As mentioned in the comments, the source for detexify is available on GitHub at https://github.com/kirel/detexify.
The symbols database is provided at lib/latex/symbols.yaml in a YAML format (sample below) which is easily extensible and satisfies your requirements for information about the required package(s) and mode (text or math).
# Table 212: wasysym Biological Symbols
- package: wasysym
bothmodes:
- \female
- \male
- package: skull
mathmode:
- \skull
# Table 254: wasysym General Symbols
- package: wasysym
textmode:
- \LEFTarrow
# <...>
- \recorder
bothmodes:
- \checked #
# <...>
- \invdiameter #
SVG output can be created by adapting a rake task provided in lib/rake/symbol_task.rb. I present my initial adaptation of this code below. Disclaimer: I am a newbie to Ruby, and there are likely better ways to do this since I'm stripping away most of Daniel's code here. Take this as a starting point rather than the standard. :-)
require 'rake/tasklib'
require 'erb'
require 'latex/symbol'
class SymbolTask < Rake::TaskLib
TEMPLATE = ERB.new <<-LATEX #open('template.tex.erb').read
\\documentclass[10pt]{article}
\\usepackage[utf8]{inputenc}
<%= @packages %>
\\pagestyle{empty}
\\begin{document}
<%= @command %>
\\end{document}
LATEX
TMP = 'tmp'
OUT = 'images/latex'
attr_accessor :name, :tmp, :out
# initialize sets the name and calls a block to get
# the rest of the options
def initialize(name = :symbols)
@name = name
yield self if block_given?
define
end
# define creates the new task(s)
def define
#desc "prepare necessary directories"
#task :prepare do
directory TMP
directory OUT
#end
all_image_tasks = Latex::Symbol::List.map do |symbol|
define_single_tex_task symbol
define_single_dvi_task symbol
define_single_image_task symbol
end
desc "create svg images from all symbols"
task :gen_svg => all_image_tasks
end
def define_single_image_task symbol
file "#{File.join(OUT, symbol.filename)}.svg" => [OUT, "#{File.join(TMP, symbol.filename)}.dvi"] do |t|
# Now convert to image
puts "Creating image... #{t.name}"
sh %|dvisvgm -n #{File.join(TMP, symbol.filename)}.dvi #{t.name}| do |ok, res|
if ! ok
puts "Major Failure creating image! (status = #{res.exitstatus})"
end
end
end
"#{File.join(OUT, symbol.filename)}.svg" # need the names
end
def define_single_dvi_task symbol
file "#{File.join(TMP, symbol.filename)}.dvi" => [TMP, "#{File.join(TMP, symbol.filename)}.tex"] do
puts "Generating dvi for #{symbol}..."
sh %|latex -interaction=batchmode -output-directory=#{TMP} #{File.join(TMP, symbol.filename)}.tex| do |ok, res|
if ! ok
puts "Major Failure creating dvi! (status = #{res.exitstatus})"
end
end
end
end
def define_single_tex_task symbol
file "#{File.join(TMP, symbol.filename)}.tex" => TMP do |t|
open(t.name, 'w+') do |texfile|
# setup variables
@packages = ''
@packages << "\\usepackage{#{symbol[:package]}}\n" if symbol[:package]
@packages << "\\usepackage[#{symbol[:fontenc]}]{fontenc}\n" if symbol[:fontenc]
@command = symbol.mathmode ? "$#{symbol.command}$" : symbol.command
# write symbol to tempfile
puts "Generating latex for #{symbol}..."
texfile.puts TEMPLATE.result(binding)
end
end
end
end
I made these modifications on a clone of the detexify repository, but the only files required are lib/rake/symbol_task.rb, lib/latex/symbol.rb, and lib/latex/symbols.yaml.
To build all SVG outputs, execute rake gen_svg at a Ruby command prompt. dvisvgm is required; alternatively, the Ruby code could be modified to use pdflatex with pdf2svg (untested) or Inkscape (on the command line) to perform the conversion to SVG.
Best Answer
The other answers have provided you the reasons why
\mathbb{+}does not work off-hand. If you would like to use these symbols in a math context, you can declare it as a math symbol, with proper spacings (e.g.+in math mode should have spacing around it matching that of\mathbinbecause it is a binary operator etc.). See this answer for more details.In this case, the
+is a Math symbol defined infontmath.ltxas such:Motivated by this, you can define the blackboard
+math symbol in a similar way, by declaring a symbol font and then a math symbol like so:which gives:
You should be able to extrapolate from this for other symbols by yourself.
Resident font gurus would hopefully correct this or post a new answer if there is an easier way to do this.