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Image Transform Functions

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Yegor Pelykh edited this page Oct 6, 2023 · 3 revisions

Image Transform Functions

Image transformations can be applied using the static methods of the Transform abstract class. Most image transformation functions work on a copy of the input image, returning the modified copy. Such functions are prefixed with copy. Those functions that do not have the copy prefix modify the image in place, returning a modified copy.

bakeOrientation

Transform.bakeOrientation(opt: TransformOptions): MemoryImage

If image has an orientation value in its EXIF data, this will rotate the image so that it physically matches its orientation. This can be used to bake the orientation of the image for image formats that don't support EXIF data.

Parameters:

  • image: MemoryImage source.

Returns: the new MemoryImage.

copyCrop

Transform.copyCrop(opt: CopyCropOptions): MemoryImage

Create a cropped copy of the image.

Parameters:

  • image: MemoryImage source.
  • rect: coordinates of the crop area of type Rectangle.
  • radius (optional): the corner radius of the crop area. Default is 0.
  • antialias (optional): sets whether anti-aliasing should be applied to the crop area. Default is true.

Returns: the new MemoryImage.

copyCropCircle

Transform.copyCropCircle(opt: CopyCropCircleOptions): MemoryImage

Returns a circle cropped copy of image, centered at center and with the given radius.

Parameters:

  • image: MemoryImage source.
  • radius (optional): radius of the crop area. Default is min(image.width, image.height).
  • center (optional): center point of the crop area. Default is image.width / 2 for X coordinate and image.height / 2 for Y coordinate.
  • antialias (optional): sets whether anti-aliasing should be applied to the crop area. Default is true.

Returns: the new MemoryImage.

copyExpandCanvas

Transform.copyExpandCanvas(opt: CopyExpandCanvasOptions): MemoryImage

Returns a copy of the image, where the original image has been placed on a new canvas of specified size at a specified location, and the rest of the canvas is filled with the specified color or transparent if no color is provided.

Parameters:

  • image: MemoryImage source.
  • newWidth (optional): width of the expanded canvas. If newWidth is undefined, the padding must be specified. Default is undefined.
  • newHeight (optional): height of the expanded canvas. If newHeight is undefined, the padding must be specified. Default is undefined.
  • padding (optional): padding that will be applied to the image to calculate expanded canvas size. If padding is undefined, the newWidth and newHeight parameters must be specified. Default is undefined.
  • position (optional): position of the source image in the expanded canvas, specified as an enumeration value of type ExpandCanvasPosition. Default is ExpandCanvasPosition.center.
  • backgroundColor (optional): if defined, set all pixels to that color. If not, leave them transparent. Default is undefined.
  • toImage (optional): if defined, modifies an existing MemoryImage rather than creating a new one. Default is undefined.

Returns: the new MemoryImage.

copyFlip

Transform.copyFlip(opt: FlipOptions): MemoryImage

Returns a copy of the image, flipped by the given direction.

Parameters:

  • image: MemoryImage source.
  • direction: flip direction.

Returns: the modified MemoryImage.

copyRectify

Transform.copyRectify(opt: CopyRectifyOptions): MemoryImage

Returns a copy of the image, where the given rectangle has been mapped to the full image.

Parameters:

  • image: MemoryImage source.
  • topLeft: coordinates of the top left point of the area, of type Point.
  • topRight: coordinates of the top right point of the area, of type Point.
  • bottomLeft: coordinates of the bottom left point of the area, of type Point.
  • bottomRight: coordinates of the bottom right point of the area, of type Point.
  • interpolation (optional): the interpolation type that is used to obtain colors in non-integer coordinates. Default is Interpolation.nearest.
  • toImage (optional): the image in which to place the mapped area. Default is the image copied from image.

Returns: the new MemoryImage.

copyResize

Transform.copyResize(opt: CopyResizeOptionsUsingWidth |  CopyResizeOptionsUsingHeight): MemoryImage

Returns a resized copy of the image.

Parameters:

  • image: MemoryImage source.
  • width (optional): the width of the resized image. If width isn't specified, then it will be determined by the aspect ratio of image and height.
  • height (optional): the height of the resized image. If height isn't specified, then it will be determined by the aspect ratio of image and width.
  • interpolation (optional): interpolation type. Default is Interpolation.nearest.
  • maintainAspect (optional): if is true, image will fill the new resolution without changing the aspect ratio, using backgroundColor. Otherwise, image will be stretched. Only used if both width and height are specified. Default is false.
  • backgroundColor (optional): color for filling empty space when maintainAspect is true. Default is undefined.

Returns: the new MemoryImage.

copyResizeCropSquare

Transform.copyResizeCropSquare(opt: CopyResizeCropSquareOptions): MemoryImage

Returns a resized and square cropped copy of the image of size.

Parameters:

  • image: MemoryImage source.
  • size: size of the cropped copy.
  • interpolation (optional): interpolation type. Default is Interpolation.nearest.
  • radius (optional): radius of the crop area. Default is 0.
  • antialias (optional): sets whether anti-aliasing should be applied to the crop area. Default is true.

Returns: the new MemoryImage.

copyRotate

Transform.copyRotate(opt: CopyRotateOptions): MemoryImage

Returns a copy of the image, rotated by angle degrees.

Parameters:

  • image: MemoryImage source.
  • angle: the angle to rotate.
  • interpolation (optional): interpolation type. Default is Interpolation.nearest.

Returns: the new MemoryImage.

flip

Transform.flip(opt: FlipOptions): MemoryImage

Flips the image using the given direction.

Parameters:

  • image: MemoryImage source.
  • direction: flip direction.

Returns: the modified MemoryImage.

flipVertical

Transform.flipVertical(opt: TransformOptions): MemoryImage

Flips the image vertically.

Parameters:

  • image: MemoryImage source.

Returns: the modified MemoryImage.

flipHorizontal

ImageTransform.flipHorizontal(opt: TransformOptions): MemoryImage

Flips the image horizontally.

Parameters:

  • image: MemoryImage source.

Returns: the modified MemoryImage.

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