Write an image file.
write.image(img, file = "tmp.ppm", max.x=NULL, max.y=NULL, depth = NULL, gammatype="ITU",
whitep = NULL, temp = NULL, cspace = NULL, black = 0, exposure = 1)
image data, an object of class "adimpro".
file name, the extension determines the image file format.
maximum value of pixels in x dimension.
maximum value of pixels in y dimension.
color depth, either 8 or 16 (bit)! The value is reset to 8 if the specified image file format does not allow for 16 Bit encoding.
character, determines the type of gamma correction within the image.
"ITU" stands for ITU-R BT.709-3 as e.g. used by dcraw
. Alternatives recognized
within the package are "None", "sRGB" and "CIE" (CIE L*). NULL
keeps the actual setting.
gammatype="histogram"
forces histogram equalization based on the corresponding greyvalue image.
defines the output color space, default is img$cspace
can be set to "sRGB", "Adobe" (Adobe 1998), "wGamut" (Wide Gamut), "kodak" (Kodak ProPhoto)
"xyz", "yuv", "yiq" and "hsi"
White point in xyY
space. Can be given as one of (character)
c("A","B","C","E","D50","D55","D65","D75","F2","F7","F11")
or as a two element numeric
vector of chromatic xy
coordinates. "D65"
corresponds to the default white point of "sRGB"
and "Adobe"
RGB-spaces. NULL
keeps the actual setting.
Color temperature. Can be used to specify chromatic xy
coordinates of the
whitepoint. Only used if is.null(whitep)
.
Adjustment for black color. Color values with luminance <= black will be assigned to black in RGB. Adjustment ist done in xyY space.
Multiplicative factor for all color channels (in xyz or rgb spaces). Applied in linear color space, i.e. if the image is gamma corrected the gamma correction is reversed first.
Nothing is returned.
This function writes the image data in img
to the file
file
. Color depth depth
is used for writing, but if
image has a component "depth", this argument will be ignored. Note: Not
all target formats support 16bit coding. The target format is
determined from the file extension, and should be one of the many that
ImageMagick supports.
Note that write image by default applies a gamma correction with gammatype="ITU"
.
This provides a good standard for display on a screen. For printing
cspace="Adobe"
should be prefered. Images that are intended for further editing should preferably be saved in an image format that allows for
16Bit depth (tiff, png) using either cspace="Adobe"
, cspace="wGamut"
or cspace="kodak"
and preferably no gamma
correction to prevent from additional loss of information.