# ttfcairoglyphviewer
# Copyright (C) 2006  Mathieu Blondel
# 
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA

$LOAD_PATH.unshift("../lib/")

require 'gtk2'
require 'cairo'
require 'ttf'

class Cairo::Context

    def draw_square(x, y)
        rectangle(x-10, y-10, 20, 20)
        set_source_rgb(255.0, 0.0, 0.0)
        fill_preserve
        set_line_join(Cairo::LINE_JOIN_ROUND)
        set_line_width(1)       
        stroke
    end

    def draw_circle(x, y)
        arc(x, y, 10, 0, 2 * Math::PI)
        fill_preserve
        set_line_join(Cairo::LINE_JOIN_ROUND)
        set_line_width(1)       
        stroke
    end

    def draw_blue_circle(x, y)
        set_source_rgb(0.0, 0.0, 255.0)
        draw_circle(x, y)
    end

    def draw_green_circle(x, y)
        set_source_rgb(0.0, 255.0, 0)
        draw_circle(x, y)
    end

    def draw_markers(glyph)
        i = 0
        points = glyph.points
        start_new_contour = true
        while i < points.length                  
            if start_new_contour
                # The -y is needed because the directions of the y-axis
                # with SVG and TrueType are opposed.
                draw_square(points[i].abs_x, -(points[i].abs_y))
                first_point = points[i]
            end
        
            if points[i].end_of_contour?
                close_path
                start_new_contour = true
                i += 1
            else
                if points[i].on_curve? and points[i + 1].on_curve?             
                    draw_square(points[i + 1].abs_x, -(points[i + 1].abs_y))
                    
                    i += 1
                else
                    if points[i + 1].end_of_contour?
                        # Close the contour
                        draw_blue_circle(points[i + 1].abs_x, 
                                      -(points[i + 1].abs_y))
                        i += 1           
                    elsif points[i + 2].on_curve?
                        draw_blue_circle(points[i + 1].abs_x,
                                      -(points[i + 1].abs_y))
                    
                        draw_square(points[i + 2].abs_x,
                                    -(points[i + 2].abs_y))
                        i += 2
                    else
                        # This is an implied on-curve point
                        impl_x = (points[i + 2].abs_x - points[i + 1].abs_x) / 2
                        impl_x += points[i + 1].abs_x
                        impl_y = (points[i + 2].abs_y - points[i + 1].abs_y) / 2
                        impl_y += points[i + 1].abs_y
        
                        draw_blue_circle(points[i + 1].abs_x,
                                         -(points[i + 1].abs_y))
                        draw_green_circle(impl_x, -(impl_y))
                        i += 1                
                    end
                end
        
                start_new_contour = false
            end
        
        end
    end

    def max_y(glyph)
        max_y = 0
        glyph.points.each do |pnt|
            max_y = pnt.abs_y if pnt.abs_y > max_y
        end
        max_y
    end

    def draw_simple_glyph(glyph)
        set_source_rgba(1.0, 1.0, 1.0)
        paint
        points = glyph.points
        
        start_new_contour = true
        i = 0

        scale(0.25, 0.25)
        translate(0, max_y(glyph) + 20)


        # Obviously this could be optimized because almost the same
        # while loop is used twice but I had troubles to draw markers
        # and paths at the same time. FIXME!
        while i < points.length                  
            if start_new_contour
                # The -y is needed because the directions of the y-axis
                # with SVG and TrueType are opposed.
                move_to(points[i].abs_x, -(points[i].abs_y))
                first_point = points[i]
            end
        
            if points[i].end_of_contour?
                close_path
                start_new_contour = true
                i += 1
            else
                if points[i].on_curve? and points[i + 1].on_curve?             
                    line_to(points[i + 1].abs_x, -(points[i + 1].abs_y))
                    
                    i += 1
                else
                    if points[i + 1].end_of_contour?
                        # Close the contour
                        quad_to(points[i + 1].abs_x, 
                                      -(points[i + 1].abs_y),
                                      first_point.abs_x,
                                      -(first_point.abs_y))
                        i += 1           
                    elsif points[i + 2].on_curve?
                        quad_to(points[i + 1].abs_x,
                                      -(points[i + 1].abs_y),
                                       points[i + 2].abs_x,
                                       -(points[i + 2].abs_y))
                        i += 2
                    else
                        # This is an implied on-curve point
                        impl_x = (points[i + 2].abs_x - points[i + 1].abs_x) / 2
                        impl_x += points[i + 1].abs_x
                        impl_y = (points[i + 2].abs_y - points[i + 1].abs_y) / 2
                        impl_y += points[i + 1].abs_y
        
                        quad_to(points[i + 1].abs_x,
                                      -(points[i + 1].abs_y),
                                      impl_x,
                                      -(impl_y))
                        i += 1                
                    end
                end
        
                start_new_contour = false
            end
        
        end
        
        set_source_rgb(0.0, 0.0, 0.0)
        #fill_preserve
        set_line_join(Cairo::LINE_JOIN_MITER)
        set_line_width(4)
        
        stroke

        draw_markers(glyph)
    end
end

font = TTFFont::TTF::File.new(ARGV[0])

enc_tbl = font.get_table(:cmap).encoding_tables.find do |t|
    t.class == TTFFont::TTF::Table::Cmap::EncodingTable4
end

if ARGV[1] == "-g"
    offs = font.get_table(:loca).glyph_offsets[ARGV[2].to_i]
    glyph = font.get_table(:glyf).get_glyph_at_offset(offs)
elsif ARGV[1] == "-c"
    char_code = ARGV[2].unpack("U")[0]
    glyph = enc_tbl.get_glyph_for_unicode(char_code)
else
    exit!
end

if glyph.composite?
   puts "Composite glyph not supported yet"
   exit! 
end

Gtk.init
w = Gtk::Window.new.add(vb = Gtk::VBox.new)
vb.add(da = Gtk::DrawingArea.new)
da.set_size_request(300, 300)

da.signal_connect("expose-event") do |widget, event|
    cr = widget.window.create_cairo_context
    cr.draw_simple_glyph(glyph)
end

w.show_all

w.signal_connect("delete-event") do
    Gtk.main_quit
end

Gtk.main