2.1.2.3 TextAlignmentMode Flags
TextAlignmentMode Flags specify the relationship between a reference point and a bounding rectangle, for text alignment. These flags can be combined to specify multiple options, with the restriction that only one flag can be chosen that alters the drawing position in the playback device context.
Horizontal text alignment is performed when the font has a horizontal default baseline.
|
Constant/value |
Description |
|---|---|
|
TA_NOUPDATECP 0x0000 |
The drawing position in the playback device context MUST NOT be updated after each text output call. The reference point MUST be passed to the text output function. |
|
TA_LEFT 0x0000 |
The reference point MUST be on the left edge of the bounding rectangle. |
|
TA_TOP 0x0000 |
The reference point MUST be on the top edge of the bounding rectangle. |
|
TA_UPDATECP 0x0001 |
The drawing position in the playback device context MUST be updated after each text output call. It MUST be used as the reference point. |
|
TA_RIGHT 0x0002 |
The reference point MUST be on the right edge of the bounding rectangle. |
|
TA_CENTER 0x0006 |
The reference point MUST be aligned horizontally with the center of the bounding rectangle. |
|
TA_BOTTOM 0x0008 |
The reference point MUST be on the bottom edge of the bounding rectangle. |
|
TA_BASELINE 0x0018 |
The reference point MUST be on the baseline of the text. |
|
TA_RTLREADING 0x0100 |
The text MUST be laid out in right-to-left reading order, instead of the default left-to-right order. This SHOULD be applied only when the font that is defined in the playback device context is either Hebrew or Arabic.<39> |
TextAlignmentMode flags specify three different components of text alignment:
The horizontal position of the reference point is determined by TA_RIGHT and TA_CENTER; if those bits are clear, the alignment MUST be TA_LEFT.
The vertical position of the reference point is determined by TA_BOTTOM and TA_BASELINE; if those bits are clear, the alignment MUST be TA_TOP.
Whether to update the output position in the playback device context after text output is determined by TA_UPDATECP; if that bit is clear, the position MUST NOT be updated.
This is the reason for defining three different zero values in the enumeration; they represent the default states of the three components of text alignment.