See comments inline.
On 7/26/2016 11:57 PM, Phil Race wrote:
I have a lot of doubts about this as well as trouble
getting my head around all of it.
Given that apps need to 'buy in' to the floating point
I am not sure what we are gaining
but I need to make sure I understand the problem.
It affects only the methods that the 3rd party code
can over-ride
in subclasses and that are called by the JDK internal
code.
There are just two protected methods that matter :-
PlainView.drawSelectedText(..)
and
PlainView.drawUnselectedText(..)
The hidpi precison matters since they are drawing a
sub-range of the text.
Is there any other method that matters / is used in
this way ?
I have found the following methods which relate to
text drawing, can be overridden and could have floating
point coordinates:
javax.swing.text.PlainView.drawLine(...)
javax.swing.text.PlainView.lineToRect(...)
javax.swing.text.PasswordView.drawEchoCharacter(...)
javax.swing.plaf.TextUI.modelToView(...)
javax.swing.plaf.TextUI.viewToModel(...)
javax.swing.plaf.TextUI.getToolTipText(...)
There is also a method which relates to a caret
position in a text:
javax.swing.text.DefaultCaret.setMagicCaretPosition(Point
p)
This requires additional investigation because
DefaultCaret extends Rectangle and so its coordinates
can't be float.
Since 3rd party code is not over-riding these they
will get the JDK
super-class version, thus losing any customisation
they might have done
in the no-longer-called int version.
Assuming that is correct, what customisation would be
lost and how much does it matter?
The example is javax.swing.text.PasswordView class
which overrides
drawSelectedText(...)/drawUnselectedText(...) methods
and draws echo chars instead of text.
The similar can be done in a custom component:
--------
public class CustomPasswordField extends FieldView {
@Override
protected int drawSelectedText(Graphics g, int x,
int y, int p0, int p1) throws BadLocationException {
// draw echo chars
}
}
--------
Switching to support new methods with floating point
coordinates will lead that real text will be shown for
old applications in password fields.
My prefernce is to deprecate the int versions and
always call the float versions
rather than the opt-in approach.
Actually my real preference would be to come up with
something that does
not involve drawing the text in chunks like this.
ie Swing should use AttributedCharacterIterator .. it
looks like the code to
do this might already be there !
106 private float drawElement(int lineIndex, Element
elem, Graphics g,
107 float x, float y, boolean fractionalCharBounds)
108 throws BadLocationException
109 {
110 int p0 = elem.getStartOffset();
111 int p1 = elem.getEndOffset();
112 p1 = Math.min(getDocument().getLength(), p1);
113
114 if (lineIndex == 0) {
115 x += firstLineOffset;
116 }
117 AttributeSet attr = elem.getAttributes();
118 if (Utilities.isComposedTextAttributeDefined(attr)) {
119 g.setColor(unselected);
120 x = Utilities.drawComposedText(this, attr, g, x, y,
121 p0-elem.getStartOffset(),
122 p1-elem.getStartOffset());
123 } else {
In fact what *that* illustrates is that applications
already cannot expect
their over-ridden methods to be called, so this fix is
trying to fix something
that can't be fixed.
The javadoc for the "protected PlainView.drawLine(...)"
method is:
---------
/**
* Renders a line of text, suppressing whitespace
at the end
* and expanding any tabs. This is implemented to
make calls
* to the methods {@code drawUnselectedText} and
* {@code drawSelectedText} so that the way
selected and
* unselected text are rendered can be customized.
---------
Applications can rely on this behaviour and stopping
to call the
drawSelectedText(...)/drawUnselectedText(...) methods
with int coordinates will be incompatible change.
So why can't we do that ? Just deprecate those int
methods, don't add
the float methods and use ACI ..
New float methods allow to easily migrate on new API
for applications without significant changes.
BTW getTabSize() is supposed to be a character count
isn't it ? Not a pixel
count. So why does it need a float version.
Could you review the updated fix:
http://cr.openjdk.java.net/~alexsch/8156217/webrev.04
- methods with int coordinates which can be
overridden are deprecated
- getFractionalTabSize() method is removed
Thanks,
Alexandr.
-phil
On 06/30/2016 08:50 AM, Alexandr Scherbatiy wrote:
On 6/28/2016 8:14 PM, Alan Snyder wrote:
Suppose an application is only partially fixed to
use/override the floating point methods. Perhaps it
uses a library that has not been fixed.
Is there a more fine grained way to detect
programmer awareness or lack of awareness of the new
methods?
Here is a slightly updated version which adds
public
isUseFloatingPointAPI()/setUseFloatingPointAPI()
methods to the PlainView and WrappedPlainView classes:
http://cr.openjdk.java.net/~alexsch/8156217/webrev.02
Using the floating point API is disabled by default
and enabled for standard Swing text component
classes. This has advantage that selection will work
for text component in users applications on HiDPI
display.
But it still has the same problem. Applications
which use custom View classes needs to updated them
to implement corresponding text drawing methods with
floating point arguments and enable the floating
point API usage.
Thanks,
Alexandr.
Alan
On Jun 28, 2016, at 9:59 AM, Alexandr Scherbatiy
<alexandr.scherba...@oracle.com
<mailto:alexandr.scherba...@oracle.com>> wrote:
Hello,
I tried to merge this fix with the 8132119
Provide public API for text related methods in
SwingUtilities2
and found a flow in the used algorithm.
For each method that uses integer coordinates the
fix adds a pair with floating point arguments.
The fix 8156217 uses only methods with floating
point values to correctly handle a selected text.
This leads that overridden method with integer
arguments in user code is not called anymore.
I think that this can be handled in the following way:
- Add a property that enables to use methods with
floating point arguments in Swing.
By default it is false and all work as before.
The issue with selected text is reproduced.
An application with enabled property does not
have issue with the selected text but a user should
override
all methods with floating point values if he
uses corresponding methods with integer values.
Here is a proposed solution where new public
system property
"javax.swing.floatingPoints.enabled" is added:
http://cr.openjdk.java.net/~alexsch/8156217/webrev.01
- Fix the enhancement JDK-8157461 Glyph image
rendering for HiDPI displays
Thanks,
Alexandr.
On 6/16/2016 6:07 PM, Alexandr Scherbatiy wrote:
On 6/16/2016 4:47 PM, Alexandr Scherbatiy wrote:
I tried to look deeper in the code and it seems
there is a rounding issue when float values are
summed up.
Suppose a transform with scale 1.5 is used and
the 'a' char advance is 10 in a dev space.
The 'a' char has advance 10 / 1.5 =
6.666666666666667 as double value and 6.6666665
when it is cast to float in user space.
The width of a string which consists of 15 'a'
chars is 15 * 6.6666665 = 100.000000.
But the same width calculated as sum of each
glyph advance in
StandardGlyphVector.initPositions() method is
99.999992.
--------------
double scale = 1.5;
float advance = (float) (10 / scale);
int N = 15;
System.out.printf("%d * %f = %f\n", N,
advance, N * advance);
float sum = 0;
for (int i = 0; i < N; i++) {
sum += advance;
}
System.out.printf("sum: %f\n", sum);
--------------
Because of this a string drawn from float
position 99.999998 is shifted one pixel left
which affects the text selection code in Swing:
------------------------
g.scale(1.5, 1.5);
String TEXT = "aaaaaaaaaaaaaaaa";
Rectangle2D rect =
font.getStringBounds(TEXT, 0, index,
g.getFontMetrics().getFontRenderContext());
float selectedTextPosition = (float)
rect.getWidth(); // 99.999992
g.drawString(TEXT.substring(0, index), x,
y); // non-selected text
g.drawString(TEXT.substring(index,
TEXT.length()), x + selectedTextPosition, y); //
selected text is shifted to one pixel left
------------------------
The last step is how coordinates are scaled in
Graphics2D.drawString() method.
If the graphics has scale 1.5 and zero
translate the transformed coordinates are:
(99.999992 + 0) * 1.5 = 149.999985
(100.000000 + 0) * 1.5 = 150.000000
Both of them are rounded to the same value.
If the translate is set to integer 1 value:
(99.999992 + 1) * 1.5 = 151.499989 // shifted
to one pixel left
(100.000000 + 1) * 1.5 = 151.500000
A position 99.999992 in user space is rounded to
151 in dev space.
A position 100.000000 in user space is rounded to
152 in dev space.
And this difference can depend on the translate
even it has integer value in user space because it
is multiplied on the graphics scale.
Thanks,
Alexandr.
Thanks,
Alexandr.
On 6/2/2016 11:41 PM, Alexandr Scherbatiy wrote:
On 5/31/2016 10:40 PM, Phil Race wrote:
I applied this and it is *much* better but
there still seem to be some tiny quirks.
When I drag the mouse to select text down and
then up again, as I pass the
original mouse click point vertically, repaint
seem to jiggle vertically by a pixel.
Perhaps a rounding issue in the repaint code's
calculation of the location of
the target y. I think I may see the same in
left/right dragging along a line too.
So I think this is repaint and not text
related. Can you take a look.
I am able to reproduce this only using a
floating point scale.
It looks like 2d issue. I used a test which
draws a text in two pieces. The second piece of
the text is shifted from the first piece by the
floating point size of the the first piece of
the text.
-----------
Rectangle2D rect =
font.getStringBounds(TEXT, 0, index,
g.getFontMetrics().getFontRenderContext());
float selectedTextPosition = (float)
rect.getWidth();
g.drawString(TEXT.substring(0, index), x, y);
g.drawString(TEXT.substring(index,
TEXT.length()), x + selectedTextPosition, y);
-----------
The second piece of the text can be shifted in
the 2 cases:
a) graphics scale is 1.5 and translation is 1.
b) graphics scale is 2.25 without applied
translation
I have filed an issue on it:
JDK-8158370 Text drawn from float pointing
position and with float pointing scale is shifted
https://bugs.openjdk.java.net/browse/JDK-8158370
Thanks,
Alexandr.
-phil.
On 05/06/2016 12:31 PM, Alexandr Scherbatiy wrote:
Hello,
Could you review the fix:
bug:
https://bugs.openjdk.java.net/browse/JDK-8156217
webrev:
http://cr.openjdk.java.net/~alexsch/8156217/webrev.00
This is the second part of the fix related
to the fact that char width can be fractional
in user space.
http://mail.openjdk.java.net/pipermail/swing-dev/2016-May/005814.html
The Font.getStringBounds(...) method is used
for the fractional string width calculation by
Swing in user space.
Thanks,
Alexandr.
