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# Image.downscaleTo Method

Module: Image

## Definition

Downscales the image so that its maximum dimension equals the given maximum size, while preserving the aspect ratio.

Note

If the maximum dimension is already smaller than the given maximum size, the function does nothing and the returned scale ratio is 1.

Python

    downscale_to(self, dst_image: Image, max_size: int) -> float

Parameters

> `dst_image` Image
> in Destination image.
> `max_size` int
> in Maximum image size, in pixels. The value must be greater than 0.

Returns

> `float`
> The scaling ratio applied to the image. Range is ]0:1].

Exceptions

> FaceException
> An error has occurred during Face Library execution.

Dart

    double downscaleTo(Image dstImage, int maxSize)

Parameters

> `dstImage` Image
> in Destination image.
> `maxSize` int
> in Maximum image size, in pixels. The value must be greater than 0.

Returns

> `double`
> The scaling ratio applied to the image. Range is ]0:1].

Exceptions

> FaceException
> An error has occurred during Face Library execution.

C#

    public float DownscaleTo(Image dstImage, int maxSize)

Parameters

> `dstImage` Image
> in Destination image.
> `maxSize` int
> in Maximum image size, in pixels. The value must be greater than 0.

Returns

> `float`
> The scaling ratio applied to the image. Range is ]0:1].

Exceptions

> FaceException
> An error has occurred during Face Library execution.

Java

    public float downscaleTo(Image dstImage, int maxSize) throws FaceException

Parameters

> `dstImage` Image
> in Destination image.
> `maxSize` int
> in Maximum image size, in pixels. The value must be greater than 0.

Returns

> `float`
> The scaling ratio applied to the image. Range is ]0:1].

Exceptions

> FaceException
> An error has occurred during Face Library execution.

Swift

    public func downscaleTo(dstImage: Image, maxSize: Int32) throws -> Float

Parameters

> `dstImage` Image
> in Destination image.
> `maxSize` Int32
> in Maximum image size, in pixels. The value must be greater than 0.

Returns

> `Float`
> The scaling ratio applied to the image. Range is ]0:1].

Exceptions

> FaceException
> An error has occurred during Face Library execution.

C

    int id3FaceImage_DownscaleTo (
        ID3_FACE_IMAGE hImage,
        ID3_FACE_IMAGE hDstImage,
        int maxSize,
        float * scaleRatio)

Parameters

> `hImage` ID3_FACE_IMAGE
> in Handle to the Image object.
> `hDstImage` ID3_FACE_IMAGE
> in Destination image.
> `maxSize` int
> in Maximum image size, in pixels. The value must be greater than 0.
> `scaleRatio` float *
> out The scaling ratio applied to the image. Range is ]0:1].

Returns

> `int`
> An error code.
> See id3FaceError file for the list of possible error codes.