|AHELP for CIAO 4.9 ChIPS v1||
Retrieves the attribute value(s) of the image.
get_image() get_image(id) get_image(id, attribute)
The function arguments.
|id||A ChipsId structure identifying the item, or a string containing the name of the object.|
|attribute||The name of the attribute to retrieve, such as 'threshold' or 'colormap'.|
The get_image command returns a structure containing all the attribute values of the image. To retrieve the value of a specific attribute, provide the attribute name and the id or ChipsId of the object.
Some values are set to "None" in the returned structure. These entries generally correspond to attributes which may only be modified at creation time, such as the object id.
Please see the "Image Preferences and Attributes" section below the examples for a list of the image preferences.
The get_image_range command returns the X and Y ranges of the current image. The values are returned as [xmin, xmax, ymin, ymax]. There are also individual commands for retrieving just the x and y range: get_image_xrange and get_image_yrange.
To see if a image is hidden or visible, use the get_image_visible command.
The module of advanced ChIPS functions contains other commands for retrieving attribute values (refer to "ahelp chips" for information on loading the module):
get_image_alpha get_image_colormap get_image_colormap_interpolated get_image_colormap_size get_image_depth get_image_interpolation get_image_invert_colormap get_image_range get_image_scale_channels get_image_threshold get_image_visible get_image_xrange get_image_yrange
chips> add_image("img.fits") chips> get_image()
A image is created and becomes current. Calling get_image with no argument returns all the attributes of the object with the following output:
alpha = [1.0, 1.0] colormap = 3 colormap_interpolate = True colormap_size = 256 depth = 100 id = None interpolation = 0 invert_colormap = False scale_channels = True stem = None threshold = [0.0, 29.0]
The remaining calls show how get_image can be used to access individual attributes of the image. Similarly, a get_image().attribute call accesses the individual attribute of the image.
chips> add_image('img.fits') chips> add_image('img2.fits') chips> get_image('image1')
Two images are created. get_image is called with the id of the first image, returning all attributes.
chips> add_image('img.fits') chips> get_image_colormap() chips> get_image().colormap
An image is created and the 'colormap' attribute is accessed using get_image_colormap, and equivalently get_image().colormap.
chips> imgatt = get_image() chips> print(imgatt)
Retrieve a structure containing the attribute values of the current image and store the results in "imgatt". Print the contents of "imgatt".
The attributes associated with images are given in the following table, where the "Set?" column refers to whether the attribute can be changed using the set_image() command. To change the image preference settings prepend "image." to the attribute name.
|alpha||A two-element array of the minimum and maximum values to use for the alpha channel.||The values are normalized to the data range, so should be in the range 0 to 1, inclusive. A setting of [1,1] is fully opaque whereas [0.5,0.5] makes every pixel 50 per cent transparent, and [0,1] makes the minimum value fully transparent and the maximum value fully opaque.||[-1, -1]||Yes|
|colormap||the color map used to display the image||red|green|blue|grayscale| rainbow|hsv|heat|cool| usercmap1|usercmap2|usercmap3; see the colormap section of "ahelp chipsopt"||grayscale||Yes|
|colormap_interpolate||should the colormap be interpolated over the size of the colormap||see the Booleans section of "ahelp chipsopt"||true||Yes|
|colormap_size||number of entries to use from the color map||256||Yes|
|depth||Value indicating the depth of the image||see the Depth section of "ahelp chipsopt"||default||Yes|
|interpolation||the interpolation method used to display the image pixels||neighbor|bilinear|bicubic||neighbor||Yes|
|invert_colormap||should the colormap be inverted?||see the Booleans section of "ahelp chipsopt"||false||Yes|
|scale_channels||when displaying true-color images, should each channel (other than alpha) be normalized to its own range (true) or the range of all the channels (false).||see the Booleans section of "ahelp chipsopt"||true||Yes|
|stem||stem to use for image ids||An alpha-numeric character sequence that does not contain a space||image||No|
|threshold||A two-element array of the minimum and maximum values to use for thresholding the image.||The values are normalized to the data range, so should be in the range 0 to 1, inclusive. A setting of [0,1] means use the whole pixel range whilst [0.05,0.95] would only use the central 90% of the pixel range.||[-1, -1]||Yes|
|wcs||The name of the coordinate system to use||"logical", "physical", "world". You can also use the names of the transforms, such as "sky" and "EQPOS".||"world", if available and supported (WCS-TAN).||No|
See the bugs pages on the ChIPS website for an up-to-date listing of known bugs.