---
title: "multiply(by:preBias:postBias:destination:)"
framework: accelerate
role: symbol
role_heading: Instance Method
path: "accelerate/vimage/pixelbuffer/multiply(by:prebias:postbias:destination:)-3bh2a"
---

# multiply(by:preBias:postBias:destination:)

Multiplies each pixel in a 32-bit planar pixel buffer by the specified factor.

## Declaration

```swift
func multiply(by factor: Float, preBias: Float, postBias: Float, destination: vImage.PixelBuffer<vImage.PlanarF>)
```

## Parameters

- `factor`: The multiplication factor.
- `preBias`: A value that the function adds to the source before multiplication.
- `postBias`: A value that the function adds to the result after multiplication.
- `destination`: The destination pixel buffer.

## Discussion

Discussion This function applies the following operation to each pixel: destination = ((source + preBias) * factor) + postBias For example, the following code multiplies each pixel value in a 32-bit planar buffer by 2:    let buffer = vImage.PixelBuffer<vImage.PlanarF>(        pixelValues: [0.1, 0.2, 0.3, 0.4, 0.5],        size: vImage.Size(width: 5,                          height: 1))

buffer.multiply(by: 2,                    preBias: 0, postBias: 0,                    destination: buffer)

// Prints "[0.2, 0.4, 0.6, 0.8, 1.0]"    print(buffer.array)

## See Also

### Scalar Multiplication

- [multiply(by:divisor:preBias:postBias:destination:)](accelerate/vimage/pixelbuffer/multiply(by:divisor:prebias:postbias:destination:)-7jo6v.md)