FontFaceObserver class
A FontFaceObserver is responsible for loading and detecting when a font has been successfully loaded into the browser and is ready for use in the DOM or drawn into a canvas. If you need to load fonts with an authenticated request, you can handle the networking part yourself and then still use FontFaceObserver to detect when it is ready by passing in the font as a base64 data or Blob URI.
Constructors
- FontFaceObserver(String family, {String style = _normal, String weight = _normal, String stretch = _normal, String testString = _defaultTestString, int timeout = _defaultTimeout, @Deprecated('This option does nothing now that simulated font load event support is removed') dynamic useSimulatedLoadEvents = false, String group = defaultGroup})
- Construct a new FontFaceObserver. The CSS font family name is the only required parameter.
Properties
- family ↔ String
-
CSS font family
getter/setter pair
- group → String
-
Returns the group that this FontFaceObserver is in
no setter
- hashCode → int
-
The hash code for this object.
no setterinherited
- key → String
-
Returns the key for this FontFaceObserver
no setter
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- stretch ↔ String
-
CSS font stretch
getter/setter pair
- style ↔ String
-
CSS font style
getter/setter pair
- testString ↔ String
-
Returns the test string used to detect this font load
getter/setter pair
- timeout ↔ int
-
How long to wait in ms when detecting font loads before timing out
getter/setter pair
- useSimulatedLoadEvents → bool
-
This option is always false now that simulated font load event support is removed
final
- weight ↔ String
-
CSS font weight
getter/setter pair
Methods
-
check(
) → Future< FontLoadResult> - Wait for the font face represented by this FontFaceObserver to become available in the browser. It will asynchronously return a FontLoadResult with the result of whether or not the font is loaded or the timeout was reached while waiting for it to become available.
-
load(
String url) → Future< FontLoadResult> - Load the font into the browser given a url that could be a network url or a pre-built data or blob url.
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
toString(
) → String -
A string representation of this object.
inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited
Static Methods
-
getLoadedFontKeys(
) → Iterable< String> - Returns the font keys for all currently loaded fonts
-
getLoadedGroups(
) → Iterable< String> - Returns the groups that the currently loaded fonts are in. There will not be duplicate group entries if there are multiple fonts in the same group.
-
unload(
String key, String group) → Future< bool> -
Unloads a font by passing in the
keyandgroupthat was used to load it originally. It will decremement the use count for a matching font and if no one else is using it, then it will be removed from the browser by removing the style element and removing the internal tracking of the font. -
unloadGroup(
String group) → Future< int> -
Sets the use count for the given
groupto zero for any fonts in that group, then unloads any fonts that are not used any more. A font will only be actually unloaded from the browser once its use count is zero. So, if the same font is used by multiple different groups it will have a count of uses per group and will need to be unloaded from each group to truly unload it from the browser.
Constants
- defaultGroup → const String
- The default group used for a font if none is specified.