Ubuntu Manpage: Imager::Font::BBox - objects representing the bounding box of a string.

Provided by: libimager-perl_1.023+dfsg-1build2_amd64

NAME

       Imager::Font::BBox - objects representing the bounding box of a string.

SYNOPSIS

         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;

DESCRIPTION

       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.

METHODS

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.

OBSOLETE METHODS

       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.

INTERNAL FUNCTIONS

       new(...)
           Called by Imager::Font->bounding_box() to create the object.

BUGS

       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.

AUTHOR

       Tony Cook <tony@develop-help.com>