invalid property assignment unsupported type qfont

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• Qt Development
• QML and Qt Quick

MenuBarStyle, setting the font

Need to change the font of a Menubar. However, this code doen`t seem to work

The error is: qrc:/MainWindow.qml:51 Invalid property assignment: unsupported type "QFont"

What am I missing?

Hi! The correct way to do it is either like this:

or like that:

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The QFont class specifies a query for a font used for drawing text. More …

def __init__()

def capitalization()

def clearFeatures()

def clearVariableAxes()

def defaultFamily()

def exactMatch()

def families()

def family()

def featureTags()

def featureValue()

def fixedPitch()

def fromString()

def hintingPreference()

def isCopyOf()

def isFeatureSet()

def isVariableAxisSet()

def italic()

def kerning()

def legacyWeight()

def letterSpacing()

def letterSpacingType()

def __ne__()

def __lt__()

def __eq__()

def overline()

def pixelSize()

def pointSize()

def pointSizeF()

def resolve()

def resolveMask()

def setBold()

def setCapitalization()

def setFamilies()

def setFamily()

def setFeature()

def setFixedPitch()

def setHintingPreference()

def setItalic()

def setKerning()

def setLegacyWeight()

def setLetterSpacing()

def setOverline()

def setPixelSize()

def setPointSize()

def setPointSizeF()

def setResolveMask()

def setStretch()

def setStrikeOut()

def setStyle()

def setStyleHint()

def setStyleName()

def setStyleStrategy()

def setUnderline()

def setVariableAxis()

def setWeight()

def setWordSpacing()

def stretch()

def strikeOut()

def style()

def styleHint()

def styleName()

def styleStrategy()

def toString()

def underline()

def unsetFeature()

def unsetVariableAxis()

def variableAxisTags()

def variableAxisValue()

def weight()

def wordSpacing()

Static functions #

def cacheStatistics()

def cleanup()

def initialize()

def insertSubstitution()

def insertSubstitutions()

def removeSubstitutions()

def substitute()

def substitutes()

def substitutions()

This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE

Detailed Description #

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

QFont can be regarded as a query for one or more fonts on the system.

When you create a QFont object you specify various attributes that you want the font to have. Qt will use the font with the specified attributes, or if no matching font exists, Qt will use the closest matching installed font. The attributes of the font that is actually used are retrievable from a QFontInfo object. If the window system provides an exact match exactMatch() returns true . Use QFontMetricsF to get measurements, e.g. the pixel length of a string using QFontMetrics::width().

Attributes which are not specifically set will not affect the font selection algorithm, and default values will be preferred instead.

To load a specific physical font, typically represented by a single file, use QRawFont instead.

Note that a QGuiApplication instance must exist before a QFont can be used. You can set the application’s default font with QGuiApplication::setFont().

If a chosen font does not include all the characters that need to be displayed, QFont will try to find the characters in the nearest equivalent fonts. When a QPainter draws a character from a font the QFont will report whether or not it has the character; if it does not, QPainter will draw an unfilled square.

Create QFonts like this:

serifFont = QFont ( "Times" , 10 , QFont . Bold ) sansFont = QFont ( "Helvetica [Cronyx]" , 12 )

The attributes set in the constructor can also be set later, e.g. setFamily() , setPointSize() , setPointSizeF() , setWeight() and setItalic() . The remaining attributes must be set after construction, e.g. setBold() , setUnderline() , setOverline() , setStrikeOut() and setFixedPitch() . QFontInfo objects should be created after the font’s attributes have been set. A QFontInfo object will not change, even if you change the font’s attributes. The corresponding “get” functions, e.g. family() , pointSize() , etc., return the values that were set, even though the values used may differ. The actual values are available from a QFontInfo object.

If the requested font family is unavailable you can influence the font matching algorithm by choosing a particular StyleHint and StyleStrategy with setStyleHint() . The default family (corresponding to the current style hint) is returned by defaultFamily() .

You can provide substitutions for font family names using insertSubstitution() and insertSubstitutions() . Substitutions can be removed with removeSubstitutions() . Use substitute() to retrieve a family’s first substitute, or the family name itself if it has no substitutes. Use substitutes() to retrieve a list of a family’s substitutes (which may be empty). After substituting a font, you must trigger the updating of the font by destroying and re-creating all QFont objects.

Every QFont has a key() which you can use, for example, as the key in a cache or dictionary. If you want to store a user’s font preferences you could use QSettings, writing the font information with toString() and reading it back with fromString() . The operator<<() and operator>>() functions are also available, but they work on a data stream.

It is possible to set the height of characters shown on the screen to a specified number of pixels with setPixelSize() ; however using setPointSize() has a similar effect and provides device independence.

Loading fonts can be expensive, especially on X11. QFont contains extensive optimizations to make the copying of QFont objects fast, and to cache the results of the slow window system functions it depends upon.

The font matching algorithm works as follows:

The specified font families (set by setFamilies() ) are searched for. If not, a replacement font that supports the writing system is selected. The font matching algorithm will try to find the best match for all the properties set in the QFont . How this is done varies from platform to platform. If no font exists on the system that can support the text, then special “missing character” boxes will be shown in its place.

If the selected font, though supporting the writing system in general, is missing glyphs for one or more specific characters, then Qt will try to find a fallback font for this or these particular characters. This feature can be disabled using NoFontMerging style strategy.

In Windows a request for the “Courier” font is automatically changed to “Courier New”, an improved version of Courier that allows for smooth scaling. The older “Courier” bitmap font can be selected by setting the PreferBitmap style strategy (see setStyleStrategy() ).

Once a font is found, the remaining attributes are matched in order of priority:

fixedPitch() pointSize() (see below) weight() style()

If you have a font which matches on family, even if none of the other attributes match, this font will be chosen in preference to a font which doesn’t match on family but which does match on the other attributes. This is because font family is the dominant search criteria.

The point size is defined to match if it is within 20% of the requested point size. When several fonts match and are only distinguished by point size, the font with the closest point size to the one requested will be chosen.

The actual family, font size, weight and other font attributes used for drawing text will depend on what’s available for the chosen family under the window system. A QFontInfo object can be used to determine the actual values used for drawing the text.

f = QFont ( "Helvetica" )

If you had both an Adobe and a Cronyx Helvetica, you might get either.

f = QFont ( "Helvetica [Cronyx]" )

You can specify the foundry you want in the family name. The font f in the above example will be set to “Helvetica [Cronyx]”.

To determine the attributes of the font actually used in the window system, use a QFontInfo object, e.g.

info = QFontInfo ( f1 ) family = info . family ()

To find out font metrics use a QFontMetrics object, e.g.

fm = QFontMetrics ( f1 ) textWidthInPixels = fm . horizontalAdvance ( "How many pixels wide is self text?" ) textHeightInPixels = fm . height ()

For more general information on fonts, see the comp.fonts FAQ . Information on encodings can be found from the UTR17 page.

See also QFontMetrics QFontInfo QFontDatabase

Style hints are used by the font matching algorithm to find an appropriate default family if a selected font family is not available.

Constant Description QFont.AnyStyle leaves the font matching algorithm to choose the family. This is the default. QFont.SansSerif the font matcher prefer sans serif fonts. QFont.Helvetica is a synonym for SansSerif . QFont.Serif the font matcher prefers serif fonts. QFont.Times is a synonym for Serif . QFont.TypeWriter the font matcher prefers fixed pitch fonts. QFont.Courier a synonym for TypeWriter . QFont.OldEnglish the font matcher prefers decorative fonts. QFont.Decorative is a synonym for OldEnglish . QFont.Monospace the font matcher prefers fonts that map to the CSS generic font-family ‘monospace’. QFont.Fantasy the font matcher prefers fonts that map to the CSS generic font-family ‘fantasy’. QFont.Cursive the font matcher prefers fonts that map to the CSS generic font-family ‘cursive’. QFont.System the font matcher prefers system fonts.

(inherits enum.Flag ) The style strategy tells the font matching algorithm what type of fonts should be used to find an appropriate default family.

The following strategies are available:

Constant Description QFont.PreferDefault the default style strategy. It does not prefer any type of font. QFont.PreferBitmap prefers bitmap fonts (as opposed to outline fonts). QFont.PreferDevice prefers device fonts. QFont.PreferOutline prefers outline fonts (as opposed to bitmap fonts). QFont.ForceOutline forces the use of outline fonts. QFont.NoAntialias don’t antialias the fonts. QFont.NoSubpixelAntialias avoid subpixel antialiasing on the fonts if possible. QFont.PreferAntialias antialias if possible. QFont.NoFontMerging If the font selected for a certain writing system does not contain a character requested to draw, then Qt automatically chooses a similar looking font that contains the character. The NoFontMerging flag disables this feature. Please note that enabling this flag will not prevent Qt from automatically picking a suitable font when the selected font does not support the writing system of the text. QFont.PreferNoShaping Sometimes, a font will apply complex rules to a set of characters in order to display them correctly. In some writing systems, such as Brahmic scripts, this is required in order for the text to be legible, but in e.g. Latin script, it is merely a cosmetic feature. The PreferNoShaping flag will disable all such features when they are not required, which will improve performance in most cases (since Qt 5.10).

Any of these may be OR-ed with one of these flags:

Constant Description QFont.PreferMatch prefer an exact match. The font matcher will try to use the exact font size that has been specified. QFont.PreferQuality prefer the best quality font. The font matcher will use the nearest standard point size that the font supports.

This enum describes the different levels of hinting that can be applied to glyphs to improve legibility on displays where it might be warranted by the density of pixels.

Constant Description QFont.PreferDefaultHinting Use the default hinting level for the target platform. QFont.PreferNoHinting If possible, render text without hinting the outlines of the glyphs. The text layout will be typographically accurate and scalable, using the same metrics as are used e.g. when printing. QFont.PreferVerticalHinting If possible, render text with no horizontal hinting, but align glyphs to the pixel grid in the vertical direction. The text will appear crisper on displays where the density is too low to give an accurate rendering of the glyphs. But since the horizontal metrics of the glyphs are unhinted, the text’s layout will be scalable to higher density devices (such as printers) without impacting details such as line breaks. QFont.PreferFullHinting If possible, render text with hinting in both horizontal and vertical directions. The text will be altered to optimize legibility on the target device, but since the metrics will depend on the target size of the text, the positions of glyphs, line breaks, and other typographical detail will not scale, meaning that a text layout may look different on devices with different pixel densities.

Please note that this enum only describes a preference, as the full range of hinting levels are not supported on all of Qt’s supported platforms. The following table details the effect of a given hinting preference on a selected set of target platforms.

PreferDefaultHinting PreferNoHinting PreferVerticalHinting PreferFullHinting Windows and DirectWrite enabled in Qt Full hinting Vertical hinting Vertical hinting Full hinting FreeType Operating System setting No hinting Vertical hinting (light) Full hinting Cocoa on macOS No hinting No hinting No hinting No hinting

New in version 4.8.

(inherits enum.IntEnum ) Qt uses a weighting scale from 1 to 1000 compatible with OpenType. A weight of 1 will be thin, whilst 1000 will be extremely black.

This enum contains the predefined font weights:

Constant Description QFont.Thin 100 QFont.ExtraLight 200 QFont.Light 300 QFont.Normal 400 QFont.Medium 500 QFont.DemiBold 600 QFont.Bold 700 QFont.ExtraBold 800 QFont.Black 900

This enum describes the different styles of glyphs that are used to display text.

Constant Description QFont.StyleNormal Normal glyphs used in unstyled text. QFont.StyleItalic Italic glyphs that are specifically designed for the purpose of representing italicized text. QFont.StyleOblique Glyphs with an italic appearance that are typically based on the unstyled glyphs, but are not fine-tuned for the purpose of representing italicized text. See also Weight

(inherits enum.IntEnum ) Predefined stretch values that follow the CSS naming convention. The higher the value, the more stretched the text is.

Constant Description QFont.AnyStretch 0 Accept any stretch matched using the other QFont properties (added in Qt 5.8) QFont.UltraCondensed 50 QFont.ExtraCondensed 62 QFont.Condensed 75 QFont.SemiCondensed 87 QFont.Unstretched 100 QFont.SemiExpanded 112 QFont.Expanded 125 QFont.ExtraExpanded 150 QFont.UltraExpanded 200 See also setStretch() stretch()

Rendering option for text this font applies to.

Constant Description QFont.MixedCase This is the normal text rendering option where no capitalization change is applied. QFont.AllUppercase This alters the text to be rendered in all uppercase type. QFont.AllLowercase This alters the text to be rendered in all lowercase type. QFont.SmallCaps This alters the text to be rendered in small-caps type. QFont.Capitalize This alters the text to be rendered with the first character of each word as an uppercase character.

font – QFont

Constructs a font that is a copy of font .

Constructs a font object that uses the application’s default font.

See also font()

families – list of strings

pointSize – int

weight – int

italic – bool

Constructs a font object with the specified families , pointSize , weight and italic settings.

If pointSize is zero or negative, the point size of the font is set to a system-dependent default value. Generally, this is 12 points.

Each family name entry in families may optionally also include a foundry name, e.g. “Helvetica [Cronyx]”. If the family is available from more than one foundry and the foundry isn’t specified, an arbitrary foundry is chosen. If the family isn’t available a family will be set using the font matching algorithm.

See also Weight setPointSize() setWeight() setItalic() setStyleHint() setFamilies() font()

pd – QPaintDevice

Constructs a font from font for use on the paint device pd .

family – str

Constructs a font object with the specified family , pointSize , weight and italic settings.

The family name may optionally also include a foundry name, e.g. “Helvetica [Cronyx]”. If the family is available from more than one foundry and the foundry isn’t specified, an arbitrary foundry is chosen. If the family isn’t available a family will be set using the font matching algorithm.

This will split the family string on a comma and call setFamilies() with the resulting list. To preserve a font that uses a comma in its name, use the constructor that takes a QStringList.

See also Weight setFamily() setPointSize() setWeight() setItalic() setStyleHint() setFamilies() font()

Returns true if weight() is a value greater than Medium ; otherwise returns false .

See also weight() setBold() bold()

Capitalization

Returns the current capitalization type of the font.

See also setCapitalization()

Clears any previously set features on the QFont .

See setFeature() for more details on font features.

See also Tag setFeature() unsetFeature() featureTags() featureValue()

Clears any previously set variable axis values on the QFont .

See setVariableAxis() for more details on variable axes.

See also Tag setVariableAxis() unsetVariableAxis() isVariableAxisSet() variableAxisValue()

Returns the family name that corresponds to the current style hint.

See also StyleHint styleHint() setStyleHint()

Returns true if a window system font exactly matching the settings of this font is available.

See also QFontInfo

list of strings

Returns the requested font family names, i.e. the names set in the last setFamilies() call or via the constructor. Otherwise it returns an empty list.

See also setFamily() setFamilies() family() substitutes() substitute()

Returns the requested font family name. This will always be the same as the first entry in the families() call.

See also setFamily() substitutes() substitute() setFamilies() families()

.list of QFont.Tag

Returns a list of tags for all font features currently set on this QFont .

See also Tag setFeature() unsetFeature() isFeatureSet() clearFeatures()

Returns the value set for a specific feature tag . If the tag has not been set, 0 will be returned instead.

See also Tag setFeature() unsetFeature() featureTags() isFeatureSet()

Returns true if fixed pitch has been set; otherwise returns false .

See also setFixedPitch() fixedPitch()

arg__1 – str

Sets this font to match the description descrip . The description is a comma-separated list of the font attributes, as returned by toString() .

See also toString()

HintingPreference

Returns the currently preferred hinting level for glyphs rendered with this font.

See also setHintingPreference()

arg__2 – str

Inserts substituteName into the substitution table for the family familyName .

After substituting a font, trigger the updating of the font by destroying and re-creating all QFont objects.

See also insertSubstitutions() removeSubstitutions() substitutions() substitute() substitutes()

arg__2 – list of strings

Inserts the list of families substituteNames into the substitution list for familyName .

See also insertSubstitution() removeSubstitutions() substitutions() substitute()

arg__1 – QFont

Returns true if this font and f are copies of each other, i.e. one of them was created as a copy of the other and neither has been modified since. This is much stricter than equality.

See also operator=() operator==()

Returns true if a value for the feature given by tag has been set on the QFont , otherwise returns false.

Returns true if a value for the variable axis given by tag has been set on the QFont , otherwise returns false.

See setVariableAxis() for more details on font variable axes.

See also Tag setVariableAxis() unsetVariableAxis() variableAxisValue() clearVariableAxes()

Returns true if the style() of the font is not StyleNormal

See also setItalic() style()

Returns true if kerning should be used when drawing text with this font.

See also setKerning()

Returns the font’s key, a textual representation of a font. It is typically used as the key for a cache or dictionary of fonts.

See also QMap

This function is deprecated.

Use weight() instead.

Returns the weight of the font converted to the non-standard font weight scale used in Qt 5 and earlier versions.

Since Qt 6, the OpenType standard’s font weight scale is used instead of a non-standard scale. This requires conversion from values that use the old scale. For convenience, this function may be used when porting from code which uses the old weight scale.

See also setLegacyWeight() setWeight() weight() QFontInfo

Returns the letter spacing for the font.

See also setLetterSpacing() letterSpacingType() setWordSpacing()

SpacingType

Returns the spacing type used for letter spacing.

See also letterSpacing() setLetterSpacing() setWordSpacing()

Returns true if this font is different from f ; otherwise returns false .

Two QFonts are considered to be different if their font attributes are different.

See also operator==()

Provides an arbitrary comparison of this font and font f . All that is guaranteed is that the operator returns false if both fonts are equal and that (f1 < f2) == !(f2 < f1) if the fonts are not equal.

This function is useful in some circumstances, for example if you want to use QFont objects as keys in a QMap.

See also operator==() operator!=() isCopyOf()

Returns true if this font is equal to f ; otherwise returns false.

Two QFonts are considered equal if their font attributes are equal.

See also operator!=() isCopyOf()

Returns true if overline has been set; otherwise returns false .

See also setOverline()

Returns the pixel size of the font if it was set with setPixelSize() . Returns -1 if the size was set with setPointSize() or setPointSizeF() .

See also setPixelSize() pointSize() pointSize() pixelSize()

Returns the point size of the font. Returns -1 if the font size was specified in pixels.

See also setPointSize() pointSizeF()

See also pointSize() setPointSizeF() pixelSize() pointSize() pixelSize()

Removes all the substitutions for familyName .

See also insertSubstitutions() insertSubstitution() substitutions() substitute()

Returns a new QFont that has attributes copied from other that have not been previously set on this font.

arg__1 – bool

If enable is true sets the font’s weight to Bold ; otherwise sets the weight to Normal .

For finer boldness control use setWeight() .

If styleName() is set, this value may be ignored, or if supported on the platform, the font artificially embolded.

bold() setWeight()

arg__1 – Capitalization

Sets the capitalization of the text in this font to caps .

A font’s capitalization makes the text appear in the selected capitalization mode.

See also capitalization()

arg__1 – list of strings

Sets the list of family names for the font. The names are case insensitive and may include a foundry name. The first family in families will be set as the main family for the font.

See also family() families() setFamily() setStyleHint() QFontInfo

Sets the family name of the font. The name is case insensitive and may include a foundry name.

See also family() setStyleHint() setFamilies() families() QFontInfo

value – int

This is an overloaded function.

Applies an integer value to the typographical feature specified by tag when shaping the text. This provides advanced access to the font shaping process, and can be used to support font features that are otherwise not covered in the API.

The feature is specified by a tag , which is typically encoded from the four-character feature name in the font feature map.

This integer value passed along with the tag in most cases represents a boolean value: A zero value means the feature is disabled, and a non-zero value means it is enabled. For certain font features, however, it may have other interpretations. For example, when applied to the salt feature, the value is an index that specifies the stylistic alternative to use.

For example, the frac font feature will convert diagonal fractions separated with a slash (such as 1/2 ) with a different representation. Typically this will involve baking the full fraction into a single character width (such as ½ ).

If a font supports the frac feature, then it can be enabled in the shaper by setting features["frac"] = 1 in the font feature map.

By default, Qt will enable and disable certain font features based on other font properties. In particular, the kern feature will be enabled/disabled depending on the kerning() property of the QFont . In addition, all ligature features ( liga , clig , dlig , hlig ) will be disabled if a letterSpacing() is applied, but only for writing systems where the use of ligature is cosmetic. For writing systems where ligatures are required, the features will remain in their default state. The values set using setFeature() and related functions will override the default behavior. If, for instance, the feature “kern” is set to 1, then kerning will always be enabled, regardless of whether the kerning property is set to false. Similarly, if it is set to 0, then it will always be disabled. To reset a font feature to its default behavior, you can unset it using unsetFeature() .

Tag clearFeatures() unsetFeature() featureTags()

If enable is true, sets fixed pitch on; otherwise sets fixed pitch off.

See also fixedPitch() QFontInfo

hintingPreference – HintingPreference

Set the preference for the hinting level of the glyphs to hintingPreference . This is a hint to the underlying font rendering system to use a certain level of hinting, and has varying support across platforms. See the table in the documentation for HintingPreference for more details.

The default hinting preference is PreferDefaultHinting .

See also hintingPreference()

Sets the style() of the font to StyleItalic if enable is true; otherwise the style is set to StyleNormal .

If styleName() is set, this value may be ignored, or if supported on the platform, the font may be rendered tilted instead of picking a designed italic font-variant.

italic() QFontInfo

Enables kerning for this font if enable is true; otherwise disables it. By default, kerning is enabled.

When kerning is enabled, glyph metrics do not add up anymore, even for Latin text. In other words, the assumption that width(‘a’) + width(‘b’) is equal to width(“ab”) is not necessarily true.

See also kerning() QFontMetrics

legacyWeight – int

Use setWeight() instead.

Sets the weight of the font to legacyWeight using the legacy font weight scale of Qt 5 and previous versions.

If styleName() is set, this value may be ignored for font selection.

legacyWeight() setWeight() weight() QFontInfo

type – SpacingType

spacing – float

Sets the letter spacing for the font to spacing and the type of spacing to type .

Letter spacing changes the default spacing between individual letters in the font. The spacing between the letters can be made smaller as well as larger either in percentage of the character width or in pixels, depending on the selected spacing type.

See also letterSpacing() letterSpacingType() setWordSpacing()

If enable is true, sets overline on; otherwise sets overline off.

See also overline() QFontInfo

arg__1 – int

Sets the font size to pixelSize pixels, with a maxiumum size of an unsigned 16-bit integer.

Using this function makes the font device dependent. Use setPointSize() or setPointSizeF() to set the size of the font in a device independent manner.

See also pixelSize()

Sets the point size to pointSize . The point size must be greater than zero.

See also pointSize() setPointSizeF()

arg__1 – float

Sets the point size to pointSize . The point size must be greater than zero. The requested precision may not be achieved on all platforms.

See also pointSizeF() setPointSize() setPixelSize()

Sets the stretch factor for the font.

The stretch factor matches a condensed or expanded version of the font or applies a stretch transform that changes the width of all characters in the font by factor percent. For example, setting factor to 150 results in all characters in the font being 1.5 times (ie. 150%) wider. The minimum stretch factor is 1, and the maximum stretch factor is 4000. The default stretch factor is AnyStretch , which will accept any stretch factor and not apply any transform on the font.

The stretch factor is only applied to outline fonts. The stretch factor is ignored for bitmap fonts.

When matching a font with a native non-default stretch factor, requesting a stretch of 100 will stretch it back to a medium width font.

stretch() Stretch

If enable is true, sets strikeout on; otherwise sets strikeout off.

See also strikeOut() QFontInfo

style – Style

Sets the style of the font to style .

See also style() italic() QFontInfo

arg__1 – StyleHint

strategy – StyleStrategy

Sets the style hint and strategy to hint and strategy , respectively.

If these aren’t set explicitly the style hint will default to AnyStyle and the style strategy to PreferDefault .

Qt does not support style hints on X11 since this information is not provided by the window system.

See also StyleHint styleHint() StyleStrategy styleStrategy() QFontInfo

Sets the style name of the font to styleName . When set, other style properties like style() and weight() will be ignored for font matching, though they may be simulated afterwards if supported by the platform’s font engine.

Due to the lower quality of artificially simulated styles, and the lack of full cross platform support, it is not recommended to use matching by style name together with matching by style properties

See also styleName()

s – StyleStrategy

Sets the style strategy for the font to s .

See also styleStrategy() StyleStrategy

If enable is true, sets underline on; otherwise sets underline off.

See also underline() QFontInfo

value – float

Applies a value to the variable axis corresponding to tag .

Variable fonts provide a way to store multiple variations (with different weights, widths or styles) in the same font file. The variations are given as floating point values for a pre-defined set of parameters, called “variable axes”. Specific instances are typically given names by the font designer, and, in Qt, these can be selected using setStyleName() just like traditional sub-families.

In some cases, it is also useful to provide arbitrary values for the different axes. For instance, if a font has a Regular and Bold sub-family, you may want a weight in-between these. You could then manually request this by supplying a custom value for the “wght” axis in the font.

QFont font ; font . setVariableAxis ( "wght" , ( QFont :: Normal + QFont :: Bold ) / 2.0 f );

If the “wght” axis is supported by the font and the given value is within its defined range, a font corresponding to the weight 550.0 will be provided.

There are a few standard axes than many fonts provide, such as “wght” (weight), “wdth” (width), “ital” (italic) and “opsz” (optical size). They each have indivdual ranges defined in the font itself. For instance, “wght” may span from 100 to 900 ( Thin to Black ) whereas “ital” can span from 0 to 1 (from not italic to fully italic).

A font may also choose to define custom axes; the only limitation is that the name has to meet the requirements for a Tag (sequence of four latin-1 characters.)

By default, no variable axes are set.

In order to use variable axes on Windows, the application has to run with either the FreeType or DirectWrite font databases. See the documentation for QGuiApplication() for more information on how to select these technologies.

unsetVariableAxis

weight – Weight

Sets the weight of the font to weight , using the scale defined by Weight enumeration.

weight() QFontInfo

Sets the word spacing for the font to spacing .

Word spacing changes the default spacing between individual words. A positive value increases the word spacing by a corresponding amount of pixels, while a negative value decreases the inter-word spacing accordingly.

Word spacing will not apply to writing systems, where indiviaul words are not separated by white space.

See also wordSpacing() setLetterSpacing()

Returns the stretch factor for the font.

See also setStretch()

Returns true if strikeout has been set; otherwise returns false .

See also setStrikeOut()

Returns the style of the font.

See also setStyle()

Returns the StyleHint .

The style hint affects the font matching algorithm . See StyleHint for the list of available hints.

See also setStyleHint() StyleStrategy styleHint()

Returns the requested font style name. This can be used to match the font with irregular styles (that can’t be normalized in other style properties).

See also setStyleName() setFamily() setStyle()

StyleStrategy

Returns the StyleStrategy .

The style strategy affects the font matching algorithm. See StyleStrategy for the list of available strategies.

See also setStyleStrategy() setStyleHint() StyleHint

Returns the first family name to be used whenever familyName is specified. The lookup is case insensitive.

If there is no substitution for familyName , familyName is returned.

To obtain a list of substitutions use substitutes() .

See also setFamily() insertSubstitutions() insertSubstitution() removeSubstitutions()

Returns a list of family names to be used whenever familyName is specified. The lookup is case insensitive.

If there is no substitution for familyName , an empty list is returned.

See also substitute() insertSubstitutions() insertSubstitution() removeSubstitutions()

Returns a sorted list of substituted family names.

See also insertSubstitution() removeSubstitutions() substitute()

other – QFont

Swaps this font instance with other . This function is very fast and never fails.

Returns a description of the font. The description is a comma-separated list of the attributes, perfectly suited for use in QSettings, and consists of the following:

Font family Point size Pixel size Style hint Font weight Font style Underline Strike out Fixed pitch Always 0 Capitalization Letter spacing Word spacing Stretch Style strategy Font style (omitted when unavailable) See also fromString()

Returns true if underline has been set; otherwise returns false .

See also setUnderline()

Unsets the tag from the map of explicitly enabled/disabled features.

Even if the feature has not previously been added, this will mark the font features map as modified in this QFont , so that it will take precedence when resolving against other fonts.

Unsetting an existing feature on the QFont reverts behavior to the default.

See also Tag clearFeatures() setFeature() featureTags() featureValue()

Unsets a previously set variable axis value given by tag .

If no value has previously been given for this tag, the QFont will still consider its variable axes as set when resolving against other QFont values.

setVariableAxis

Returns a list of tags for all variable axes currently set on this QFont .

See also Tag setVariableAxis() unsetVariableAxis() isVariableAxisSet() clearVariableAxes()

Returns the value set for a specific variable axis tag . If the tag has not been set, 0.0 will be returned instead.

Returns the weight of the font, using the same scale as the Weight enumeration.

See also setWeight() Weight QFontInfo

Returns the word spacing for the font.

See also setWordSpacing() setLetterSpacing()

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"Invalid property assignment:.. read-only property" in Qml

I'm attempting to use a list property in Qml for an underlying C++ object. I would like to be able to read and write it. The documentation for QQmlListProperty says that only the READ function is implemented, and is used for reading and writing the object. I get the error message:

Invalid property assignment: "string" is a read-only property

when I try to run the app. Here are the relevant source files:

Any idea what I'm doing wrong?

QQmlListProperty can only be used for lists of QObject-derived object pointers.

Since a QStringList is transparently exposed to JavaScript as an array type, you can expose such a property directly in two ways:

As a Q_PROPERTY , with the caveat that modifications are expensive, since the entire string list is retrieved, then modified, then written back. For large lists this is slow.

As a reference returned from a Q_INVOKABLE method: the data is accessed directly.

• Is it the case that, for QQmlListProperty, I need to have a setter? I knew that QDeclarativeListProperty had the restriction that the list could not be written except as a whole, but the documentation for QQmlListProperty indicated that this restriction had been lifted: "The QQmlListProperty encapsulates a group of function pointers that represet the set of actions QML can perform on the list - adding items, retrieving items and clearing the list." So the essential question is, how do I enable QML to add an item to a QQmlListProperty, as the documentation says I ought to be able to do? –  Scott Deerwester Mar 11, 2014 at 11:32
• @ScottDeerwester As I've said in the first line of the answer: you can't use a QQmlListProperty with a non-QObject class. That's your problem. You use it with a QString, and it won't ever work. Your addString "setter" is correct, you simply use the QQmlListProperty with a class that it can't be used with. –  Kuba hasn't forgotten Monica Mar 11, 2014 at 12:02
• All right, I'm using QStringList for QStrings. Hopefully I'll be able to get other lists of QObject subclass pointers working with QQmlListProperty. –  Scott Deerwester Mar 16, 2014 at 2:15

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• QTBUG-80440

MqttClient Invalid Property assignment: unsupported type "ushort"

• Resolution: Done
• Fix Version/s: 6.4.1 , 6.5.0 Beta1 , 6.5
• Affects Version/s: 5.13.0 RC 3 , 5.15.11 , 6.2.6 , 6.3.1 , 6.4.0
• Component/s: MQTT
• Reported_by_support_2H22
• reported_by_support_standard

I think is same as described for other module here:  https://bugreports.qt.io/browse/QTBUG-46790

Make  Q_PROPERTY(quint16 port READ port WRITE setPort NOTIFY portChanged) to int with range check in getter/setter.

2. qrc:/main.qml:125 TypeError_ Propety 'destory' of object 0 is not a function

This I don't understand, maybe more experienced person know how to fix. 

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