Description Usage Arguments Value Author(s) Examples
View source: R/recolorPhylopic.R
This function adds transparency and/or change color of a picture (array).
1 | recolorPhylopic(img, alpha = 0.2, color = NULL)
|
img |
array a picture loaded by |
alpha |
numeric transparency factor between 0 (transparent) and 1 (opaque). |
color |
array a color name (e.g. "red", "steelblue") or an hexadecimal value (e.g. "#ff0000") |
This function returns a picture matrix with colors and/or transparency altered.
This matrix can be plotted with the function graphics::rasterImage()
(see examples).
Nicolas CASAJUS, nicolas.casajus@fondationbiodiversite.com
Nicolas LOISEAU, nicolas.loiseau1@gmail.com
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 | # Download Rlogo in png format
download.file(
url = "https://www.r-project.org/logo/Rlogo.png",
destfile = "Rlogo.png"
)
# Import Rlogo (require `png` package)
rlogo <- png::readPNG("Rlogo.png")
# Get image dimensions
xmax <- dim(rlogo)[2]
ymax <- dim(rlogo)[1]
# Remove figure margins
o_par <- par()
par(mar = rep(0, 4))
### ORIGINAL IMAGE ------
# Empty plot
xmin <- 0
ymin <- xmin
plot(
x = xmin,
x = ymin,
xlim = c(xmin, xmax), # X-axis extent (number of image rows)
ylim = c(ymin, ymax), # Y-axis extent (number of image cols)
asp = 1, # Preserve x-axis/y-axis ratio
ann = FALSE, # Remove figure annotations
axes = FALSE, # Remove figure axes
type = "n" # Remove figure data
)
# Add Rlogo
graphics::rasterImage(
image = rlogo,
xleft = xmin,
ybottom = ymin,
xright = xmax,
ytop = ymax,
angle = 0
)
### IMAGE WITH TRANSPARENCY ------
# Empty plot
plot(
x = 0,
xlim = c(0, xmax),
ylim = c(0, ymax),
asp = 1,
ann = FALSE,
axes = FALSE,
type = "n"
)
# Add transparency
rlogo_alpha <- recolorPhylopic(rlogo, alpha = 0.25, color = NULL)
# Add Rlogo
graphics::rasterImage(
image = rlogo_alpha,
xleft = 0,
ybottom = 0,
xright = xmax,
ytop = ymax,
angle = 0
)
### MONOCHROMATIC IMAGE ------
# Empty plot
plot(
x = 0,
xlim = c(0, xmax),
ylim = c(0, ymax),
asp = 1,
ann = FALSE,
axes = FALSE,
type = "n"
)
# Add transparency
rlogo_blue <- recolorPhylopic(rlogo, alpha = 1, color = "steelblue")
# Add Rlogo
graphics::rasterImage(
image = rlogo_blue,
xleft = 0,
ybottom = 0,
xright = xmax,
ytop = ymax,
angle = 0
)
# Delete downloaded Rlogo
file.remove("Rlogo.png")
# Reset default par()
par(o_par)
|
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