Hi, I'm using panel.polygon inside a custom panel function to generate filled polygons for an xyplot. Everything is as expected until I specify a value < 1 for alpha to fill with a semi-transparent color and output to pdf. The plot symbols appear malformed. Am I doing something wrong here?
Thanks, Mark Here is an example (pdfs are attached): library(lattice) ## example data set.seed(101) ex.data <- data.frame(x = sort(runif(10)), y = rnorm(10)) ## plot an opaque polygon ex.panel1 <- function(x, y) { yy.up <- y + 0.25 yy.lo <- y - 0.25 panel.polygon(c(x, rev(x)), c(yy.up, rev(yy.lo)), border = NA, col = "lightblue", alpha = 1) panel.xyplot(x, y, type = "p") } ## output to pdf (this one is OK) trellis.device(device = pdf, color = TRUE, file = "plt1.pdf") xyplot(y ~ x, data = ex.data, panel = ex.panel1) dev.off() ## plot a semi-transparent polygon ex.panel2 <- function(x, y, alpha) { yy.up <- y + 0.25 yy.lo <- y - 0.25 panel.polygon(c(x, rev(x)), c(yy.up, rev(yy.lo)), border = NA, col = "lightblue", alpha = 0.5) # note change panel.xyplot(x, y, type = "p") } ## output to pdf (symbols are now malformed) trellis.device(device = pdf, color = TRUE, file = "plt2.pdf") xyplot(y ~ x, data = ex.data, panel = ex.panel2) dev.off() > sessionInfo() R version 2.8.1 (2008-12-22) i386-pc-mingw32 locale: LC_COLLATE=English_United States.1252;LC_CTYPE=English_United States.1252;LC_MONETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252 attached base packages: [1] stats graphics grDevices utils datasets methods base other attached packages: [1] lattice_0.17-17 loaded via a namespace (and not attached): [1] grid_2.8.1
plt1.pdf
Description: Adobe PDF document
plt2.pdf
Description: Adobe PDF document
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