Struct cairo_font_extents_t
The cairo_font_extents_t structure stores metric information for
a font. Values are given in the current user-space coordinate
system.
Because font metrics are in user-space coordinates, they are
mostly, but not entirely, independent of the current transformation
matrix. If you call cairo_scale(cr, 2.0, 2.0),
text will be drawn twice as big, but the reported text extents will
not be doubled. They will change slightly due to hinting (so you
can't assume that metrics are independent of the transformation
matrix), but otherwise will remain unchanged.
Fields
| Name |
Type |
Description |
ascent
|
double |
the distance that the font extends above the baseline.
Note that this is not always exactly equal to the maximum
of the extents of all the glyphs in the font, but rather
is picked to express the font designer's intent as to
how the font should align with elements above it.
|
descent
|
double |
the distance that the font extends below the baseline.
This value is positive for typical fonts that include
portions below the baseline. Note that this is not always
exactly equal to the maximum of the extents of all the
glyphs in the font, but rather is picked to express the
font designer's intent as to how the the font should
align with elements below it.
|
height
|
double |
the recommended vertical distance between baselines when
setting consecutive lines of text with the font. This
is greater than @ascent+@descent by a
quantity known as the line spacing
or external leading. When space
is at a premium, most fonts can be set with only
a distance of @ascent+@descent between lines.
|
max_x_advance
|
double |
the maximum distance in the X direction that
the the origin is advanced for any glyph in the font.
|
max_y_advance
|
double |
the maximum distance in the Y direction that
the the origin is advanced for any glyph in the font.
this will be zero for normal fonts used for horizontal
writing. (The scripts of East Asia are sometimes written
vertically.)
|