LanczosResample

Kotlin |Java

@UnstableApi
public final class LanczosResample implements GlEffect

A GlEffect that applies a Lanczos-windowed sinc function when resampling an image. See Filters for Common Resampling Tasks, Ken Turkowski.

The filter rescales images in both dimensions with the same scaling factor.

Summary

Public methods
`boolean`	`isNoOp(int inputWidth, int inputHeight)` Returns whether a applies no change at every timestamp.
`static LanczosResample`	`scaleToFit(@IntRange(from = 1) int width, @IntRange(from = 1) int height)` Creates an instance.
`static LanczosResample`	`scaleToFitWithFlexibleOrientation( @IntRange(from = 1) int firstDimension, @IntRange(from = 1) int secondDimension )` Creates an instance.
`GlShaderProgram`	`toGlShaderProgram(Context context, boolean useHdr)` Returns a `GlShaderProgram` that applies the effect.

Inherited methods

From androidx.media3.common.Effect

long

getDurationAfterEffectApplied(long durationUs)

Returns the expected duration of the output stream when the effect is applied given a input durationUs.

Public methods

isNoOp

public boolean isNoOp(int inputWidth, int inputHeight)

Returns whether a applies no change at every timestamp.

This can be used as a hint to skip this instance.

For scaling factors near 1, this effect applies no change because the Lanczos algorithm won't bring a big improvement over bilinear or nearest sampling using the GPU texture units.

scaleToFit

public static LanczosResample scaleToFit(@IntRange(from = 1) int width, @IntRange(from = 1) int height)

Creates an instance.

Parameters
`@IntRange(from = 1) int width`	The width inside which the output contents will fit.
`@IntRange(from = 1) int height`	The height inside which the output contents will fit.

scaleToFitWithFlexibleOrientation

public static LanczosResample scaleToFitWithFlexibleOrientation(
    @IntRange(from = 1) int firstDimension,
    @IntRange(from = 1) int secondDimension
)

Creates an instance.

The output resolution will be either firstDimension x secondDimension or secondDimension x firstDimension. The longer of firstDimension or secondDimension will have the same orientation as the longer side of the Size passed in to configure.

Parameters
`@IntRange(from = 1) int firstDimension`	The first dimension of the output contents.
`@IntRange(from = 1) int secondDimension`	The second dimension of the output contents.

toGlShaderProgram

public GlShaderProgram toGlShaderProgram(Context context, boolean useHdr)

Returns a GlShaderProgram that applies the effect.

Parameters
`Context context`	A `Context`.
`boolean useHdr`	Whether input textures come from an HDR source. If `true`, colors will be in linear RGB BT.2020. If `false`, colors will be in linear RGB BT.709.

Throws
`androidx.media3.common.VideoFrameProcessingException`	If an error occurs while creating the `GlShaderProgram`.