[OpenJDK 2D-Dev] RFR: 8242004: TextLayout throws Exception with a non-invertible transform

[Jayathirth D v]

Hi Phil,

I see your point of allowing queries on text layout without throwing exceptions.

I was also under the impression that we should not see text getting drawn when we try to draw it using TextLayout with your change.

For more clarification I am adding what I tested :
I used code from your test case and tried drawing using TextLayout and drawString(). Without your change in both the cases we see NoninvertibleTransformException. After your change in case of TextLayout.draw() we are actually seeing the text but in case of drawString() text is not getting drawn.

Verification test I used:
import javax.swing.*;
import java.awt.*;
import java.awt.font.FontRenderContext;
import java.awt.font.TextLayout;
import java.awt.geom.AffineTransform;

public class NonInvertibleTransformTextTest extends JPanel {

    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D)g;

        AffineTransform at = new AffineTransform(1f, 0.0f, -15, 0.0, -1, -30);

        // First use case of drawing using TextLayout
        FontRenderContext frc = new FontRenderContext(at, false, false);
        Font font = new Font(Font.DIALOG, Font.PLAIN, 12);
        TextLayout tl = new TextLayout("ABC", font, frc);
        tl.draw(g2, 50, 50);

        // Second use case of drawing using drawString()
        //g2.setTransform(at);
        //g2.drawString("ABC", 50, 50);
    }

    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.getContentPane().add(new NonInvertibleTransformTextTest());
        f.setSize(300, 200);
        f.setVisible(true);
    }
}
May be I am wrongly using TextLayout.draw() to check expected behaviour after the change.
Please clarify.

Thanks,
Jay

> On 10-Apr-2020, at 7:45 PM, Philip Race <philip.race at oracle.com> wrote:
> 
> Oh and if you do draw it, it still goes through the GV path so nothing should draw there.
> 
> This is what I meant by :
> > Subsequent rendering of the TextLayoutwill be handled by the other checks being added.
> 
> The shape returned might be not be null but I don't think you'll get more than a line ..
> 
> -phil.
> 
> On 4/10/20, 12:57 AM, Philip Race wrote:
>> 
>> 
>> 
>> On 4/9/20, 10:26 PM, Jayathirth D v wrote:
>>> 
>>> Hi Phil,
>>> 
>>> I went through all use cases captured in test case (TextLayout, drawXXXX).
>>> 
>>> With updated change there is difference in behaviour between how we interpret non-invertible transform between TextLayout.draw() and drawXXXX() API’s.
>>> In case of TextLayout.draw() we are overriding non-invertible transform and allowing text rendering to happen, but in case of drawXXXX() we just return and doesn’t allow text rendering to continue. Is it okay to have this difference in behaviour?
>> 
>> It becomes tricky. 
>> Do you have a suggestion ?
>> Remember that the TextLayout is returned and does not have to be drawn, but could be
>> by both drawing it directly or asking for the outline shape and rendering that.
>> It can also be queried for the layout etc. There needs to be something returned that
>> does not cause other problems. And patently there can't be apps that would care because
>> today they can't get that far.
>> And there's no defined behaviour in this case.
>> 
>> So if you have specific code suggestions ..
>>> 
>>> Also in test case its better if we continue to test all use cases and then fail instead of failing at first instance and added test case needs change in Copyright year from 2015 to 2020.
>> 
>> oops. 
>> 
>> -phil.
>> 
>>> 
>>> Thanks,
>>> Jay
>>> 
>>>> On 10-Apr-2020, at 7:53 AM, Philip Race <philip.race at oracle.com <mailto:philip.race at oracle.com>> wrote:
>>>> 
>>>> D**n copy/paste, yes you correctly inferred the webrev is at
>>>> <cr-url>/<my openjdk id>/<bugid> ie : http://cr.openjdk.java.net/~prr/8242004/ <http://cr.openjdk.java.net/%7Eprr/8242004/> 
>>>> 
>>>> -phil.
>>>> 
>>>> 
>>>> On 4/9/20, 7:00 PM, Jayathirth D v wrote:
>>>>> 
>>>>> Hi Phil,
>>>>> 
>>>>> Please share webrev link, you have added JBS link for webrev.
>>>>> I went to path where you usually share webrev's and found http://cr.openjdk.java.net/~prr/8242004/ <http://cr.openjdk.java.net/%7Eprr/8242004/> 
>>>>> 
>>>>> Thanks,
>>>>> Jay
>>>>> 
>>>>> 
>>>>>> On 10-Apr-2020, at 12:49 AM, Philip Race <philip.race at oracle.com <mailto:philip.race at oracle.com>> wrote:
>>>>>> 
>>>>>> Any takers ?
>>>>>> 
>>>>>> -phil
>>>>>> 
>>>>>> On 4/3/20, 1:29 PM, Philip Race wrote:
>>>>>>> bug: https://bugs.openjdk.java.net/browse/JDK-8242004 <https://bugs.openjdk.java.net/browse/JDK-8242004>
>>>>>>> webrev: https://bugs.openjdk.java.net/browse/JDK-8242004 <https://bugs.openjdk.java.net/browse/JDK-8242004>
>>>>>>> 
>>>>>>> Several code paths can end up in the method shown in the bug report
>>>>>>> with a non-invertible transform.
>>>>>>> 
>>>>>>> As much as possible, we can prevent them reaching here by checking in the rendering code.
>>>>>>> 
>>>>>>> If we do get here, which should now be possible only when directly creating
>>>>>>> a TextLayout, we can use a default TX. Subsequent rendering of the TextLayout
>>>>>>> will be handled by the other checks being added.
>>>>>>> 
>>>>>>> A regression test is provided which checks various APIs to make sure no
>>>>>>> exception is thrown.
>>>>>>> 
>>>>>>> -phil.
>>>>>>> 
>>>>>>> 
>>>>> 
>>> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mail.openjdk.java.net/pipermail/2d-dev/attachments/20200410/61816eae/attachment-0001.htm>