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The QTextEdit class provides a widget that is used to edit and display both plain and rich text. More...
#include <QTextEdit>
Inherits QAbstractScrollArea.
Inherited by QTextBrowser.
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The QTextEdit class provides a widget that is used to edit and display both plain and rich text.
QTextEdit is an advanced WYSIWYG viewer/editor supporting rich text formatting using HTML-style tags. It is optimized to handle large documents and to respond quickly to user input.
QTextEdit works on paragraphs and characters. A paragraph is a formatted string which is word-wrapped to fit into the width of the widget. By default when reading plain text, one newline signifies a paragraph. A document consists of zero or more paragraphs. The words in the paragraph are aligned in accordance with the paragraph's alignment. Paragraphs are separated by hard line breaks. Each character within a paragraph has its own attributes, for example, font and color.
QTextEdit can display images, lists and tables. If the text is too large to view within the text edit's viewport, scroll bars will appear. The text edit can load both plain text and HTML files (a subset of HTML 3.2 and 4).
If you just need to display a small piece of rich text use QLabel.
Note that we do not intend to add a full-featured web browser widget to Qt (because that would easily double Qt's size and only a few applications would benefit from it). The rich text support in Qt is designed to provide a fast, portable and efficient way to add reasonable online help facilities to applications, and to provide a basis for rich text editors.
The shape of the mouse cursor on a QTextEdit is Qt::IBeamCursor by default. It can be changed through the viewport()'s cursor property.
QTextEdit can display a large HTML subset, including tables and images.
The text is set or replaced using setHtml() which deletes any existing text and replaces it with the text passed in the setHtml() call. If you call setHtml() with legacy HTML, and then call toHtml(), the text that is returned may have different markup, but will render the same. The entire text can be deleted with clear().
Text itself can be inserted using the QTextCursor class or using the convenience functions insertHtml(), insertPlainText(), append() or paste(). QTextCursor is also able to insert complex objects like tables or lists into the document, and it deals with creating selections and applying changes to selected text.
By default the text edit wraps words at whitespace to fit within the text edit widget. The setLineWrapMode() function is used to specify the kind of line wrap you want, or NoWrap if you don't want any wrapping. Call setLineWrapMode() to set a fixed pixel width FixedPixelWidth, or character column (e.g. 80 column) FixedColumnWidth with the pixels or columns specified with setLineWrapColumnOrWidth(). If you use word wrap to the widget's width WidgetWidth, you can specify whether to break on whitespace or anywhere with setWordWrapMode().
The find() function can be used to find and select a given string within the text.
If you want to limit the total number of paragraphs in a QTextEdit, as it is for example open useful in a log viewer, then you can use QTextDocument's maximumBlockCount property for that.
When QTextEdit is used read-only the key bindings are limited to navigation, and text may only be selected with the mouse:
| Keypresses | Action |
|---|---|
| Qt::UpArrow | Moves one line up. |
| Qt::DownArrow | Moves one line down. |
| Qt::LeftArrow | Moves one character to the left. |
| Qt::RightArrow | Moves one character to the right. |
| PageUp | Moves one (viewport) page up. |
| PageDown | Moves one (viewport) page down. |
| Home | Moves to the beginning of the text. |
| End | Moves to the end of the text. |
| Alt+Wheel | Scrolls the page horizontally (the Wheel is the mouse wheel). |
| Ctrl+Wheel | Zooms the text. |
| Ctrl+A | Selects all text. |
The text edit may be able to provide some meta-information. For example, the documentTitle() function will return the text from within HTML <title> tags.
All the information about using QTextEdit as a display widget also applies here.
The current char format's attributes are set with setFontItalic(), setFontWeight(), setFontUnderline(), setFontFamily(), setFontPointSize(), setTextColor() and setCurrentFont(). The current paragraph's alignment is set with setAlignment().
Selection of text is handled by the QTextCursor class, which provides functionality for creating selections, retrieving the text contents or deleting selections. You can retrieve the object that corresponds with the user-visible cursor using the textCursor() method. If you want to set a selection in QTextEdit just create one on a QTextCursor object and then make that cursor the visible cursor using setCursor(). The selection can be copied to the clipboard with copy(), or cut to the clipboard with cut(). The entire text can be selected using selectAll().
When the cursor is moved and the underlying formatting attributes change, the currentCharFormatChanged() signal is emitted to reflect the new attributes at the new cursor position.
QTextEdit holds a QTextDocument object which can be retrieved using the document() method. You can also set your own document object using setDocument(). QTextDocument emits a textChanged() signal if the text changes and it also provides a isModified() function which will return true if the text has been modified since it was either loaded or since the last call to setModified with false as argument. In addition it provides methods for undo and redo.
QTextEdit also supports custom drag and drop behavior. By default, QTextEdit will insert plain text, HTML and rich text when the user drops data of these MIME types onto a document. Reimplement canInsertFromMimeData() and insertFromMimeData() to add support for additional MIME types.
For example, to allow the user to drag and drop an image onto a QTextEdit, you could the implement these functions in the following way:
bool TextEdit::canInsertFromMimeData( const QMimeData *source ) const
{
if (source->hasImage())
return true;
else
return QTextEdit::canInsertFromMimeData(source);
}
We add support for image MIME types by returning true. For all other MIME types, we use the default implementation.
void TextEdit::insertFromMimeData( const QMimeData *source )
{
if (source->hasImage())
{
QImage image = qvariant_cast<QImage>(source->imageData());
QTextCursor cursor = this->textCursor();
QTextDocument *document = this->document();
document->addResource(QTextDocument::ImageResource, QUrl("image"), image);
cursor.insertImage("image");
}
}
We unpack the image from the QVariant held by the MIME source and insert it into the document as a resource.
The list of key bindings which are implemented for editing:
| Keypresses | Action |
|---|---|
| Backspace | Deletes the character to the left of the cursor. |
| Delete | Deletes the character to the right of the cursor. |
| Ctrl+C | Copy the selected text to the clipboard. |
| Ctrl+Insert | Copy the selected text to the clipboard. |
| Ctrl+K | Deletes to the end of the line. |
| Ctrl+V | Pastes the clipboard text into text edit. |
| Shift+Insert | Pastes the clipboard text into text edit. |
| Ctrl+X | Deletes the selected text and copies it to the clipboard. |
| Shift+Delete | Deletes the selected text and copies it to the clipboard. |
| Ctrl+Z | Undoes the last operation. |
| Ctrl+Y | Redoes the last operation. |
| LeftArrow | Moves the cursor one character to the left. |
| Ctrl+LeftArrow | Moves the cursor one word to the left. |
| RightArrow | Moves the cursor one character to the right. |
| Ctrl+RightArrow | Moves the cursor one word to the right. |
| UpArrow | Moves the cursor one line up. |
| Ctrl+UpArrow | Moves the cursor one word up. |
| DownArrow | Moves the cursor one line down. |
| Ctrl+Down Arrow | Moves the cursor one word down. |
| PageUp | Moves the cursor one page up. |
| PageDown | Moves the cursor one page down. |
| Home | Moves the cursor to the beginning of the line. |
| Ctrl+Home | Moves the cursor to the beginning of the text. |
| End | Moves the cursor to the end of the line. |
| Ctrl+End | Moves the cursor to the end of the text. |
| Alt+Wheel | Scrolls the page horizontally (the Wheel is the mouse wheel). |
To select (mark) text hold down the Shift key whilst pressing one of the movement keystrokes, for example, Shift+Right Arrow will select the character to the right, and Shift+Ctrl+Right Arrow will select the word to the right, etc.
See also QTextDocument, QTextCursor, Application Example, Syntax Highlighter Example, and Rich Text Processing.
| Constant | Value | Description |
|---|---|---|
| QTextEdit::AutoNone | 0 | Don't do any automatic formatting. |
| QTextEdit::AutoBulletList | 0x00000001 | Automatically create bullet lists (e.g. when the user enters an asterisk ('*') in the left most column, or presses Enter in an existing list item. |
| QTextEdit::AutoAll | 0xffffffff | Apply all automatic formatting. Currently only automatic bullet lists are supported. |
The AutoFormatting type is a typedef for QFlags<AutoFormattingFlag>. It stores an OR combination of AutoFormattingFlag values.
| Constant | Value |
|---|---|
| QTextEdit::MoveBackward | 0 |
| QTextEdit::MoveForward | 1 |
| QTextEdit::MoveWordBackward | 2 |
| QTextEdit::MoveWordForward | 3 |
| QTextEdit::MoveUp | 4 |
| QTextEdit::MoveDown | 5 |
| QTextEdit::MoveLineStart | 6 |
| QTextEdit::MoveLineEnd | 7 |
| QTextEdit::MoveHome | 8 |
| QTextEdit::MoveEnd | 9 |
| QTextEdit::MovePageUp | 10 |
| QTextEdit::MovePageDown | 11 |
| Constant | Value |
|---|---|
| QTextEdit::NoWrap | 0 |
| QTextEdit::WidgetWidth | 1 |
| QTextEdit::FixedPixelWidth | 2 |
| QTextEdit::FixedColumnWidth | 3 |
This property holds whether the text edit accepts rich text insertions by the user.
When this propery is set to false text edit will accept only plain text input from the user. For example through clipboard or drag and drop.
This property's default is true.
This property was introduced in Qt 4.1.
Access functions:
This property holds the enabled set of auto formatting features.
The value can be any combination of the values in the AutoFormattingFlag enum. The default is AutoNone. Choose AutoAll to enable all automatic formatting.
Currently, the only automatic formatting feature provided is AutoBulletList; future versions of Qt may offer more.
Access functions:
This property specifies the width of the cursor in pixels. The default value is 1.
This property was introduced in Qt 4.2.
Access functions:
This property holds the title of the document parsed from the text.
Access functions:
This property provides an HTML interface to the text of the text edit.
toHtml() returns the text of the text edit as html.
setHtml() changes the text of the text edit. Any previous text is removed and the undo/redo history is cleared. The input text is interpreted as rich text in html format.
Note: It is the responsibility of the caller to make sure that the text is correctly decoded when a QString containing HTML is created and passed to setHtml().
Access functions:
See also Supported HTML Subset and plainText.
This property holds the position (in pixels or columns depending on the wrap mode) where text will be wrapped.
If the wrap mode is FixedPixelWidth, the value is the number of pixels from the left edge of the text edit at which text should be wrapped. If the wrap mode is FixedColumnWidth, the value is the column number (in character columns) from the left edge of the text edit at which text should be wrapped.
Access functions:
See also lineWrapMode.
This property holds the line wrap mode.
The default mode is WidgetWidth which causes words to be wrapped at the right edge of the text edit. Wrapping occurs at whitespace, keeping whole words intact. If you want wrapping to occur within words use setWordWrapMode(). If you set a wrap mode of FixedPixelWidth or FixedColumnWidth you should also call setLineWrapColumnOrWidth() with the width you want.
Access functions:
See also lineWrapColumnOrWidth.
This property was introduced in Qt 4.1.
Access functions:
This property gets and sets the text edit's contents as plain text. Previous contents are removed and undo/redo history is reset when the property is set. If the text edit has another content type, it will not be replaced by plain text when you call toPlainText().
This property was introduced in Qt 4.3.
Access functions:
See also html.
This property holds whether the text edit is read-only.
In a read-only text edit the user can only navigate through the text and select text; modifying the text is not possible.
This property's default is false.
Access functions:
This property holds whether Tab changes focus or is accepted as input.
In some occasions text edits should not allow the user to input tabulators or change indentation using the Tab key, as this breaks the focus chain. The default is false.
Access functions:
This property holds the tab stop width in pixels.
This property was introduced in Qt 4.1.
Access functions:
Specifies how the label should interact with user input if it displays text.
If the flags contain either Qt::LinksAccessibleByKeyboard or Qt::TextSelectableByKeyboard then the focus policy is also automatically set to Qt::ClickFocus.
The default value depends on whether the QTextEdit is read-only or editable, and whether it is a QTextBrowser or not.
This property was introduced in Qt 4.2.
Access functions:
This property holds whether undo and redo are enabled.
Users are only able to undo or redo actions if this property is true, and if there is an action that can be undone (or redone).
Access functions:
This property holds the mode QTextEdit will use when wrapping text by words.
Access functions:
See also QTextOption::WrapMode.
Constructs an empty QTextEdit with parent parent.
Constructs a QTextEdit with parent parent. The text edit will display the text text. The text is interpreted as html.
Destructor.
Returns the alignment of the current paragraph.
See also setAlignment().
Returns the reference of the anchor at position pos, or an empty string if no anchor exists at that point.
Appends a new paragraph with text to the end of the text edit.
Note: The new paragraph appended will have the same character format and block format as the current paragraph, determined by the position of the cursor.
See also currentCharFormat() and QTextCursor::blockFormat().
This function returns true if the contents of the MIME data object, specified by source, can be decoded and inserted into the document. It is called for example when during a drag operation the mouse enters this widget and it is necessary to determine whether it is possible to accept the drag and drop operation.
Reimplement this function to enable drag and drop support for additional MIME types.
Returns whether text can be pasted from the clipboard into the textedit.
This function was introduced in Qt 4.2.
Deletes all the text in the text edit.
Note that the undo/redo history is cleared by this function.
See also cut(), setPlainText(), and setHtml().
Shows the standard context menu created with createStandardContextMenu().
If you do not want the text edit to have a context menu, you can set its contextMenuPolicy to Qt::NoContextMenu. If you want to customize the context menu, reimplement this function. If you want to extend the standard context menu, reimplement this function, call createStandardContextMenu() and extend the menu returned.
Information about the event is passed in the event object.
void MyTextEdit::contextMenuEvent(QContextMenuEvent *event)
{
QMenu *menu = createStandardContextMenu();
menu->addAction(tr("My Menu Item"));
//...
menu->exec(event->globalPos());
delete menu;
}
Reimplemented from QWidget.
Copies any selected text to the clipboard.
See also copyAvailable().
This signal is emitted when text is selected or de-selected in the text edit.
When text is selected this signal will be emitted with yes set to true. If no text has been selected or if the selected text is de-selected this signal is emitted with yes set to false.
If yes is true then copy() can be used to copy the selection to the clipboard. If yes is false then copy() does nothing.
See also selectionChanged().
This function returns a new MIME data object to represent the contents of the text edit's current selection. It is called when the selection needs to be encapsulated into a new QMimeData object; for example, when a drag and drop operation is started, or when data is copyied to the clipboard.
If you reimplement this function, note that the ownership of the returned QMimeData object is passed to the caller. The selection can be retrieved by using the textCursor() function.
This function creates the standard context menu which is shown when the user clicks on the line edit with the right mouse button. It is called from the default contextMenuEvent() handler. The popup menu's ownership is transferred to the caller.
Returns the char format that is used when inserting new text.
See also setCurrentCharFormat().
This signal is emitted if the current character format has changed, for example caused by a change of the cursor position.
The new format is f.
See also setCurrentCharFormat().
Returns the font of the current format.
See also setCurrentFont(), setFontFamily(), and setFontPointSize().
returns a QTextCursor at position pos (in viewport coordinates).
This signal is emitted whenever the position of the cursor changed.
returns a rectangle (in viewport coordinates) that includes the cursor.
This is an overloaded member function, provided for convenience.
returns a rectangle (in viewport coordinates) that includes the cursor of the text edit.
Copies the selected text to the clipboard and deletes it from the text edit.
If there is no selected text nothing happens.
Returns a pointer to the underlying document.
See also setDocument().
Ensures that the cursor is visible by scrolling the text edit if necessary.
Returns previously set extra selections.
This function was introduced in Qt 4.2.
See also setExtraSelections().
Finds the next occurrence of the string, exp, using the given options. Returns true if exp was found and changes the cursor to select the match; otherwise returns false.
Returns the font family of the current format.
See also setFontFamily(), setCurrentFont(), and setFontPointSize().
Returns true if the font of the current format is italic; otherwise returns false.
See also setFontItalic().
Returns the point size of the font of the current format.
See also setFontFamily(), setCurrentFont(), and setFontPointSize().
Returns true if the font of the current format is underlined; otherwise returns false.
See also setFontUnderline().
Returns the font weight of the current format.
See also setFontWeight(), setCurrentFont(), setFontPointSize(), and QFont::Weight.
This function inserts the contents of the MIME data object, specified by source, into the text edit at the current cursor position. It is called whenever text is inserted as the result of a clipboard paste operation, or when the text edit accepts data from a drag and drop operation.
Reimplement this function to enable drag and drop support for additional MIME types.
Convenience slot that inserts text which is assumed to be of html formatting at the current cursor position.
It is equivalent to:
edit->textCursor().insertHtml(fragment);
Note: When using this function with a style sheet, the style sheet will only apply to the current block in the document. In order to apply a style sheet throughout a document, use QTextDocument::setDefaultStyleSheet() instead.
Convenience slot that inserts text at the current cursor position.
It is equivalent to
edit->textCursor().insertText(text);
Loads the resource specified by the given type and name.
This function is an extension of QTextDocument::loadResource().
See also QTextDocument::loadResource().
Merges the properties specified in modifier into the current character format by calling QTextCursor::mergeCharFormat on the editor's cursor. If the editor has a selection then the properties of modifier are directly applied to the selection.
See also QTextCursor::mergeCharFormat().
Moves the cursor by performing the given operation.
If mode is QTextCursor::KeepAnchor, the cursor selects the text it moves over. This is the same effect that the user achieves when they hold down the Shift key and move the cursor with the cursor keys.
This function was introduced in Qt 4.2.
See also QTextCursor::movePosition().
Pastes the text from the clipboard into the text edit at the current cursor position.
If there is no text in the clipboard nothing happens.
To change the behavior of this function, i.e. to modify what QTextEdit can paste and how it is being pasted, reimplement the virtual canInsertFromMimeData() and insertFromMimeData() functions.
Convenience function to print the text edit's document to the given printer. This is equivalent to calling the print method on the document directly except that this function also supports QPrinter::Selection as print range.
This function was introduced in Qt 4.3.
See also QTextDocument::print().
Redoes the last operation.
If there is no operation to redo, i.e. there is no redo step in the undo/redo history, nothing happens.
This function was introduced in Qt 4.2.
See also undo().
This signal is emitted whenever redo operations become available (available is true) or unavailable (available is false).
Scrolls the text edit so that the anchor with the given name is visible; does nothing if the name is empty, or is already visible, or isn't found.
Selects all text.
See also copy(), cut(), and textCursor().
This signal is emitted whenever the selection changes.
See also copyAvailable().
Sets the alignment of the current paragraph to a. Valid alignments are Qt::AlignLeft, Qt::AlignRight, Qt::AlignJustify and Qt::AlignCenter (which centers horizontally).
See also alignment().
Sets the char format that is be used when inserting new text to format by calling QTextCursor::setCharFormat() on the editor's cursor. If the editor has a selection then the char format is directly applied to the selection.
See also currentCharFormat().
Sets the font of the current format to f.
See also currentFont(), setFontPointSize(), and setFontFamily().
Makes document the new document of the text editor.
The parent QObject of the provided document remains the owner of the object. If the current document is a child of the text editor, then it is deleted.
See also document().
This function allows temporarily marking certain regions in the document with a given color, specified as selections. This can be useful for example in a programming editor to mark a whole line of text with a given background color to indicate the existence of a breakpoint.
This function was introduced in Qt 4.2.
See also QTextEdit::ExtraSelection and extraSelections().
Sets the font family of the current format to fontFamily.
See also fontFamily() and setCurrentFont().
If italic is true, sets the current format to italic; otherwise sets the current format to non-italic.
See also fontItalic().
Sets the point size of the current format to s.
Note that if s is zero or negative, the behavior of this function is not defined.
See also fontPointSize(), setCurrentFont(), and setFontFamily().
If underline is true, sets the current format to underline; otherwise sets the current format to non-underline.
See also fontUnderline().
Sets the font weight of the current format to the given weight, where the value used is in the range defined by the QFont::Weight enum.
See also fontWeight(), setCurrentFont(), and setFontFamily().
Sets the text edit's text. The text can be plain text or HTML and the text edit will try to guess the right format.
Use setHtml() or setPlainText() directly to avoid text edit's guessing.
This function was introduced in Qt 4.2.
See also text().
Sets the text color of the current format to c.
See also textColor().
Sets the visible cursor.
See also textCursor().
This signal is emitted whenever the document's content changes; for example, when text is inserted or deleted, or when formatting is applied.
Returns the text color of the current format.
See also setTextColor().
Returns a copy of the QTextCursor that represents the currently visible cursor. Note that changes on the returned cursor do not affect QTextEdit's cursor; use setTextCursor() to update the visible cursor.
See also setTextCursor().
Undoes the last operation.
If there is no operation to undo, i.e. there is no undo step in the undo/redo history, nothing happens.
This function was introduced in Qt 4.2.
See also redo().
This signal is emitted whenever undo operations become available (available is true) or unavailable (available is false).
Zooms in on the text by making the base font size range points larger and recalculating all font sizes to be the new size. This does not change the size of any images.
See also zoomOut().
Zooms out on the text by making the base font size range points smaller and recalculating all font sizes to be the new size. This does not change the size of any images.
See also zoomIn().
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