readImage {EBImage} | R Documentation

## Image I/O

### Description

Functions to choose, read and write images from/to files and URL's. Supported image formats are determined by the ImageMagick installation.

### Usage

      chooseImage(colormode = Grayscale)
      readImage(files, colormode = Grayscale, ...)

      ## S4 method for signature 'Image':
      writeImage(x, files, ...)

### Arguments

`x` | An object of `Image`.
`files` | A character vector of files/URL's to read from or to write to.
`colormode` | An integer value for the color mode of images after they are read. By default all images will be converted to Grayscale on read.
`...` | Reserved.

### Details

If `files` is missing when writing images, `fileName(x)` method will be used to select a single file to write to. Otherwise, the length of this vector must be equal either 1 or the number of 2D images in the stack.

When writing images in formats supporting non-lossless compression (like JPEG), the quality can be spcified used a numeric `quality` argument with the range `[1,100]`. Higher values correspond to better quality. Defaults to 95.

The file format is deduced from the file name extension(s), there is neither a need nor a way to specify the format explicitly.

`ImageMagick` is used to perform all image I/O operations. Therefore, the package supports all the file types supported by `ImageMagick`.

When reading images, files of different formats can be mixed in any consequence, including mixing single 2D images with TIFF image stacks. The result will contain a stack of all images and stacks cropped (filled with background if images are smaller) at the size of the first image read.

`choose.image` is an interactive function that does not return to R until either Ok or Cancel button is pressed in the GUI dialog. It uses `GTK+2` File Open Dialog to select images. Multiple images can be selected and loaded at once. By default this functions reads images as `TrueColor`. This function will produce an error message if the package was compiled without `GTK+` support.

### Value

For `readImage` and `chooseImage` a new instance of `Image`.
For `writeImage` an invisible `NULL`.

### Author(s)

Oleg Sklyar, osklyar@ebi.ac.uk, 2005-2006

### References

ImageMagick: http://www.imagemagick.org.

### See Also

`Image, Image, channel`

### Examples

        f <- paste( system.file(package="EBImage"), "images/Gene1_G.tif", sep="/" )
        ii = readImage(f)
      if ( interactive() ) {
        url <- c("http://www.google.com/intl/en/images/logo.gif")
        im <- readImage (url, TrueColor)
        ## Not run: writeImage (im, "googlelogo.tif")
        ## Not run: im1 <- channel ( chooseImage(), "gray")
      }

[Package EBImage version 2.2.0 Index]