
>>>> called and not the deprecated(integer based) one
>>>> and also the floating point based getBreakLocation() API uses 
>>>> floating point API based calculations.
>>>>
>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8212904
>>>> webrev: http://cr.openjdk.java.net/~psadhukhan/8212904/webrev.0/
>>>>
>>>> Regards
>>>> Prasanta
>>>
>>>
>>
>
>

-------------- next part --------------
import java.awt.BorderLayout;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.IOException;
import java.net.URISyntaxException;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.ScrollPaneConstants;
import javax.swing.SwingUtilities;

public class JTextAreaTest {

    static JFrame frame;
    static JFrame frame1;
    static int wraponHeight;
    static int wrapoffHeight;

    public static void doWrapOnTest() {

        frame = new JFrame();
        frame.setSize( 720, 300 );
        frame.setLayout( new BorderLayout() );
        
        JTextArea textArea = new JTextArea();
        textArea.setLineWrap( true );
        textArea.setWrapStyleWord( true );
        
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < 100; i++) {
            sb.append( "zz zzz zzzz zz zz zz zzz xzzzz zzzzzzzzzzzzzzzzx yyyyyyy tttttttttt sssss hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh\n" );
        }
        textArea.setText( sb.toString() );
        JScrollPane pane = new JScrollPane( textArea, 
			                    ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS, 
					    ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED );
        frame.add( pane, BorderLayout.CENTER );
        frame.setVisible( true );

	wraponHeight = textArea.getHeight();
        System.out.println("wraponheight " + wraponHeight);
    }

    public static void doWrapOffTest() {
        frame1 = new JFrame();
        frame1.setSize( 720, 300 );
        frame1.setLayout( new BorderLayout() );

        JTextArea textArea1 = new JTextArea();
        textArea1.setLineWrap( true );
        
        StringBuffer sb1 = new StringBuffer();
        for (int i = 0; i < 100; i++) {
            sb1.append( "zz zzz zzzz zz zz zz zzz xzzzz zzzzzzzzzzzzzzzzx yyyyyyy tttttttttt sssss hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh\n" );
        }
        textArea1.setText( sb1.toString() );
        JScrollPane pane1 = new JScrollPane( textArea1, 
			                     ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS, 
					     ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED );
        frame1.add( pane1, BorderLayout.CENTER );
        frame1.setLocationRelativeTo(null);
        frame1.setVisible( true );
        wrapoffHeight = textArea1.getHeight();
        System.out.println("wrapoffheight " + wrapoffHeight);
    }

    public static void main( String[] args ) throws Exception {
        System.setProperty( "sun.java2d.uiScale", "1.25" );
        try {
            SwingUtilities.invokeAndWait(() -> doWrapOnTest());
	    Thread.sleep(2000);
            SwingUtilities.invokeAndWait(() -> doWrapOffTest());
	    Thread.sleep(2000);

            if (wraponHeight == wrapoffHeight) {
                throw new RuntimeException("JTextArea line wrapping incorrect when using UI scale");
            }
	} finally {
            SwingUtilities.invokeAndWait(() -> frame.dispose());
            SwingUtilities.invokeAndWait(() -> frame1.dispose());
	}
    }
}