QPictureIO ¶

概要 ¶

详细描述 ¶

QPictureIO contains a QIODevice object that is used for picture data I/O. The programmer can install new picture file formats in addition to those that Qt provides.

You don’t normally need to use this class; load() , save() .

另请参阅

QPicture QPixmap QFile

class QPictureIO ¶

QPictureIO(ioDevice, format)

QPictureIO(fileName, format)

param format

str

param fileName

unicode

param ioDevice

QIODevice

构造 QPictureIO object with all parameters set to zero.

构造 QPictureIO object with the I/O device ioDevice 和 format tag.

PySide2.QtGui.QPictureIO. description ( ) ¶

返回类型

unicode

Returns the picture description string.

另请参阅

setDescription()

PySide2.QtGui.QPictureIO. fileName ( ) ¶

返回类型

unicode

Returns the file name currently set.

另请参阅

setFileName()

PySide2.QtGui.QPictureIO. format ( ) ¶

返回类型

str

Returns the picture format string or None if no format has been explicitly set.

另请参阅

setFormat()

PySide2.QtGui.QPictureIO. gamma ( ) ¶

返回类型

float

Returns the gamma value at which the picture will be viewed.

另请参阅

setGamma()

static PySide2.QtGui.QPictureIO. inputFormats ( ) ¶

返回类型

Returns a sorted list of picture formats that are supported for picture input.

PySide2.QtGui.QPictureIO. ioDevice ( ) ¶

返回类型

QIODevice

Returns the IO device currently set.

另请参阅

setIODevice()

static PySide2.QtGui.QPictureIO. outputFormats ( ) ¶

返回类型

Returns a sorted list of picture formats that are supported for picture output.

PySide2.QtGui.QPictureIO. 参数 ( ) ¶

返回类型

str

Returns the picture’s parameters string.

另请参阅

setParameters()

PySide2.QtGui.QPictureIO. picture ( ) ¶

返回类型

QPicture

Returns the picture currently set.

另请参阅

setPicture()

static PySide2.QtGui.QPictureIO. pictureFormat ( fileName ) ¶

参数

fileName – unicode

返回类型

QByteArray

static PySide2.QtGui.QPictureIO. pictureFormat ( arg__1 ) ¶

参数

arg__1 – QIODevice

返回类型

QByteArray

这是重载函数。

Returns a string that specifies the picture format of the picture read from IO device d , or 0 if the device cannot be read or if the format is not recognized.

Make sure that d is at the right position in the device (for example, at the beginning of the file).

另请参阅

pos()

PySide2.QtGui.QPictureIO. quality ( ) ¶

返回类型

int

Returns the quality of the written picture, related to the compression ratio.

另请参阅

setQuality() save()

PySide2.QtGui.QPictureIO. read ( ) ¶

返回类型

bool

Reads an picture into memory and returns true if the picture was successfully read; otherwise returns false .

Before reading an picture you must set an IO device or a file name. If both an IO device and a file name have been set, the IO device will be used.

Setting the picture file format string is optional.

Note that this function does not set the format used to read the picture. If you need that information, use the pictureFormat() static functions.

范例：

iio = QPictureIO()
pixmap = QPixmap()
iio.setFileName("vegeburger.pic")
if iio.read():         # OK
    picture = iio.picture()
    painter = QPainter(pixmap)
    painter.drawPicture(0, 0, picture)
											

另请参阅

setIODevice() setFileName() setFormat() write() load()

PySide2.QtGui.QPictureIO. setDescription ( arg__1 ) ¶

参数

arg__1 – unicode

Sets the picture description string for picture handlers that support picture descriptions to description .

Currently, no picture format supported by Qt uses the description string.

另请参阅

description()

PySide2.QtGui.QPictureIO. setFileName ( arg__1 ) ¶

参数

arg__1 – unicode

Sets the name of the file to read or write an picture from to fileName .

另请参阅

fileName() setIODevice()

PySide2.QtGui.QPictureIO. setFormat ( arg__1 ) ¶

参数

arg__1 – str

Sets the picture format to format for the picture to be read or written.

It is necessary to specify a format before writing an picture, but it is not necessary to specify a format before reading an picture.

If no format has been set, Qt guesses the picture format before reading it. If a format is set the picture will only be read if it has that format.

另请参阅

read() write() format()

PySide2.QtGui.QPictureIO. setGamma ( arg__1 ) ¶

参数

arg__1 – float

Sets the gamma value at which the picture will be viewed to gamma . If the picture format stores a gamma value for which the picture is intended to be used, then this setting will be used to modify the picture. Setting to 0.0 will disable gamma correction (i.e. any specification in the file will be ignored).

The default value is 0.0.

另请参阅

gamma()

PySide2.QtGui.QPictureIO. setIODevice ( arg__1 ) ¶

参数

arg__1 – QIODevice

Sets the IO device to be used for reading or writing an picture.

Setting the IO device allows pictures to be read/written to any block-oriented QIODevice .

若 ioDevice is not null, this IO device will override file name settings.

另请参阅

setFileName()

PySide2.QtGui.QPictureIO. setParameters ( arg__1 ) ¶

参数

arg__1 – str

Sets the picture’s parameter string to 参数 . This is for picture handlers that require special parameters.

Although the current picture formats supported by Qt ignore the parameters string, it may be used in future extensions or by contributions (for example, JPEG).

另请参阅

parameters()

PySide2.QtGui.QPictureIO. setPicture ( arg__1 ) ¶

参数

arg__1 – QPicture

Sets the picture to picture .

另请参阅

picture()

PySide2.QtGui.QPictureIO. setQuality ( arg__1 ) ¶

参数

arg__1 – int

Sets the quality of the written picture to q , related to the compression ratio.

q must be in the range -1..100. Specify 0 to obtain small compressed files, 100 for large uncompressed files. (-1 signifies the default compression.)

另请参阅

quality() save()

PySide2.QtGui.QPictureIO. setStatus ( arg__1 ) ¶

参数

arg__1 – int

Sets the picture IO status to status . A non-zero value indicates an error, whereas 0 means that the IO operation was successful.

另请参阅

status()

PySide2.QtGui.QPictureIO. status ( ) ¶

返回类型

int

Returns the picture’s IO status. A non-zero value indicates an error, whereas 0 means that the IO operation was successful.

另请参阅

setStatus()

PySide2.QtGui.QPictureIO. write ( ) ¶

返回类型

bool

Writes an picture to an IO device and returns true if the picture was successfully written; otherwise returns false .

Before writing an picture you must set an IO device or a file name. If both an IO device and a file name have been set, the IO device will be used.

The picture will be written using the specified picture format.

范例：

iio = QPictureIO()
picture = QPicture()
painter = QPainter(picture)
painter.drawPixmap(0, 0, pixmap)
iio.setPicture(picture)
iio.setFileName("vegeburger.pic")
iio.setFormat("PIC")
if iio.write():
    return True # returned true if written successfully
											

另请参阅

setIODevice() setFileName() setFormat() read() save()