The object replacement character (U+FFFC) is used to represent
inline objects such as images in rich-text. To enable this,
we have special handling of it in QTextEngine. For classes
where inline images are not supported, it will just be hidden
from the visual text, which is unexpected.
Instead of always special-casing it, we make this dependent
on whether the document layout has registered any object handlers.
If they have not, then there will be no visual representation of
the object, and it is better to show the glyph for it.
For anything based on QTextDocument, there will always be the
image handler, so U+FFFC will still have special handling there,
but for non-rich labels and plain text editors the glyph will
be shown instead.
Note that there was also a bug in QLineEdit, where the object
replacement character was always replaced by a space. This was
introduced in 2007, in a patch which replaced a !ch.isPrint()
with a check for "the most obvious non-printable characters"
to reduce the number of characters that were not shown. However,
U+FFFC is a printable character and would thus not have been
filtered by the !isPrint() condition, so I think this was a
mistake at the time. However, due to the special-casing of
the character in Qt, it would not have had any effect until
now.
This also changes the QTextLayout::cursorToXForInlineObject()
test to actually test proper inline objects, as this was
previously using a hack which depended on the inline object
code to be used even for plain QTextLayouts with no handlers
for these.
[ChangeLog][Text] The object replacement character (U+FFFC)
is now only filtered out in rich text controls, where they
represent inline objects. In other controls, its glyphs will
be shown as with other text.
Pick-to: 6.5
Fixes: QTBUG-101526
Change-Id: I7fcaf2b10918feb41589e1098016efbf79a0e62d
Reviewed-by: Lars Knoll <lars@knoll.priv.no>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
This was added by 9ff76c27b9 on
the basis that it signifies a shaping error and would later assert
or crash.
But the line is easily reachable by user code. If Harfbuzz returns
0 glyphs, it just means it is unable to shape the string, for instance
if the input string only contains default ignorables (like a ZWJ)
and does not have any appropriate glyph to use for replacement.
Qt expects there to always be at least one glyph in the output
(num_glyphs == 0 is used to indicate shaping is not yet done), so
to avoid asserts later on, we simply populate the output with a
single 0 token, which is a required entry in the font that is
reserved for representing unrepresentable characters.
This also adds a test and therefore a zero-width joiner to the test
font to reproduce the issue.
[ChangeLog][QtGui][Text] Fixed a possible crash with certain fonts
when shaping strings consisting only of control characters.
Fixes: QTBUG-89155
Pick-to: 5.15
Pick-to: 6.0
Change-Id: Ia0dd6a04844c9be90dcab6c464bebe339a3dab11
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
The sample lineedit in Qt's own font dialog shouldn't have its font
affected by stylesheets.
Not only does this hampers the ability to preview the font, it actually
overrides the font selection as that one is taken directly from the
widget.
Task-number: QTBUG-41513
Change-Id: I11d0bef8c7bf7bdae4cc08b6b9276d0fc14a75fb
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@theqtcompany.com>
Eskil Abrahamsen Blomfeldt
Pierre Rossi