Crop images and templates

Remove or add margins to images and templates.

Usage

crop(
  stimuli,
  width = 1,
  height = 1,
  x_off = NULL,
  y_off = NULL,
  fill = wm_opts("fill")
)

Arguments

stimuli

list of stimuli

width, height

dimensions of cropped image in pixels or proportion (<2)

x_off, y_off

offset in pixels or proportion (<1) (NULL centers cropped image)

fill

background color if cropping goes outside the original image, see color_conv()

Value

list of stimuli with cropped tems and/or images

Details

Dimensions and offsets can be set in pixels or proportions. For width and height, values less than 2 will be interpreted as proportions, otherwise pixels. For x_off and y_off, values between -1 and 1 are interpreted as proportions, otherwise pixels.

Cropping is anchored at the image center (or calculated template centroid if there is no image) unless x_off or y_off are set.

See also

Stimulus manipulation functions align(), crop_tem(), greyscale(), horiz_eyes(), image_func(), mask_oval(), mask(), mirror(), pad(), resize(), rotate(), to_size()

Examples

stimuli <- demo_stim()

# crop to 60% width and 80% height (centered)
crop(stimuli, width = .60, height = .80)


# crop to upper right quadrant
crop(stimuli, .5, .5, x_off = .5, y_off = 0)


# \donttest{
# negative offset with fill
crop(stimuli, 260, 260, 
     x_off = -10, y_off = -10, 
     fill = c("red", "dodgerblue"))

# }