TextMetrics
The TextMetrics interface represents the dimensions of a piece of text in the canvas; a TextMetrics instance can be retrieved using the CanvasRenderingContext2D.measureText() method.
Properties
The read-only actualBoundingBoxAscent property of the TextMetrics interface is a double giving the distance from the horizontal line indicated by the CanvasRenderingContext2D.textBaseline attribute to the top of the bounding rectangle used to render the text, in CSS pixels.
The read-only actualBoundingBoxDescent property of the TextMetrics interface is a double giving the distance from the horizontal line indicated by the CanvasRenderingContext2D.textBaseline attribute to the bottom of the bounding rectangle used to render the text, in CSS pixels.
The read-only actualBoundingBoxLeft property of the TextMetrics interface is a double giving the distance parallel to the baseline from the alignment point given by the CanvasRenderingContext2D.textAlign property to the left side of the bounding rectangle of the given text, in CSS pixels; positive numbers indicating a distance going left from the given alignment point.
The read-only actualBoundingBoxRight property of the TextMetrics interface is a double giving the distance parallel to the baseline from the alignment point given by the CanvasRenderingContext2D.textAlign property to the right side of the bounding rectangle of the given text, in CSS pixels.
The read-only alphabeticBaseline property of the TextMetrics interface is a double giving the distance from the horizontal line indicated by the CanvasRenderingContext2D.textBaseline property to the alphabetic baseline of the line box, in CSS pixels.
The read-only emHeightAscent property of the TextMetrics interface returns the distance from the horizontal line indicated by the CanvasRenderingContext2D.textBaseline property to the top of the em square in the line box, in CSS pixels.
The read-only emHeightDescent property of the TextMetrics interface returns the distance from the horizontal line indicated by the CanvasRenderingContext2D.textBaseline property to the bottom of the em square in the line box, in CSS pixels.
The read-only fontBoundingBoxAscent property of the TextMetrics interface returns the distance from the horizontal line indicated by the CanvasRenderingContext2D.textBaseline attribute, to the top of the highest bounding rectangle of all the fonts used to render the text, in CSS pixels.
The read-only fontBoundingBoxDescent property of the TextMetrics interface returns the distance from the horizontal line indicated by the CanvasRenderingContext2D.textBaseline attribute to the bottom of the bounding rectangle of all the fonts used to render the text, in CSS pixels.
The read-only hangingBaseline property of the TextMetrics interface is a double giving the distance from the horizontal line indicated by the CanvasRenderingContext2D.textBaseline property to the hanging baseline of the line box, in CSS pixels.
The read-only ideographicBaseline property of the TextMetrics interface is a double giving the distance from the horizontal line indicated by the CanvasRenderingContext2D.textBaseline property to the ideographic baseline of the line box, in CSS pixels.