R语言简单程序代码 r语言编写程序

作者简介

作者：吴健 中国科学院大学 R语言、统计学爱好者，尤其擅长R语言和Arcgis在生态领域的应用分享

上一期我们已经对R语言绘制基本矩形框，文本和线条进行了介绍，本文将在上一期的基础上，通过自编函数快速绘制流程图。

第一步：自定义绘制基本矩形和文本的函数。利用该函数可以快速的根据字段的长度和宽度绘制相应的矩形框，该矩形框为流程图的基本图元。

tableBox <- function(labels, x=0.5, y=0.5) {

    nlabel <- length(labels)#确定标签个数

    taplevp <- viewport(x=x, y=y, width=max(stringWidth(labels))+ unit(4, "mm"),

                        height=unit(nlabel, "lines"))#根据标签的多少绘制矩形框

    pushViewport(taplevp)

    grid.roundrect()

    if (nlabel > 1) {

        for (i in 1:(nlabel-1)) {

            fill <- c("white", "grey")[i%%2+1]

            grid.clip(y=unit(i, "lines"), just="bottom")

            grid.roundrect(gp=gpar(fill=fill))

        }

    }

    grid.clip()#绘制灰色阴影

    grid.text(labels, x=unit(2, "mm"), y=unit(nlabel:1-0.5, 'lines'),just='left')#添加文本

    popViewport()

}

第二步：确定矩形框在绘图窗口的位置，并以该位置为连接线的起点和终点，绘制带箭头的连接线。

boxGrob <- function(labels, x=0.5, y=0.5) {

    grob(labels=labels, x=x, y=y, cl="box")

}#存储矩形框的基本信息


drawDetails.box <- function(x, ...) {

    tableBox(x$labels, x$x, x$y)

}#确定矩形框的基本位置


xDetalis.box <- function(x, theta) {

    nlines <- length(x$labels)

    height <- unit(nlines, 'lines')

    width <- unit(4, "mm")+max(stringWidth(x$labels)) 

    grobX(roundrectGrob(x=x$x, y=x$y, width=width, height=height), theta)

}#确定矩形框在X轴的位置（东西方向）


yDetalis.box <- function(x, theta) {

    nlines <- length(x$labels)

    height <- unit(nlines, 'lines')

    width <- unit(4, "mm")+max(stringWidth(x$labels)) 

    grobY(rectGrob(x=x$x, y=x$y, width=width, height=height), theta)

}#确定矩形框在Y轴的位置（南北方向）

第三步：以上述两个函数为基础绘制流程图

library(grid)

#确定矩形框的大小和矩形框里面的标签

box1 <- boxGrob(c("book_author_table", "ID", "book", "author"),x=0.25)

box2 <- boxGrob(c("book_table", "ISBN", "title", "pub"), x=0.6, y=0.75)

box3 <- boxGrob(c("author_table", "ID", "name", "gender"), x=0.6, y=0.25)

box4 <- boxGrob(c("publisher_table", "ID", "name","country"), x=0.85,y=0.75)

box5 <- boxGrob(c("gender_table", "ID", "gender"), x=0.85,y=0.25)

#绘制矩形框及标签

grid.draw(box1)

grid.draw(box2)

grid.draw(box3)

grid.draw(box4)

grid.draw(box5)

#绘制不同矩形框之间的连接线

grid.curve(xDetalis.box(box1, "east"),

    yDetalis.box(box1, "south")+ unit(1.5, "lines") ,

    xDetalis.box(box2, "west"),

    yDetalis.box(box2, "north")- unit(1.5, "lines") ,

    inflect=TRUE,

    arrow=arrow(type="closed",angle=15,length=unit(2, "mm")),gp=gpar(fill="black"))


grid.curve(xDetalis.box(box1, "east"),

    yDetalis.box(box1, "north") - unit(3.5, "lines"),

    xDetalis.box(box3, "west"),

    yDetalis.box(box3, "south") + unit(2.5, "lines"),

    inflect=T, square=T,curvature=-1,

    arrow=arrow(type="closed", angle=15, length=unit(2, "mm")), gp=gpar(fill="black"))


grid.curve(xDetalis.box(box2, "east"),

    yDetalis.box(box2, "south") + unit(0.5, "lines"),

    xDetalis.box(box4, "west"),

    yDetalis.box(box4, "north") - unit(1.5, "lines"),

    inflect=TRUE,

    arrow=arrow(type="closed", angle=15, length=unit(2, "mm")), gp=gpar(fill="black"))


grid.curve(xDetalis.box(box3, "east"),

    yDetalis.box(box3, "south") + unit(0.5, "lines"),

    xDetalis.box(box5, "west"),

    yDetalis.box(box5, "north")- unit(1.5, "lines"),

    inflect=TRUE,

    arrow=arrow(type="closed", angle=15, length=unit(2, "mm")), gp=gpar(fill="black"))