<summary> Determines an appropriate font to use to render the range of text. </summary> <param name="source">The text source implementation holds the text and locale.</param> <param name="textLength">Length of the text to analyze.</param> <param name="baseFontCollection">Default font collection to use.</param> <param name="baseFont">Base font to check (optional).</param> <param name="baseFamilyName">Family name of the base font. If you pass null, no matching will be done against the family.</param> <param name="baseWeight">Desired weight.</param> <param name="baseStyle">Desired style.</param> <param name="baseStretch">Desired stretch.</param> <param name="mappedLength">Length of text mapped to the mapped font. This will always be less or equal to the input text length and greater than zero (if the text length is non-zero) so that the caller advances at least one character each call.</param> <param name="mappedFont">The font that should be used to render the first mappedLength characters of the text. If it returns NULL, then no known font can render the text, and mappedLength is the number of unsupported characters to skip.</param> <param name="scale">Scale factor to multiply the em size of the returned font by.</param> <returns> Standard HRESULT error code. </returns>
<summary> A font fallback definition used for mapping characters to fonts capable of supporting them. </summary>