- closes#1298
- allows for much faster halo drawing and simliar quality for
radius values in the 1-2 px range
- also moves grid_renderer away from using freetype stroker completely
since halo quality is not critical for this renderer
(we can have outlined text now!)
+ allow fractional halo_radius
+ TODO: Rename halo_fill to stroke
halo_radius to stroke-width
+ TODO: Implement proper 'halo' effect
1. Modified Text Symbolizer
a) corrected line fragment centering (for 2nd and subsequent lines, when line breaks occur).
b) adjusted vertical alignment calculation so that:
i) middle -> has the center of the text line(s) at the point origin
ii) bottom -> has the text line(s) below the point origin
iii) top -> has the text line(s) above the point origin
c) added new text_symbolizer attribute: 'wrap_before', value range: true/false, default == false
allows line breaks at first wrap_char before wrap_width as an alternative to the original
which was to create the line break at the first wrap_char after wrap_width
d) added new text_symbolizer attribute: 'horizontal_alignment', value range: left/middle/right, default == middle
i) left -> has all text line(s) to left of the point origin
ii) middle -> has all text line(s) centered on the the point origin
iii) right -> has all text line(s) to the right of the point origin
NOTE: dx, dy position adjustments are applied after alignments and before Justify.
e) added new text_symbolizer attribute: 'justify_alignment', value range: left/middle/right, default == middle
i) left -> after alignments, has all text line(s) are left justified (left to right reading)
ii) middle -> after alignments, has all text line(s) center justified
iii) right -> after alignments, has all text line(s) right justified (right to left reading)
f) added new text_symbolizer attribute: 'opacity', value range: 0.0 thru 1.0; 1.0 == fully opaque
g) modified positioning to compensate for both line_spacing and character_spacing, to ensure proper
centering of the text envelope. Also ensure that centering occurs correctly even if no wrapping
occurs. Line spacing is uniform and consistent and compensates for errors between text_size and
the actual size (ci.height is inconsistent, depending on case and character); fixes issue with
multi-line text where some lines have a slight gap and others are compressed together.
2. Modified shield_symbolizer
a) added the attributes:
i) allow_overlap
ii) vertical_alignment
iii) horizontal_alignment
iv) justify_alignment
v) wrap_width
vi) wrap_character
vii) wrap_before
viii) text_convert
ix) line_spacing
x) character_spacing
xi) opacity
b) added new shield_symbolizer attribute: 'unlock_image', value range: true/false, default == false
i) false == image and text placement behaviour same as before
ii) true == image placement independant of text, image is always centered at geometry point, text placed per attributes,
dx/dy only affect text.
Allows user to create point markers with text, but both the text and image rendering collision detection are done
as a pair (they come and go together - solves problem if using point_symbolizer and text_symbolizers where one or the
other are omitted due to overlaps, but not both)
c) extended choices for the attribute 'placement' to include vertex; effect is limited to the shield_symbolizer
Allows an attempted placement at every vertex available, gives additional shield placement volume when using line geometry
d) ensured that the text placement was not updating the detector unless a shield image was actually placed.
e) added new shield_symbolizer attribute: 'no_text', value range: true/false, default = false
When set true, the text for the feature is ignored ('space' subsituted) so that pure graphic symbols can be used
and no text is rendered over top of them.
* text_convert="none|toupper|tolower"
Convert all text to upper/lower case before rendering. "none" doesn't do
anything with the text and is the default. Works for labels along lines
or at points.
* line_spacing="<number>"
Add this many pixels space between two lines in text labels that have
been broken into several lines. Default is 0. Doesn't do anything for
labels along lines.
* character_spacing="<number>"
Add this many pixels space between two characters in a text. Default is 0.
Currently only works for text labels on point geometries. This should
also be implemented for labels along lines, but I'll leave that for
another day.
* wrap_character="<character>"
Instead of breaking text into lines on spaces, use this character. This
is useful, when you want to make sure that labels are broken at the right
spot. Note that you'll probably want to make wrap_width small so that
your lines are actually broken, otherwise you'll see the wrap_character
in the output. Default is ' ' (space). Doesn't do anything for labels
along lines.
