Geometry Helpers
ImageMagick uses a handy geometry syntax to specify coordinates and shapes for use in image transformations. You can either specify these manually as strings or use the helper functions below.
geometry_point(x, y) geometry_area(width = NULL, height = NULL, x_off = 0, y_off = 0) geometry_size_pixels(width = NULL, height = NULL, preserve_aspect = TRUE) geometry_size_percent(width = 100, height = NULL)
x |
left offset in pixels |
y |
top offset in pixels |
width |
in pixels |
height |
in pixels |
x_off |
offset in pixels on x axis |
y_off |
offset in pixels on y axis |
preserve_aspect |
if FALSE, resize to width and height exactly, loosing original
aspect ratio. Only one of |
See ImageMagick Manual
for details about the syntax specification.
Examples of geometry strings:
"500x300" – Resize image keeping aspect ratio, such that width does not exceed 500 and the height does not exceed 300.
"500x300!" – Resize image to 500 by 300, ignoring aspect ratio
"500x" – Resize width to 500 keep aspect ratio
"x300" – Resize height to 300 keep aspect ratio
"50%x20%" – Resize width to 50 percent and height to 20 percent of original
"500x300+10+20" – Crop image to 500 by 300 at position 10,20
# Specify a point
logo <- image_read("logo:")
image_annotate(logo, "Some text", location = geometry_point(100, 200), size = 24)
# Specify image area
image_crop(logo, geometry_area(300, 300), repage = FALSE)
image_crop(logo, geometry_area(300, 300, 100, 100), repage = FALSE)
# Specify image size
image_resize(logo, geometry_size_pixels(300))
image_resize(logo, geometry_size_pixels(height = 300))
image_resize(logo, geometry_size_pixels(300, 300, preserve_aspect = FALSE))
# resize relative to current size
image_resize(logo, geometry_size_percent(50))
image_resize(logo, geometry_size_percent(50, 20))Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.