Interfaces (Others)

NOTE

The initial APIs of this module are supported since API version 11. Newly added APIs will be marked with a superscript to indicate their earliest API version.

This module uses the physical pixel unit, px.

The module operates under a single-threaded model. The caller needs to manage thread safety and context state transitions.

TextBlobRunBuffer

Describes a series of consecutive glyphs with the same attributes in a text blob.

System capability: SystemCapability.Graphics.Drawing

Name	Type	Read-Only	Optional	Description
glyph	number	No	No	Index of the glyph. The value is an integer. If a floating point number is passed in, the value is rounded down.
positionX	number	No	No	X coordinate of the start point of the text blob. The value is a floating point number.
positionY	number	No	No	Y coordinate of the start point of the text blob. The value is a floating point number.

FontMetrics

Describes the attributes that describe the font size and layout. A typeface has similar font metrics.

Atomic service API: This API can be used in atomic services since API version 22.

System capability: SystemCapability.Graphics.Drawing

Name	Type	Read-Only	Optional	Description
flags¹²⁺	FontMetricsFlags	No	Yes	Font measurement flags that are valid.
top	number	No	No	Maximum distance from the baseline to the highest coordinate of the text. The value is a floating point number.
ascent	number	No	No	Distance from the baseline to the highest coordinate of the text. The value is a floating point number.
descent	number	No	No	Distance from the baseline to the lowest coordinate of the text. The value is a floating point number.
bottom	number	No	No	Maximum distance from the baseline to the lowest coordinate of the text. The value is a floating point number.
leading	number	No	No	Interline spacing, that is, the distance from the descent of one line of text to the ascent of the next line. The value is a floating point number.
avgCharWidth¹²⁺	number	No	Yes	Average character width.
maxCharWidth¹²⁺	number	No	Yes	Maximum character width.
xMin¹²⁺	number	No	Yes	Horizontal distance from the leftmost edge of any glyph bounding box to the origin. This value is usually less than 0, indicating the minimum horizontal coordinate across all glyph bounding boxes.
xMax¹²⁺	number	No	Yes	Horizontal distance from the rightmost edge of any glyph bounding box to the origin. The value is a positive number, indicating the maximum horizontal coordinate across all glyph bounding boxes.
xHeight¹²⁺	number	No	Yes	Height of the lowercase letter x. The value is usually a negative value.
capHeight¹²⁺	number	No	Yes	Height of a capital letter. The value is usually a negative value.
underlineThickness¹²⁺	number	No	Yes	Thickness of the underline.
underlinePosition¹²⁺	number	No	Yes	Vertical distance from the baseline to the top of the underline. The value is usually a positive number.
strikethroughThickness¹²⁺	number	No	Yes	Thickness of the strikethrough.
strikethroughPosition¹²⁺	number	No	Yes	Vertical distance from the baseline to the bottom of the strikethrough. The value is usually a negative value.

FontFeature²⁰⁺

Defines font features, which are typesetting rules within a font that determine how glyphs look, such as ligatures, alternates, and superscripts/subscripts.

Atomic service API: This API can be used in atomic services since API version 22.

System capability: SystemCapability.Graphics.Drawing

Name	Type	Read-Only	Optional	Description
name	string	No	No	Name of a font feature. Common font feature names include liga, frac, and case. A font feature needs a TTF file to work.
value	number	No	No	Value of a font feature, which is a floating point number. You are advised to determine the valid value range by using a font viewing tool or referring to the font document.