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有谁知道里面的哪个参数geom_abline()不影响 x 和 y 比例?

draw_panel()w/i函数GeomAbline获取底层的“范围”,但该线通常应该位于原始比例之外:

GeomAbline <- ggproto("GeomAbline", Geom,
  draw_panel = function(data, panel_params, coord) {
    ranges <- coord$backtransform_range(panel_params)

    data$x    <- ranges$x[1]
    data$xend <- ranges$x[2]
    data$y    <- ranges$x[1] * data$slope + data$intercept
    data$yend <- ranges$x[2] * data$slope + data$intercept

    GeomSegment$draw_panel(unique(data), panel_params, coord)
  },

  default_aes = aes(colour = "black", size = 0.5, linetype = 1, alpha = NA),
  required_aes = c("slope", "intercept"),

  draw_key = draw_key_abline
)

我的猜测是参数/函数ggplot2::StatIdentityggplot2::PositionIdentity设置ggplot2:layer()geom_abline(). 但我不明白这是如何工作的?我的动机是写一个新geom_*的也不影响 x 和 y 比例。

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1 回答 1

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根据@teunbrand 的评论,解决方案如下:

在内部ggplot2::scale_x_continuous()只有以下美学会影响 x 缩放:c("x", "xmin", "xmax", "xend", "xintercept", "xmin_final", "xmax_final", "xlower", "xmiddle", "xupper", "x0"). 但是,由于geom_abline()不包含任何这些美学,因此不影响尺度。

这同样适用于 y 缩放。顺便说一句,这些变量对应于ggplot2:::ggplot_global$x_aes和中的字符ggplot2:::ggplot_global$y_aes,但由于我不知道的原因,它们没有被使用。

为了说明我已经改写geom_point()了,但与美学c("x_new", "y")

geom_my_point <- function(mapping = NULL, data = NULL, stat = "identity",
                            position = "identity", na.rm = FALSE,
                            show.legend = NA, inherit.aes = TRUE, ...) {
  ggplot2::layer(
    geom = GeomMyPoint, mapping = mapping,
    data = data, stat = stat, position = position,
    show.legend = show.legend, inherit.aes = inherit.aes,
    params = list(na.rm = na.rm, ...)
  )
}


GeomMyPoint <- ggplot2::ggproto("GeomMyPoint", ggplot2::GeomPoint,
  required_aes = c("x_new", "y"),
  
  draw_panel = function(data, panel_scales, coord) {
    if (is.character(data$shape)) {
      data$shape <- translate_shape_string(data$shape)
    }

    ## Transform the data first
    coords <- coord$transform(data, panel_scales)

    ## Construct a grid grob
    grid::pointsGrob(
      x = coords$x_new,
      y = coords$y,
      pch = coords$shape,
      gp = grid::gpar(
        col = alpha(coords$colour, coords$alpha),
        fill = alpha(coords$fill, coords$alpha),
        fontsize = coords$size * ggplot2::.pt + coords$stroke * ggplot2::.stroke / 2,
        lwd = coords$stroke * ggplot2::.stroke / 2
      )
    )
  }
)

geom_my_point()with noesthetic的输出x对应于图形“gg2”;因此红点不会影响 x 比例:

d <- data.frame(x = runif(200))
d$y <- 1 * d$x + rnorm(200, 0, 0.2)
d$x2 <- d$x * 2

require("ggplot2")
gg1 <- ggplot(d) + geom_point(aes(x, y)) + geom_point(aes(x = x2, y = y), col = 2) + ggtitle("gg1")
gg2 <- ggplot(d) + geom_point(aes(x, y)) + geom_my_point(aes(x_new = x2, y = y), col = 2) + ggtitle("gg2")

在此处输入图像描述

于 2021-10-21T14:23:13.140 回答