影响pdf中颜色外观的alpha级别与R中png绘图的alpha级别

当我在

rgb

中指定

alpha

级别并将绘图另存为

pdf

（颜色透明度小于1）时，我试图找出为什么颜色会显得暗淡。保存为

png

时不会发生这种情况

考虑以下3个测试数据：

# Figure 1
# pdf with alpha specified in rgb
# blues are dull and muted relative to colors in plot window
pdf('test1.pdf', height = 4, width = 4)
plot(1,1, type = 'n')
rect(0, 0, 1, 2, col = rgb(red = 0, green = 0, blue = 1, alpha = 0.1))
abline(v = 1.3, col = 'blue', lwd = 5)
dev.off()

因此，在使用

pdf

时，如何使用透明颜色，同时保持控制台/打印窗口中显示的常规颜色方案

编辑：我正在使用Windows7，刚刚意识到这在Windows8或10上似乎不是问题。不过，我确实在MacOS10.7.5（Lion）上复制了它。我也知道，我在2013年使用的任何版本的R都有这个问题，还有这个更新的版本

> sessionInfo()
R version 3.3.1 (2016-06-21)
Platform: i386-w64-mingw32/i386 (32-bit)
Running under: Windows 7 (build 7601) Service Pack 1

locale:
[1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] reshape2_1.4.1 abind_1.4-5    CTSim_0.1.7   

loaded via a namespace (and not attached):
 [1] Rcpp_0.12.5       raster_2.5-8      magrittr_1.5      MASS_7.3-45       splines_3.3.1     fdrtool_1.2.15   
 [7] lattice_0.20-33   FNN_1.1           quadprog_1.5-5    subplex_1.1-6     stringr_1.0.0     plyr_1.8.4       
[13] tools_3.3.1       xts_0.9-7         GUILDS_1.2.1      parallel_3.3.1    grid_3.3.1        gstat_1.1-3      
[19] poilog_0.4        poweRlaw_0.60.3   intervals_0.15.1  numDeriv_2014.2-1 sads_0.3.1        bbmle_1.0.18     
[25] VGAM_1.0-2        sp_1.2-3          stringi_1.1.1     pracma_1.9.3      stats4_3.3.1      spacetime_1.1-5  
[31] zoo_1.7-13    

---

无法在MacOS 10.11.6或Ubuntu 14.10上复制。您是否尝试过Cairo:：CairoPDF（）？通过您的编辑，问题似乎更可能出在您的PDF查看器上。尝试在Windows 7中编写一个文件，并在其他系统中打开它以查看。。。。或者，如果可能的话，在同一系统上尝试其他PDF查看器。是的，你们都是对的。在GIMP中打开文件时，颜色看起来很好。是时候放弃Adobe Acrobat Professional 8了！

# Figure 3
# pdf, alpha not specified in rgb
# colors are same as plot window
pdf('test3.pdf', height = 4, width = 4)
plot(1,1, type = 'n')
rect(0, 0, 1, 2, col = rgb(red = 0, green = 0, blue = 1))
abline(v = 1.3, col = 'blue', lwd = 5)
dev.off()

> sessionInfo()
R version 3.3.1 (2016-06-21)
Platform: i386-w64-mingw32/i386 (32-bit)
Running under: Windows 7 (build 7601) Service Pack 1

locale:
[1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] reshape2_1.4.1 abind_1.4-5    CTSim_0.1.7   

loaded via a namespace (and not attached):
 [1] Rcpp_0.12.5       raster_2.5-8      magrittr_1.5      MASS_7.3-45       splines_3.3.1     fdrtool_1.2.15   
 [7] lattice_0.20-33   FNN_1.1           quadprog_1.5-5    subplex_1.1-6     stringr_1.0.0     plyr_1.8.4       
[13] tools_3.3.1       xts_0.9-7         GUILDS_1.2.1      parallel_3.3.1    grid_3.3.1        gstat_1.1-3      
[19] poilog_0.4        poweRlaw_0.60.3   intervals_0.15.1  numDeriv_2014.2-1 sads_0.3.1        bbmle_1.0.18     
[25] VGAM_1.0-2        sp_1.2-3          stringi_1.1.1     pracma_1.9.3      stats4_3.3.1      spacetime_1.1-5  
[31] zoo_1.7-13