R 如何按定义的顺序将图像合并到一个文件中

我有大约100张图片（png）。我不想手动操作，而是希望将它们按定义的顺序（基于文件名）放在一个单独的pdf中（每行12个图像）

有人有什么建议吗

我试着按照托马斯在下面告诉我的，把它们贴在旁边，留一个黑色的边距，我怎样才能去掉它

setwd(workingDir);
files <- list.files(path=".", pattern="*.png", all.files=T, full.names=T)
filelist <- lapply(files, readPNG)
names(filelist) <- paste0(basename((files)))
list2env(filelist, envir=.GlobalEnv)


par(mar=rep(0,4))
layout(matrix(1:length(names(filelist)), ncol=15, byrow=TRUE))

for(i in 1:length(names(filelist))) {
  img <- readPNG(names(filelist[i]))
  plot(NA,xlim=0:1,ylim=0:1,xaxt="n",yaxt="n")
  rasterImage(img,0,0,1,1)
}


dev.print(pdf, "output.pdf") 

setwd（工作目录）；
文件您可以使用
光栅图像
功能和png包将它们全部打印在一起。下面是一个简单的例子，展示了如何在PNG中读取，然后（多次）打印

library（“png”）#用于在png中阅读
#示例图像
img请注意，Thomas概述的解决方案在多平面图像中引入了一些源图像中不存在的空白。将参数
xaxs='i'
和
yaxs='i'
添加到
plot（）
将删除它

library("png") # for reading in PNGs

# example image
img <- readPNG(system.file("img", "Rlogo.png", package="png"))

# setup plot
dev.off()
par(mai=rep(0,4)) # no margins

# layout the plots into a matrix w/ 12 columns, by row
layout(matrix(1:120, ncol=12, byrow=TRUE))

# do the plotting
for(i in 1:120) {
  plot(NA,xlim=0:1,ylim=0:1,bty="n",axes=0,xaxs = 'i',yaxs='i')
  rasterImage(img,0,0,1,1)
}

# write to PDF
dev.print(pdf, "output.pdf")

library（“png”）#用于在png中阅读
#示例图像
img有时你只想把一堆PNG图像放入一个PDF文件中，每页一个图像，以便使用PDF阅读器快速方便地查看它们。我是这样做的，在上面的解决方案的基础上，如果需要缩小图像以适应输出PDF（但保留纵横比）。这使您可以轻松地捆绑各种大小的PNG图像

library(png)
# Define a function to get the xright and ytop arguments for rasterImage()
get.raster.image.area.scaling <- function(pngfile) {
  imga <- attr(readPNG(pngfile, info=TRUE), "info")
  img.width <- imga$dim[1] / imga$dpi[1]  # width of PNG image in inches
  img.height <- imga$dim[2] / imga$dpi[2]  # height of PNG image in inches
  img.aspect <- img.height/img.width  # aspect ratio of PNG image
  ri <- list()
  if(img.width > my.width || img.height > my.height) {
    # shrink to fit output device page
    diff.width <- img.width - my.width
    diff.height <- img.height - my.height
    if(diff.width >= diff.height) {
      # shrink to fit width
      ri$width <- 1.0  # xright for rasterImage (fraction of device area)
      new.height <- img.aspect * my.width # (in)
      ri$height <- new.height/my.height  # ytop for rasterImage (fraction of device area)
    } else if(diff.height > diff.width) {
      # shrink to fit height
      ri$height <- 1.0  # ytop for rasterImage (fraction of device area)
      new.width <- my.height / img.aspect # (in)
      ri$width <- new.width/my.width  # xright for rasterImage (fraction of device area)
    } else stop("need to debug unexpected situation\n")
  } else {
    # no shrinking of PNG image needed
    ri$width <- img.width / my.width
    ri$height <- img.height / my.height
  }
  return(ri)
}  # end of get.raster.image.area.scaling()

pngfiles <- c("yourfile1.png", "yourfile2.png", "yourfile3.png")
num.png <- length(pngfiles)
my.width <- 8  # dimensions of desired PDF device output (in)
my.height <- 10
pdf(file = "testplot.pdf", width=my.width, height=my.height, pointsize=12)
par(mai=rep(0,4)) # no margins
for(i in 1:num.png) {
  img <- readPNG(pngfiles[i], native=TRUE)
  ri <- get.raster.image.area.scaling(pngfiles[i])
  plot(NA, xlim=0:1, ylim=0:1, bty="n", axes=0, xaxs = 'i', yaxs='i')
  rasterImage(img, 0, 0, ri$width, ri$height)
}
dev.off()

库（png）
#定义一个函数以获取光栅图像（）的xright和ytop参数
老实说，get.graster.image.area.scaling不知道怎么做。我以为使用“par”定义了一行中有多少图像…我尝试了你告诉我的，但我得到了一个错误。我更新了我的帖子。请看一下好吗？@EpiMan在调用
plot
时，指定
bty=“n”
（意思是boxtype=none）。
library(png)
# Define a function to get the xright and ytop arguments for rasterImage()
get.raster.image.area.scaling <- function(pngfile) {
  imga <- attr(readPNG(pngfile, info=TRUE), "info")
  img.width <- imga$dim[1] / imga$dpi[1]  # width of PNG image in inches
  img.height <- imga$dim[2] / imga$dpi[2]  # height of PNG image in inches
  img.aspect <- img.height/img.width  # aspect ratio of PNG image
  ri <- list()
  if(img.width > my.width || img.height > my.height) {
    # shrink to fit output device page
    diff.width <- img.width - my.width
    diff.height <- img.height - my.height
    if(diff.width >= diff.height) {
      # shrink to fit width
      ri$width <- 1.0  # xright for rasterImage (fraction of device area)
      new.height <- img.aspect * my.width # (in)
      ri$height <- new.height/my.height  # ytop for rasterImage (fraction of device area)
    } else if(diff.height > diff.width) {
      # shrink to fit height
      ri$height <- 1.0  # ytop for rasterImage (fraction of device area)
      new.width <- my.height / img.aspect # (in)
      ri$width <- new.width/my.width  # xright for rasterImage (fraction of device area)
    } else stop("need to debug unexpected situation\n")
  } else {
    # no shrinking of PNG image needed
    ri$width <- img.width / my.width
    ri$height <- img.height / my.height
  }
  return(ri)
}  # end of get.raster.image.area.scaling()

pngfiles <- c("yourfile1.png", "yourfile2.png", "yourfile3.png")
num.png <- length(pngfiles)
my.width <- 8  # dimensions of desired PDF device output (in)
my.height <- 10
pdf(file = "testplot.pdf", width=my.width, height=my.height, pointsize=12)
par(mai=rep(0,4)) # no margins
for(i in 1:num.png) {
  img <- readPNG(pngfiles[i], native=TRUE)
  ri <- get.raster.image.area.scaling(pngfiles[i])
  plot(NA, xlim=0:1, ylim=0:1, bty="n", axes=0, xaxs = 'i', yaxs='i')
  rasterImage(img, 0, 0, ri$width, ri$height)
}
dev.off()