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
Hierarchy
↳ QImage
Index
Constructors
Properties
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
- 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:
| Name | Type |
|---|---|
native | NativeElement |
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:
| Name | Type |
|---|---|
filename | string |
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:
| Name | Type |
|---|---|
width | number |
height | number |
format | QImageFormat |
Returns: QImage
+ new QImage(size: QSize, format: QImageFormat): QImage
Overrides Component.constructor
Constructs an image with the given size and format
Parameters:
| Name | Type |
|---|---|
size | QSize |
format | QImageFormat |
Returns: QImage
Properties
native
• native: NativeElement | null
Inherited from Component.native
Methods
allGray
â–¸ 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
â–¸ bitPlaneCount(): number
Returns the number of bit planes in the image
Returns: number
bytesPerLine
â–¸ bytesPerLine(): number
Returns the number of bytes per image scanline
Returns: number
cacheKey
â–¸ 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
â–¸ color(i: number): number
Returns the color in the color table at index i. The first color is at index 0
Parameters:
| Name | Type |
|---|---|
i | number |
Returns: number
colorCount
â–¸ colorCount(): number
Returns the size of the color table for the image
Returns: number
convertTo
â–¸ convertTo(format: QImageFormat, flags: ImageConversionFlag): void
Detach and convert the image to the given format in place
Parameters:
| Name | Type | Default |
|---|---|---|
format | QImageFormat | - |
flags | ImageConversionFlag | ImageConversionFlag.AutoColor |
Returns: void
convertToFormat
â–¸ convertToFormat(format: QImageFormat, flags: ImageConversionFlag): QImage
Returns a copy of the image in the given format
Parameters:
| Name | Type | Default |
|---|---|---|
format | QImageFormat | - |
flags | ImageConversionFlag | ImageConversionFlag.AutoColor |
Returns: QImage
copy
â–¸ copy(rectangle: QRect): QImage
Returns a sub-area of the image as a new image
Parameters:
| Name | Type |
|---|---|
rectangle | QRect |
Returns: QImage
â–¸ copy(x: number, y: number, width: number, height: number): QImage
This is an overloaded function
Parameters:
| Name | Type |
|---|---|
x | number |
y | number |
width | number |
height | number |
Returns: QImage
createAlphaMask
â–¸ 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:
| Name | Type | Default |
|---|---|---|
flags | ImageConversionFlag | ImageConversionFlag.AutoColor |
Returns: QImage
createHeuristicMask
â–¸ createHeuristicMask(clipTight: boolean): QImage
Creates and returns a 1-bpp heuristic mask for this image
Parameters:
| Name | Type | Default |
|---|---|---|
clipTight | boolean | true |
Returns: QImage
depth
â–¸ depth(): number
Returns the depth of the image
Returns: number
devicePixelRatio
â–¸ devicePixelRatio(): number
Returns the device pixel ratio for the image. This is the ratio between device pixels and device independent pixels.
Returns: number
dotsPerMeterX
â–¸ 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
â–¸ 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
â–¸ fill(color: QColor | GlobalColor): void
Fills the entire image with the given color
Parameters:
| Name | Type |
|---|---|
color | QColor | GlobalColor |
Returns: void
format
â–¸ format(): QImageFormat
Returns the format of the image
Returns: QImageFormat
hasAlphaChannel
â–¸ hasAlphaChannel(): boolean
Returns true if the image has a format that respects the alpha channel, otherwise returns false
Returns: boolean
height
â–¸ height(): number
Returns the height of the image
Returns: number
invertPixels
â–¸ invertPixels(mode: QImageInvertMode): void
Inverts all pixel values in the image
Parameters:
| Name | Type | Default |
|---|---|---|
mode | QImageInvertMode | QImageInvertMode.InvertRgb |
Returns: void
isGrayscale
â–¸ isGrayscale(): boolean
For 32-bit images, this function is equivalent to allGray()
Returns: boolean
isNull
â–¸ isNull(): boolean
Returns true if it is a null image, otherwise returns false
Returns: boolean
load
â–¸ 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:
| Name | Type | Default |
|---|---|---|
fileName | string | - |
format | string | null | null |
Returns: boolean
loadFromData
â–¸ loadFromData(data: Buffer, format: string | null): boolean
Loads an image from the specified buffer
Parameters:
| Name | Type | Default |
|---|---|---|
data | Buffer | - |
format | string | null | null |
Returns: boolean
mirrored
â–¸ 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:
| Name | Type | Default |
|---|---|---|
horizontal | boolean | false |
vertical | boolean | true |
Returns: QImage
offset
â–¸ 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
â–¸ pixelColor(point: QPoint): QColor
Returns the color of the pixel at the given position as a QColor
Parameters:
| Name | Type |
|---|---|
point | QPoint |
Returns: QColor
â–¸ pixelColor(x: number, y: number): QColor
Returns the color of the pixel at coordinates (x, y) as a QColor
Parameters:
| Name | Type |
|---|---|
x | number |
y | number |
Returns: QColor
pixelIndex
â–¸ pixelIndex(point: QPoint): number
Returns the pixel index at the given position
Parameters:
| Name | Type |
|---|---|
point | QPoint |
Returns: number
â–¸ pixelIndex(x: number, y: number): number
Returns the pixel index at (x, y)
Parameters:
| Name | Type |
|---|---|
x | number |
y | number |
Returns: number
rect
â–¸ rect(): QRect
Returns the enclosing rectangle (0, 0, width(), height()) of the image
Returns: QRect
reinterpretAsFormat
â–¸ 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:
| Name | Type |
|---|---|
format | QImageFormat |
Returns: boolean
save
â–¸ 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:
| Name | Type | Default |
|---|---|---|
fileName | string | - |
format | string | null | null |
quality | number | -1 |
Returns: boolean
scaled
â–¸ 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:
| Name | Type |
|---|---|
size | QSize |
aspectRatioMode | AspectRatioMode |
transformMode | TransformationMode |
Returns: QImage
â–¸ 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:
| Name | Type |
|---|---|
width | number |
height | number |
aspectRatioMode | AspectRatioMode |
transformMode | TransformationMode |
Returns: QImage
scaledToHeight
â–¸ 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:
| Name | Type | Default |
|---|---|---|
height | number | - |
mode | TransformationMode | TransformationMode.FastTransformation |
Returns: QImage
scaledToWidth
â–¸ 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:
| Name | Type | Default |
|---|---|---|
width | number | - |
mode | TransformationMode | TransformationMode.FastTransformation |
Returns: QImage
setAlphaChannel
â–¸ setAlphaChannel(alphaChannel: QImage): void
Sets the alpha channel of this image to the given alphaChannel
Parameters:
| Name | Type |
|---|---|
alphaChannel | QImage |
Returns: void
setColor
â–¸ 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:
| Name | Type |
|---|---|
index | number |
colorValue | number |
Returns: void
setColorCount
â–¸ setColorCount(colorCount: number): void
Resizes the color table to contain colorCount entries
Parameters:
| Name | Type |
|---|---|
colorCount | number |
Returns: void
setDevicePixelRatio
â–¸ setDevicePixelRatio(ratio: number): void
Sets the device pixel ratio for the image. This is the ratio between image pixels and device-independent pixels
Parameters:
| Name | Type |
|---|---|
ratio | number |
Returns: void
setDotsPerMeterX
â–¸ setDotsPerMeterX(x: number): void
Sets the number of pixels that fit horizontally in a physical meter, to x
Parameters:
| Name | Type |
|---|---|
x | number |
Returns: void
setDotsPerMeterY
â–¸ setDotsPerMeterY(y: number): void
Sets the number of pixels that fit vertically in a physical meter, to y
Parameters:
| Name | Type |
|---|---|
y | number |
Returns: void
setOffset
â–¸ 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:
| Name | Type |
|---|---|
offset | QPoint |
Returns: void
setPixel
â–¸ setPixel(position: QPoint, indexOrRgb: number): void
Sets the pixel index or color at the given position to indexOrRgb
Parameters:
| Name | Type |
|---|---|
position | QPoint |
indexOrRgb | number |
Returns: void
â–¸ setPixel(x: number, y: number, indexOrRgb: number): void
Sets the pixel index or color at (x, y) to indexOrRgb
Parameters:
| Name | Type |
|---|---|
x | number |
y | number |
indexOrRgb | number |
Returns: void
setPixelColor
â–¸ setPixelColor(position: QPoint, color: QColor): void
Sets the color at the given position to color
Parameters:
| Name | Type |
|---|---|
position | QPoint |
color | QColor |
Returns: void
â–¸ setPixelColor(x: number, y: number, color: QColor): void
Sets the pixel color at (x, y) to color
Parameters:
| Name | Type |
|---|---|
x | number |
y | number |
color | QColor |
Returns: void
setText
â–¸ setText(key: string, value: string): void
Sets the image text to the given text and associate it with the given key
Parameters:
| Name | Type |
|---|---|
key | string |
value | string |
Returns: void
size
â–¸ size(): QSize
Returns the size of the image, i.e. its width() and height()
Returns: QSize
sizeInBytes
â–¸ sizeInBytes(): number
Returns the image data size in bytes
Returns: number
swap
â–¸ swap(other: QImage): void
Swaps image other with this image. This operation is very fast and never fails
Parameters:
| Name | Type |
|---|---|
other | QImage |
Returns: void
text
â–¸ 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:
| Name | Type |
|---|---|
key | string |
Returns: string
textKeys
â–¸ textKeys(): string[]
Returns the text keys for this image
Returns: string[]
valid
â–¸ valid(pos: QPoint): boolean
Returns true if pos is a valid coordinate pair within the image; otherwise returns false
Parameters:
| Name | Type |
|---|---|
pos | QPoint |
Returns: boolean
â–¸ valid(x: number, y: number): boolean
Returns true if QPoint(x, y) is a valid coordinate pair within the image; otherwise returns false
Parameters:
| Name | Type |
|---|---|
x | number |
y | number |
Returns: boolean
width
â–¸ width(): number
Returns the width of the image
Returns: number
Static fromQVariant
â–¸ fromQVariant(variant: QVariant): QImage
Parameters:
| Name | Type |
|---|---|
variant | QVariant |
Returns: QImage