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java.lang.Objectcom.trolltech.qt.QSignalEmitter
com.trolltech.qt.QtJambiObject
com.trolltech.qt.gui.QFont
public class QFont
The QFont class specifies a font used for drawing text.
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 QFontMetrics to get measurements, e.g. the pixel length of a string using QFontMetrics::width().
Use QApplication::setFont() to set the application's default font.
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:
QFont serifFont("Times", 10, QFont::Bold); QFont sansFont("Helvetica [Cronyx]", 12);
The attributes set in the constructor can also be set later, e.g. setFamily, setPointSize, setPointSizeFloat(), setWeight and setItalic. The remaining attributes must be set after contstruction, 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 QFont::StyleHint and QFont::StyleStrategy with setStyleHint. The default family (corresponding to the current style hint) is returned by defaultFamily.
The font-matching algorithm has a lastResortFamily and lastResortFont in cases where a suitable match cannot be found. You can provide substitutions for font family names using insertSubstitution and insertSubstitutions. Substitutions can be removed with removeSubstitution. 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).
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.
Under X11 you can set a font using its system specific name with setRawName.
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:
Note that the actual font matching algorithm varies from platform to platform.
Once a font is found, the remaining attributes are matched in order of priority:
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.
Examples:
QFont f("Helvetica");
If you had both an Adobe and a Cronyx Helvetica, you might get either.
QFont f("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.
QFontInfo info(f1); QString family = info.family();
To find out font metrics use a QFontMetrics object, e.g.
QFontMetrics fm(f1); int textWidthInPixels = fm.width("How many pixels wide is this text?"); int textHeightInPixels = fm.height();
For more general information on fonts, see the comp.fonts FAQ. Information on encodings can be found from Roman Czyborra's page.
Map Example
Nested Class Summary | |
---|---|
static class |
QFont.Stretch
Predefined stretch values that follow the CSS naming convention. |
static class |
QFont.Style
This enum describes the different styles of glyphs that are used to display text. |
static class |
QFont.StyleHint
Style hints are used by the font matching algorithm to find an appropriate default family if a selected font family is not available. |
static class |
QFont.StyleStrategy
The style strategy tells the font matching algorithm what type of fonts should be used to find an appropriate default family. |
static class |
QFont.Weight
Qt uses a weighting scale from 0 to 99 similar to, but not the same as, the scales used in Windows or CSS. |
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter |
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QSignalEmitter.AbstractSignal, QSignalEmitter.Signal0, QSignalEmitter.Signal1<A>, QSignalEmitter.Signal2<A,B>, QSignalEmitter.Signal3<A,B,C>, QSignalEmitter.Signal4<A,B,C,D>, QSignalEmitter.Signal5<A,B,C,D,E>, QSignalEmitter.Signal6<A,B,C,D,E,F>, QSignalEmitter.Signal7<A,B,C,D,E,F,G>, QSignalEmitter.Signal8<A,B,C,D,E,F,G,H>, QSignalEmitter.Signal9<A,B,C,D,E,F,G,H,I> |
Constructor Summary | |
---|---|
QFont()
Constructs a font object that uses the application's default font. |
|
QFont(QFont arg__1)
Constructs a font that is a copy of arg__1. |
|
QFont(QFont arg__1,
QPaintDeviceInterface pd)
Constructs a font from arg__1 for use on the paint device pd. |
|
QFont(java.lang.String family)
Equivalent to QFont(family, -1, -1, false). |
|
QFont(java.lang.String family,
int pointSize)
Equivalent to QFont(family, pointSize, -1, false). |
|
QFont(java.lang.String family,
int pointSize,
int weight)
Equivalent to QFont(family, pointSize, weight, false). |
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QFont(java.lang.String family,
int pointSize,
int weight,
boolean italic)
Constructs a font object with the specified family, pointSize, weight and italic settings. |
Method Summary | |
---|---|
boolean |
bold()
Returns true if weight is a value greater than QFont::Normal; otherwise returns false. |
static void |
cleanup()
|
int |
compareTo(java.lang.Object other)
|
java.lang.String |
defaultFamily()
Returns the family name that corresponds to the current style hint. |
boolean |
equals(java.lang.Object other)
|
boolean |
exactMatch()
Returns true if a window system font exactly matching the settings of this font is available. |
java.lang.String |
family()
Returns the requested font family name, i.e. the name set in the constructor or the last setFont() call. |
boolean |
fixedPitch()
Returns true if fixed pitch has been set; otherwise returns false. |
static QFont |
fromNativePointer(QNativePointer nativePointer)
This function returns the QFont instance pointed to by nativePointer |
boolean |
fromString(java.lang.String arg__1)
Sets this font to match the description arg__1. |
long |
handle()
Returns the window system handle to the font, for low-level access. |
static void |
initialize()
|
static void |
insertSubstitution(java.lang.String arg__1,
java.lang.String arg__2)
Inserts arg__2 into the substitution table for the family arg__1. |
static void |
insertSubstitutions(java.lang.String arg__1,
java.util.List<java.lang.String> arg__2)
Inserts the list of families arg__2 into the substitution list for arg__1. |
boolean |
isCopyOf(QFont arg__1)
Returns true if this font and arg__1 are copies of each other, i.e. one of them was created as a copy of the other and neither has been modified since. |
boolean |
italic()
Returns true if the style of the font is not QFont::StyleNormal |
boolean |
kerning()
Returns true if kerning should be used when drawing text with this font. |
java.lang.String |
key()
Returns the font's key, a textual representation of a font. |
java.lang.String |
lastResortFamily()
Returns the "last resort" font family name. |
java.lang.String |
lastResortFont()
Returns a "last resort" font name for the font matching algorithm. |
static QNativePointer |
nativePointerArray(QFont[] array)
This function returns a QNativePointer that is pointing to the specified QFont array. |
boolean |
overline()
Returns true if overline has been set; otherwise returns false. |
int |
pixelSize()
Returns the pixel size of the font if it was set with setPixelSize. |
int |
pointSize()
Returns the point size of the font. |
double |
pointSizeF()
Returns the point size of the font. |
boolean |
rawMode()
Returns true if raw mode is used for font name matching; otherwise returns false. |
java.lang.String |
rawName()
Returns the name of the font within the underlying window system. |
void |
readFrom(QDataStream arg__1)
Reads a QFont from arg__1. |
static void |
removeSubstitution(java.lang.String arg__1)
Removes all the substitutions for arg__1. |
int |
resolve()
|
void |
resolve(int mask)
|
QFont |
resolve(QFont arg__1)
Returns a new QFont that has attributes copied from arg__1 that have not been previously set on this font. |
void |
setBold(boolean arg__1)
If arg__1 is true sets the font's weight to QFont::Bold; otherwise sets the weight to QFont::Normal. |
void |
setFamily(java.lang.String arg__1)
Sets the family name of the font. |
void |
setFixedPitch(boolean arg__1)
If arg__1 is true, sets fixed pitch on; otherwise sets fixed pitch off. |
void |
setItalic(boolean b)
Sets the style of the font to QFont::StyleItalic if b is true; otherwise the style is set to QFont::StyleNormal. |
void |
setKerning(boolean arg__1)
Enables kerning for this font if arg__1 is true; otherwise disables it. |
void |
setOverline(boolean arg__1)
If arg__1 is true, sets overline on; otherwise sets overline off. |
void |
setPixelSize(int arg__1)
Sets the font size to arg__1 pixels. |
void |
setPointSize(int arg__1)
Sets the point size to arg__1. |
void |
setPointSizeF(double arg__1)
Sets the point size to arg__1. |
void |
setRawMode(boolean arg__1)
If arg__1 is true, turns raw mode on; otherwise turns raw mode off. |
void |
setRawName(java.lang.String arg__1)
Sets a font by its system specific name. |
void |
setStretch(int arg__1)
Sets the stretch factor for the font. |
void |
setStrikeOut(boolean arg__1)
If arg__1 is true, sets strikeout on; otherwise sets strikeout off. |
void |
setStyle(QFont.Style style)
Sets the style of the font to style. |
void |
setStyleHint(QFont.StyleHint arg__1)
Equivalent to setStyleHint(arg__1, PreferDefault). |
void |
setStyleHint(QFont.StyleHint arg__1,
QFont.StyleStrategy arg__2)
Sets the style hint and strategy to arg__1 and arg__2, respectively. |
void |
setStyleStrategy(QFont.StyleStrategy s)
Sets the style strategy for the font to s. |
void |
setUnderline(boolean arg__1)
If arg__1 is true, sets underline on; otherwise sets underline off. |
void |
setWeight(int arg__1)
Sets the weight the font to arg__1, which should be a value from the QFont::Weight enumeration. |
int |
stretch()
Returns the stretch factor for the font. |
boolean |
strikeOut()
Returns true if strikeout has been set; otherwise returns false. |
QFont.Style |
style()
Returns the style of the font. |
QFont.StyleHint |
styleHint()
Returns the StyleHint. |
QFont.StyleStrategy |
styleStrategy()
Returns the StyleStrategy. |
static java.lang.String |
substitute(java.lang.String arg__1)
Returns the first family name to be used whenever arg__1 is specified. |
static java.util.List<java.lang.String> |
substitutes(java.lang.String arg__1)
Returns a list of family names to be used whenever arg__1 is specified. |
static java.util.List<java.lang.String> |
substitutions()
Returns a sorted list of substituted family names. |
java.lang.String |
toString()
Returns a description of the font. |
boolean |
underline()
Returns true if underline has been set; otherwise returns false. |
int |
weight()
Returns the weight of the font which is one of the enumerated values from QFont::Weight. |
void |
writeTo(QDataStream arg__1)
Writes thisQFont to arg__1. |
Methods inherited from class com.trolltech.qt.QtJambiObject |
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dispose, disposed, finalize, reassignNativeResources, tr, tr, tr |
Methods inherited from class com.trolltech.qt.QSignalEmitter |
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blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread |
Methods inherited from class java.lang.Object |
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clone, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Methods inherited from interface com.trolltech.qt.QtJambiInterface |
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disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership |
Constructor Detail |
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public QFont(QFont arg__1)
Constructs a font that is a copy of arg__1.
public QFont(java.lang.String family, int pointSize, int weight)
Equivalent to QFont(family, pointSize, weight, false).
public QFont(java.lang.String family, int pointSize)
Equivalent to QFont(family, pointSize, -1, false).
public QFont(java.lang.String family)
Equivalent to QFont(family, -1, -1, false).
public QFont(java.lang.String family, int pointSize, int weight, boolean italic)
Constructs a font object with the specified family, pointSize, weight and italic settings.
If pointSize is <= 0, it is set to 12.
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.
public QFont()
Constructs a font object that uses the application's default font.
public QFont(QFont arg__1, QPaintDeviceInterface pd)
Constructs a font from arg__1 for use on the paint device pd.
Method Detail |
---|
public final boolean bold()
Returns true if weight is a value greater than QFont::Normal; otherwise returns false.
public final java.lang.String defaultFamily()
Returns the family name that corresponds to the current style hint.
public final boolean exactMatch()
Returns true if a window system font exactly matching the settings of this font is available.
public final java.lang.String family()
Returns the requested font family name, i.e. the name set in the constructor or the last setFont() call.
public final boolean fixedPitch()
Returns true if fixed pitch has been set; otherwise returns false.
public final boolean fromString(java.lang.String arg__1)
Sets this font to match the description arg__1. The description is a comma-separated list of the font attributes, as returned by toString.
public final long handle()
Returns the window system handle to the font, for low-level access. Using this function is not portable.
public final boolean isCopyOf(QFont arg__1)
Returns true if this font and arg__1 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.
public final boolean italic()
Returns true if the style of the font is not QFont::StyleNormal
public final boolean kerning()
Returns true if kerning should be used when drawing text with this font.
public final java.lang.String key()
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.
public final java.lang.String lastResortFamily()
Returns the "last resort" font family name.
The current implementation tries a wide variety of common fonts, returning the first one it finds. Is is possible that no family is found in which case an empty string is returned.
public final java.lang.String lastResortFont()
Returns a "last resort" font name for the font matching algorithm. This is used if the last resort family is not available. It will always return a name, if necessary returning something like "fixed" or "system".
The current implementation tries a wide variety of common fonts, returning the first one it finds. The implementation may change at any time, but this function will always return a string containing something.
It is theoretically possible that there really isn't a lastResortFont in which case Qt will abort with an error message. We have not been able to identify a case where this happens. Please report it as a bug if it does, preferably with a list of the fonts you have installed.
public final void writeTo(QDataStream arg__1)
public final void readFrom(QDataStream arg__1)
public final boolean overline()
Returns true if overline has been set; otherwise returns false.
public final int pixelSize()
Returns the pixel size of the font if it was set with setPixelSize. Returns -1 if the size was set with setPointSize or setPointSizeF.
public final int pointSize()
Returns the point size of the font. Returns -1 if the font size was specified in pixels.
public final double pointSizeF()
Returns the point size of the font. Returns -1 if the font size was specified in pixels.
public final boolean rawMode()
Returns true if raw mode is used for font name matching; otherwise returns false.
public final java.lang.String rawName()
Returns the name of the font within the underlying window system.
On Windows and Mac OS X, this is usually just the family name of a TrueType font.
On X11, depending on whether Qt was built with FontConfig support, it is an XLFD (X Logical Font Description) or a FontConfig pattern. An XLFD may be returned even if FontConfig support is enabled.
Using the return value of this function is usually not portable.
public final int resolve()
public final void resolve(int mask)
public final QFont resolve(QFont arg__1)
Returns a new QFont that has attributes copied from arg__1 that have not been previously set on this font.
public final void setBold(boolean arg__1)
If arg__1 is true sets the font's weight to QFont::Bold; otherwise sets the weight to QFont::Normal.
For finer boldness control use setWeight.
public final void setFamily(java.lang.String arg__1)
Sets the family name of the font. The name is case insensitive and may include a foundry name.
The arg__1 name may optionally also include a foundry name, e.g. "Helvetica [Cronyx]". If the arg__1 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.
public final void setFixedPitch(boolean arg__1)
If arg__1 is true, sets fixed pitch on; otherwise sets fixed pitch off.
public final void setItalic(boolean b)
Sets the style of the font to QFont::StyleItalic if b is true; otherwise the style is set to QFont::StyleNormal.
public final void setKerning(boolean arg__1)
Enables kerning for this font if arg__1 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 neccesairly true.
public final void setOverline(boolean arg__1)
If arg__1 is true, sets overline on; otherwise sets overline off.
public final void setPixelSize(int arg__1)
Sets the font size to arg__1 pixels.
Using this function makes the font device dependent. Use setPointSize or setPointSizeF to set the size of the font in a device independent manner.
public final void setPointSize(int arg__1)
Sets the point size to arg__1. The point size must be greater than zero.
public final void setPointSizeF(double arg__1)
Sets the point size to arg__1. The point size must be greater than zero. The requested precision may not be achieved on all platforms.
public final void setRawMode(boolean arg__1)
If arg__1 is true, turns raw mode on; otherwise turns raw mode off. This function only has an effect under X11.
If raw mode is enabled, Qt will search for an X font with a complete font name matching the family name, ignoring all other values set for the QFont. If the font name matches several fonts, Qt will use the first font returned by X. QFontInfo cannot be used to fetch information about a QFont using raw mode (it will return the values set in the QFont for all parameters, including the family name).
Warning: Do not use raw mode unless you really, really need it! In most (if not all) cases, setRawName is a much better choice.
public final void setRawName(java.lang.String arg__1)
Sets a font by its system specific name. The function is particularly useful under X, where system font settings (for example X resources) are usually available in XLFD (X Logical Font Description) form only. You can pass an XLFD as arg__1 to this function.
A font set with setRawName is still a full-featured QFont. It can be queried (for example with italic) or modified (for example with setItalic) and is therefore also suitable for rendering rich text.
If Qt's internal font database cannot resolve the raw name, the font becomes a raw font with arg__1 as its family.
Note that the present implementation does not handle wildcards in XLFDs well, and that font aliases (file fonts.alias in the font directory on X11) are not supported.
public final void setStretch(int arg__1)
Sets the stretch factor for the font.
The stretch factor changes the width of all characters in the font by arg__1 percent. For example, setting arg__1 to 150 results in all characters in the font being 1.5 times (ie. 150%) wider. The default stretch factor is 100. The minimum stretch factor is 1, and the maximum stretch factor is 4000.
The stretch factor is only applied to outline fonts. The stretch factor is ignored for bitmap fonts.
NOTE: QFont cannot stretch XLFD fonts. When loading XLFD fonts on X11, the stretch factor is matched against a predefined set of values for the SETWIDTH_NAME field of the XLFD.
public final void setStrikeOut(boolean arg__1)
If arg__1 is true, sets strikeout on; otherwise sets strikeout off.
public final void setStyle(QFont.Style style)
Sets the style of the font to style.
public final void setStyleHint(QFont.StyleHint arg__1)
Equivalent to setStyleHint(arg__1, PreferDefault).
public final void setStyleHint(QFont.StyleHint arg__1, QFont.StyleStrategy arg__2)
Sets the style hint and strategy to arg__1 and arg__2, 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.
public final void setStyleStrategy(QFont.StyleStrategy s)
Sets the style strategy for the font to s.
public final void setUnderline(boolean arg__1)
If arg__1 is true, sets underline on; otherwise sets underline off.
public final void setWeight(int arg__1)
Sets the weight the font to arg__1, which should be a value from the QFont::Weight enumeration.
public final int stretch()
Returns the stretch factor for the font.
public final boolean strikeOut()
Returns true if strikeout has been set; otherwise returns false.
public final QFont.Style style()
Returns the style of the font.
public final QFont.StyleHint styleHint()
Returns the StyleHint.
The style hint affects the font matching algorithm. See QFont::StyleHint for the list of available hints.
public final QFont.StyleStrategy styleStrategy()
Returns the StyleStrategy.
The style strategy affects the font matching algorithm. See QFont::StyleStrategy for the list of available strategies.
public final java.lang.String toString()
Returns a description of the font. The description is a comma-separated list of the attributes, perfectly suited for use in QSettings.
toString
in class java.lang.Object
public final boolean underline()
Returns true if underline has been set; otherwise returns false.
public final int weight()
Returns the weight of the font which is one of the enumerated values from QFont::Weight.
public static void cleanup()
public static void initialize()
public static void insertSubstitution(java.lang.String arg__1, java.lang.String arg__2)
Inserts arg__2 into the substitution table for the family arg__1.
public static void insertSubstitutions(java.lang.String arg__1, java.util.List<java.lang.String> arg__2)
Inserts the list of families arg__2 into the substitution list for arg__1.
public static void removeSubstitution(java.lang.String arg__1)
Removes all the substitutions for arg__1.
public static java.lang.String substitute(java.lang.String arg__1)
Returns the first family name to be used whenever arg__1 is specified. The lookup is case insensitive.
If there is no substitution for arg__1, arg__1 is returned.
To obtain a list of substitutions use substitutes.
public static java.util.List<java.lang.String> substitutes(java.lang.String arg__1)
Returns a list of family names to be used whenever arg__1 is specified. The lookup is case insensitive.
If there is no substitution for arg__1, an empty list is returned.
public static java.util.List<java.lang.String> substitutions()
Returns a sorted list of substituted family names.
public static QFont fromNativePointer(QNativePointer nativePointer)
nativePointer
- the QNativePointer of which object should be returned.public static QNativePointer nativePointerArray(QFont[] array)
array
- the array that the returned pointer will point to.
public boolean equals(java.lang.Object other)
equals
in class java.lang.Object
public int compareTo(java.lang.Object other)
compareTo
in interface java.lang.Comparable
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