alpha in colors

[raredd]

Hi, Karl, this probably is not qtlcharts-specific, but ?heat.colors and the other palettes default to using an alpha parameter (which can be removed with alpha = NULL), but with any values, 00-ff, I get results like this:

library('qtlcharts')
data(geneExpr)
iplotCorr(geneExpr$expr, geneExpr$genotype, reorder = TRUE,
          chartOpts = list(corcolors = heat.colors(3),
                           scatcolors = c('#ff0000','#00ff0000','#0000ff')))

I've been using something like this to remove the alpha

rm_alpha <- function(x) {
  ## example
  # rm_alpha(c('#000000ff', 'red', '#nohexcol'))
  if (is.null(x)) NULL else gsub('(^#[A-Fa-f0-9]{6})[A-Fa-f0-9]{2}$', '\\1', x)
}

Or something easier to check all the chartOpts at once right at the end

rm_alpha_chartOpts <- function(co) {
  ## example
  # co <- list(pointcolor = NULL, rectcolor = '#f7f7f7', scatcolor = 'red',
  #            width = 700, height = 500)
  # rm_alpha_chartOpts(co)
  co[] <- lapply(seq_along(co), function(x)
    if (grepl('color', names(co[x]))) rm_alpha(co[[x]]) else co[[x]])
  co
}

And now the colors render (although without the transparency)

iplotCorr(geneExpr$expr, geneExpr$genotype, reorder = TRUE,
          chartOpts = rm_alpha_chartOpts(list(
                        corcolors = heat.colors(3),
                        scatcolors = c('#ff0000','#00ff0000','#0000ff'))))

Or just not using them would be another solution :}

Edit, now that I think about it, svg doesn't support alpha transparency, correct?

[kbroman]

SVG does support alpha transparency, but not via the color hex codes. One needs to use a separate "opacity" attribute.

I'll need to implement a separate chart option if you want the points in the scatterplot to be less-than-fully opaque.

(If the browser doesn't understand the color code, it just makes it black.)