This product supplies the code for displaying scaled profile images. The core scaling is provided by gs.image, while this product provides

• A content provider to provide a high-level API,
• A view to display the image at different sizes,
• A class to map a user to an image, and
• The missing image resource that is shown if the image cannot be found.

The groupserver.UserImage content provider is used by almost all the code that needs to display a profile image:

.. code-highlight:: xml

  <div tal:define="user view/userInstanceToShow"
       tal:replace="structure provider:groupserver.UserImage" />

It returns a <div> element (with the userimage and photo classes) that contains an <img> element. The src attribute of the <img> element points to the view, if the user has a profile image, or the missing image resource. The size of the image defaults to 50×70 pixels [1] with the width and height attributes of the <img> element set. However, if the longest length of the image is less that 40 pixels then a data URI is used to embed the profile image in the page, rather than using a normal URL.

Two optional arguments can be passed to the content provider to change the size: width and height. While the size of the image will be changed, the aspect ratio of the image is preserved (see View below):

.. code-highlight:: xml

  <div tal:define="user view/userInstanceToShow;
                   width string:14; height string:18;"
       tal:replace="structure provider:groupserver.UserImage" />

The view /p/{userId}/gs-profile-image is a view that returns the image for the user. The gs-profile-image view provides an API for viewing the profile image at different sizes [2]. Two optional arguments can be passed as part of a path, to set the width and the height of the image.

• Not providing any arguments displays the original image that the participant uploaded: <http://groupserver.org/p/mpj17/gs-profile-image>.
• If only one argument is provided, the width is set and the height will be calculated, keeping the same aspect ratio as the original image. A new image will be returned that is scaled as requested. For example, setting the width to 100px: <http://groupserver.org/p/mpj17/gs-profile-image/100>.
• The height is specified after the width. The image will be scaled so neither the width nor the height will be exceeded. However, the aspect ratio will be preserved, so one dimension may be smaller than requested [3]. For example, ensuring that the width does not exceed 100px, and the height is smaller than to 125px: <http://groupserver.org/p/mpj17/gs-profile-image/100/125>.

The scaling of the image is carried out by the UserImage class. If the participant lacks an image then the viewer is redirected to the missing image resource instead.

The class gs.profile.image.base.UserImage is a subclass of gs.image.GSImage. It differs in the constructor, which takes a context and a user-info, rather than a file.

The context and user-info are used to construct a glob for the file [4], looking in the groupserver.user.image data-directory (usually found beneath var/instance/groupserver.data in the GroupServer directory). A glob is used so different file types, with different extensions, can be used.

If the file cannot be found then an IOError is thrown. The error has the following properties set.

errno:

The error number is set to errno.ENOENT.

filename:

The glob that was used to try and find the file.

If the file is found then it is opened and passed to the constructor for GSImage.

The resource /++resource++gs-profile-image-base-missing.jpg is the missing profile image image.

• Code repository: https://github.com/groupserver/gs.profile.image.base
• Questions and comments to http://groupserver.org/groups/development
• Report bugs at https://redmine.iopen.net/projects/groupserver