Add alpha channel to image array

Usage

add_img_array_alpha(x, alpha)

Arguments

x: image array to use
alpha: global alpha value to use. Numeric. Scales from 0 to 1, with 0 being fully transparent and 1 being fully visible

Value

image array with 4th channel for transparency

Details

Add 4th alpha channel to 3 channel RGB image arrays

Examples

x <- matrix(rnorm(4), nrow = 2)

add_img_array_alpha(x, alpha = 0.1)
#> , , 1
#> 
#>           [,1]       [,2]
#> [1,] 0.5387268 -1.8945692
#> [2,] 0.2446392  0.1201384
#> 
#> , , 2
#> 
#>           [,1]       [,2]
#> [1,] 0.5387268 -1.8945692
#> [2,] 0.2446392  0.1201384
#> 
#> , , 3
#> 
#>           [,1]       [,2]
#> [1,] 0.5387268 -1.8945692
#> [2,] 0.2446392  0.1201384
#> 
#> , , 4
#> 
#>      [,1] [,2]
#> [1,]  0.1  0.1
#> [2,]  0.1  0.1
#>