image

​
A module for capturing and manipulating image objects from other modules for use with hs.drawing.
API Overview
Constants - Useful values which cannot be changed
​additionalImageNames​
​systemImageNames​
Functions - API calls offered directly by the extension
​getExifFromPath​
Constructors - API calls which return an object, typically one that offers API methods
​iconForFile​
​iconForFileType​
​imageFromAppBundle​
​imageFromASCII​
​imageFromMediaFile​
​imageFromName​
​imageFromPath​
​imageFromURL​
Methods - API calls which can only be made on an object returned by a constructor
​colorAt​
​copy​
​croppedCopy​
​encodeAsURLString​
​getLoupedeckArray​
​name​
​saveToFile​
​setName​
​setSize​
​size​
​template​
API Documentation
Constants
​additionalImageNames​
Signature
hs.image.additionalImageNames[]
Type
Constant
Description
Table of arrays containing the names of additional internal system images which may also be available for use with hs.drawing.image and hs.image.imageFromName.
Notes
The list of these images was pulled from a collection located in the repositories at https://github.com/hetima?tab=repositories. As these image names are (for the most part) not formally listed in Apple's documentation or published APIs, their use cannot be guaranteed across all OS X versions. If you identify any images which may be missing or could be added, please file an issue at https://github.com/Hammerspoon/hammerspoon.
​systemImageNames​
Signature
hs.image.systemImageNames[]
Type
Constant
Description
Table containing the names of internal system images for use with hs.drawing.image
Notes
Image names pulled from NSImage.h
This table has a __tostring() metamethod which allows listing it's contents in the Hammerspoon console by typing hs.image.systemImageNames.
Functions
​getExifFromPath​
| Signature | hs.image.getExifFromPath(path) -> table | nil | | -----------------------------------------------------|---------------------------------------------------------------------------------------------------------| | Type | Function | | Description | Gets the EXIF metadata information from an image file. | | Parameters |
path - The path to the image file.
| | Returns |
A table of EXIF metadata, or nil if no metadata can be found or the file path is invalid.
|
Constructors
​iconForFile​
Signature
hs.image.iconForFile(file) -> object
Type
Constructor
Description
Creates an hs.image object for the file or files specified
Parameters
file - the path to a file or an array of files to generate an icon for.
Returns
An hs.image object or nil, if there was an error. The image will be the icon for the specified file or an icon representing multiple files if an array of multiple files is specified.
​iconForFileType​
Signature
hs.image.iconForFileType(fileType) -> object
Type
Constructor
Description
Creates an hs.image object of the icon for the specified file type.
Parameters
fileType - the file type, specified as a filename extension or a universal type identifier (UTI).
Returns
An hs.image object or nil, if there was an error
​imageFromAppBundle​
Signature
hs.image.imageFromAppBundle(bundleID) -> object
Type
Constructor
Description
Creates an hs.image object using the icon from an App
Parameters
bundleID - A string containing the bundle identifier of an application
Returns
An hs.image object or nil, if no app icon was found
​imageFromASCII​
Signature
hs.image.imageFromASCII(ascii[, context]) -> object
Type
Constructor
Description
Creates an image from an ASCII representation with the specified context.
Parameters
ascii - A string containing a representation of an image
context - An optional table containing the context for each shape in the image. A shape is considered a single drawing element (point, ellipse, line, or polygon) as defined at https://github.com/cparnot/ASCIImage and http://cocoamine.net/blog/2015/03/20/replacing-photoshop-with-nsstring/.
The context table is an optional (possibly sparse) array in which the index represents the order in which the shapes are defined. The last (highest) numbered index in the sparse array specifies the default settings for any unspecified index and any settings which are not explicitly set in any other given index.
Each index consists of a table which can contain one or more of the following keys:
fillColor - the color with which the shape will be filled (defaults to black) Color is defined in a table containing color component values between 0.0 and 1.0 for each of the keys:
red (default 0.0)
green (default 0.0)
blue (default 0.0)
alpha (default 1.0)
strokeColor - the color with which the shape will be stroked (defaults to black)
lineWidth - the line width (number) for the stroke of the shape (defaults to 1 if anti-aliasing is on or (√2)/2 if it is off -- approximately 0.7)
shouldClose - a boolean indicating whether or not the shape should be closed (defaults to true)
antialias - a boolean indicating whether or not the shape should be antialiased (defaults to true)
Returns
An hs.image object, or nil if an error occured
Notes
To use the ASCII diagram image support, see https://github.com/cparnot/ASCIImage and http://cocoamine.net/blog/2015/03/20/replacing-photoshop-with-nsstring
The default for lineWidth, when antialiasing is off, is defined within the ASCIImage library. Geometrically it represents one half of the hypotenuse of the unit right-triangle and is a more accurate representation of a "real" point size when dealing with arbitrary angles and lines than 1.0 would be.
​imageFromMediaFile​
Signature
hs.image.imageFromMediaFile(file) -> object
Type
Constructor
Description
Creates an hs.image object from a video file or the album artwork of an audio file or directory
Parameters
file - A string containing the path to an audio or video file or an album directory
Returns
An hs.image object
Notes
If a thumbnail can be generated for a video file, it is returned as an hs.image object, otherwise the filetype icon
For audio files, this function first determines the containing directory (if not already a directory)
It checks if any of the following common filenames for album art are present:
cover.jpg
front.jpg
art.jpg
album.jpg
folder.jpg
If one of the common album art filenames is found, it is returned as an hs.image object
This is faster than extracting image metadata and allows for obtaining artwork associated with file formats such as .flac/.ogg
If no common album art filenames are found, it attempts to extract image metadata from the file. This works for .mp3/.m4a files
If embedded image metadata is found, it is returned as an hs.image object, otherwise the filetype icon
​imageFromName​
Signature
hs.image.imageFromName(string) -> object
Type
Constructor
Description
Returns the hs.image object for the specified name, if it exists.
Parameters
Name - the name of the image to return.
Returns
An hs.image object or nil, if no image was found with the specified name.
Notes
Some predefined labels corresponding to OS X System default images can be found in hs.image.systemImageNames.
Names are not required to be unique: The search order is as follows, and the first match found is returned:
an image whose name was explicitly set with the setName method since the last full restart of Hammerspoon
Hammerspoon's main application bundle
the Application Kit framework (this is where most of the images listed in hs.image.systemImageNames are located)
Image names can be assigned by the image creator or by calling the hs.image:setName method on an hs.image object.
​imageFromPath​
Signature
hs.image.imageFromPath(path) -> object
Type
Constructor
Description
Loads an image file
Parameters
path - A string containing the path to an image file on disk
Returns
An hs.image object, or nil if an error occured
​imageFromURL​
Signature
hs.image.imageFromURL(url[, callbackFn]) -> object
Type
Constructor
Description
Creates an hs.image object from the contents of the specified URL.
Parameters
url - a web url specifying the location of the image to retrieve
callbackFn - an optional callback function to be called when the image fetching is complete
Returns
An hs.image object or nil, if the url does not specify image contents or is unreachable, or if a callback function is supplied
Notes
If a callback function is supplied, this function will return nil immediately and the image will be fetched asynchronously
Methods
​colorAt​
Signature
hs.image:colorAt(point) -> table
Type
Method
Description
Reads the color of the pixel at the specified location.
Parameters
point - a hs.geometry.point
Returns
A hs.drawing.color object
​copy​
Signature
hs.image:copy() -> imageObject
Type
Method
Description
Returns a copy of the image
Parameters
None
Returns
a new hs.image object
​croppedCopy​
Signature
hs.image:croppedCopy(rectangle) -> object
Type
Method
Description
Returns a copy of the portion of the image specified by the rectangle specified.
Parameters
rectangle - a table with 'x', 'y', 'h', and 'w' keys specifying the portion of the image to return in the new image.
Returns
a copy of the portion of the image specified
​encodeAsURLString​
Signature
hs.image:encodeAsURLString([scale], [type]) -> string
Type
Method
Description
Returns a bitmap representation of the image as a base64 encoded URL string
Parameters
scale - an optional boolean, default false, which indicates that the image size (which macOS represents as points) should be scaled to pixels. For images that have Retina scale representations, this may result in an encoded image which is scaled down from the original source.
type - optional case-insensitive string paramater specifying the bitmap image type for the encoded string (default PNG)
PNG - save in Portable Network Graphics (PNG) format
TIFF - save in Tagged Image File Format (TIFF) format
BMP - save in Windows bitmap image (BMP) format
GIF - save in Graphics Image Format (GIF) format
JPEG - save in Joint Photographic Experts Group (JPEG) format
Returns
the bitmap image representation as a Base64 encoded string
Notes
You can convert the string back into an image object with hs.image.imageFromURL, e.g. hs.image.imageFromURL(string)
​getLoupedeckArray​
Signature
hs.image:getLoupedeckArray() -> table
Type
Method
Description
Translates an hs.image object into an RGB array string suitable for the Loupedeck CT device.
Parameters
None
Returns
A string containing the RGB data
​name​
| Signature | hs.image:name([name]) -> imageObject | string | | -----------------------------------------------------|---------------------------------------------------------------------------------------------------------| | Type | Method | | Description | Get or set the name of the image represented by the hs.image object. | | Parameters |
name - an optional string specifying the new name for the hs.image object.
| | Returns |
if no argument is provided, returns the current name. If a new name is specified, returns the hs.image object or nil if the name cannot be changed.
| | Notes |
see also hs.image:setName for a variant that returns a boolean instead.
|
​saveToFile​
Signature
hs.image:saveToFile(filename, [scale], [filetype]) -> boolean
Type
Method
Description
Save the hs.image object as an image of type filetype to the specified filename.
Parameters
filename - the path and name of the file to save.
scale - an optional boolean, default false, which indicates that the image size (which macOS represents as points) should be scaled to pixels. For images that have Retina scale representations, this may result in a saved image which is scaled down from the original source.
filetype - optional case-insensitive string paramater specifying the file type to save (default PNG)
PNG - save in Portable Network Graphics (PNG) format
TIFF - save in Tagged Image File Format (TIFF) format
BMP - save in Windows bitmap image (BMP) format
GIF - save in Graphics Image Format (GIF) format
JPEG - save in Joint Photographic Experts Group (JPEG) format
Returns
Status - a boolean value indicating success (true) or failure (false)
Notes
Saves image at the size in points (or pixels, if scale is true) as reported by hs.image:size() for the image object
​setName​
Signature
hs.image:setName(Name) -> boolean
Type
Method
Description
Assigns the name assigned to the hs.image object.
Parameters
Name - the name to assign to the hs.image object.
Returns
Status - a boolean value indicating success (true) or failure (false) when assigning the specified name.
Notes
This method is included for backwards compatibility and is considered deprecated. It is equivalent to hs.image:name(name) and true or false.
​setSize​
Signature
hs.image:setSize(size [, absolute]) -> object
Type
Method
Description
Returns a copy of the image resized to the height and width specified in the size table.
Parameters
size - a table with 'h' and 'w' keys specifying the size for the new image.
absolute - an optional boolean specifying whether or not the copied image should be resized to the height and width specified (true), or whether the copied image should be scaled proportionally to fit within the height and width specified (false). Defaults to false.
Returns
a copy of the image object at the new size
Notes
This method is included for backwards compatibility and is considered deprecated. It is equivalent to hs.image:copy():size(size, [absolute]).
​size​
| Signature | hs.image:size([size, [absolute]] ) -> imageObject | size | | -----------------------------------------------------|---------------------------------------------------------------------------------------------------------| | Type | Method | | Description | Get or set the size of the image represented byt he hs.image object. | | Parameters |
size - an optional table with 'h' and 'w' keys specifying the size for the image.
absolute - when specifying a new size, an optional boolean, default false, specifying whether or not the image should be resized to the height and width specified (true), or whether the copied image should be scaled proportionally to fit within the height and width specified (false).
| | Returns |
If arguments are provided, return the hs.image object; otherwise returns the current size
| | Notes |
See also hs.image:setSize for creating a copy of the image at a new size.
|
​template​
| Signature | hs.image:template([state]) -> imageObject | boolean | | -----------------------------------------------------|---------------------------------------------------------------------------------------------------------| | Type | Method | | Description | Get or set whether the image is considered a template image. | | Parameters |
state - an optional boolean specifying whether or not the image should be a template.
| | Returns |
if a parameter is provided, returns the hs.image object; otherwise returns the current value
| | Notes |
Template images consist of black and clear colors (and an alpha channel). Template images are not intended to be used as standalone images and are usually mixed with other content to create the desired final appearance.
Images with this flag set to true usually appear lighter than they would with this flag set to false.
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