| geometry {magick} | R Documentation |
Geometry Helpers
Description
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.
Usage
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)
Arguments
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 |
Details
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
See Also
Other image:
_index_,
analysis,
animation,
attributes(),
color,
composite,
defines,
device,
edges,
editing,
effects(),
fx,
morphology,
ocr,
options(),
painting,
segmentation,
transform(),
video
Examples
# 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))