By default, images (such as JPEG, PNG, BMP, SVG) that are placed in panels are not scaled. This section demonstrates the four different scaling options available.
Here’s a multi-panel figure with four panels, to contain the images. In each case, we’ll use the copy of the R logo contained in the multipanelfigure package. This is a PNG file, 800 pixels wide and 700 pixels high, with a resolution of 300 dots per inch (DPI). That gives it a native size of 2.67” by 2.33”.
library(multipanelfigure)
figure <- multi_panel_figure(
width = c(1, 5),
height = c(1, 1, 4),
unit = "inches")
r_logo <- system.file("extdata/Rlogo.png", package = "multipanelfigure")
By default, the image is not rescaled, which means that only the central part of the image is displayed.
(figure %<>% fill_panel(r_logo))
## Setting row to 1
## Setting column to 1
By setting scaling = "stretch"
, all the image is
displayed, fitting the panel exactly, but the height-to-width ratio had
been altered, distorting the image.
(figure %<>% fill_panel(r_logo, scaling = "stretch"))
## Setting row to 1
## Setting column to 2
Setting scaling = "fit"
means that the image is shrunked
or grown so that it just fits inside the panel without the
height-to-width ratio being distorted.
(figure %<>% fill_panel(r_logo, scaling = "fit"))
## Setting row to 2
## Setting column to 1
Setting scaling = "shrink"
, works the same way as
scaling = "fit"
when the image is larger than the
panel.
(figure %<>% fill_panel(r_logo, scaling = "shrink", row = 3, column = 1))
If the image is smaller than the panel,
scaling = "shrink"
works like
scaling = "none"
.
(figure %<>% fill_panel(r_logo, scaling = "shrink", row = 2:3, column = 2))
By default, plots and images are clipped so that they don’t overrun the panel that they were put in. (See, for example, Panel A in the previous plot.) To demonstrate the effect of clipping, let’s use a 3 by 3 multi-panel figure, and fill all but the centre panel.
library(grid)
figure2 <- multi_panel_figure(
width = rep.int(1.25, 3),
height = rep.int(1.25, 3),
unit = "inches")
rhino <- system.file("extdata/rhino.jpg", package = "multipanelfigure")
for(position in list(c(1, 1), c(1, 2), c(1, 3), c(2, 1), c(2, 3), c(3, 1), c(3, 2), c(3, 3)))
{
figure2 %<>%
fill_panel(
rectGrob(gp = gpar(fill = "#91A45E")),
row = position[1],
column = position[2])
}
figure2
When we try to display the rhino, only the central part of the image is shown, since there is no rescaling, and the panel isn’t big enough.
(figure2 %>% fill_panel(rhino))
## Setting row to 2
## Setting column to 2