Interface FontLoaderInterface

The FontLoaderInterface is used when displaying annotations.

The underlying optimized rendering algorithms of annotations must have access to glyph data and metrics, but these information are not accessible through the native javascript api. For these reasons, the api must be able to parse font files and retrieve such data.

There may be some specific fonts needed to display your annotations. Just register them to the system with registerFont. You may register fonts from their url, or from their data with an ArrayBuffer. Font loading takes place when annotations are parsed and included in the AnnotationRendererInterface. Even if loadFont is provided, the font loading mechanism will automatically take place when required.

The api provides a fixed size default font (included in its script, nothing needs to be done to get this default font), that supports usual special characters of annotations, the 3djuump Infinite default font.

If a font is not found in the FontLoaderInterface, then the default font is used. And if the default font could not be loaded, then the 3djuump Infinite default font is used. You may override the default font when registering fonts. There can be only one default font. The default font is changed through calling registerFont or setDefaultFont accordingly. If such a font is not valid, then the api will use the 3djuump Infinite default font.

Family names in the FontLoaderInterface are case insensitive, all family names will be used lowercase.

For memory reasons, there is only one FontLoaderInterface, and thus FontLoaderInterface(s) cannot be created, but is accessed through InfiniteApiControllerInterface.getFontLoader.

You may choose to load specific fonts beforehand, in that case when all the fonts are loaded, a FontLoaderInterfaceSignal signal is sent when the loading is over.

/** 
 * Sample to illustrate the loading of fonts.
 */
import { FontLoaderInterface, InfiniteFactory, FontLoaderInterfaceSignal, InfiniteEvent, FontLoadingStatus, FontInterface } from 'generated_files/documentation/appinfiniteapi';

// font loading is used wheen loading annotations

// what to do when fonts are loaded
let lFontLoaded : (pEvent : InfiniteEvent) => void;
// get the font loader, no need to create it, all the time available (singleton)
const lFontLoader : FontLoaderInterface = InfiniteFactory.GetInfiniteApiController().getFontLoader();
// register font Open Sans normal (no bold, no italic) by its url
const lFontRegistered : boolean = lFontLoader.registerFont('Open Sans', false, false, 'resources/fonts/OpenSans-Regular.otf');
console.assert(lFontRegistered, 'font should be registered');

// what to do when fonts is loaded ?
lFontLoader.addEventListener(FontLoaderInterfaceSignal.FontsLoaded, lFontLoaded);
// load explicitly font, if not, font will be loaded if required when loading annotations
const lLoadStatus : FontLoadingStatus = lFontLoader.loadFont('Open Sans', false, false);
console.assert(lLoadStatus === FontLoadingStatus.FLS_LoadingStarted, 'Font loading should be started');

// when fonts are loaded => what do we do ?
// perhaps some gui code ?
lFontLoaded = (_pEvent : InfiniteEvent) : void =>
{
    // get all registered fonts and their status
    const lFonts : Array<FontInterface> = [];
    lFontLoader.getRegisteredFonts(lFonts);
    let i : number;
    let lErrorCount : number = 0;
    for (i = 0; i < lFonts.length; i += 1)
    {
        if (lFonts[i].error !== undefined)
        {
            lErrorCount += 1;
        }
    }
    console.assert(lErrorCount === 0, 'There should be no font in error');
    // when font is loaded, we unload it, but perhaps we should make some gui code ? :)
    lFontLoader.unregisterFont('Open Sans', false, false);
};

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Or asynchronously :

/** 
 * Sample to illustrate the asynchronous loading of fonts.
 */
import { FontLoaderInterface, InfiniteFactory, FontLoadingStatus, FontInterface } from 'generated_files/documentation/appinfiniteapi';

// font loading is used wheen loading annotations

// get the font loader, no need to create it, all the time available (singleton)
const lFontLoader : FontLoaderInterface = InfiniteFactory.GetInfiniteApiController().getFontLoader();
// register font Open Sans normal (no bold, no italic) by its url
const lFontRegistered : boolean = lFontLoader.registerFont('Open Sans', false, false, 'resources/fonts/OpenSans-Regular.otf');
console.assert(lFontRegistered, 'font should be registered');

const waitForResult = async () : Promise<void> =>
{
    // load explicitly font, if not, font will be loaded if required when loading annotations
    const lLoadStatus : FontLoadingStatus = lFontLoader.loadFont('Open Sans', false, false);
    console.assert(lLoadStatus === FontLoadingStatus.FLS_LoadingStarted, 'Font loading should be started');
    // wait for loading to complete
    await lFontLoader.asyncWaitForFontsLoaded();
    // fonts are now loaded => what do we do ?
    // perhaps some gui code ?
    // get all registered fonts and their status
    const lFonts : Array<FontInterface> = [];
    lFontLoader.getRegisteredFonts(lFonts);
    let i : number;
    let lErrorCount : number = 0;
    for (i = 0; i < lFonts.length; i += 1)
    {
        if (lFonts[i].error !== undefined)
        {
            lErrorCount += 1;
        }
    }
    console.assert(lErrorCount === 0, 'There should be no font in error');
    // when font is loaded, we unload it, but perhaps we should make some gui code ? :)
    lFontLoader.unregisterFont('Open Sans', false, false);
};

waitForResult();

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Please make sure the destination browser supports promises before using async calls.

Remember that font loading is only used with Annotations.

See

• InfiniteFactory
• AnnotationRendererInterface