Problem: I want to implement a text editing widget for text with additional tags.
I'd like some tags to be invisible in some cases so that they do not distract the user.
Environment: I'm using PyQt and prefer to use QPlainTextWidget and QSyntaxHighlighter.
Approach: With QSyntaxHighlighter I can set QTextCharFormat for the strings which match my requirement. QTextCharFormat has gives me all font properties like size, colors, etc. but: I haven't found a option to hide the text or reduce its size to zero.
I don't want to remove or replace the tags, as this will introduce a lot more code (copying should contain tags and without I can't use QSyntaxHighlighter for formating the remaining text according to the tags).
Update: So far I found a ugly hack. By setting the QTextFormat::FontLetterSpacing to a small value, the text will consume less and less space. In combination with a transparent color the text is something like invisible.
Problem: In my test this worked only for letter spacings down to 0.016 %. Below the spacing is reseted to 100 %.
You can use the underlying QTextDocument for this. It consists of blocks whose visibility can be turned on and off using setVisible. Use a QTextCursor to insert the text and new blocks and switch visibility. As a bonus the copy function copies the content of non-visible blocks anyway.
Notes: See the documentation of QTextCursor for more information. In another question here is was reported that setting the visibility is not working on QTextEdits.
Example:
from PyQt5 import QtWidgets, QtGui
app = QtWidgets.QApplication([])
w = QtWidgets.QPlainTextEdit()
w.show()
t = QtGui.QTextCursor(w.document())
t.insertText('plain text')
t.insertBlock()
t.insertText('tags, tags, tags')
t.block().setVisible(False)
print(w.document().toPlainText())
app.exec_()
Related
I want to show some text in a QToolButton derived class but it needs to be word wrapped. I would like to do it in an "automatic" way (instead of using \n when needed) just as one can do it when using QLabel and setting word wrapp to true, but I couldn't find anything on Qt Assistant that would do that for me.
So, is it possible? And how is it done? If there is nothing like word wrapping for QToolButton, how could I get around this without using "hard code layout" (that is, \n)?
I've added QLabel widgets to my QTreeWidget to work around the word wrapping issue in QTreeWidget. (see how to word wrap a QTreeWidgetItem). The QLabel widgets appear to have spacing around the text which for some reason disappears when the text wraps. It also does not show up when the Label text is blank.
I tried setting setContentsMargin(0,0,0,0) on the QLabel but that didn't work. I also tried setStyleSheet("border: 0px; margin: 0px; padding: 0px;") which also didn't help.
Screenshot:
You can see that it depends on the length of the description whether QT decides to put that spacing buffer around the words. It only happens when the word wrap is enabled. Further playing around seems to indicate its dependent on spaces in the description string. No spaces in the string prevents the additional space around the words. Probably something to do with what the QLabel is doing with its word wrap property.
# This code is Ruby because I'm using the qtbindings gem
tree = Qt::TreeWidget.new
tree.setColumnCount(2)
tree.setHeaderLabels(["Name", "Description"])
top_node = Qt::TreeWidgetItem.new(["top"])
top_node.setCheckState(0, Qt::Unchecked)
tree.addTopLevelItem(top_node)
desc_label = Qt::Label.new("description")
desc_label.setWordWrap(true) # Remove and it works
tree.setItemWidget(top_node, 1, desc_label)
node = Qt::TreeWidgetItem.new(["test1"])
node.setCheckState(0, Qt::Unchecked)
top_node.addChild(node)
desc_label = Qt::Label.new("description1 is long and very interesting")
desc_label.setWordWrap(true) # Remove and it works
tree.setItemWidget(node, 1, desc_label)
What you see is effect of layouting logic for drawing/positioning of QLabel (you may see these routines in https://qt.gitorious.org/qt/qt/source/f7b3072924fb57b3979ff4d536eb213270be1047:src/gui/widgets/qlabel.cpp#sizeForWidth, see sizeForWidth() method).
What you may do is:
You may change the behavior little by trying to set setTextFormat() and use PlainText or RichText for all custom items explicitly. But it may not help.
My recommendation is to subclass used QItemDelegate or QStyledItemDelegate and reimplement the sizeHint( const QStyleOptionViewItem & option, const QModelIndex & index ) for returning desired size, height for you customized item. Then to use setItemDelegate() to view.
My workaround was to set the label's minimum height as follows:
desc_label.setMinimumHeight(desc_label.fontMetrics.height * 2)
This matches what the Label is doing automatically with some of the strings and prevents the inconsistenly sized labels with blank or one-word strings.
I solved the problem by setting the fixed height or maximum height:
label.setMaximumHeight(label.fontMetrics().height() * n);
or
label.setFixedHeight(label.fontMetrics().height() * n);
where n is max considered/estimated lines of the label content.
Unfortunately, setting the minimum height, label.setMinimumHeight(...) does not work, otherwise it was more rational since it is not clear that the wrapped text may have how much lines. Also label.setContentMargin(0,0,0,0) does not work.
For example, we have a QLabel with MaximumWidth set to 400.
When we try to display some text with pixel width more than 400, it's shown cut off.
Is there any way to make QLabel display this string in multiple lines without using QFontMetrics or the like?
If I understood your question correctly, you should use the setWordWrap function for your label, with true as its parameter.
QLabel lbl("long long string");
lbl.setWordWrap(true);
In order to show multiple lines in QLabel, right click on QLabel and select 'change rich text'. This brings up dialog where you can type the text as you want to see including enter key. Setting the word wrap is not required for this.
If you set the word wrap as well (in QLabel properties) than it will wrap each individual line in the Qlabel if it was longer than the real estate.
As another option to wrap text using Qt Designer, you can check the box under Property Editor for a QLabel:
How do I set line height in QLabel when in WordWrap mode?
Use HTML text:
QString template = "<p style=\"line-height:%1%\">%2<p>";
QString targetText = template.arg(myPercentage).arg(myTex);
QLabel *l = new QLabel(targetText, this);
where myPercentage is like 60 - 80.
You will get condensed lines in the WordWrap mode
There is no line spacing property in QLabel. You can change the widget font, which will change the line's height, but I suspect that is not what you want.
Line height is computed from the QFont of the widget and can be obtained by the QFontMetrics associated with the widget. Using this information, you may create your own widget that has a line spacing property (and a text wrap mode), but that represents a lot of low-level work.
You can also edit the HTML of the QLabel directly in Qt Designer.
Select the label in Qt Designer.
In the Property Editor, under the QLabel section, select the text property and press the ... button.
Select the "source" tab and edit the HTML from there.
Here are two examples that control the line spacing of a QLabel using HTML (tested in Qt 5.7). I am sure there are many more (and some better) ways to write the HTML, but this should be a good start.
Example 1
<html><head/><body>
<p style="line-height:120"><span>
This is the first line of the label.<br>
This is the second line.<br>
This is the third and final line.
</span></p>
</body></html>
This example is neater if the line spacing is the same for the whole paragraph.
Example 2
<html><head/><body>
<p style="line-height:20"><span>This is the first line of the label.</span></p>
<p style="line-height:20"><span>This is the second line.</span></p>
<p style="line-height:100"><span>This is the third and final line.</span></p>
</body></html>
This example allows you to control the spacing of each line individually. I had to make the height of the last line 100 to prevent Qt from cutting it in half. I assume it affects how Qt calculates the height of the label as a widget.
Is it possible to have individual indentation of items in a QTreeWidget?
In specific, I have have a column containing both text, icon and for some of them a CheckBox. The items without a CheckBox gets shifted to the left so the indentation of the icon and the text is not inline with the others. Could maybe be fixed with a hidden CheckBox if that is possible?
Maybe the use of Delegates will give you a nice and proper implementation. You'll have the opportunity to re-implement the paint() and sizeHint() methods, and therefore, choose the way your QTreeWidgetItem are being drawn...
More documentation here : http://doc.trolltech.com/4.6/model-view-delegate.html
An example : http://doc.trolltech.com/4.6/itemviews-pixelator.html
Hope it helps a bit !
You can try using the QWidget::setContentMargins() on the widget returned by QTreeWidget::itemWidget().