Running examples in 'plothelper-Ex.R' failed
The error most likely occurred in:

> base::assign(".ptime", proc.time(), pos = "CheckExEnv")
> ### Name: geom_multi_raster
> ### Title: Geom Layer for Drawing Multiple Rasters
> ### Aliases: geom_multi_raster
> 
> ### ** Examples
> 
> # Example 1: use vectors and a list. 
> mycolor=list(
+ 	c1=matrix(c("red", "blue", "green", "yellow"), nrow=2), 
+ 	c2=matrix(c("green", "yellow")), 
+ 	c3=matrix(c("purple", "red")))
> xmin=1: 3
> xmax=(1: 3)+0.8 
> ymin=c(0, 1, 2)
> ymax=c(1, 3, 5)
> ggplot()+
+ 	geom_multi_raster(aes(xmin=xmin, xmax=xmax, 
+ 	ymin=ymin, ymax=ymax, raster=mycolor))
> #
> # Example 2: you can also use a tibble 
> # data frame, that is, put them together 
> # by tibble::tibble.
> # tib=tibble::tibble(xmin, xmax, ymin, ymax, mycolor)
> # ggplot(tib)+
> #		geom_multi_raster(aes(xmin=xmin, xmax=xmax, 
> #		ymin=ymin, ymax=ymax, raster=mycolor))
> #
> # Example 3: the same as example 1
> # except flip=TRUE.
> ggplot()+coord_flip()+
+ 	geom_multi_raster(aes(xmin=xmin, xmax=xmax, 
+ 	ymin=ymin, ymax=ymax, raster=mycolor), flip=TRUE)
 ----------- FAILURE REPORT -------------- 
 --- failure: the condition has length > 1 ---
 --- srcref --- 
: 
 --- package (from environment) --- 
plothelper
 --- call from context --- 
FUN(X[[i]], ...)
 --- call from argument --- 
if (grepl("magick", class(X))) {
    magick::image_rotate(X, degrees = 90)
} else {
    X = grDevices::as.raster(X)
    t(X[nrow(X):1, ])
}
 --- R stacktrace ---
where 1: FUN(X[[i]], ...)
where 2: lapply(pieces, .fun, ...)
where 3: structure(lapply(pieces, .fun, ...), dim = dim(pieces))
where 4: plyr::llply(coords$raster, .fun = CHECK_RASTER_TIBBLE_FLIP)
where 5: mapply(grid::rasterGrob, image = if (flip == FALSE) plyr::llply(coords$raster, 
    .fun = CHECK_RASTER_TIBBLE) else plyr::llply(coords$raster, 
    .fun = CHECK_RASTER_TIBBLE_FLIP), x = MIDX, y = MIDY, width = WIDTH, 
    height = HEIGHT, default.units = "native", interpolate = coords$interpolate, 
    SIMPLIFY = FALSE)
where 6: f(...)
where 7: (function (...) 
f(...))(data, panel_params, coord, flip = TRUE, na.rm = FALSE)
where 8: do.call(self$draw_panel, args)
where 9: FUN(X[[i]], ...)
where 10: lapply(split(data, data$PANEL), function(data) {
    if (empty(data)) 
        return(zeroGrob())
    panel_params <- layout$panel_params[[data$PANEL[1]]]
    do.call(self$draw_panel, args)
})
where 11: f(..., self = self)
where 12: self$geom$draw_layer(data, self$geom_params, layout, layout$coord)
where 13: f(..., self = self)
where 14: l$draw_geom(d, layout)
where 15: (function (l, d) 
l$draw_geom(d, layout))(dots[[1L]][[1L]], dots[[2L]][[1L]])
where 16: mapply(FUN = f, ..., SIMPLIFY = FALSE)
where 17: Map(function(l, d) l$draw_geom(d, layout), plot$layers, data)
where 18: ggplot_gtable.ggplot_built(data)
where 19: ggplot_gtable(data)
where 20: print.ggplot(x)
where 21: (function (x, ...) 
UseMethod("print"))(x)

 --- value of length: 2 type: logical ---
[1] FALSE FALSE
 --- function from context --- 
function (X) 
{
    if (is.null(X)) {
        stop("Rasters must not be NULL or NA.")
    }
    else if (grDevices::is.raster(X)) {
        t(X[nrow(X):1, ])
    }
    else if (grepl("magick", class(X))) {
        magick::image_rotate(X, degrees = 90)
    }
    else {
        X = grDevices::as.raster(X)
        t(X[nrow(X):1, ])
    }
}
<bytecode: 0x540ce50>
<environment: namespace:plothelper>
 --- function search by body ---
Function CHECK_RASTER_TIBBLE_FLIP in namespace plothelper has this body.
 ----------- END OF FAILURE REPORT -------------- 
Fatal error: the condition has length > 1