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.

This class is a JS wrapper around Qt's QImage class

Example

const { QImage } = require('@nodegui/nodegui');

const image = new QImage();

Hierarchy

• Component

  ↳ QImage

Index

Constructors

• constructor

Properties

• native

Methods

• allGray
• bitPlaneCount
• bytesPerLine
• cacheKey
• color
• colorCount
• convertTo
• convertToFormat
• copy
• createAlphaMask
• createHeuristicMask
• depth
• devicePixelRatio
• dotsPerMeterX
• dotsPerMeterY
• fill
• format
• hasAlphaChannel
• height
• invertPixels
• isGrayscale
• isNull
• load
• loadFromData
• mirrored
• offset
• pixelColor
• pixelIndex
• rect
• reinterpretAsFormat
• save
• scaled
• scaledToHeight
• scaledToWidth
• setAlphaChannel
• setColor
• setColorCount
• setDevicePixelRatio
• setDotsPerMeterX
• setDotsPerMeterY
• setOffset
• setPixel
• setPixelColor
• setText
• size
• sizeInBytes
• swap
• text
• textKeys
• valid
• width
• fromBuffer
• fromQVariant

Constructors

constructor

+ new QImage(): QImage

Overrides Component.constructor

Constructs a null image

Returns: QImage

+ new QImage(native: NativeElement): QImage

Overrides Component.constructor

Constructs a null image Constructs an image and tries to load the image from the file with the given fileName Constructs an image with the given width, height and format Constructs an image with the given size and format

Parameters:

Returns: QImage

+ new QImage(filename: string): QImage

Overrides Component.constructor

Constructs an image and tries to load the image from the file with the given fileName

Parameters:

Returns: QImage

+ new QImage(width: number, height: number, format: QImageFormat): QImage

Overrides Component.constructor

Constructs an image with the given width, height and format

Parameters:

Returns: QImage

+ new QImage(size: QSize, format: QImageFormat): QImage

Overrides Component.constructor

Constructs an image with the given size and format

Parameters:

Returns: QImage

Properties

native

• native: NativeElement | null

Inherited from Component.native

Methods

allGray

▸ allGray(): boolean

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

Returns: boolean

bitPlaneCount

▸ bitPlaneCount(): number

Returns the number of bit planes in the image

Returns: number

bytesPerLine

▸ bytesPerLine(): number

Returns the number of bytes per image scanline

Returns: number

cacheKey

▸ cacheKey(): number

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

Returns: number

color

▸ color(i: number): number

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

Parameters:

Returns: number

colorCount

▸ colorCount(): number

Returns the size of the color table for the image

Returns: number

convertTo

▸ convertTo(format: QImageFormat, flags: ImageConversionFlag): void

Detach and convert the image to the given format in place

Parameters:

Returns: void

convertToFormat

▸ convertToFormat(format: QImageFormat, flags: ImageConversionFlag): QImage

Returns a copy of the image in the given format

Parameters:

Returns: QImage

copy

▸ copy(rectangle: QRect): QImage

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

Parameters:

Returns: QImage

▸ copy(x: number, y: number, width: number, height: number): QImage

This is an overloaded function

Parameters:

Returns: QImage

createAlphaMask

▸ createAlphaMask(flags: ImageConversionFlag): 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 QImageFormat::Format_RGB32

Parameters:

Returns: QImage

createHeuristicMask

▸ createHeuristicMask(clipTight: boolean): QImage

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

Parameters:

Returns: QImage

depth

▸ depth(): number

Returns the depth of the image

Returns: number

devicePixelRatio

▸ devicePixelRatio(): number

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

Returns: number

dotsPerMeterX

▸ dotsPerMeterX(): number

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

Returns: number

dotsPerMeterY

▸ dotsPerMeterY(): number

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

Returns: number

fill

▸ fill(color: QColor | GlobalColor): void

Fills the entire image with the given color

Parameters:

Returns: void

format

▸ format(): QImageFormat

Returns the format of the image

Returns: QImageFormat

hasAlphaChannel

▸ hasAlphaChannel(): boolean

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

Returns: boolean

height

▸ height(): number

Returns the height of the image

Returns: number

invertPixels

▸ invertPixels(mode: QImageInvertMode): void

Inverts all pixel values in the image

Parameters:

Returns: void

isGrayscale

▸ isGrayscale(): boolean

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

Returns: boolean

isNull

▸ isNull(): boolean

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

Returns: boolean

load

▸ load(fileName: string, format: string | null): boolean

Loads an image from the file with the given fileName. Returns true if the image was successfully loaded; otherwise invalidates the image and returns false

Parameters:

Returns: boolean

loadFromData

▸ loadFromData(data: Buffer, format: string | null): boolean

Loads an image from the specified buffer

Parameters:

Returns: boolean

mirrored

▸ mirrored(horizontal: boolean, vertical: boolean): QImage

Returns a mirror of the image, mirrored in the horizontal and/or the vertical direction depending on whether horizontal and vertical are set to true or false

Parameters:

Returns: QImage

offset

▸ offset(): QPoint

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

Returns: QPoint

pixelColor

▸ pixelColor(point: QPoint): QColor

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

Parameters:

Returns: QColor

▸ pixelColor(x: number, y: number): QColor

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

Parameters:

Returns: QColor

pixelIndex

▸ pixelIndex(point: QPoint): number

Returns the pixel index at the given position

Parameters:

Returns: number

▸ pixelIndex(x: number, y: number): number

Returns the pixel index at (x, y)

Parameters:

Returns: number

rect

▸ rect(): QRect

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

Returns: QRect

reinterpretAsFormat

▸ reinterpretAsFormat(format: QImageFormat): boolean

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

Parameters:

Returns: boolean

save

▸ save(fileName: string, format: string | null, quality: number): boolean

Saves the image to the file with the given fileName, using the given image file format and quality factor. If format is null, QImage will attempt to guess the format by looking at fileName's suffix.

Parameters:

Returns: boolean

scaled

▸ scaled(size: QSize, aspectRatioMode: AspectRatioMode, transformMode: TransformationMode): QImage

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

Parameters:

Returns: QImage

▸ scaled(width: number, height: number, aspectRatioMode: AspectRatioMode, transformMode: TransformationMode): QImage

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

Parameters:

Returns: QImage

scaledToHeight

▸ scaledToHeight(height: number, mode: TransformationMode): QImage

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

Parameters:

Returns: QImage

scaledToWidth

▸ scaledToWidth(width: number, mode: TransformationMode): QImage

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

Parameters:

Returns: QImage

setAlphaChannel

▸ setAlphaChannel(alphaChannel: QImage): void

Sets the alpha channel of this image to the given alphaChannel

Parameters:

Returns: void

setColor

▸ setColor(index: number, colorValue: number): void

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

Parameters:

Returns: void

setColorCount

▸ setColorCount(colorCount: number): void

Resizes the color table to contain colorCount entries

Parameters:

Returns: void

setDevicePixelRatio

▸ setDevicePixelRatio(ratio: number): void

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

Parameters:

Returns: void

setDotsPerMeterX

▸ setDotsPerMeterX(x: number): void

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

Parameters:

Returns: void

setDotsPerMeterY

▸ setDotsPerMeterY(y: number): void

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

Parameters:

Returns: void

setOffset

▸ setOffset(offset: QPoint): void

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

Parameters:

Returns: void

setPixel

▸ setPixel(position: QPoint, indexOrRgb: number): void

Sets the pixel index or color at the given position to indexOrRgb

Parameters:

Returns: void

▸ setPixel(x: number, y: number, indexOrRgb: number): void

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

Parameters:

Returns: void

setPixelColor

▸ setPixelColor(position: QPoint, color: QColor): void

Sets the color at the given position to color

Parameters:

Returns: void

▸ setPixelColor(x: number, y: number, color: QColor): void

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

Parameters:

Returns: void

setText

▸ setText(key: string, value: string): void

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

Parameters:

Returns: void

size

▸ size(): QSize

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

Returns: QSize

sizeInBytes

▸ sizeInBytes(): number

Returns the image data size in bytes

Returns: number

swap

▸ swap(other: QImage): void

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

Parameters:

Returns: void

text

▸ text(key: string): string

Returns the image text associated with the given key. If the specified key is an empty string, the whole image text is returned, with each key-text pair separated by a newline

Parameters:

Returns: string

textKeys

▸ textKeys(): string[]

Returns the text keys for this image

Returns: string[]

valid

▸ valid(pos: QPoint): boolean

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

Parameters:

Returns: boolean

▸ valid(x: number, y: number): boolean

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

Parameters:

Returns: boolean

width

▸ width(): number

Returns the width of the image

Returns: number

Static fromBuffer

▸ fromBuffer(buffer: Buffer, width: number, height: number, format: QImageFormat): QImage

Parameters:

Returns: QImage

Static fromQVariant

▸ fromQVariant(variant: QVariant): QImage

Parameters:

Returns: QImage