The Addressable Image Action Group
This prototype action group provides 'pixel level' access to an image. Any arbitrary region of the image can be retrieved at arbitrary scale, up to full scale.
In this way the image is available at any size up to full size and with any crop at any size.
These methods require parameters. Parameters used in the <actionGroup> are named and described in <parameter> elements. Those names are embedded in actions and
substituted with real parameter values by consuming applications.
This action group can facilitate zooming for applications that provide user controls on region selection. For this reason, we include a couple of actions
(getTechMetadata and getViewer) which could be handled in the default set. getTechMetadata is included here explicitly to provide the full image
geometry that zooming viewers might need. getViewer is included as an example of zooming access to the image.
The getRectWithSize action is the essential addressable image action. The rest of the actions are "convenience" methods that provide useful
functionality without requiring all of the getRectWithSize parameters.
Required Parameters:
output_height_pixels:
The height of the resulting scaled image expressed in pixels
<parameter label="Output height" name="output_height_pixels">The height of the resulting scaled image expressed in pixels</parameter>
output_width_pixels:
The width of the resulting scaled image expressed in pixels
<parameter label="Output width" name="output_width_pixels">The width of the resulting scaled image expressed in pixels</parameter>
region_width_pixels:
The width of the requested region expressed in pixels at full resolution
<parameter label="Region width" name="region_width_pixels">The width of the requested region expressed in pixels at full resolution</parameter>
region_height_pixels:
The height of the requested region expressed in pixels at full resolution
<parameter label="Region height" name="region_height_pixels">The height of the requested region expressed in pixels at full resolution</parameter>
region_left_pixels:
The left edge of the requested region expressed in pixels at full resolution
<parameter label="Region left" name="region_left_pixels">The left edge of the requested region expressed in pixels at full resolution</parameter>
region_top_pixels:
The top edge of the requested region expressed in pixels at full resolution
<parameter label="Region top" name="region_top_pixels">The top edge of the requested region expressed in pixels at full resolution</parameter>
getRectWithSize
The essential method that provides a scaled region of the image. It returns a region of an image based on scale, width, and height parameters.
For example, the actionable URL for a getRectWithSize call might look as follows:
<action format="image/jpeg" label="Get region and scale width and height" name="getRectWithSize" uri="http://fedora.at.northwestern.edu/fedora/fedora/get/ec:3404/nubehav:00013/getRectWithSize?OUTWIDTH=(output_height_pixels)&OUTHEIGHT=(output_height_pixels)&WIDTH=(region_width_pixels)&HEIGHT=(region_height_pixels)&X=(region_left_pixels)&Y=(region_top_pixels)" />
getRectWithHeight
Get region and scale height
For example, the actionable URL for a getRectWithHeight call might look as follows:
<action format="image/jpeg" label="Get region and scale height" name="getRectWithHeight" uri="http://fedora.at.northwestern.edu/fedora/fedora/get/ec:3404/nubehav:00013/getRectWithHeight?OUTHEIGHT=(output_height_pixels)&WIDTH=(region_width_pixels)&HEIGHT=(region_height_pixels)&X=(region_left_pixels)&Y=(region_top_pixels)" />
getRectWithWidth
Get region and scale width
For example, the actionable URL for a getRectWithWidth call might look as follows:
<action format="image/jpeg" label="Get region and scale width" name="getRectWithWidth" uri="http://fedora.at.northwestern.edu/fedora/fedora/get/ec:3404/nubehav:00013/getRectWithWidth?OUTWIDTH=(output_width_pixels)&WIDTH=(region_width_pixels)&HEIGHT=(region_height_pixels)&X=(region_left_pixels)&Y=(region_top_pixels)" />
getWithSize
Get full image scaled in width and height
For example, the actionable URL for a getWithSize call might look as follows:
<action format="image/jpeg" label="Get full image scaled in width and height" name="getWithSize" uri="http://fedora.at.northwestern.edu/fedora/fedora/get/ec:3404/nubehav:00013/getWithSize?OUTWIDTH=(output_height_pixels)&OUTHEIGHT=(output_height_pixels)" />
getWithWidth
Get full image scaled in width
For example, the actionable URL for a getWithWidth call might look as follows:
<action format="image/jpeg" label="Get full image scaled in width" name="getWithWidth" uri="http://fedora.at.northwestern.edu/fedora/fedora/get/ec:3404/nubehav:00013/getWithWidth?OUTWIDTH=(output_height_pixels)" />
getWithHeight
Get full image scaled in height
For example, the actionable URL for a getWithHeight call might look as follows:
<action format="image/jpeg" label="Get full image scaled in height" name="getWithHeight" uri="http://fedora.at.northwestern.edu/fedora/fedora/get/ec:3404/nubehav:00013/getWithHeight?OUTHEIGHT=(output_height_pixels)" />
getTechMetadata
Returns technical metadata for an image. Viewing applications often need the image geometry. A method such as this probably belongs in "basicImage" as well, and perhaps other "actionGroups".
For example, the actionable URL for a getTechMetadata call might look as follows:
<action format="text/XML" label="TechMetadata" name="getTechMetadata" uri="http://fedora.at.northwestern.edu/fedora/fedora/get/ec:3404/nubehav:00013/getTechMetadata" />
getViewer
Supplies a viewer from the local repository for an image.
For example, the actionable URL for a getViewer call might look as follows:
<action format="text/XML" label="TechMetadata" name="getViewer" uri="http://fedora.at.northwestern.edu/fedora/fedora/get/ec:3404/nubehav:00013/getViewer" />
