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Mathematica Import/Export Format

PNM (.pnm)

MIME types: image/x-portable-anymap, image/pbm
PNM raster image format.
Generic format of the Portable family of image formats.
Includes the PBM (monochrome), PGM (gray-level) and PPM (RGB color) image formats.
Native format of the Netpbm graphics software package.
Primarily used as an intermediate file format on Unix systems.
PNM is an acronym derived from Portable Any Map.
ASCII or binary format.
Stores raster images formatted as plain text, representing each pixel as color values.
  • Export creates binary PNM files.
  • If multiple images are present in a PNM file, Import returns the first of the images.
  • Import["file.pnm"] imports a PNM file, returning a graphics object.
  • Export["file.pnm", expr] exports graphics or any other expression as a PNM raster image.
  • Export by default generates binary PNM files.
  • Import["file.pnm"] returns an expression of the form Graphics[Raster[data], opts], where data is an array of color values.
  • Export["file.pnm", expr] creates a PNM image with the same image size as the displayed form of expr.
  • Because PNM is a raster image format, all fonts are rasterized on export.
  • Import["file.pnm", elem] imports the specified element from a PNM file.
  • Import["file.pnm", {elem, suba, subb, ...}] imports a subelement.
  • Import["file.pnm", {{elem1, elem2, ...}}] imports multiple elements.
  • The import format can be specified with Import["file", "PNM"] or Import["file", {"PNM", elem, ...}].
  • Export["file.pnm", expr, elem] creates a PNM file by treating expr as specifying element elem.
  • Export["file.pnm", {expr1, expr2, ...}, {{elem1, elem2, ...}}] treats each expri as specifying the corresponding elemi.
  • Export["file.pnm", expr, opt1->val1, ...] exports expr with the specified option elements taken to have the specified values.
  • Export["file.pnm", {elem1->expr1, elem2->expr2, ...}, "Rules"] uses rules to specify the elements to be exported.
  • See the reference pages for full general information on Import and Export.
  • In the notebook front end, Insert ► Picture and the Open menu allow import of a PNM file into a cell.
  • Save Selection As exports the selected part of a notebook as a PNM file.
"Elements" list of elements and options available in this file
"Rules"full list of rules for each element and option
"Options"list of rules for options, properties and settings
  • Data representation elements:
"Data"array of color values
"Graphics"Graphics object representing an image
"GrayLevels"array of normalized gray-level values
"RGBColorArray"array of RGBColor objects
  • Import and Export by default use the "Graphics"element for PNM files.
"ImageSize"raster dimensions
  • General option:
ImageSizeAutomaticoverall image size
"ColorMap"Nonedetermines the color-reduction palette used for representing the imported PNM image
"DitheringMethod""FloydSteinberg"the dithering method used when color reduction is performed on Import
  • The following settings can be given for "ColorMap":
Automaticchooses an adaptive set of at most 256 colors
nadaptive set of at most n colors
{color1, color2, ...}list of RGBColor objects
Noneno color reduction is performed
  • The "DitheringMethod" option specifies the dithering algorithm used for generating the color-reduction palette on Import:
"FloydSteinberg"Floyd-Steinberg error diffusion dithering
Noneno dithering is used
"ImageTopOrientation"Toporientation of the exported image
  • Detailed property:
"ColorSpace"Automaticcolor space of the image