ggplot2: Ändern des Layouts der Legende

Question

Im Moment sieht die Legende standardmäßig etwa so:

Legend Title 
x-1 
y-2 
z-3 

Aber ist es möglich, es so etwas wie dies aussehen zu lassen?

Legend Title 
x-1 y-2 z-3 

Answer 1

und hier ist ein Hack. kann es Fehler sein, aber:

build_legend <- function(name, mapping, layers, default_mapping, theme) { 
    legend_data <- plyr::llply(layers, build_legend_data, mapping, default_mapping) 

    # determine if the elements are aligned horizontally or vertically 
    horiz<-(!is.null(theme$legend.align) && theme$legend.align=="horizontal") 

    # Calculate sizes for keys - mainly for v. large points and lines 
    size_mat <- do.call("cbind", plyr::llply(legend_data, "[[", "size")) 
    if (is.null(size_mat)) { 
    key_sizes <- rep(0, nrow(mapping)) 
    } else { 
    key_sizes <- apply(size_mat, 1, max) 
    } 

    title <- theme_render(
    theme, "legend.title", 
    name, x = 0, y = 0.5 
) 

             # Compute heights and widths of legend table 
    nkeys <- nrow(mapping) 
    hgap <- vgap <- unit(0.3, "lines") 

    numeric_labels <- all(sapply(mapping$.label, is.language)) || suppressWarnings(all(!is.na(sapply(mapping$.label, "as.numeric")))) 
    hpos <- numeric_labels * 1 

    labels <- lapply(mapping$.label, function(label) { 
    theme_render(theme, "legend.text", label, hjust = hpos, x = hpos, y = 0.5) 
    }) 

    # align horizontally 
    if(!horiz){ 
    label_width <- do.call("max", lapply(labels, grobWidth)) 
    label_width <- convertWidth(label_width, "cm") 
    label_heights <- do.call("unit.c", lapply(labels, grobHeight)) 
    label_heights <- convertHeight(label_heights, "cm") 

    width <- max(unlist(plyr::llply(legend_data, "[[", "size")), 0) 
    key_width <- max(theme$legend.key.size, unit(width, "mm")) 

    widths <- unit.c(
        hgap, key_width, 
        hgap, label_width, 
        max(
         unit(1, "grobwidth", title) - key_width - label_width, 
         hgap 
         ) 
        ) 
    widths <- convertWidth(widths, "cm") 

    heights <- unit.c(
         vgap, 
         unit(1, "grobheight", title), 
         vgap, 
         unit.pmax(
           theme$legend.key.size, 
           label_heights, 
           unit(key_sizes, "mm") 
           ), 
         vgap 
        ) 
    heights <- convertHeight(heights, "cm") 

    }else{ 
    label_width <- do.call("unit.c", lapply(labels, grobWidth)) 
    label_width <- convertWidth(label_width, "cm") 
    label_heights <- do.call("max", lapply(labels, grobHeight)) 
    label_heights <- convertHeight(label_heights, "cm") 

    height <- max(unlist(plyr::llply(legend_data, "[[", "size")), 0) 
    key_heights <- max(theme$legend.key.size, unit(height, "mm")) 

    key_width <- unit.pmax(theme$legend.key.size, unit(key_sizes, "mm")) 
    # width of (key gap label gap) x nkeys 
    kglg_width<-do.call("unit.c",lapply(1:length(key_width), function(i)unit.c(key_width[i], hgap, label_width[i], hgap))) 
    widths <- unit.c(
         hgap, 
         kglg_width, 
         max(
          unit(0,"lines"), 
          unit.c(unit(1, "grobwidth", title) - (sum(kglg_width) - hgap)) 
         ) 
        ) 
    widths <- convertWidth(widths, "cm") 

    heights <- unit.c(
         vgap, 
         unit(1, "grobheight", title), 
         vgap, 
         max(
          theme$legend.key.size, 
          label_heights, 
          key_heights 
          ), 
         vgap 
         ) 
    heights <- convertHeight(heights, "cm") 

    } 

    # Layout the legend table 
    legend.layout <- grid.layout(
    length(heights), length(widths), 
    widths = widths, heights = heights, 
    just = c("left", "centre") 
) 

    fg <- ggname("legend", frameGrob(layout = legend.layout)) 
    fg <- placeGrob(fg, theme_render(theme, "legend.background")) 

    fg <- placeGrob(fg, title, col = 2:(length(widths)-1), row = 2) 
    for (i in 1:nkeys) { 

    if(!horiz){ 
     fg <- placeGrob(fg, theme_render(theme, "legend.key"), col = 2, row = i+3) 
    }else{ 
     fg <- placeGrob(fg, theme_render(theme, "legend.key"), col = 1+(i*4)-3, row = 4) 
    } 

    for(j in seq_along(layers)) { 
     if (!is.null(legend_data[[j]])) { 
     legend_geom <- Geom$find(layers[[j]]$geom$guide_geom()) 
     key <- legend_geom$draw_legend(legend_data[[j]][i, ], 
      c(layers[[j]]$geom_params, layers[[j]]$stat_params)) 
     if(!horiz){ 
      fg <- placeGrob(fg, ggname("key", key), col = 2, row = i+3) 
     }else{ 
      fg <- placeGrob(fg, ggname("key", key), col = 1+(i*4)-3, row = 4) 
     } 
     } 
    } 
    label <- theme_render(
     theme, "legend.text", 
     mapping$.label[[i]], hjust = hpos, 
     x = hpos, y = 0.5 
    ) 
    if(!horiz){ 
     fg <- placeGrob(fg, label, col = 4, row = i+3) 
    }else{ 
     fg <- placeGrob(fg, label, col = 1+(i*4)-1, row = 4) 
    } 
    } 
    fg 
} 

assignInNamespace("build_legend", build_legend, "ggplot2") 

# test and usage 
# specify by opts(legend.align="horizontal") 
p1<-qplot(mpg, wt, data=mtcars, colour=cyl)+opts(legend.align="horizontal",legend.position="bottom") 
p2<-qplot(mpg, wt, data=mtcars, colour=cyl) 

Answer 2

Es gibt etwas wie guide_legends_box mit einer Option "horizontal", aber ich kann es nicht funktionieren.

> d <- qplot(carat, price, data=dsamp, colour=clarity) + 
+ scale_color_hue("clarity") + 
+ guide_legends_box("clarity",horizontal=T) 

gibt:

Fehler in Waage $ legend_desc: $ Operator ist ungültig für die Atom Vektoren

Vielleicht wissen Sie, was los hier vor sich geht. Ich persönlich denke, dass ein Teil der in der Dokumentation erwähnten Funktionalität noch nicht implementiert ist.

Answer 3

Heutzutage kann man einfach legend.direction verwenden = "horizontal". Zum Beispiel:

qplot(carat, price, data=diamonds, colour=color) + opts(legend.position="top", legend.direction="horizontal") 

Answer 4

Die neueste ggplot2 hat opts für theme() veraltet:

qplot(carat, price, data=diamonds, colour=color) + 
    theme(legend.position="top", legend.direction="horizontal")