Glazoom extension for Firefox 3 Tutorial

Author: Daniel Glazman <daniel@glazman.org>

1. About Glazoom
2. Installing Glazoom
   1. Disabling or uninstalling Glazoom
   2. Updating Glazoom to a more recent version
3. Zooming on an element or an image, and back
4. Zoom in and out in one click
5. Selecting directly an abitrary zoom factor
6. Selecting directly a pre-defined zoom factor
7. Setting Glazoom options
   1. Toggle between full zoom and text zoom
   2. Limit the zoom factor when focusing on an element
   3. Focus on enclosing table cells 
   4. Zoom policy
   5. Predefined zoom factors
   6. The "about" dialog

1. About Glazoom

1. The ability to zoom on a given block of text or image or object.  That feature is extremely important in terms of accessibility, allowing visually impaired people to render one given chunk of text or an image in the full width of the browser's window. No other browser offers that feature for the time being, and accessibility groups have warmly greeted Glazoom. Here's the normal desktop view of the home page of french newspaper Le Monde (click on the thumbnail to see a larger view):

   

   and now a zoom on the first headline (top left of the home page)

   

2. The second feature is a direct UI control over the fullZoom factor of the page through a new panel sitting in the status bar of Firefox:

   

2. Installing Glazoom

Just click on this link (addons.mozilla.org) and  follow the steps to install the extension. Firefox 3 will need to be restarted to install the extension. That's all !

Warning, Glazoom does not work with versions of  Firefox older than version 3.

2.1. Disabling or uninstalling Glazoom

Seriously, you don't want to do that :-) If you really really need it, select the "Add-ons" menu entry in the Tools menu of Firefox 3 to do that.

2.2 Updating Glazoom to a more recent version

If you have enabled automatic notification of extension updates, Firefox 3 will notify you directly when a new version is available. Otherwise, just follow again the installation process described above.

3. Zooming on an element or an image, and back

1. Go to your favorite web page. In this document, we'll use again http://lemonde.fr .
2. Right-click on the element you want to focus on and select the menu entry "Zoom on element"

   

3. Say "woaaaaah coooool!" :-)
4. To go back to the normal view with a 1:1 zoom factor, right-click again on the page and select the menu entry "Real size (1:1)"

Warning, this feature is disabled - because impossible to achieve - in Text Zoom mode.

4. Zoom in and out in one click

You can zoom the page in and out with one click only using the Glazoom statusbar panel:

Click on the magnifying glass containing a minus to zoom out, and on the magnifying glass containing a plus to zoom in. The factor factor is not increased or decreased by a given fixed value but uses a list of pre-defined zoom factors that you can edit easily. Zooming in and out then changes the zoom factor to the next or previous zoom factor in the list, if any.

Selecting directly an abitrary zoom factor

The textbox with a dropdown arrow in the screenshot just above is editable. Just click in the text and modify the zoom factor directly then hit the return key. The trailing percent sign is optional.

5. Selecting directly a pre-defined zoom factor

You can also select directly a pre-defined zoom factor clicking on the dropdown arrow in the Glazoom statusbar panel. That opens a menupopup. Just select the pre-defined zoom factor you want.

6. Setting Glazoom options

As in the previous section, click on the dropdown arrow in the Glazoom statusbar panel and select the "Options" menu entry. This opens the following dialog:

6.1. Toggle between full zoom and text zoom

The default behaviour of Firefox 3 is to zoom the entire page, including images and external objects like Flash applets. But a second type of zoom, Text Zoom, can be applied by Firefox. In that case, only text is zoomed in or out, the rest of the page remaining untouched, including images and the layout of the page. Just uncheck the first checkbox at the top of the options dialog to use Text Zoom instead of Full Zoom. Check the checkbox to go back to the default Full Zoom behaviour.

Here's http://lemonde.fr when a Text Zoom factor of 200% is applied:

6.2. Limit the zoom factor when focusing on an element

Using the "Maximum zoom factor" text field, you can limit the zoom factor applied when you focus on a given element or image to a maximum value. That feature is useful to preserve the readability of a text if the block you're focusing on is narrow. Just enter an integer in the text field. A value of 0 (zero) means no limit.

6.3. Focus on enclosing table cells 

If the element you're focusing on is inside a table cell, you can improve readability focusing on that table cell instead of your original element. That's particularly useful for news web site that often use table cells containing text and images illustrating the article. Just check the "focus on enclosing table cell if any" checkbox.

6.4. Zoom policy

It's always nice to have the same zoom factor applied to all pages of a given web site, even if you open them in new tabs or even independent windows. Just check the "same zoom level for all pages from same domain" to enable that feature.

6.5. Predefined zoom factors

The last text field of the options dialog is an ordered comma-separated list of all the pre-defined zoom factors. This list does not use percentages but real numbers. 200% for instance is 2. 15% is 0.15.

6.6 The "about" dialog

Click on the link "About Glazoom" in the options dialog to get more information about the Glazoom extension.