Carbon


ATSUCalculateBaselineDeltas

Header: ATSUnicode.h Carbon status: Supported

Calculates the optimal baseline positions for glyphs in a line of text.

OSStatus ATSUCalculateBaselineDeltas (
    ATSUStyle iStyle, 
    BslnBaselineClass iBaselineClass, 
    BslnBaselineRecord oBaselineDeltas
);
Parameter descriptions
iStyle

A reference to a valid style object whose primary baseline you wish to use to determine optimal glyph placement in a style run (that is, style object) or line(s) of text (that is, text layout object) . You cannot pass NULL for this parameter.

iBaselineClass

The primary baseline to use in calculating the distance to each of the other baseline types in a style run (that is, style object). See “Baseline Type Constants” in the Font Manager for a description of possible values. Pass the constant kBSLNNoBaselineOverride if you want to use the standard baseline value from the current font.

oBaselineDeltas

On return, an array of the distances from a specified baseline to each of the other baseline types in the style object. You cannot pass NULL for this parameter.

function result

A result code.

DISCUSSION

You can call the ATSUCalculateBaselineDeltas function to calculate the distances from a specified baseline type to each of other baseline types in a specified style object. ATSUCalculateBaselineDeltas takes into account font and text size when performing these calculations.

ATSUI uses these distances to determine the cross-stream shifting to apply to the glyphs in a style run. You can use the resulting array to set or obtain the optimal baseline positions of lines in a text layout object identified by the text layout attribute tag kATSULineBaselineValuesTag. For a description of this tag constant, see “Text Layout Attribute Tag Constants”.

VERSION NOTES

Available beginning with ATSUI 1.0.

AVAILABILITY

Supported in Carbon. Available in Carbon 1.0.2 and later when running Mac OS 8.5 or later.


© 2000 Apple Computer, Inc. (Last Updated 6/30/2000)