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Import/Export 导入/导出 格式

PNG (.png)

Registered MIME type: image/png
PNG raster image format.
Commonly used for graphics and photographic images on the web.
PNG is an acronym for Portable Network Graphics.
Binary format.
Stores a single image.
Stores color bitmaps at a resolution of 8 or 16 bits per channel.
Grayscale images are represented at a depth of 1, 2, 4, 8 or 16 bits per pixel.
Supports alpha channels for 8-bit and 16-bit RGB and grayscale images.
Has support for color-reduction palettes using up to 256 8-bit RGB colors.
Developed in 1995 as an open and patent-free alternative to the GIF format.
Published as international standard ISO/IEC 15948:2003 and ISO/IEC 15948:2004.
  • Import and Export fully support Version 1.2 of the PNG format.
  • Import["file.png"] imports a PNG file as an image.
  • Export["file.png", expr] exports an image, graphics or any other expression as a raster image to PNG.
  • When exporting Mathematica graphics or arbitrary expressions to PNG, the resulting image has the same raster size as its displayed form.
  • Image objects are by default exported at their raster size.
  • Because PNG is a raster image format, all fonts are rasterized on export.
  • Import["file.png", elem] imports the specified element from a PNG file.
  • Import["file.png", {elem, suba, subb, ...}] imports a subelement.
  • Import["file.png", {{elem1, elem2, ...}}] imports multiple elements.
  • The import format can be specified with Import["file", "PNG"] or Import["file", {"PNG", elem, ...}].
  • Export["file.png", expr, elem] creates a PNG file by treating expr as specifying element elem.
  • Export["file.png", {expr1, expr2, ...}, {{elem1, elem2, ...}}] treats each expri as specifying the corresponding elemi.
  • Export["file.png", expr, opt1->val1, ...] exports expr with the specified option elements taken to have the specified values.
  • Export["file.png", {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.
"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
"Image"raster image, given as an Image object
"GrayLevels"array of normalized gray-level values
"RGBColorArray"array of RGBColor objects
  • Import and Export by default use the "Image" element for PNG files.
  • Elements of PNG files using a color-reduction palette:
"ColorMap"color-reduction palette used in the file
"RawData"array of color indices
"BitDepth"bits used to represent each color channel in the file
"ColorSpace"color encoding used in the file
"ImageSize"raster dimensions
  • General option:
ImageSizeAutomaticoverall image size
"ImageTopOrientation"Toporientation of the exported image
Import a PNG file as an image:
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Show the elements that can be imported from this file:
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Get the "BitDepth" and "ImageSize" elements:
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Export arbitrary inline graphics to PNG:
In[1]:=
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Export a Mathematica expression as a raster to PNG:
In[1]:=
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In[2]:=
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