Imager::Font::BBox - objects representing the bounding box of a string.
use Imager::Font;
# get the object
my $font = Imager::Font->new(...);
my $bbox = $font->bounding_box(string=>$text, size=>$size);
# methods
my $start = $bbox->start_offset;
my $left_bearing = $bbox->left_bearing;
my $right_bearing = $bbox->right_bearing;
my $end = $bbox->end_offset;
my $gdescent = $box->global_descent;
my $gascent = $bbox->global_ascent;
my $ascent = $bbox->ascent;
my $decent = $bbox->descent;
my $total_width = $bbox->total_width;
my $fheight = $bbox->font_height;
my $theight = $bbox->text_height;
my $display_width = $bbox->display_width;
Objects of this class are returned by the Imager::Font bounding_box()
method when it is called in scalar context.
This will hopefully make the information from this method more
accessible.
- start_offset()
- neg_width
- left_bearing
- Returns the horizontal offset from the selected drawing location to the
left edge of the first character drawn. If this is positive, the first
glyph is to the right of the drawing location.
The alias neg_width() is present to match the
bounding_box() documentation for list context.
The alias left_bearing() is present to match font
terminology.
- advance_width()
- The advance width of the string, if the driver supports that, otherwise
the same as end_offset.
- right_bearing
- The distance from the right of the last glyph to the end of the advance
point.
If the glyph overflows the right side of the advance width
this value is negative.
- display_width
- The distance from the left-most pixel of the left-most glyph to the
right-most pixel of the right-most glyph.
Equals advance_width - left_bearing - right_bearing (and
implemented that way.)
- global_descent()
- The lowest position relative to the font baseline that any character in
the font reaches in the character cell. Normally negative.
At least one font we've seen has reported a positive number
for this.
- global_ascent()
- The highest position relative to the font baseline that any character in
the font reaches in the character cell. Normally positive.
- descent()
- The lowest position relative to the font baseline that any character in
the supplied string reaches. Negative when any character's glyph reaches
below the baseline.
- ascent()
- The highest position relative to the font baseline that any character in
the supplied string reaches. Positive if any character's glyph reaches
above the baseline.
- font_height()
- The maximum displayed height of any string using this font.
- text_height()
- The displayed height of the supplied string.
These methods include bugs kept for backwards compatibility and shouldn't be
used in new code.
- total_width()
- The total displayed width of the string.
New code should use display_width().
This depends on end_offset(), and is limited by it's
backward compatibility.
- end_offset
- pos_width
- The offset from the selected drawing location to the right edge of the
last character drawn. Should always be positive.
You can use the alias pos_width() if you are used to
the bounding_box() documentation for list context.
For backwards compatibility this method returns the maximum of
the advance width and the offset of the right edge of the last
glyph.
- new(...)
- Called by Imager::Font->bounding_box() to create the
object.
Doesn't reproduce the functionality that you get using the x and y parameters to
Imager::Font->bounding_box(). I considered:
my ($left, $top, $right, $bottom) = $box->offset(x=>$x, y=>$y)
but this is about as clumsy as the original.
Tony Cook <tony@develop-help.com>
Imager(3), Imager::Font(3)