在格子图中使用图案添加/代替背景颜色

Question

我正在使用R晶格包中的水平图。我得到的情节看起来如下所示。

我现在的问题是我需要生成一个黑白版本进行打印。

有没有办法将颜色更改为灰度并为矩形提供背景图案，以便红色可以与蓝色区分开来？例如，可以想到点或对角线破折号。

谢谢！

Answer 1

点会更容易添加，只需在顶部添加panel.points即可。为图例添加点可能会有点困难。以下函数在网格图形中执行。

grid.colorbar(runif(10, -2, 5))

require(RColorBrewer)
require(scales)

diverging_palette <- function(d = NULL, centered = FALSE, midpoint = 0,
                              colors = RColorBrewer::brewer.pal(7,"PRGn")){

  half <- length(colors)/2

  if(!length(colors)%%2)
    stop("requires odd number of colors")
  if( !centered && !(midpoint <=  max(d) && midpoint >= min(d)))
    warning("Midpoint is outside the data range!")

  values <-  if(!centered) {
    low <- seq(min(d), midpoint, length=half)
    high <- seq(midpoint, max(d), length=half)
    c(low[-length(low)], midpoint, high[-1])
  } else {
    mabs <- max(abs(d - midpoint))
    seq(midpoint-mabs, midpoint + mabs, length=length(colors))
  }

  scales::gradient_n_pal(colors, values = values)

}

colorbarGrob <- function(d, x = unit(0.5, "npc"), 
                         y = unit(0.1,"npc"),
                         height=unit(0.8,"npc"),
                         width=unit(0.5, "cm"), size=0.7,
                         margin=unit(1,"mm"), tick.length=0.2*width,
                         pretty.breaks = grid.pretty(range(d)),
                         digits = 2, show.extrema=TRUE,
                         palette = diverging_palette(d), n = 1e2,
                         point.negative=TRUE,   gap =5,
                         interpolate=TRUE,
                         ...){

  ## includes extreme limits of the data
  legend.vals <- unique(round(sort(c(pretty.breaks, min(d), max(d))), digits)) 

  legend.labs <- if(show.extrema)
    legend.vals else unique(round(sort(pretty.breaks), digits)) 

  ## interpolate the colors
  colors <- palette(seq(min(d), max(d), length=n))
  ## 1D strip of colors, from bottom <-> min(d) to top <-> max(d)
  lg <- rasterGrob(rev(colors), # rasterGrob draws from top to bottom
                   y=y, interpolate=interpolate,
                   x=x, just=c("left", "bottom"),
                   width=width, height=height)


  ## box around color strip
  bg <- rectGrob(x=x, y=y, just=c("left", "bottom"),
                 width=width, height=height, gp=gpar(fill="transparent"))

  ## positions of the tick marks
  pos.y <- y + height * rescale(legend.vals)
  if(!show.extrema) pos.y <-  pos.y[-c(1, length(pos.y))]

  ## tick labels
  ltg <- textGrob(legend.labs, x = x + width + margin, y=pos.y,
                          just=c("left", "center"))
  ## right tick marks
  rticks <- segmentsGrob(y0=pos.y, y1=pos.y,
                         x0 = x + width,
                         x1 = x + width - tick.length,
                         gp=gpar())
  ## left tick marks
 lticks <- segmentsGrob(y0=pos.y, y1=pos.y,
                        x0 = x ,
                        x1 = x + tick.length,
                        gp=gpar())

  ## position of the dots
  if(any( d < 0 )){
  yneg <- diff(range(c(0, d[d<0])))/diff(range(d))  * height
  clipvp <- viewport(clip=TRUE, x=x, y=y, width=width, height=yneg,
                     just=c("left", "bottom"))
  h <- convertUnit(yneg, "mm", "y", valueOnly=TRUE)

  pos <- seq(0, to=h, by=gap)
  }
  ## coloured dots
  cg <- if(!point.negative || !any( d < 0 )) nullGrob() else
  pointsGrob(x=unit(rep(0.5, length(pos)), "npc"), y = y + unit(pos, "mm") ,
          pch=21, gp=gpar(col="white", fill="black"),size=unit(size*gap, "mm"), vp=clipvp)
  ## for more general pattern use the following
  ## gridExtra::patternGrob(x=unit(0.5, "npc"), y = unit(0.5, "npc") , height=unit(h,"mm"), 
  ##   pattern=1,granularity=unit(2,"mm"), gp=gpar(col="black"), vp=clipvp)

  gTree(children=gList(lg,  lticks, rticks, ltg, bg, cg),
        width = width + margin + max(stringWidth(legend.vals)), ... , cl="colorbar")
}

grid.colorbar <- function(...){
  g <- colorbarGrob(...)
  grid.draw(g)
  invisible(g)
}

widthDetails.colorbar <- function(x){
 x$width 
}

编辑：对于图案填充，您可以将pointsGrob替换为gridExtra::patternGrob（您也可以将其替换为矩阵的图块）。

Answer 2

使用两种以上的图案（例如，具有不同密度的45°和135°定向线）会令人困惑，IMO。 （尽管我不知道如何使用晶格来做到这一点。）您可以使用灰度来实现可读模式，请参阅col.regions中的levelplot()参数。

library(RColorBrewer)
cols <- colorRampPalette(brewer.pal(8, "RdBu"))
p <- levelplot(Harman23.cor$cov, scales=list(x=list(rot=45)), 
               xlab="", ylab="", col.regions=cols)
# versus all greys
p <- levelplot(Harman23.cor$cov, scales=list(x=list(rot=45)), 
               xlab="", ylab="", col.regions=gray.colors)
p <- levelplot(Harman23.cor$cov, scales=list(x=list(rot=45)), 
               xlab="", ylab="", col.regions=gray.colors(6), cuts=6)

Answer 3

我找到了一种手动绘制到水平图面板并在所有单元格上绘制对角线填充图案的方法，其值大于0.5

但是，我无法在颜色键图例中绘制相同的图案。经过几个小时的阅读论坛并试图理解格子源代码，我无法得到线索。也许别人可以解决这个问题。这是我得到的：

library(lattice)
library(RColorBrewer)
cols <- colorRampPalette(brewer.pal(8, "RdBu"))

data <- Harman23.cor$cov    

fx <- fy <- c()
for (r in seq(nrow(data)))
  for (c in seq(ncol(data)))
  {
    if (data[r, c] > 0.5)
    {
      fx <- c(fx, r);
      fy <- c(fy, c);
    }
  }

diag_pattern <- function(...)
{
  panel.levelplot(...)
  for (i in seq(length(fx)))
  {
    panel.linejoin(x = c(fx[i],fx[i]+.5), y= c(fy[i]+.5,fy[i]), col="black")
    panel.linejoin(x = c(fx[i]-.5,fx[i]+.5), y= c(fy[i]+.5,fy[i]-.5), col="black")
    panel.linejoin(x = c(fx[i]-.5,fx[i]), y= c(fy[i],fy[i]-.5), col="black")   
  }
}      

p <- levelplot(data, scales=list(x=list(rot=45)), 
               xlab="", ylab="", col.regions=cols, panel=diag_pattern)
print(p)