Qt Jambi Home

com.trolltech.qt.gui
Class QPixmap

java.lang.Object
  extended by com.trolltech.qt.QSignalEmitter
      extended by com.trolltech.qt.QtJambiObject
          extended by com.trolltech.qt.gui.QPixmap
All Implemented Interfaces:
QPaintDeviceInterface, QtJambiInterface
Direct Known Subclasses:
QBitmap

public class QPixmap
extends QtJambiObject
implements QPaintDeviceInterface

The QPixmap class is an off-screen image representation that can be used as a paint device.

Qt provides four classes for handling image data: QImage, QPixmap, QBitmap and QPicture. QImage is designed and optimized for I/O, and for direct pixel access and manipulation, while QPixmap is designed and optimized for showing images on screen. QBitmap is only a convenience class that inherits QPixmap, ensuring a depth of 1. The isQBitmap function returns true if a QPixmap object is really a bitmap, otherwise returns false. Finally, the QPicture class is a paint device that records and replays QPainter commands.

A QPixmap can easily be displayed on the screen using QLabel or one of QAbstractButton's subclasses (such as QPushButton and QToolButton). QLabel has a pixmap property, whereas QAbstractButton has an icon property. And because QPixmap is a QPaintDevice subclass, QPainter can be used to draw directly onto pixmaps.

In addition to the ordinary constructors, a QPixmap can be constructed using the static grabWidget and grabWindow functions which creates a QPixmap and paints the given widget, or window, in it.

Note that the pixel data in a pixmap is internal and is managed by the underlying window system. Pixels can only be accessed through QPainter functions or by converting the QPixmap to a QImage. Depending on the system, QPixmap is stored using a RGB32 or a premultiplied alpha format. If the image has an alpha channel, and if the system allows, the preferred format is premultiplied alpha. Note also that QPixmap, unlike QImage, may be hardware dependent. On X11 and Mac, a QPixmap is stored on the server side while a QImage is stored on the client side (on Windows, these two classes have an equivalent internal representation, i.e. both QImage and QPixmap are stored on the client side and don't use any GDI resources).

There are functions to convert between QImage and QPixmap. Typically, the QImage class is used to load an image file, optionally manipulating the image data, before the QImage object is converted into a QPixmap to be shown on screen. Alternatively, if no manipulation is desired, the image file can be loaded directly into a QPixmap. On Windows, the QPixmap class also supports conversion between HBITMAP and QPixmap.

QPixmap provides a collection of functions that can be used to obtain a variety of information about the pixmap. In addition, there are several functions that enables transformation of the pixmap.

QPixmap objects can be passed around by value since the QPixmap class uses implicit data sharing. For more information, see the Implicit Data Sharing documentation. QPixmap objects can also be streamed.

Reading and Writing Image Files

QPixmap provides several ways of reading an image file: The file can be loaded when constructing the QPixmap object, or by using the load() or loadFromData() functions later on. When loading an image, the file name can either refer to an actual file on disk or to one of the application's embedded resources. See The Qt Resource System overview for details on how to embed images and other resource files in the application's executable.

Simply call the save() function to save a QPixmap object.

The complete list of supported file formats are available through the QImageReader::supportedImageFormats() and QImageWriter::supportedImageFormats() functions. New file formats can be added as plugins. By default, Qt supports the following formats:

FormatDescriptionQt's support
BMPWindows BitmapRead/write
GIFGraphic Interchange Format (optional)Read
JPGJoint Photographic Experts GroupRead/write
JPEGJoint Photographic Experts GroupRead/write
PNGPortable Network GraphicsRead/write
PBMPortable BitmapRead
PGMPortable GraymapRead
PPMPortable PixmapRead/write
XBMX11 BitmapRead/write
XPMX11 PixmapRead/write

(To configure Qt with GIF support, pass -qt-gif to the configure script or check the appropriate option in the graphical installer.)

Pixmap Information

QPixmap provides a collection of functions that can be used to obtain a variety of information about the pixmap:

Available Functions
GeometryThe size, width and height functions provide information about the pixmap's size. The rect function returns the image's enclosing rectangle.
Alpha componentThe hasAlphaChannel returns true if the pixmap has a format that respects the alpha channel, otherwise returns false, while the hasAlpha function returns true if the pixmap has an alpha channel or a mask (otherwise false).

The alphaChannel function returns the alpha channel as a new QPixmap object, while the mask function returns the mask as a QBitmap object. The alpha channel and mask can be set using the setAlphaChannel and setMask functions, respectively.

Low-level informationThe depth function returns the depth of the pixmap. The defaultDepth function returns the default depth, i.e. the depth used by the application on the given screen.

The cacheKey function returns a number that uniquely identifies the contents of the QPixmap object.

The x11Info() function returns information about the configuration of the X display used to display the widget. The x11PictureHandle() function returns the X11 Picture handle of the pixmap for XRender support. Note that the two latter functions are only available on x11.

Pixmap Conversion

A QPixmap object can be converted into a QImage using the toImage function. Likewise, a QImage can be converted into a QPixmap using the fromImage. If this is too expensive an operation, you can use QBitmap::fromImage() instead.

In addition, on Windows, the QPixmap class supports conversion to and from HBitmap: the toWinHBITMAP() function creates a HBITMAP equivalent to the QPixmap, based on the given HBitmapFormat, and returns the HBITMAP handle. The fromWinHBITMAP() function returns a QPixmap that is equivalent to the given bitmap which has the specified format.

Pixmap Transformations

QPixmap supports a number of functions for creating a new pixmap that is a transformed version of the original: The createHeuristicMask function creates and returns a 1-bpp heuristic mask (i.e. a QBitmap) for this pixmap. It works by selecting a color from one of the corners and then chipping away pixels of that color, starting at all the edges. The createMaskFromColor function creates and returns a mask (i.e. a QBitmap) for the pixmap based on a given color.

The scaled, scaledToWidth and scaledToHeight functions return scaled copies of the pixmap, while the copy function creates a QPixmap that is a plain copy of the original one.

The transformed function returns a copy of the pixmap that is transformed with the given transformation matrix and transformation mode: Internally, the transformation matrix is adjusted to compensate for unwanted translation, i.e. transformed returns the smallest pixmap containing all transformed points of the original pixmap. The static trueMatrix function returns the actual matrix used for transforming the pixmap.

There are also functions for changing attributes of a pixmap. in-place: The fill function fills the entire image with the given color, the setMask function sets a mask bitmap, and the setAlphaChannel function sets the pixmap's alpha channel.

See Also:
QBitmap, QImage, QImageReader, QImageWriter

Nested Class Summary
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
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
QPixmap()
          Constructs a null pixmap.
QPixmap(int w, int h)
          Constructs a pixmap with the given w and h.
QPixmap(QPixmap arg__1)
          Constructs a pixmap that is a copy of the given arg__1.
QPixmap(QSize arg__1)
          Constructs a pixmap of the given arg__1.
QPixmap(java.lang.String fileName)
          This is an overloaded constructor provided for convenience.
QPixmap(java.lang.String[] xpm)
          Constructs a pixmap from the given xpm data, which must be a valid XPM image.
QPixmap(java.lang.String fileName, java.lang.String format)
          This is an overloaded constructor provided for convenience.
QPixmap(java.lang.String fileName, java.lang.String format, Qt.ImageConversionFlag... flags)
          This is an overloaded constructor provided for convenience.
QPixmap(java.lang.String fileName, java.lang.String format, Qt.ImageConversionFlags flags)
          Constructs a pixmap from the file with the given fileName.
 
Method Summary
 QPixmap alphaChannel()
          Returns the alpha channel of the pixmap as a new grayscale QPixmap in which each pixel's red, green, and blue values are given the alpha value of the original pixmap.
 long cacheKey()
          Returns a number that identifies this QPixmap.
 QPixmap copy()
          Equivalent to copy(QRect()).
 QPixmap copy(int x, int y, int width, int height)
          Returns a deep copy of the subset of the pixmap that is specified by the rectangle QRect( x, y, width, height).
 QPixmap copy(QRect rect)
          Returns a deep copy of the subset of the pixmap that is specified by the given rect.
 QBitmap createHeuristicMask()
          Equivalent to createHeuristicMask(true).
 QBitmap createHeuristicMask(boolean clipTight)
          Creates and returns a heuristic mask for this pixmap.
 QBitmap createMaskFromColor(QColor maskColor)
          Creates and returns a mask for this pixmap based on the given maskColor.
 QBitmap createMaskFromColor(QColor maskColor, Qt.MaskMode mode)
          Creates and returns a mask for this pixmap based on the given maskColor.
static int defaultDepth()
          Returns the default pixmap depth used by the application.
 int depth()
          Returns the depth of the pixmap.
 int devType()
          

 void fill()
          Equivalent to fill(Qt::white).
 void fill(QColor fillColor)
          Fills the pixmap with the given fillColor.
 void fill(QWidget widget, int xofs, int yofs)
          Fills the pixmap with the widget's background color or pixmap.
 void fill(QWidget widget, QPoint ofs)
          Fills the pixmap with the widget's background color or pixmap according to the given offset.
static QPixmap fromImage(QImage image)
          Equivalent to fromImage(image, Qt::AutoColor).
static QPixmap fromImage(QImage image, Qt.ImageConversionFlag... flags)
          Converts the given image to a pixmap using the specified flags to control the conversion.
static QPixmap fromImage(QImage image, Qt.ImageConversionFlags flags)
          Converts the given image to a pixmap using the specified flags to control the conversion.
static QPixmap fromNativePointer(QNativePointer nativePointer)
          This function returns the QPixmap instance pointed to by nativePointer
static QPixmap grabWidget(QWidget widget)
          Equivalent to grabWidget(widget, 0, 0, -1, -1).
static QPixmap grabWidget(QWidget widget, int x)
          Equivalent to grabWidget(widget, x, 0, -1, -1).
static QPixmap grabWidget(QWidget widget, int x, int y)
          Equivalent to grabWidget(widget, x, y, -1, -1).
static QPixmap grabWidget(QWidget widget, int x, int y, int w)
          Equivalent to grabWidget(widget, x, y, w, -1).
static QPixmap grabWidget(QWidget widget, int x, int y, int w, int h)
          Creates a pixmap and paints the given widget, restricted by QRect(x, y, w, h), in it.
static QPixmap grabWidget(QWidget widget, QRect rect)
          Creates a pixmap and paints the given widget, restricted by the given rect, in it.
static QPixmap grabWindow(long arg__1)
          Equivalent to grabWindow(arg__1, 0, 0, -1, -1).
static QPixmap grabWindow(long arg__1, int x)
          Equivalent to grabWindow(arg__1, x, 0, -1, -1).
static QPixmap grabWindow(long arg__1, int x, int y)
          Equivalent to grabWindow(arg__1, x, y, -1, -1).
static QPixmap grabWindow(long arg__1, int x, int y, int w)
          Equivalent to grabWindow(arg__1, x, y, w, -1).
static QPixmap grabWindow(long arg__1, int x, int y, int w, int h)
          Creates and returns a pixmap constructed by grabbing the contents of the given arg__1 restricted by QRect(x, y, w, h).
 boolean hasAlpha()
          Returns true if this pixmap has an alpha channel, or has a mask, otherwise returns false.
 boolean hasAlphaChannel()
          Returns true if the pixmap has a format that respects the alpha channel, otherwise returns false.
 int height()
          Returns the height of the pixmap.
 int heightMM()
          Returns the height of the paint device in millimeters.
 boolean isNull()
          Returns true if this is a null pixmap; otherwise returns false.
 boolean isQBitmap()
          Returns true if this is a QBitmap; otherwise returns false.
 boolean load(java.lang.String fileName)
          This is an overloaded method provided for convenience.
 boolean load(java.lang.String fileName, java.lang.String format)
          This is an overloaded method provided for convenience.
 boolean load(java.lang.String fileName, java.lang.String format, Qt.ImageConversionFlag... flags)
          This is an overloaded method provided for convenience.
 boolean load(java.lang.String fileName, java.lang.String format, Qt.ImageConversionFlags flags)
          Loads a pixmap from the file with the given fileName.
 boolean loadFromData(byte[] data)
          This is an overloaded method provided for convenience.
 boolean loadFromData(byte[] data, java.lang.String format)
          This is an overloaded method provided for convenience.
 boolean loadFromData(byte[] data, java.lang.String format, Qt.ImageConversionFlag... flags)
          This is an overloaded method provided for convenience.
 boolean loadFromData(byte[] data, java.lang.String format, Qt.ImageConversionFlags flags)
          Loads a pixmap from the binary data.
 boolean loadFromData(QByteArray data)
          This is an overloaded method provided for convenience.
 boolean loadFromData(QByteArray data, java.lang.String format)
          This is an overloaded method provided for convenience.
 boolean loadFromData(QByteArray data, java.lang.String format, Qt.ImageConversionFlag... flags)
          This is an overloaded method provided for convenience.
 boolean loadFromData(QByteArray data, java.lang.String format, Qt.ImageConversionFlags flags)
          Loads a pixmap from the binary data using the specified format and conversion flags.
 int logicalDpiX()
          Returns the horizontal resolution of the device in dots per inch, which is used when computing font sizes.
 int logicalDpiY()
          Returns the vertical resolution of the device in dots per inch, which is used when computing font sizes.
 QBitmap mask()
          Returns the mask, or a null bitmap if no mask has been set.
 int metric(QPaintDevice.PaintDeviceMetric arg__1)
          Returns the metric information for the given paint device arg__1.
static QNativePointer nativePointerArray(QPixmap[] array)
          This function returns a QNativePointer that is pointing to the specified QPixmap array.
 int numColors()
          Returns the number of different colors available for the paint device.
 QPaintEngine paintEngine()
          

Returns a pointer to the paint engine used for drawing on the device.

 boolean paintingActive()
          Returns true if the device is currently being painted on, i.e. someone has called QPainter::begin() but not yet called QPainter::end() for this device; otherwise returns false.
 int physicalDpiX()
          Returns the horizontal resolution of the device in dots per inch.
 int physicalDpiY()
          Returns the horizontal resolution of the device in dots per inch.
 void readFrom(QDataStream arg__1)
          Reads a QPixmap from arg__1.
 QRect rect()
          Returns the pixmap's enclosing rectangle.
 boolean save(QIODevice dev)
          This is an overloaded method provided for convenience.
 boolean save(QIODevice dev, java.lang.String format)
          This is an overloaded method provided for convenience.
 boolean save(QIODevice dev, java.lang.String format, int quality)
          This function writes a QPixmap to the given dev using the specified image file format and quality factor.
 boolean save(java.lang.String fileName)
          This is an overloaded method provided for convenience.
 boolean save(java.lang.String fileName, java.lang.String format)
          This is an overloaded method provided for convenience.
 boolean save(java.lang.String fileName, java.lang.String format, int quality)
          Saves the pixmap to the file with the given fileName using the specified image file format and quality factor.
 QPixmap scaled(int w, int h)
          Equivalent to scaled(w, h, Qt::IgnoreAspectRatio, Qt::FastTransformation).
 QPixmap scaled(int w, int h, Qt.AspectRatioMode aspectMode)
          Equivalent to scaled(w, h, aspectMode, Qt::FastTransformation).
 QPixmap scaled(int w, int h, Qt.AspectRatioMode aspectMode, Qt.TransformationMode mode)
          Returns a copy of the pixmap scaled to a rectangle with the given w and h according to the given aspectMode and mode.
 QPixmap scaled(QSize s)
          Equivalent to scaled(s, Qt::IgnoreAspectRatio, Qt::FastTransformation).
 QPixmap scaled(QSize s, Qt.AspectRatioMode aspectMode)
          Equivalent to scaled(s, aspectMode, Qt::FastTransformation).
 QPixmap scaled(QSize s, Qt.AspectRatioMode aspectMode, Qt.TransformationMode mode)
          Scales the pixmap to the given s, using the aspect ratio and transformation modes specified by aspectMode and mode.
 QPixmap scaledToHeight(int h)
          Equivalent to scaledToHeight(h, Qt::FastTransformation).
 QPixmap scaledToHeight(int h, Qt.TransformationMode mode)
          Returns a scaled copy of the image.
 QPixmap scaledToWidth(int w)
          Equivalent to scaledToWidth(w, Qt::FastTransformation).
 QPixmap scaledToWidth(int w, Qt.TransformationMode mode)
          Returns a scaled copy of the image.
 void setAlphaChannel(QPixmap arg__1)
          Sets the alpha channel of this pixmap to the given arg__1 by converting the arg__1 into 32 bit and using the intensity of the RGB pixel values.
 void setMask(QBitmap arg__1)
          Sets a mask bitmap.
 QSize size()
          Returns the size of the pixmap.
 QImage toImage()
          Converts the pixmap to a QImage.
 QPixmap transformed(QMatrix arg__1, Qt.TransformationMode mode)
          This convenience function loads the arg__1 into a QTransform and calls the overloaded function.
 QPixmap transformed(QTransform arg__1, Qt.TransformationMode mode)
          Returns a copy of the pixmap that is transformed using the given transformation arg__1 and transformation mode.
static QMatrix trueMatrix(QMatrix m, int w, int h)
          This convenience function loads the matrix m into a QTransform and calls the overloaded function with the QTransform and the width w and the height h.
static QTransform trueMatrix(QTransform m, int w, int h)
          Returns the actual matrix used for transforming a pixmap with the given w, h and m.
 int width()
          Returns the width of the pixmap.
 int widthMM()
          Returns the width of the paint device in millimeters.
 void writeTo(QDataStream arg__1)
          Writes thisQPixmap to arg__1.
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Constructor Detail

QPixmap

public QPixmap(int w,
               int h)

Constructs a pixmap with the given w and h.

The content of the pixmap is uninitialized. If either w or h is zero, a null pixmap is constructed.

See Also:
isNull

QPixmap

public QPixmap(QPixmap arg__1)

Constructs a pixmap that is a copy of the given arg__1.

See Also:
copy

QPixmap

public QPixmap(QSize arg__1)

Constructs a pixmap of the given arg__1.


QPixmap

public QPixmap()

Constructs a null pixmap.

See Also:
isNull

QPixmap

public QPixmap(java.lang.String[] xpm)
Constructs a pixmap from the given xpm data, which must be a valid XPM image.

Errors are silently ignored.


QPixmap

public QPixmap(java.lang.String fileName,
               java.lang.String format,
               Qt.ImageConversionFlags flags)
Constructs a pixmap from the file with the given fileName. If the file does not exist or is of an unknown format, the pixmap becomes a null pixmap.

The loader attempts to read the pixmap using the specified format. If the format is not specified (which is the default), the loader probes the file for a header to guess the file format.

The file name can either refer to an actual file on disk or to one of the application's embedded resources. See the \l{resources.html}{Resource System} overview for details on how to embed images and other resource files in the application's executable.

If the image needs to be modified to fit in a lower-resolution result (e.g. converting from 32-bit to 8-bit), use the flags to control the conversion.

The fileName, format and flags parameters are passed on to load(). This means that the data in fileName is not compiled into the binary. If fileName contains a relative path (e.g. the filename only) the relevant file must be found relative to the runtime working directory.


QPixmap

public QPixmap(java.lang.String fileName,
               java.lang.String format,
               Qt.ImageConversionFlag... flags)
This is an overloaded constructor provided for convenience.


QPixmap

public QPixmap(java.lang.String fileName,
               java.lang.String format)
This is an overloaded constructor provided for convenience.


QPixmap

public QPixmap(java.lang.String fileName)
This is an overloaded constructor provided for convenience.

Method Detail

alphaChannel

public final QPixmap alphaChannel()

Returns the alpha channel of the pixmap as a new grayscale QPixmap in which each pixel's red, green, and blue values are given the alpha value of the original pixmap. The color depth of the returned pixmap is the system depth on X11 and 8-bit on Windows and Mac OS X.

You can use this function while debugging to get a visible image of the alpha channel. If the pixmap doesn't have an alpha channel, i.e., the alpha channel's value for all pixels equals 0xff), a null pixmap is returned. You can check this with the isNull() function.

We show an example:

            pixmap = QPixmap(100, 100);
            pixmap.fill(Qt::transparent);

            QRadialGradient gradient(50, 50, 50, 50, 50);
            gradient.setColorAt(0, QColor::fromRgbF(1, 0, 0, 1));
            gradient.setColorAt(1, QColor::fromRgbF(0, 0, 0, 0));
            QPainter painter(&pixmap);
            painter.fillRect(0, 0, 100, 100, gradient);

            channelImage = pixmap.alphaChannel();
            update();

The pixmap and channelImage QPixmaps

See Also:
setAlphaChannel, Information

cacheKey

public final long cacheKey()

Returns a number that identifies this QPixmap. Distinct QPixmap objects can only have the same cache key if they refer to the same contents.

The cacheKey will change when the pixmap is altered.


copy

public final QPixmap copy(int x,
                          int y,
                          int width,
                          int height)

Returns a deep copy of the subset of the pixmap that is specified by the rectangle QRect( x, y, width, height).


copy

public final QPixmap copy()

Equivalent to copy(QRect()).


copy

public final QPixmap copy(QRect rect)

Returns a deep copy of the subset of the pixmap that is specified by the given rect. For more information on deep copies, see the Implicit Data Sharing documentation.

If the given rect is empty, the whole image is copied.

See Also:
operator=, QPixmap, Transformations

createHeuristicMask

public final QBitmap createHeuristicMask()

Equivalent to createHeuristicMask(true).


createHeuristicMask

public final QBitmap createHeuristicMask(boolean clipTight)

Creates and returns a heuristic mask for this pixmap.

The function works by selecting a color from one of the corners and then chipping away pixels of that color, starting at all the edges. If clipTight is true (the default) the mask is just large enough to cover the pixels; otherwise, the mask is larger than the data pixels.

The mask may not be perfect but it should be reasonable, so you can do things such as the following:

    QPixmap myPixmap;
    myPixmap->setMask(myPixmap->createHeuristicMask());

This function is slow because it involves converting to/from a QImage, and non-trivial computations.

See Also:
QImage::createHeuristicMask, createMaskFromColor

createMaskFromColor

public final QBitmap createMaskFromColor(QColor maskColor)

Creates and returns a mask for this pixmap based on the given maskColor. Same as calling createMaskFromColor(maskColor, Qt::MaskInColor)

See Also:
createHeuristicMask, QImage::createMaskFromColor

createMaskFromColor

public final QBitmap createMaskFromColor(QColor maskColor,
                                         Qt.MaskMode mode)

Creates and returns a mask for this pixmap based on the given maskColor. If the mode is Qt::MaskInColor, all pixels matching the maskColor will be opaque. If mode is Qt::MaskOutColor, all pixels matching the maskColor will be transparent.

This function is slow because it involves converting to/from a QImage.

See Also:
createHeuristicMask, QImage::createMaskFromColor

depth

public final int depth()

Returns the depth of the pixmap.

The pixmap depth is also called bits per pixel (bpp) or bit planes of a pixmap. A null pixmap has depth 0.

Specified by:
depth in interface QPaintDeviceInterface
See Also:
defaultDepth, Information

fill

public final void fill()

Equivalent to fill(Qt::white).


fill

public final void fill(QColor fillColor)

Fills the pixmap with the given fillColor.

See Also:
Transformations

fill

public final void fill(QWidget widget,
                       int xofs,
                       int yofs)

Fills the pixmap with the widget's background color or pixmap. The given point, (xofs, yofs), defines an offset in widget coordinates to which the pixmap's top-left pixel will be mapped to.


fill

public final void fill(QWidget widget,
                       QPoint ofs)

Fills the pixmap with the widget's background color or pixmap according to the given offset.

The QPoint ofs defines a point in widget coordinates to which the pixmap's top-left pixel will be mapped to. This is only significant if the widget has a background pixmap; otherwise the pixmap will simply be filled with the background color of the widget.


hasAlpha

public final boolean hasAlpha()

Returns true if this pixmap has an alpha channel, or has a mask, otherwise returns false.

See Also:
hasAlphaChannel, alphaChannel, mask

hasAlphaChannel

public final boolean hasAlphaChannel()

Returns true if the pixmap has a format that respects the alpha channel, otherwise returns false.

See Also:
alphaChannel, hasAlpha

height

public final int height()

Returns the height of the pixmap.

Specified by:
height in interface QPaintDeviceInterface
See Also:
size, Information

heightMM

public final int heightMM()

Returns the height of the paint device in millimeters.

Specified by:
heightMM in interface QPaintDeviceInterface
See Also:
height

isNull

public final boolean isNull()

Returns true if this is a null pixmap; otherwise returns false.

A null pixmap has zero width, zero height and no contents. You cannot draw in a null pixmap.


isQBitmap

public final boolean isQBitmap()

Returns true if this is a QBitmap; otherwise returns false.


logicalDpiX

public final int logicalDpiX()

Returns the horizontal resolution of the device in dots per inch, which is used when computing font sizes. For X11, this is usually the same as could be computed from widthMM, but it varies on Windows.

Note that if the logicalDpiX doesn't equal the physicalDpiX, the corresponding QPaintEngine must handle the resolution mapping.

Specified by:
logicalDpiX in interface QPaintDeviceInterface
See Also:
logicalDpiY, physicalDpiX

logicalDpiY

public final int logicalDpiY()

Returns the vertical resolution of the device in dots per inch, which is used when computing font sizes. For X11, this is usually the same as could be computed from heightMM, but it varies on Windows.

Note that if the logicalDpiY doesn't equal the physicalDpiY, the corresponding QPaintEngine must handle the resolution mapping.

Specified by:
logicalDpiY in interface QPaintDeviceInterface
See Also:
logicalDpiX, physicalDpiY

mask

public final QBitmap mask()

Returns the mask, or a null bitmap if no mask has been set.

See Also:
setMask, Information

numColors

public final int numColors()

Returns the number of different colors available for the paint device. Since this value is an int, it will not be sufficient to represent the number of colors on 32 bit displays, in this case INT_MAX is returned instead.

Specified by:
numColors in interface QPaintDeviceInterface

writeTo

public final void writeTo(QDataStream arg__1)
Writes thisQPixmap to arg__1.


readFrom

public final void readFrom(QDataStream arg__1)
Reads a QPixmap from arg__1.


paintingActive

public final boolean paintingActive()

Returns true if the device is currently being painted on, i.e. someone has called QPainter::begin() but not yet called QPainter::end() for this device; otherwise returns false.

Specified by:
paintingActive in interface QPaintDeviceInterface
See Also:
QPainter::isActive

physicalDpiX

public final int physicalDpiX()

Returns the horizontal resolution of the device in dots per inch.

Note that if the physicalDpiX doesn't equal the logicalDpiX, the corresponding QPaintEngine must handle the resolution mapping.

Specified by:
physicalDpiX in interface QPaintDeviceInterface
See Also:
physicalDpiY, logicalDpiX

physicalDpiY

public final int physicalDpiY()

Returns the horizontal resolution of the device in dots per inch.

Note that if the physicalDpiY doesn't equal the logicalDpiY, the corresponding QPaintEngine must handle the resolution mapping.

Specified by:
physicalDpiY in interface QPaintDeviceInterface
See Also:
physicalDpiX, logicalDpiY

rect

public final QRect rect()

Returns the pixmap's enclosing rectangle.

See Also:
Information

scaled

public final QPixmap scaled(int w,
                            int h,
                            Qt.AspectRatioMode aspectMode)

Equivalent to scaled(w, h, aspectMode, Qt::FastTransformation).


scaled

public final QPixmap scaled(int w,
                            int h)

Equivalent to scaled(w, h, Qt::IgnoreAspectRatio, Qt::FastTransformation).


scaled

public final QPixmap scaled(int w,
                            int h,
                            Qt.AspectRatioMode aspectMode,
                            Qt.TransformationMode mode)

Returns a copy of the pixmap scaled to a rectangle with the given w and h according to the given aspectMode and mode.

If either the w or the h is zero or negative, this function returns a null pixmap.


scaled

public final QPixmap scaled(QSize s,
                            Qt.AspectRatioMode aspectMode)

Equivalent to scaled(s, aspectMode, Qt::FastTransformation).


scaled

public final QPixmap scaled(QSize s)

Equivalent to scaled(s, Qt::IgnoreAspectRatio, Qt::FastTransformation).


scaled

public final QPixmap scaled(QSize s,
                            Qt.AspectRatioMode aspectMode,
                            Qt.TransformationMode mode)

Scales the pixmap to the given s, using the aspect ratio and transformation modes specified by aspectMode and mode.

If the given s is empty, this function returns a null pixmap.

See Also:
isNull, Transformations

scaledToHeight

public final QPixmap scaledToHeight(int h)

Equivalent to scaledToHeight(h, Qt::FastTransformation).


scaledToHeight

public final QPixmap scaledToHeight(int h,
                                    Qt.TransformationMode mode)

Returns a scaled copy of the image. The returned image is scaled to the given h using the specified transformation mode. The width of the pixmap is automatically calculated so that the aspect ratio of the pixmap is preserved.

If h is 0 or negative, a null pixmap is returned.

See Also:
isNull, Transformations

scaledToWidth

public final QPixmap scaledToWidth(int w)

Equivalent to scaledToWidth(w, Qt::FastTransformation).


scaledToWidth

public final QPixmap scaledToWidth(int w,
                                   Qt.TransformationMode mode)

Returns a scaled copy of the image. The returned image is scaled to the given w using the specified transformation mode. The height of the pixmap is automatically calculated so that the aspect ratio of the pixmap is preserved.

If w is 0 or negative, a null pixmap is returned.

See Also:
isNull, Transformations

setAlphaChannel

public final void setAlphaChannel(QPixmap arg__1)

Sets the alpha channel of this pixmap to the given arg__1 by converting the arg__1 into 32 bit and using the intensity of the RGB pixel values.

The effect of this function is undefined when the pixmap is being painted on.

See Also:
alphaChannel, Transformations

setMask

public final void setMask(QBitmap arg__1)

Sets a mask bitmap.

The arg__1 bitmap defines the clip mask for this pixmap. Every pixel in arg__1 corresponds to a pixel in this pixmap. Pixel value 1 means opaque and pixel value 0 means transparent. The mask must have the same size as this pixmap.

Warning: Setting the mask on a pixmap will cause any alpha channel data to be cleared. For example:

            QPixmap alpha("image-with-alpha.png");
            QPixmap alphacopy = alpha;
            alphacopy.setMask(alphacopy.mask());

Now, alpha and alphacopy are visually different.

Setting a null mask resets the mask.

The effect of this function is undefined when the pixmap is being painted on.

See Also:
mask, Transformations, QBitmap

size

public final QSize size()

Returns the size of the pixmap.

See Also:
width, height, Information

toImage

public final QImage toImage()

Converts the pixmap to a QImage. Returns a null image if the conversion fails.

If the pixmap has 1-bit depth, the returned image will also be 1 bit deep. If the pixmap has 2- to 8-bit depth, the returned image has 8-bit depth. If the pixmap has greater than 8-bit depth, the returned image has 32-bit depth.

Note that for the moment, alpha masks on monochrome images are ignored.

See Also:
fromImage, Image Formats

transformed

public final QPixmap transformed(QMatrix arg__1,
                                 Qt.TransformationMode mode)

This convenience function loads the arg__1 into a QTransform and calls the overloaded function.


transformed

public final QPixmap transformed(QTransform arg__1,
                                 Qt.TransformationMode mode)

Returns a copy of the pixmap that is transformed using the given transformation arg__1 and transformation mode. The original pixmap is not changed.

The transformation arg__1 is internally adjusted to compensate for unwanted translation; i.e. the pixmap produced is the smallest pixmap that contains all the transformed points of the original pixmap. Use the trueMatrix function to retrieve the actual matrix used for transforming the pixmap.

This function is slow because it involves transformation to a QImage, non-trivial computations and a transformation back to a QPixmap.

See Also:
trueMatrix, Transformations

width

public final int width()

Returns the width of the pixmap.

Specified by:
width in interface QPaintDeviceInterface
See Also:
size, Information

widthMM

public final int widthMM()

Returns the width of the paint device in millimeters.

Specified by:
widthMM in interface QPaintDeviceInterface
See Also:
width

devType

public int devType()

Specified by:
devType in interface QPaintDeviceInterface

metric

public int metric(QPaintDevice.PaintDeviceMetric arg__1)

Returns the metric information for the given paint device arg__1.

Specified by:
metric in interface QPaintDeviceInterface
See Also:
PaintDeviceMetric

paintEngine

public QPaintEngine paintEngine()

Returns a pointer to the paint engine used for drawing on the device.

Specified by:
paintEngine in interface QPaintDeviceInterface

defaultDepth

public static int defaultDepth()

Returns the default pixmap depth used by the application.

See Also:
depth, Information

fromImage

public static QPixmap fromImage(QImage image,
                                Qt.ImageConversionFlag... flags)

Converts the given image to a pixmap using the specified flags to control the conversion. The flags argument is a bitwise-OR of the Qt::ImageConversionFlags. Passing 0 for flags sets all the default options.

In case of monochrome and 8-bit images, the image is first converted to a 32-bit pixmap and then filled with the colors in the color table. If this is too expensive an operation, you can use QBitmap::fromImage() instead.

See Also:
toImage, Conversion

fromImage

public static QPixmap fromImage(QImage image)

Equivalent to fromImage(image, Qt::AutoColor).


fromImage

public static QPixmap fromImage(QImage image,
                                Qt.ImageConversionFlags flags)

Converts the given image to a pixmap using the specified flags to control the conversion. The flags argument is a bitwise-OR of the Qt::ImageConversionFlags. Passing 0 for flags sets all the default options.

In case of monochrome and 8-bit images, the image is first converted to a 32-bit pixmap and then filled with the colors in the color table. If this is too expensive an operation, you can use QBitmap::fromImage() instead.

See Also:
toImage, Conversion

grabWidget

public static QPixmap grabWidget(QWidget widget,
                                 QRect rect)

Creates a pixmap and paints the given widget, restricted by the given rect, in it. If the widget has any children, then they are also painted in the appropriate positions.

If no rectangle is specified (the default) the entire widget is painted.

If widget is 0, the specified rectangle doesn't overlap the widget's rectangle, or an error occurs, the function will return a null QPixmap. If the rectangle is a superset of the given widget, the areas outside the widget are covered with the widget's background.

This function actually asks widget to paint itself (and its children to paint themselves) by calling paintEvent() with painter redirection turned on. But QPixmap also provides the grabWindow function which is a bit faster grabbing pixels directly off the screen. In addition, if there are overlaying windows, grabWindow, unlike grabWidget, will see them.

Warning: Do not call this function from QWidget::paintEvent().

See Also:
grabWindow

grabWidget

public static QPixmap grabWidget(QWidget widget,
                                 int x,
                                 int y,
                                 int w)

Equivalent to grabWidget(widget, x, y, w, -1).


grabWidget

public static QPixmap grabWidget(QWidget widget,
                                 int x,
                                 int y)

Equivalent to grabWidget(widget, x, y, -1, -1).


grabWidget

public static QPixmap grabWidget(QWidget widget,
                                 int x)

Equivalent to grabWidget(widget, x, 0, -1, -1).


grabWidget

public static QPixmap grabWidget(QWidget widget)

Equivalent to grabWidget(widget, 0, 0, -1, -1).


grabWidget

public static QPixmap grabWidget(QWidget widget,
                                 int x,
                                 int y,
                                 int w,
                                 int h)

Creates a pixmap and paints the given widget, restricted by QRect(x, y, w, h), in it.

Warning: Do not call this function from QWidget::paintEvent().


grabWindow

public static QPixmap grabWindow(long arg__1,
                                 int x,
                                 int y,
                                 int w)

Equivalent to grabWindow(arg__1, x, y, w, -1).


grabWindow

public static QPixmap grabWindow(long arg__1,
                                 int x,
                                 int y)

Equivalent to grabWindow(arg__1, x, y, -1, -1).


grabWindow

public static QPixmap grabWindow(long arg__1,
                                 int x)

Equivalent to grabWindow(arg__1, x, 0, -1, -1).


grabWindow

public static QPixmap grabWindow(long arg__1)

Equivalent to grabWindow(arg__1, 0, 0, -1, -1).


grabWindow

public static QPixmap grabWindow(long arg__1,
                                 int x,
                                 int y,
                                 int w,
                                 int h)

Creates and returns a pixmap constructed by grabbing the contents of the given arg__1 restricted by QRect(x, y, w, h).

The arguments (x, y) specify the offset in the window, whereas (w, h) specify the area to be copied. If w is negative, the function copies everything to the right border of the window. If h is negative, the function copies everything to the bottom of the window.

The window system identifier (WId) can be retrieved using the QWidget::winId() function. The rationale for using a window identifier and not a QWidget, is to enable grabbing of windows that are not part of the application, window system frames, and so on.

The grabWindow function grabs pixels from the screen, not from the window, i.e. if there is another window partially or entirely over the one you grab, you get pixels from the overlying window, too. The mouse cursor is generally not grabbed.

Note on X11that if the given arg__1 doesn't have the same depth as the root window, and another window partially or entirely obscures the one you grab, you will not get pixels from the overlying window. The contents of the obscured areas in the pixmap will be undefined and uninitialized.

Warning: In general, grabbing an area outside the screen is not safe. This depends on the underlying window system.

See Also:
grabWidget, Screenshot Example

trueMatrix

public static QTransform trueMatrix(QTransform m,
                                    int w,
                                    int h)

Returns the actual matrix used for transforming a pixmap with the given w, h and m.

When transforming a pixmap using the transformed function, the transformation matrix is internally adjusted to compensate for unwanted translation, i.e. transformed returns the smallest pixmap containing all transformed points of the original pixmap. This function returns the modified matrix, which maps points correctly from the original pixmap into the new pixmap.

See Also:
transformed, Transformations

trueMatrix

public static QMatrix trueMatrix(QMatrix m,
                                 int w,
                                 int h)

This convenience function loads the matrix m into a QTransform and calls the overloaded function with the QTransform and the width w and the height h.


fromNativePointer

public static QPixmap fromNativePointer(QNativePointer nativePointer)
This function returns the QPixmap instance pointed to by nativePointer

Parameters:
nativePointer - the QNativePointer of which object should be returned.

nativePointerArray

public static QNativePointer nativePointerArray(QPixmap[] array)
This function returns a QNativePointer that is pointing to the specified QPixmap array.

Parameters:
array - the array that the returned pointer will point to.
Returns:
a QNativePointer that is pointing to the specified array.

save

public final boolean save(QIODevice dev,
                          java.lang.String format,
                          int quality)
This function writes a QPixmap to the given dev using the specified image file format and quality factor. This can be used, for example, to save a pixmap directly into a QByteArray:


save

public final boolean save(QIODevice dev,
                          java.lang.String format)
This is an overloaded method provided for convenience.


save

public final boolean save(QIODevice dev)
This is an overloaded method provided for convenience.


save

public final boolean save(java.lang.String fileName,
                          java.lang.String format,
                          int quality)
Saves the pixmap to the file with the given fileName using the specified image file format and quality factor. Returns true if successful; otherwise returns false.

The quality factor must be in the range [0,100] or -1. Specify 0 to obtain small compressed files, 100 for large uncompressed files, and -1 to use the default settings.

If format is 0, an image format will be chosen from fileName's suffix.


save

public final boolean save(java.lang.String fileName,
                          java.lang.String format)
This is an overloaded method provided for convenience.


save

public final boolean save(java.lang.String fileName)
This is an overloaded method provided for convenience.


load

public final boolean load(java.lang.String fileName,
                          java.lang.String format,
                          Qt.ImageConversionFlags flags)
Loads a pixmap from the file with the given fileName. Returns true if the pixmap was successfully loaded; otherwise returns false.

The loader attempts to read the pixmap using the specified format. If the format is not specified (which is the default), the loader probes the file for a header to guess the file format.

The file name can either refer to an actual file on disk or to one of the application's embedded resources. See the \l{resources.html}{Resource System} overview for details on how to embed pixmaps and other resource files in the application's executable.

If the data needs to be modified to fit in a lower-resolution result (e.g. converting from 32-bit to 8-bit), use the flags to control the conversion.

Note that QPixmaps are automatically added to the QPixmapCache when loaded from a file; the key used is internal and can not be acquired.


load

public final boolean load(java.lang.String fileName,
                          java.lang.String format,
                          Qt.ImageConversionFlag... flags)
This is an overloaded method provided for convenience.


load

public final boolean load(java.lang.String fileName,
                          java.lang.String format)
This is an overloaded method provided for convenience.


load

public final boolean load(java.lang.String fileName)
This is an overloaded method provided for convenience.


loadFromData

public final boolean loadFromData(byte[] data,
                                  java.lang.String format,
                                  Qt.ImageConversionFlags flags)
Loads a pixmap from the binary data. Returns true if the pixmap was loaded successfully; otherwise returns false.

The loader attempts to read the pixmap using the specified format. If the format is not specified (which is the default), the loader probes the file for a header to guess the file format.

If the data needs to be modified to fit in a lower-resolution result (e.g. converting from 32-bit to 8-bit), use the flags to control the conversion.


loadFromData

public final boolean loadFromData(byte[] data,
                                  java.lang.String format,
                                  Qt.ImageConversionFlag... flags)
This is an overloaded method provided for convenience.


loadFromData

public final boolean loadFromData(byte[] data,
                                  java.lang.String format)
This is an overloaded method provided for convenience.


loadFromData

public final boolean loadFromData(byte[] data)
This is an overloaded method provided for convenience.


loadFromData

public final boolean loadFromData(QByteArray data,
                                  java.lang.String format,
                                  Qt.ImageConversionFlags flags)
Loads a pixmap from the binary data using the specified format and conversion flags.


loadFromData

public final boolean loadFromData(QByteArray data,
                                  java.lang.String format,
                                  Qt.ImageConversionFlag... flags)
This is an overloaded method provided for convenience.


loadFromData

public final boolean loadFromData(QByteArray data,
                                  java.lang.String format)
This is an overloaded method provided for convenience.


loadFromData

public final boolean loadFromData(QByteArray data)
This is an overloaded method provided for convenience.


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