Hi

Here is one way to do it ...

col1 <- "red"

col2 <- "blue"

EU <- data.frame(EuStockMarkets)

with(EU, plot(DAX, CAC, col=col2, type="h", ylim=c(0,6000)))

par(new=TRUE)

with(EU, plot(DAX, FTSE, col=col1, type="h", ylim=c(0,6000)))

## Convert 'graphics' to 'grid'

library(gridGraphics)

grid.echo()

## grid.ls(print=grobPathListing, viewports=TRUE)

## Rasterize spikes

library(rasterize)

downViewport("graphics-window-1-1")

grid.rasterize("graphics-plot-1-spike-1")

upViewport(0)

downViewport("graphics-window-2-1")

grid.rasterize("graphics-plot-2-spike-1")

upViewport(0)

## Apply alpha adjustment to rasterized spikes

spike1 <- as.matrix(grid.get("graphics-plot-1-spike-1")$raster)

alphaSpike1 <- adjustcolor(spike1, alpha=.3)

dim(alphaSpike1) <- dim(spike1)

grid.edit("graphics-plot-1-spike-1", raster=as.raster(alphaSpike1))

spike2 <- as.matrix(grid.get("graphics-plot-2-spike-1")$raster)

alphaSpike2 <- adjustcolor(spike2, alpha=.3)

dim(alphaSpike2) <- dim(spike2)

grid.edit("graphics-plot-2-spike-1", raster=as.raster(alphaSpike2))

... though that may not be the best way and may just reflect what I have

been thinking about recently ...

https://www.stat.auckland.ac.nz/~paul/Reports/rasterize/rasterize.htmlPaul

On 01/06/18 08:56, Ed Siefker wrote:

> I have two chromatograms I want plotted on the same axes.

> I would like the plots to be transparent, so the first chart is

> not obscured.

>

> I have tried adjustcolor(..., alpha.f=0.3), the problem is that

> my chromatogram is so dense with datapoints that they

> overlap and the entire graph just ends up a solid color. The

> second histogram still obscures the first.

>

> Consider this example:

>

>

> col1 <- adjustcolor("red", alpha.f=0.3)

> col2 <- adjustcolor("blue", alpha.f=0.3)

> EU <- data.frame(EuStockMarkets)

> with(EU, plot(DAX, CAC, col=col2, type="h", ylim=c(0,6000)))

> par(new=TRUE)

> with(EU, plot(DAX, FTSE, col=col1, type="h", ylim=c(0,6000)))

>

> The density of the red plot around 2000 completely obscures the blue

> plot behind it.

>

> What I would like to do is plot both plots in solid colors, then alpha

> the entire thing, and then overlay them. Or some other method that

> achieves a comparable result.

> Thanks

>

> ______________________________________________

>

[hidden email] mailing list -- To UNSUBSCRIBE and more, see

>

https://stat.ethz.ch/mailman/listinfo/r-help> PLEASE do read the posting guide

http://www.R-project.org/posting-guide.html> and provide commented, minimal, self-contained, reproducible code.

>

--

Dr Paul Murrell

Department of Statistics

The University of Auckland

Private Bag 92019

Auckland

New Zealand

64 9 3737599 x85392

[hidden email]
http://www.stat.auckland.ac.nz/~paul/______________________________________________

[hidden email] mailing list -- To UNSUBSCRIBE and more, see

https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide

http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.