QImage

The QImage class provides a hardware-independent image representation that allows direct access to the pixel data, and can be used as a paint device. More

Inheritance diagram of PySide2.QtGui.QImage

Synopsis

Functions

Static functions

Detailed Description

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. Finally, the QPicture class is a paint device that records and replays QPainter commands.

Because QImage is a QPaintDevice subclass, QPainter can be used to draw directly onto images. When using QPainter on a QImage , the painting can be performed in another thread than the current GUI thread.

The QImage class supports several image formats described by the Format enum. These include monochrome, 8-bit, 32-bit and alpha-blended images which are available in all versions of Qt 4.x.

QImage provides a collection of functions that can be used to obtain a variety of information about the image. There are also several functions that enables transformation of the image.

QImage objects can be passed around by value since the QImage class uses implicit data sharing . QImage objects can also be streamed and compared.

Note

If you would like to load QImage objects in a static build of Qt, refer to the Plugin HowTo.

Warning

Painting on a QImage with the format Format_Indexed8 is not supported.

Reading and Writing Image Files

QImage provides several ways of loading an image file: The file can be loaded when constructing the QImage object, or by using the load() or loadFromData() functions later on. QImage also provides the static fromData() function, constructing a QImage from the given data. 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 QImage object.

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

Format

Description

Qt’s support

BMP

Windows Bitmap

Read/write

GIF

Graphic Interchange Format (optional)

Read

JPG

Joint Photographic Experts Group

Read/write

JPEG

Joint Photographic Experts Group

Read/write

PNG

Portable Network Graphics

Read/write

PBM

Portable Bitmap

Read

PGM

Portable Graymap

Read

PPM

Portable Pixmap

Read/write

XBM

X11 Bitmap

Read/write

XPM

X11 Pixmap

Read/write

Image Information

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

Available Functions

Geometry

The size() , width() , height() , dotsPerMeterX() , and dotsPerMeterY() functions provide information about the image size and aspect ratio.

The rect() function returns the image’s enclosing rectangle. The valid() function tells if a given pair of coordinates is within this rectangle. The offset() function returns the number of pixels by which the image is intended to be offset by when positioned relative to other images, which also can be manipulated using the setOffset() function.

Colors

The color of a pixel can be retrieved by passing its coordinates to the pixel() function. The pixel() function returns the color as a QRgb value indepedent of the image’s format.

In case of monochrome and 8-bit images, the colorCount() and colorTable() functions provide information about the color components used to store the image data: The colorTable() function returns the image’s entire color table. To obtain a single entry, use the pixelIndex() function to retrieve the pixel index for a given pair of coordinates, then use the color() function to retrieve the color. Note that if you create an 8-bit image manually, you have to set a valid color table on the image as well.

The hasAlphaChannel() function tells if the image’s format respects the alpha channel, or not. The allGray() and isGrayscale() functions tell whether an image’s colors are all shades of gray.

See also the Pixel Manipulation and Image Transformations sections.

Text

The text() function returns the image text associated with the given text key. An image’s text keys can be retrieved using the textKeys() function. Use the setText() function to alter an image’s text.

Low-level information

The depth() function returns the depth of the image. The supported depths are 1 (monochrome), 8, 16, 24 and 32 bits. The bitPlaneCount() function tells how many of those bits that are used. For more information see the Image Formats section.

The format() , bytesPerLine() , and sizeInBytes() functions provide low-level information about the data stored in the image.

The cacheKey() function returns a number that uniquely identifies the contents of this QImage object.

Pixel Manipulation

The functions used to manipulate an image’s pixels depend on the image format. The reason is that monochrome and 8-bit images are index-based and use a color lookup table, while 32-bit images store ARGB values directly. For more information on image formats, see the Image Formats section.

In case of a 32-bit image, the setPixel() function can be used to alter the color of the pixel at the given coordinates to any other color specified as an ARGB quadruplet. To make a suitable QRgb value, use the qRgb() (adding a default alpha component to the given RGB values, i.e. creating an opaque color) or qRgba() function. For example:

32-bit

qimage-32bit_scaled1

image = QImage(3, 3, QImage.Format_RGB32)

value = qRgb(189, 149, 39)  # 0xffbd9527
image.setPixel(1, 1, value)

value = qRgb(122, 163, 39)  # 0xff7aa327
image.setPixel(0, 1, value)
image.setPixel(1, 0, value)

value = qRgb(237, 187, 51)  # 0xffedba31
image.setPixel(2, 1, value)

In case of a 8-bit and monchrome images, the pixel value is only an index from the image’s color table. So the setPixel() function can only be used to alter the color of the pixel at the given coordinates to a predefined color from the image’s color table, i.e. it can only change the pixel’s index value. To alter or add a color to an image’s color table, use the setColor() function.

An entry in the color table is an ARGB quadruplet encoded as an QRgb value. Use the qRgb() and qRgba() functions to make a suitable QRgb value for use with the setColor() function. For example:

8-bit

qimage-8bit_scaled2

image = QImage(3, 3, QImage.Format_Indexed8)
value = qRgb(122, 163, 39) # 0xff7aa327
image.setColor(0, value)

value = qRgb(237, 187, 51) # 0xffedba31
image.setColor(1, value)

value = qRgb(189, 149, 39) # 0xffbd9527
image.setColor(2, value)

image.setPixel(0, 1, 0)
image.setPixel(1, 0, 0)
image.setPixel(1, 1, 2)
image.setPixel(2, 1, 1)

For images with more than 8-bit per color-channel. The methods setPixelColor() and pixelColor() can be used to set and get with QColor values.

QImage also provide the scanLine() function which returns a pointer to the pixel data at the scanline with the given index, and the bits() function which returns a pointer to the first pixel data (this is equivalent to scanLine(0) ).

Image Formats

Each pixel stored in a QImage is represented by an integer. The size of the integer varies depending on the format. QImage supports several image formats described by the Format enum.

Monochrome images are stored using 1-bit indexes into a color table with at most two colors. There are two different types of monochrome images: big endian (MSB first) or little endian (LSB first) bit order.

8-bit images are stored using 8-bit indexes into a color table, i.e. they have a single byte per pixel. The color table is a QVector < QRgb >, and the QRgb typedef is equivalent to an unsigned int containing an ARGB quadruplet on the format 0xAARRGGBB.

32-bit images have no color table; instead, each pixel contains an QRgb value. There are three different types of 32-bit images storing RGB (i.e. 0xffRRGGBB), ARGB and premultiplied ARGB values respectively. In the premultiplied format the red, green, and blue channels are multiplied by the alpha component divided by 255.

An image’s format can be retrieved using the format() function. Use the convertToFormat() functions to convert an image into another format. The allGray() and isGrayscale() functions tell whether a color image can safely be converted to a grayscale image.

Image Transformations

QImage supports a number of functions for creating a new image that is a transformed version of the original: The createAlphaMask() function builds and returns a 1-bpp mask from the alpha buffer in this image, and the createHeuristicMask() function creates and returns a 1-bpp heuristic mask for this image. The latter function works by selecting a color from one of the corners, then chipping away pixels of that color starting at all the edges.

The mirrored() function returns a mirror of the image in the desired direction, the scaled() returns a copy of the image scaled to a rectangle of the desired measures, and the rgbSwapped() function constructs a BGR image from a RGB image.

The scaledToWidth() and scaledToHeight() functions return scaled copies of the image.

The transformed() function returns a copy of the image 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 image containing all transformed points of the original image. The static trueMatrix() function returns the actual matrix used for transforming the image.

There are also functions for changing attributes of an image in-place:

Function

Description

setDotsPerMeterX()

Defines the aspect ratio by setting the number of pixels that fit horizontally in a physical meter.

setDotsPerMeterY()

Defines the aspect ratio by setting the number of pixels that fit vertically in a physical meter.

fill()

Fills the entire image with the given pixel value.

invertPixels()

Inverts all pixel values in the image using the given InvertMode value.

setColorTable()

Sets the color table used to translate color indexes. Only monochrome and 8-bit formats.

setColorCount()

Resizes the color table. Only monochrome and 8-bit formats.

See also

QImageReader QImageWriter QPixmap QSvgRenderer Image Composition Example Image Viewer Example Scribble Example Pixelator Example

class QImage

QImage(arg__1, arg__2, arg__3, arg__4)

QImage(arg__1, arg__2, arg__3, arg__4, arg__5)

QImage(arg__1)

QImage(size, format)

QImage(fileName[, format=None])

QImage(xpm)

QImage(width, height, format)

QImage(data, width, height, format[, cleanupFunction=None[, cleanupInfo=None]])

QImage(data, width, height, bytesPerLine, format[, cleanupFunction=None[, cleanupInfo=None]])

param cleanupInfo

void

param xpm

char[]

param cleanupFunction

QImageCleanupFunction

param format

Format

param bytesPerLine

int

param size

QSize

param arg__1

unicode

param arg__2

int

param arg__3

int

param fileName

unicode

param arg__4

Format

param arg__5

Format

param data

uchar

param width

int

param height

int

Constructs a null image.

See also

isNull()

Constructs an image with the given width , height and format .

A null image will be returned if memory cannot be allocated.

Warning

This will create a QImage with uninitialized data. Call fill() to fill the image with an appropriate pixel value before drawing onto it with QPainter .

Constructs an image with the given width , height and format , that uses an existing memory buffer, data . The width and height must be specified in pixels, data must be 32-bit aligned, and each scanline of data in the image must also be 32-bit aligned.

The buffer must remain valid throughout the life of the QImage and all copies that have not been modified or otherwise detached from the original buffer. The image does not delete the buffer at destruction. You can provide a function pointer cleanupFunction along with an extra pointer cleanupInfo that will be called when the last copy is destroyed.

If format is an indexed color format, the image color table is initially empty and must be sufficiently expanded with setColorCount() or setColorTable() before the image is used.

Constructs an image with the given width , height and format , that uses an existing memory buffer, data . The width and height must be specified in pixels. bytesPerLine specifies the number of bytes per line (stride).

The buffer must remain valid throughout the life of the QImage and all copies that have not been modified or otherwise detached from the original buffer. The image does not delete the buffer at destruction. You can provide a function pointer cleanupFunction along with an extra pointer cleanupInfo that will be called when the last copy is destroyed.

If format is an indexed color format, the image color table is initially empty and must be sufficiently expanded with setColorCount() or setColorTable() before the image is used.

PySide2.QtGui.QImage.InvertMode

This enum type is used to describe how pixel values should be inverted in the invertPixels() function.

Constant

Description

QImage.InvertRgb

Invert only the RGB values and leave the alpha channel unchanged.

QImage.InvertRgba

Invert all channels, including the alpha channel.

See also

invertPixels()

PySide2.QtGui.QImage.Format

The following image formats are available in Qt. See the notes after the table.

Constant

Description

QImage.Format_Invalid

The image is invalid.

QImage.Format_Mono

The image is stored using 1-bit per pixel. Bytes are packed with the most significant bit (MSB) first.

QImage.Format_MonoLSB

The image is stored using 1-bit per pixel. Bytes are packed with the less significant bit (LSB) first.

QImage.Format_Indexed8

The image is stored using 8-bit indexes into a colormap.

QImage.Format_RGB32

The image is stored using a 32-bit RGB format (0xffRRGGBB).

QImage.Format_ARGB32

The image is stored using a 32-bit ARGB format (0xAARRGGBB).

QImage.Format_ARGB32_Premultiplied

The image is stored using a premultiplied 32-bit ARGB format (0xAARRGGBB), i.e. the red, green, and blue channels are multiplied by the alpha component divided by 255. (If RR, GG, or BB has a higher value than the alpha channel, the results are undefined.) Certain operations (such as image composition using alpha blending) are faster using premultiplied ARGB32 than with plain ARGB32.

QImage.Format_RGB16

The image is stored using a 16-bit RGB format (5-6-5).

QImage.Format_ARGB8565_Premultiplied

The image is stored using a premultiplied 24-bit ARGB format (8-5-6-5).

QImage.Format_RGB666

The image is stored using a 24-bit RGB format (6-6-6). The unused most significant bits is always zero.

QImage.Format_ARGB6666_Premultiplied

The image is stored using a premultiplied 24-bit ARGB format (6-6-6-6).

QImage.Format_RGB555

The image is stored using a 16-bit RGB format (5-5-5). The unused most significant bit is always zero.

QImage.Format_ARGB8555_Premultiplied

The image is stored using a premultiplied 24-bit ARGB format (8-5-5-5).

QImage.Format_RGB888

The image is stored using a 24-bit RGB format (8-8-8).

QImage.Format_RGB444

The image is stored using a 16-bit RGB format (4-4-4). The unused bits are always zero.

QImage.Format_ARGB4444_Premultiplied

The image is stored using a premultiplied 16-bit ARGB format (4-4-4-4).

QImage.Format_RGBX8888

The image is stored using a 32-bit byte-ordered RGB(x) format (8-8-8-8). This is the same as the except alpha must always be 255. (added in Qt 5.2)

QImage.Format_RGBA8888

The image is stored using a 32-bit byte-ordered RGBA format (8-8-8-8). Unlike ARGB32 this is a byte-ordered format, which means the 32bit encoding differs between big endian and little endian architectures, being respectively (0xRRGGBBAA) and (0xAABBGGRR). The order of the colors is the same on any architecture if read as bytes 0xRR,0xGG,0xBB,0xAA. (added in Qt 5.2)

QImage.Format_RGBA8888_Premultiplied

The image is stored using a premultiplied 32-bit byte-ordered RGBA format (8-8-8-8). (added in Qt 5.2)

QImage.Format_BGR30

The image is stored using a 32-bit BGR format (x-10-10-10). (added in Qt 5.4)

QImage.Format_A2BGR30_Premultiplied

The image is stored using a 32-bit premultiplied ABGR format (2-10-10-10). (added in Qt 5.4)

QImage.Format_RGB30

The image is stored using a 32-bit RGB format (x-10-10-10). (added in Qt 5.4)

QImage.Format_A2RGB30_Premultiplied

The image is stored using a 32-bit premultiplied ARGB format (2-10-10-10). (added in Qt 5.4)

QImage.Format_Alpha8

The image is stored using an 8-bit alpha only format. (added in Qt 5.5)

QImage.Format_Grayscale8

The image is stored using an 8-bit grayscale format. (added in Qt 5.5)

QImage.Format_Grayscale16

The image is stored using an 16-bit grayscale format. (added in Qt 5.13)

QImage.Format_RGBX64

The image is stored using a 64-bit halfword-ordered RGB(x) format (16-16-16-16). This is the same as the except alpha must always be 65535. (added in Qt 5.12)

QImage.Format_RGBA64

The image is stored using a 64-bit halfword-ordered RGBA format (16-16-16-16). (added in Qt 5.12)

QImage.Format_RGBA64_Premultiplied

The image is stored using a premultiplied 64-bit halfword-ordered RGBA format (16-16-16-16). (added in Qt 5.12)

Note

Drawing into a QImage with is not supported.

Note

Avoid most rendering directly to most of these formats using QPainter . Rendering is best optimized to the Format_RGB32 and Format_ARGB32_Premultiplied formats, and secondarily for rendering to the Format_RGB16 , Format_RGBX8888 , Format_RGBA8888_Premultiplied , Format_RGBX64 and Format_RGBA64_Premultiplied formats

PySide2.QtGui.QImage.allGray()
Return type

bool

Returns true if all the colors in the image are shades of gray (i.e. their red, green and blue components are equal); otherwise false.

Note that this function is slow for images without color table.

See also

isGrayscale()

PySide2.QtGui.QImage.alphaChannel()
Return type

QImage

Returns the alpha channel of the image as a new grayscale QImage in which each pixel’s red, green, and blue values are given the alpha value of the original image. The color depth of the returned image is 8-bit.

You can see an example of use of this function in QPixmap ‘s alphaChannel() , which works in the same way as this function on QPixmaps.

Most usecases for this function can be replaced with QPainter and using composition modes.

Note this returns a color-indexed image if you want the alpha channel in the alpha8 format instead use convertToFormat ( Format_Alpha8 ) on the source image.

Warning

This is an expensive function.

See also

setAlphaChannel() hasAlphaChannel() convertToFormat() Pixmap Image Transformations

PySide2.QtGui.QImage.bitPlaneCount()
Return type

int

Returns the number of bit planes in the image.

The number of bit planes is the number of bits of color and transparency information for each pixel. This is different from (i.e. smaller than) the depth when the image format contains unused bits.

See also

depth() format() Image Formats

PySide2.QtGui.QImage.byteCount()
Return type

int

Note

This function is deprecated.

Returns the number of bytes occupied by the image data.

Note this method should never be called on an image larger than 2 gigabytes. Instead use sizeInBytes() .

See also

sizeInBytes() bytesPerLine() bits() Image Information

PySide2.QtGui.QImage.bytesPerLine()
Return type

int

Returns the number of bytes per image scanline.

This is equivalent to sizeInBytes() / height() if height() is non-zero.

See also

scanLine()

PySide2.QtGui.QImage.cacheKey()
Return type

qint64

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

The key will change when the image is altered.

PySide2.QtGui.QImage.color(i)
Parameters

iint

Return type

long

Returns the color in the color table at index i . The first color is at index 0.

The colors in an image’s color table are specified as ARGB quadruplets ( QRgb ). Use the qAlpha() , qRed() , qGreen() , and qBlue() functions to get the color value components.

See also

setColor() pixelIndex() Pixel Manipulation

PySide2.QtGui.QImage.colorTable()
Return type

Returns a list of the colors contained in the image’s color table, or an empty list if the image does not have a color table

See also

setColorTable() colorCount() color()

PySide2.QtGui.QImage.constBits()
Return type

uchar

Returns a pointer to the first pixel data.

Note that QImage uses implicit data sharing , but this function does not perform a deep copy of the shared pixel data, because the returned data is const.

See also

bits() constScanLine()

PySide2.QtGui.QImage.constScanLine(arg__1)
Parameters

arg__1int

Return type

PyObject

Returns a pointer to the pixel data at the scanline with index i . The first scanline is at index 0.

The scanline data is aligned on a 32-bit boundary.

Note that QImage uses implicit data sharing , but this function does not perform a deep copy of the shared pixel data, because the returned data is const.

See also

scanLine() constBits()

PySide2.QtGui.QImage.convertTo(f[, flags=Qt.AutoColor])
Parameters
  • fFormat

  • flagsImageConversionFlags

Detach and convert the image to the given format in place.

The specified image conversion flags control how the image data is handled during the conversion process.

PySide2.QtGui.QImage.convertToFormat(f[, flags=Qt.AutoColor])
Parameters
  • fFormat

  • flagsImageConversionFlags

Return type

QImage

PySide2.QtGui.QImage.convertToFormat(f, colorTable[, flags=Qt.AutoColor])
Parameters
  • fFormat

  • colorTable

  • flagsImageConversionFlags

Return type

QImage

This is an overloaded function.

Returns a copy of the image converted to the given format , using the specified colorTable .

Conversion from RGB formats to indexed formats is a slow operation and will use a straightforward nearest color approach, with no dithering.

PySide2.QtGui.QImage.convertToFormat_helper(format, flags)
Parameters
  • formatFormat

  • flagsImageConversionFlags

Return type

QImage

PySide2.QtGui.QImage.convertToFormat_inplace(format, flags)
Parameters
  • formatFormat

  • flagsImageConversionFlags

Return type

bool

PySide2.QtGui.QImage.copy([rect=QRect()])
Parameters

rectQRect

Return type

QImage

Returns a sub-area of the image as a new image.

The returned image is copied from the position (rectangle .x(), rectangle .y()) in this image, and will always have the size of the given rectangle .

In areas beyond this image, pixels are set to 0. For 32-bit RGB images, this means black; for 32-bit ARGB images, this means transparent black; for 8-bit images, this means the color with index 0 in the color table which can be anything; for 1-bit images, this means color0 .

If the given rectangle is a null rectangle the entire image is copied.

See also

QImage()

PySide2.QtGui.QImage.copy(x, y, w, h)
Parameters
  • xint

  • yint

  • wint

  • hint

Return type

QImage

This is an overloaded function.

The returned image is copied from the position (x , y ) in this image, and will always have the given width and height . In areas beyond this image, pixels are set to 0.

PySide2.QtGui.QImage.createAlphaMask([flags=Qt.AutoColor])
Parameters

flagsImageConversionFlags

Return type

QImage

Builds and returns a 1-bpp mask from the alpha buffer in this image. Returns a null image if the image’s format is Format_RGB32 .

The flags argument is a bitwise-OR of the ImageConversionFlags , and controls the conversion process. Passing 0 for flags sets all the default options.

The returned image has little-endian bit order (i.e. the image’s format is Format_MonoLSB ), which you can convert to big-endian ( Format_Mono ) using the convertToFormat() function.

See also

createHeuristicMask() Image Transformations

PySide2.QtGui.QImage.createHeuristicMask([clipTight=true])
Parameters

clipTightbool

Return type

QImage

Creates and returns a 1-bpp heuristic mask for this image.

The function works by selecting a color from one of the corners, then chipping away pixels of that color starting at all the edges. The four corners vote for which color is to be masked away. In case of a draw (this generally means that this function is not applicable to the image), the result is arbitrary.

The returned image has little-endian bit order (i.e. the image’s format is Format_MonoLSB ), which you can convert to big-endian ( Format_Mono ) using the convertToFormat() function.

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.

Note that this function disregards the alpha buffer.

See also

createAlphaMask() Image Transformations

PySide2.QtGui.QImage.createMaskFromColor(color[, mode=Qt.MaskInColor])
Parameters
  • color – long

  • modeMaskMode

Return type

QImage

Creates and returns a mask for this image based on the given color value. If the mode is MaskInColor (the default value), all pixels matching color will be opaque pixels in the mask. If mode is MaskOutColor, all pixels matching the given color will be transparent.

PySide2.QtGui.QImage.dotsPerMeterX()
Return type

int

Returns the number of pixels that fit horizontally in a physical meter. Together with dotsPerMeterY() , this number defines the intended scale and aspect ratio of the image.

See also

setDotsPerMeterX() Image Information

PySide2.QtGui.QImage.dotsPerMeterY()
Return type

int

Returns the number of pixels that fit vertically in a physical meter. Together with dotsPerMeterX() , this number defines the intended scale and aspect ratio of the image.

See also

setDotsPerMeterY() Image Information

PySide2.QtGui.QImage.fill(color)
Parameters

colorGlobalColor

This is an overloaded function.

Fills the image with the given color , described as a standard global color.

PySide2.QtGui.QImage.fill(color)
Parameters

colorQColor

PySide2.QtGui.QImage.fill(pixel)
Parameters

pixeluint

Fills the entire image with the given pixelValue .

If the depth of this image is 1, only the lowest bit is used. If you say fill(0), fill(2), etc., the image is filled with 0s. If you say fill(1), fill(3), etc., the image is filled with 1s. If the depth is 8, the lowest 8 bits are used and if the depth is 16 the lowest 16 bits are used.

Note: pixel() returns the color of the pixel at the given coordinates while QColor::pixel() returns the pixel value of the underlying window system (essentially an index value), so normally you will want to use pixel() to use a color from an existing image or rgb() to use a specific color.

See also

depth() Image Transformations

PySide2.QtGui.QImage.format()
Return type

Format

Returns the format of the image.

See also

Image Formats

static PySide2.QtGui.QImage.fromData(data[, format=None])
Parameters
  • dataQByteArray

  • format – str

Return type

QImage

This is an overloaded function.

Loads an image from the given QByteArray data .

PySide2.QtGui.QImage.hasAlphaChannel()
Return type

bool

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

See also

Image Information

PySide2.QtGui.QImage.invertPixels([mode=InvertRgb])
Parameters

modeInvertMode

Inverts all pixel values in the image.

The given invert mode only have a meaning when the image’s depth is 32. The default mode is InvertRgb , which leaves the alpha channel unchanged. If the mode is InvertRgba , the alpha bits are also inverted.

Inverting an 8-bit image means to replace all pixels using color index i with a pixel using color index 255 minus i . The same is the case for a 1-bit image. Note that the color table is not changed.

If the image has a premultiplied alpha channel, the image is first converted to an unpremultiplied image format to be inverted and then converted back.

See also

Image Transformations

PySide2.QtGui.QImage.isGrayscale()
Return type

bool

For 32-bit images, this function is equivalent to allGray() .

For color indexed images, this function returns true if color(i) is QRgb (i, i, i) for all indexes of the color table; otherwise returns false .

See also

allGray() Image Formats

PySide2.QtGui.QImage.isNull()
Return type

bool

Returns true if it is a null image, otherwise returns false .

A null image has all parameters set to zero and no allocated data.

PySide2.QtGui.QImage.load(device, format)
Parameters
  • deviceQIODevice

  • format – str

Return type

bool

This is an overloaded function.

This function reads a QImage from the given device . This can, for example, be used to load an image directly into a QByteArray .

PySide2.QtGui.QImage.load(fileName[, format=None])
Parameters
  • fileName – unicode

  • format – str

Return type

bool

PySide2.QtGui.QImage.loadFromData(data[, aformat=None])
Parameters
  • dataQByteArray

  • aformat – str

Return type

bool

This is an overloaded function.

Loads an image from the given QByteArray data .

PySide2.QtGui.QImage.mirrored([horizontally=false[, vertically=true]])
Parameters
  • horizontallybool

  • verticallybool

Return type

QImage

PySide2.QtGui.QImage.mirrored_helper(horizontal, vertical)
Parameters
  • horizontalbool

  • verticalbool

Return type

QImage

PySide2.QtGui.QImage.mirrored_inplace(horizontal, vertical)
Parameters
  • horizontalbool

  • verticalbool

PySide2.QtGui.QImage.offset()
Return type

QPoint

Returns the number of pixels by which the image is intended to be offset by when positioning relative to other images.

See also

setOffset() Image Information

PySide2.QtGui.QImage.__ne__(arg__1)
Parameters

arg__1QImage

Return type

bool

Returns true if this image and the given image have different contents; otherwise returns false .

The comparison can be slow, unless there is some obvious difference, such as different widths, in which case the function will return quickly.

See also

operator=()

PySide2.QtGui.QImage.__eq__(arg__1)
Parameters

arg__1QImage

Return type

bool

Returns true if this image and the given image have the same contents; otherwise returns false .

The comparison can be slow, unless there is some obvious difference (e.g. different size or format), in which case the function will return quickly.

See also

operator=()

PySide2.QtGui.QImage.pixel(pt)
Parameters

ptQPoint

Return type

long

Returns the color of the pixel at the given position .

If the position is not valid, the results are undefined.

Warning

This function is expensive when used for massive pixel manipulations. Use constBits() or constScanLine() when many pixels needs to be read.

See also

setPixel() valid() constBits() constScanLine() Pixel Manipulation

PySide2.QtGui.QImage.pixel(x, y)
Parameters
  • xint

  • yint

Return type

long

This is an overloaded function.

Returns the color of the pixel at coordinates (x , y ).

PySide2.QtGui.QImage.pixelColor(pt)
Parameters

ptQPoint

Return type

QColor

Returns the color of the pixel at the given position as a QColor .

If the position is not valid, an invalid QColor is returned.

Warning

This function is expensive when used for massive pixel manipulations. Use constBits() or constScanLine() when many pixels needs to be read.

PySide2.QtGui.QImage.pixelColor(x, y)
Parameters
  • xint

  • yint

Return type

QColor

This is an overloaded function.

Returns the color of the pixel at coordinates (x , y ) as a QColor .

PySide2.QtGui.QImage.pixelFormat()
Return type

QPixelFormat

Returns the Format as a QPixelFormat

PySide2.QtGui.QImage.pixelIndex(pt)
Parameters

ptQPoint

Return type

int

Returns the pixel index at the given position .

If position is not valid, or if the image is not a paletted image ( depth() > 8), the results are undefined.

See also

valid() depth() Pixel Manipulation

PySide2.QtGui.QImage.pixelIndex(x, y)
Parameters
  • xint

  • yint

Return type

int

This is an overloaded function.

Returns the pixel index at (x , y ).

PySide2.QtGui.QImage.rect()
Return type

QRect

Returns the enclosing rectangle (0, 0, width() , height() ) of the image.

See also

Image Information

PySide2.QtGui.QImage.reinterpretAsFormat(f)
Parameters

fFormat

Return type

bool

Changes the format of the image to format without changing the data. Only works between formats of the same depth.

Returns true if successful.

This function can be used to change images with alpha-channels to their corresponding opaque formats if the data is known to be opaque-only, or to change the format of a given image buffer before overwriting it with new data.

Warning

The function does not check if the image data is valid in the new format and will still return true if the depths are compatible. Operations on an image with invalid data are undefined.

Warning

If the image is not detached, this will cause the data to be copied.

PySide2.QtGui.QImage.rgbSwapped()
Return type

QImage

PySide2.QtGui.QImage.rgbSwapped_helper()
Return type

QImage

PySide2.QtGui.QImage.rgbSwapped_inplace()
PySide2.QtGui.QImage.save(device[, format=None[, quality=-1]])
Parameters
  • deviceQIODevice

  • format – str

  • qualityint

Return type

bool

This is an overloaded function.

This function writes a QImage to the given device .

This can, for example, be used to save an image directly into a QByteArray :

image = QImage()
ba = QByteArray()
buffer(ba)
buffer.open(QIODevice.WriteOnly)
image.save(buffer, "PNG") # writes image into ba in PNG format
PySide2.QtGui.QImage.save(fileName[, format=None[, quality=-1]])
Parameters
  • fileName – unicode

  • format – str

  • qualityint

Return type

bool

PySide2.QtGui.QImage.scaled(s[, aspectMode=Qt.IgnoreAspectRatio[, mode=Qt.FastTransformation]])
Parameters
  • sQSize

  • aspectModeAspectRatioMode

  • modeTransformationMode

Return type

QImage

Returns a copy of the image scaled to a rectangle defined by the given size according to the given aspectRatioMode and transformMode .

../../_images/qimage-scaling1.png
  • If aspectRatioMode is IgnoreAspectRatio , the image is scaled to size.

  • If aspectRatioMode is KeepAspectRatio , the image is scaled to a rectangle as large as possible inside size, preserving the aspect ratio.

  • If aspectRatioMode is KeepAspectRatioByExpanding , the image is scaled to a rectangle as small as possible outside size, preserving the aspect ratio.

If the given size is empty, this function returns a null image.

See also

isNull() Image Transformations

PySide2.QtGui.QImage.scaled(w, h[, aspectMode=Qt.IgnoreAspectRatio[, mode=Qt.FastTransformation]])
Parameters
  • wint

  • hint

  • aspectModeAspectRatioMode

  • modeTransformationMode

Return type

QImage

This is an overloaded function.

Returns a copy of the image scaled to a rectangle with the given width and height according to the given aspectRatioMode and transformMode .

If either the width or the height is zero or negative, this function returns a null image.

PySide2.QtGui.QImage.scaledToHeight(h[, mode=Qt.FastTransformation])
Parameters
  • hint

  • modeTransformationMode

Return type

QImage

Returns a scaled copy of the image. The returned image is scaled to the given height using the specified transformation mode .

This function automatically calculates the width of the image so that the ratio of the image is preserved.

If the given height is 0 or negative, a null image is returned.

See also

Image Transformations

PySide2.QtGui.QImage.scaledToWidth(w[, mode=Qt.FastTransformation])
Parameters
  • wint

  • modeTransformationMode

Return type

QImage

Returns a scaled copy of the image. The returned image is scaled to the given width using the specified transformation mode .

This function automatically calculates the height of the image so that its aspect ratio is preserved.

If the given width is 0 or negative, a null image is returned.

See also

Image Transformations

PySide2.QtGui.QImage.setAlphaChannel(alphaChannel)
Parameters

alphaChannelQImage

Sets the alpha channel of this image to the given alphaChannel .

If alphaChannel is an 8 bit grayscale image, the intensity values are written into this buffer directly. Otherwise, alphaChannel is converted to 32 bit and the intensity of the RGB pixel values is used.

Note that the image will be converted to the Format_ARGB32_Premultiplied format if the function succeeds.

Use one of the composition modes in CompositionMode instead.

Warning

This function is expensive.

See also

alphaChannel() Image Transformations Image Formats

PySide2.QtGui.QImage.setColor(i, c)
Parameters
  • iint

  • c – long

Sets the color at the given index in the color table, to the given to colorValue . The color value is an ARGB quadruplet.

If index is outside the current size of the color table, it is expanded with setColorCount() .

See also

color() colorCount() setColorTable() Pixel Manipulation

PySide2.QtGui.QImage.setColorCount(arg__1)
Parameters

arg__1int

Resizes the color table to contain colorCount entries.

If the color table is expanded, all the extra colors will be set to transparent (i.e qRgba (0, 0, 0, 0)).

When the image is used, the color table must be large enough to have entries for all the pixel/index values present in the image, otherwise the results are undefined.

See also

colorCount() colorTable() setColor() Image Transformations

PySide2.QtGui.QImage.setColorTable(colors)
Parameters

colors

Sets the color table used to translate color indexes to QRgb values, to the specified colors .

When the image is used, the color table must be large enough to have entries for all the pixel/index values present in the image, otherwise the results are undefined.

See also

colorTable() setColor() Image Transformations

PySide2.QtGui.QImage.setDevicePixelRatio(scaleFactor)
Parameters

scaleFactorqreal

Sets the device pixel ratio for the image. This is the ratio between image pixels and device-independent pixels.

The default scaleFactor is 1.0. Setting it to something else has two effects:

QPainters that are opened on the image will be scaled. For example, painting on a 200x200 image if with a ratio of 2.0 will result in effective (device-independent) painting bounds of 100x100.

Code paths in Qt that calculate layout geometry based on the image size will take the ratio into account: QSize layoutSize = image. size() / image. devicePixelRatio() The net effect of this is that the image is displayed as high-DPI image rather than a large image (see Drawing High Resolution Versions of Pixmaps and Images ).

See also

devicePixelRatio()

PySide2.QtGui.QImage.setDotsPerMeterX(arg__1)
Parameters

arg__1int

Sets the number of pixels that fit horizontally in a physical meter, to x .

Together with dotsPerMeterY() , this number defines the intended scale and aspect ratio of the image, and determines the scale at which QPainter will draw graphics on the image. It does not change the scale or aspect ratio of the image when it is rendered on other paint devices.

See also

dotsPerMeterX() Image Information

PySide2.QtGui.QImage.setDotsPerMeterY(arg__1)
Parameters

arg__1int

Sets the number of pixels that fit vertically in a physical meter, to y .

Together with dotsPerMeterX() , this number defines the intended scale and aspect ratio of the image, and determines the scale at which QPainter will draw graphics on the image. It does not change the scale or aspect ratio of the image when it is rendered on other paint devices.

See also

dotsPerMeterY() Image Information

PySide2.QtGui.QImage.setOffset(arg__1)
Parameters

arg__1QPoint

Sets the number of pixels by which the image is intended to be offset by when positioning relative to other images, to offset .

See also

offset() Image Information

PySide2.QtGui.QImage.setPixel(pt, index_or_rgb)
Parameters
  • ptQPoint

  • index_or_rgbuint

Sets the pixel index or color at the given position to index_or_rgb .

If the image’s format is either monochrome or paletted, the given index_or_rgb value must be an index in the image’s color table, otherwise the parameter must be a QRgb value.

If position is not a valid coordinate pair in the image, or if index_or_rgb >= colorCount() in the case of monochrome and paletted images, the result is undefined.

Warning

This function is expensive due to the call of the internal detach() function called within; if performance is a concern, we recommend the use of scanLine() or bits() to access pixel data directly.

See also

pixel() Pixel Manipulation

PySide2.QtGui.QImage.setPixel(x, y, index_or_rgb)
Parameters
  • xint

  • yint

  • index_or_rgbuint

This is an overloaded function.

Sets the pixel index or color at (x , y ) to index_or_rgb .

PySide2.QtGui.QImage.setPixelColor(pt, c)
Parameters

Sets the color at the given position to color .

If position is not a valid coordinate pair in the image, or the image’s format is either monochrome or paletted, the result is undefined.

Warning

This function is expensive due to the call of the internal detach() function called within; if performance is a concern, we recommend the use of scanLine() or bits() to access pixel data directly.

See also

pixelColor() pixel() bits() scanLine() Pixel Manipulation

PySide2.QtGui.QImage.setPixelColor(x, y, c)
Parameters
  • xint

  • yint

  • cQColor

This is an overloaded function.

Sets the pixel color at (x , y ) to color .

PySide2.QtGui.QImage.setText(key, value)
Parameters
  • key – unicode

  • value – unicode

Sets the image text to the given text and associate it with the given key .

If you just want to store a single text block (i.e., a “comment” or just a description), you can either pass an empty key, or use a generic key like “Description”.

The image text is embedded into the image data when you call save() or write() .

Not all image formats support embedded text. You can find out if a specific image or format supports embedding text by using supportsOption() . We give an example:

writer = QImageWriter()
writer.setFormat("png")
if writer.supportsOption(QImageIOHandler.Description):
    print "Png supports embedded text"

You can use supportedImageFormats() to find out which image formats are available to you.

See also

text() textKeys()

PySide2.QtGui.QImage.size()
Return type

QSize

Returns the size of the image, i.e. its width() and height() .

See also

Image Information

PySide2.QtGui.QImage.sizeInBytes()
Return type

long long

Returns the image data size in bytes.

See also

byteCount() bytesPerLine() bits() Image Information

PySide2.QtGui.QImage.smoothScaled(w, h)
Parameters
  • wint

  • hint

Return type

QImage

Returns a smoothly scaled copy of the image. The returned image has a size of width w by height h pixels.

PySide2.QtGui.QImage.swap(other)
Parameters

otherQImage

Swaps image other with this image. This operation is very fast and never fails.

PySide2.QtGui.QImage.text([key=""])
Parameters

key – unicode

Return type

unicode

PySide2.QtGui.QImage.textKeys()
Return type

list of strings

Returns the text keys for this image.

You can use these keys with text() to list the image text for a certain key.

See also

text()

static PySide2.QtGui.QImage.toImageFormat(format)
Parameters

formatQPixelFormat

Return type

Format

Converts format into a Format

static PySide2.QtGui.QImage.toPixelFormat(format)
Parameters

formatFormat

Return type

QPixelFormat

Converts format into a QPixelFormat

PySide2.QtGui.QImage.transformed(matrix[, mode=Qt.FastTransformation])
Parameters
  • matrixQMatrix

  • modeTransformationMode

Return type

QImage

PySide2.QtGui.QImage.transformed(matrix[, mode=Qt.FastTransformation])
Parameters
  • matrixQTransform

  • modeTransformationMode

Return type

QImage

static PySide2.QtGui.QImage.trueMatrix(arg__1, w, h)
Parameters
  • arg__1QMatrix

  • wint

  • hint

Return type

QMatrix

static PySide2.QtGui.QImage.trueMatrix(arg__1, w, h)
Parameters
Return type

QTransform

PySide2.QtGui.QImage.valid(pt)
Parameters

ptQPoint

Return type

bool

Returns true if pos is a valid coordinate pair within the image; otherwise returns false .

See also

rect() contains()

PySide2.QtGui.QImage.valid(x, y)
Parameters
  • xint

  • yint

Return type

bool

This is an overloaded function.

Returns true if QPoint (x , y ) is a valid coordinate pair within the image; otherwise returns false .