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- Imager::Font::BBox objects now have right_bearing() and display_wid…

…th()

  methods.  Hopefully this and the advance_width() method fills out
  the Imager bounding box interface to a useful state.
  Implemented for FT2 so far.
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1 parent 185531a commit dc35bde9992a36677aa424d8ee2aa52d51eacc15 Tony Cook committed Apr 24, 2005
Showing with 90 additions and 11 deletions.
  1. +4 −0 Changes
  2. +1 −0 datatypes.h
  3. +8 −4 freetyp2.c
  4. +10 −2 lib/Imager/Font.pm
  5. +45 −0 lib/Imager/Font/BBox.pm
  6. +22 −5 t/t38ft2font.t
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4 Changes
@@ -1066,6 +1066,10 @@ Revision history for Perl extension Imager.
checking the end of string when calculating the right side bearing
used to adjust pos_width for glyphs that overlap the right side of the
advance width.
+- Imager::Font::BBox objects now have right_bearing() and display_width()
+ methods. Hopefully this and the advance_width() method fills out
+ the Imager bounding box interface to a useful state.
+ Implemented for FT2 so far.
=================================================================
View
1 datatypes.h
@@ -235,6 +235,7 @@ enum bounding_box_index_t {
BBOX_DESCENT,
BBOX_ASCENT,
BBOX_ADVANCE_WIDTH,
+ BBOX_RIGHT_BEARING,
BOUNDING_BOX_COUNT
};
View
12 freetyp2.c
@@ -389,20 +389,24 @@ i_ft2_bbox(FT2_Fonthandle *handle, double cheight, double cwidth,
handle the case where the right the of the character overlaps the
right*/
rightb = (gm->horiAdvance - gm->horiBearingX - gm->width)/64;
- if (rightb > 0)
- rightb = 0;
+ /*if (rightb > 0)
+ rightb = 0;*/
}
}
bbox[BBOX_NEG_WIDTH] = start;
bbox[BBOX_GLOBAL_DESCENT] = handle->face->size->metrics.descender / 64;
- bbox[BBOX_POS_WIDTH] = width - rightb;
+ bbox[BBOX_POS_WIDTH] = width;
+ if (rightb < 0)
+ bbox[BBOX_POS_WIDTH] -= rightb;
bbox[BBOX_GLOBAL_ASCENT] = handle->face->size->metrics.ascender / 64;
bbox[BBOX_DESCENT] = descent;
bbox[BBOX_ASCENT] = ascent;
bbox[BBOX_ADVANCE_WIDTH] = width;
+ bbox[BBOX_RIGHT_BEARING] = rightb;
+ mm_log((1, " bbox=> negw=%d glob_desc=%d pos_wid=%d glob_asc=%d desc=%d asc=%d adv_width=%d rightb=%d\n", bbox[0], bbox[1], bbox[2], bbox[3], bbox[4], bbox[5], bbox[6], bbox[7]));
- return BBOX_ADVANCE_WIDTH + 1;
+ return BBOX_RIGHT_BEARING + 1;
}
/*
View
12 lib/Imager/Font.pm
@@ -326,7 +326,8 @@ Imager::Font - Font handling for Imager.
$global_ascent,
$descent,
$ascent,
- $advance_width) = $font->bounding_box(string=>"Foo");
+ $advance_width,
+ $right_bearing) = $font->bounding_box(string=>"Foo");
$logo = $font->logo(text => "Slartibartfast Enterprises",
size => 40,
@@ -415,7 +416,8 @@ Returns the bounding box for the specified string. Example:
$global_ascent,
$descent,
$ascent,
- $advance_width) = $font->bounding_box(string => "A Fool");
+ $advance_width,
+ $right_bearing) = $font->bounding_box(string => "A Fool");
my $bbox_object = $font->bounding_box(string => "A Fool");
@@ -453,6 +455,12 @@ start at, this is often the same as C<$pos_width>, but can be
different if the final character overlaps the right side of its
character cell.
+=item C<$right_bearing>
+
+The distance from the right side of the final glyph to the end of the
+advance width. If the final glyph overflows the advance width this
+value is negative.
+
=back
Obviously we can stuff all the results into an array just as well:
View
45 lib/Imager/Font/BBox.pm
@@ -15,6 +15,8 @@ Imager::Font::BBox - objects representing the bounding box of a string.
# 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;
@@ -23,6 +25,7 @@ Imager::Font::BBox - objects representing the bounding box of a string.
my $total_width = $bbox->total_width;
my $fheight = $bbox->font_height;
my $theight = $bbox->text_height;
+ my $display_width = $bbox->display_width;
=head1 DESCRIPTION
@@ -45,6 +48,8 @@ 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.
+
=cut
sub start_offset {
@@ -55,6 +60,10 @@ sub neg_width {
return $_[0][0];
}
+sub left_bearing {
+ return $_[0][0];
+}
+
=item end_offset()
The offset from the selected drawing location to the right edge of the
@@ -169,6 +178,42 @@ sub text_height {
$self->ascent - $self->descent;
}
+=item 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.
+
+=cut
+
+sub right_bearing {
+ my $self = shift;
+
+ @$self >= 8 && return $self->[7]; # driver gives it to us
+
+ # otherwise the closest we have is the difference between the
+ # end_pos and advance_width
+ return $self->advance_width - $self->pos_width;
+}
+
+=item display_width
+
+The distance from the left-most pixel of the left-most glyph to the
+right-most pixel of the right-most glyph.
+
+Equals advance_width - left_bearing - right_bearing (and implemented
+that way.)
+
+=cut
+
+sub display_width {
+ my ($self) = @_;
+
+ $self->advance_width - $self->left_bearing - $self->right_bearing;
+}
+
=back
=head1 INTERNAL FUNCTIONS
View
27 t/t38ft2font.t
@@ -1,6 +1,7 @@
#!perl -w
use strict;
-use Test::More tests => 138;
+use Test::More tests => 144;
+++$|;
# Before `make install' is performed this script should be runnable with
# `make test'. After `make install' it should work as `perl test.pl'
@@ -37,7 +38,7 @@ SKIP:
my @bbox=Imager::Font::FreeType2::i_ft2_bbox($ttraw, 50.0, 0, 'XMCLH', 0);
print "#bbox @bbox\n";
- is(@bbox, 7, "i_ft2_bbox() returns 7 values");
+ is(@bbox, 8, "i_ft2_bbox() returns 8 values");
ok(Imager::Font::FreeType2::i_ft2_cp($ttraw,$overlay,5,50,1,50.0,50, 'XMCLH',1,1, 0, 0), "drawn to channel");
i_line($overlay,0,50,100,50,$bgcolor,1);
@@ -187,7 +188,7 @@ SKIP:
@bbox = $oof->bounding_box(string=>"hello", size=>30);
my $bbox = $oof->bounding_box(string=>"hello", size=>30);
- is(@bbox, 7, "list bbox returned 7 items");
+ is(@bbox, 8, "list bbox returned 8 items");
ok($bbox->isa('Imager::Font::BBox'), "scalar bbox returned right class");
ok($bbox->start_offset == $bbox[0], "start_offset");
ok($bbox->end_offset == $bbox[2], "end_offset");
@@ -223,14 +224,30 @@ SKIP:
SKIP:
{
ok($exfont, "loaded existence font") or
- skip("couldn't load test font", 5);
+ skip("couldn't load test font", 11);
+
# the test font is known to have a shorter advance width for that char
my @bbox = $exfont->bounding_box(string=>"/", size=>100);
- is(@bbox, 7, "should be 7 entries");
+ is(@bbox, 8, "should be 8 entries");
isnt($bbox[6], $bbox[2], "different advance width");
my $bbox = $exfont->bounding_box(string=>"/", size=>100);
ok($bbox->pos_width != $bbox->advance_width, "OO check");
+ cmp_ok($bbox->right_bearing, '<', 0, "check right bearing");
+
+ cmp_ok($bbox->display_width, '>', $bbox->advance_width,
+ "check display width (roughly)");
+
+ # check with a char that fits inside the box
+ my $bbox = $exfont->bounding_box(string=>"!", size=>100);
+ print "# pos width ", $bbox->pos_width, "\n";
+ is($bbox->pos_width, $bbox->advance_width,
+ "check backwards compatibility");
+ cmp_ok($bbox->left_bearing, '>', 0, "left bearing positive");
+ cmp_ok($bbox->right_bearing, '>', 0, "right bearing positive");
+ cmp_ok($bbox->display_width, '<', $bbox->advance_width,
+ "display smaller than advance");
+
# name tests
# make sure the number of tests on each branch match
if (Imager::Font::FreeType2::i_ft2_can_face_name()) {

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