PNGFormat

Zusammenfassung

The PNGFormat object represents a collection of Portable Network Graphics (PNG) file properties that can be configured and used with the export method on the Layout, MapFrame, and MapView objects to create an output PNG file.

Diskussion

PNG is a versatile raster format that can be displayed in web browsers and inserted into other documents. It supports high-bit-depth color and uses a lossless compression. For maps, PNG is often the best raster format, since the lossless compression keeps text and line work legible by preventing the compression artifacts that can occur in JPEG format. PNG files can also define a transparent color; part of the image can be displayed as transparent in a web browser, allowing backgrounds, images, or colors to show through. PNGs can be generated with an accompanying world file for use as georeferenced raster data.

The createExportFormat method can be used to create a PNGFormat object if the format parameter is set to PNG. The returned PNGFormat object contains all the properties associated with a generating a PNG file. These properties can be modified accordingly to produce different output results.

Eigenschaften

Eigenschaft	Erläuterung	Datentyp
clipToElements (Lesen und schreiben)	If set to True, include the areas of the page that have map or layout element content only, rather than exporting the entire page. This property only applies when exporting a Layout object. The default value is False.	Boolean
colorMode (Lesen und schreiben)	A string constant that represents the number of bits to describe color in a pixel. The default value is 32-BIT_WITH_ALPHA. 1-BIT_MONOCHROME_THRESHOLD— 2 possible colors, black and white. The areas which are white and black are determined by the threshold value. 8-BIT_ADAPTIVE_PALETTE—Uses 256 of the most commonly-used pixel colors in the image’s palette, thereby minimizing the number of pixels whose color may change during output. 8-BIT_GRAYSCALE— 256 shades of gray. All colors are converted to grayscale. 24-BIT_TRUE_COLOR—16,777,216 possible colors. This option is good for maximum color fidelity. 32-BIT_WITH_ALPHA—16,777,216 possible colors and an alpha (transparency) channel of 255 values. This option is useful for maps or layouts with transparency.	String
filePath (Lesen und schreiben)	A string that represents the system path and file name, including the extension, for the exported file.	String
geoReferenceMapFrame (Lesen und schreiben)	The MapFrame used to control the coordinate system when the worldFile property is set to True. The default value is None.	MapFrame
height (Lesen und schreiben)	The height, in pixels, of the map area to be exported. This property only applies when exporting a MapView object. The default value is 960.	Double
resolution (Lesen und schreiben)	The effective dpi of the output vector data. The default value is 96. Hinweis: When exporting a MapView, the dpi is calculated automatically using system dpi scaling and therefore this value will be ignored.	Integer
showSelectionSymbology (Lesen und schreiben)	Show selected features in the map or map frame as selected in the output file. Setting this value to False does not affect selection within the view, only in the output file. The default value is False.	Boolean
threshold (Lesen und schreiben)	Image intensities set above this value will appear white in the output file and all other values will appear black. This property is applied only when the colorMode property is set to 1-BIT_MONOCHROME_THRESHOLD. The default value is 128.	Boolean
transparentBackground (Lesen und schreiben)	If set to True, export a transparent page instead of a white page. This property only applies when exporting a Layout object. The default value is False. Hinweis: Transparent backgrounds are only supported when colorMode is set to 32-BIT_WITH_ALPHA. This option is not available for maps, but transparency on a map is honored on export.	Boolean
width (Lesen und schreiben)	The width, in pixels, of the map area to be exported. This property only applies when exporting a MapView object. The default value is 960.	Double
worldFile (Lesen und schreiben)	If set to True and a valid georef_mapframe is set, a world file will be generated based on the map frame's coordinate system. The default value is False.	Boolean

Methodenübersicht

Methode	Erläuterung
setColorMode (color_mode)	A string constant that represents the number of bits to describe color in a pixel.

Methoden

setColorMode (color_mode)

Parameter	Erläuterung	Datentyp
color_mode	Below is a list of valid strings. 1-BIT_MONOCHROME_THRESHOLD— 2 possible colors, black and white. The areas which are white and black are determined by the threshold value. 8-BIT_ADAPTIVE_PALETTE—Uses 256 of the most commonly-used pixel colors in the image’s palette, thereby minimizing the number of pixels whose color may change during output. 8-BIT_GRAYSCALE— 256 shades of gray. All colors are converted to grayscale. 24-BIT_TRUE_COLOR— 16,777,216 possible colors. This option is good for maximum color fidelity. 32-BIT_WITH_ALPHA— 16,777,216 possible colors and an alpha (transparency) channel of 255 values. This option is useful for maps or layouts with transparency.	String

Codebeispiel

PNGFormat example

The following script exports a layout to PNG format using default property values.

p = arcpy.mp.ArcGISProject('current')
lyt = p.listLayouts()[0]

png = arcpy.mp.CreateExportFormat('PNG', r'C:\Temp\Output.png')

lyt.export(png)