Redmine/app/views/projects/gantt.rhtml

<h2><%= l(:label_gantt_chart) %></h2>
<div class="topright">
<small>
<%= l(:label_export_to) %>&nbsp;&nbsp;<%= link_to 'PDF', :zoom => @zoom, :year => @year_from, :month => @month_from, :months => @months, :output => 'pdf' %>
</small>
</div>

<table width="100%">
<tr>
<td align="left">
<%= start_form_tag %>
<input type="text" name="months" size="2" value="<%= @months %>">
<%= l(:label_months_from) %>
<%= select_month(@month_from, :prefix => "month", :discard_type => true) %>
<%= select_year(@year_from, :prefix => "year", :discard_type => true) %>
<%= hidden_field_tag 'zoom', @zoom %>
<%= submit_tag l(:button_submit), :class => "button-small" %>
<%= end_form_tag %>
</td>
<td align="right">
<%= if @zoom < 4
    link_to image_tag('zoom_in'), {:zoom => (@zoom+1), :year => @year_from, :month => @month_from, :months => @months}
  else
    image_tag 'zoom_in_g'
  end %>
<%= if @zoom > 1
    link_to image_tag('zoom_out'), :zoom => (@zoom-1), :year => @year_from, :month => @month_from, :months => @months
  else
    image_tag 'zoom_out_g'
  end %>
</td>
</tr>
</table>
<br />

<style>
.m_bg {
  position:absolute;
  top:0;
  height:16px;
  border-top: 1px solid #c0c0c0;
  border-bottom: 1px solid #c0c0c0;
  border-right: 1px solid #c0c0c0;
  text-align: center;
}

.task {
  position: absolute;
  height:8px;
  font-size:0.8em;
  color:#888;
  background:#aaa;
  padding:0;
  margin:0;
  line-height:0.8em;
}

.task_late {
  background:#f66;
}

.task_done {
  background:#66f;
}  
</style>

<% zoom = 1
@zoom.times { zoom = zoom * 2 }

subject_width = 260
header_heigth = 18

headers_heigth = header_heigth
show_weeks = false
show_days = false

if @zoom >1
    show_weeks = true
    headers_heigth = 2*header_heigth
    if @zoom > 2
        show_days = true
        headers_heigth = 3*header_heigth
    end
end

g_width = (@date_to - @date_from + 1)*zoom
g_height = [(20 * @issues.length + 6), 206].max
t_height = g_height + headers_heigth
%>

<table width="100%" border=0 cellspacing=0 cellpading=0>
<tr>
<td width=260>

<div style="position:relative;height:<%= t_height + 24 %>px;width:<%= subject_width + 1 %>px;">
<div style="right:-2px;width:<%= subject_width %>px;height:<%= headers_heigth %>px;" class="m_bg"></div>
<div style="right:-2px;width:<%= subject_width %>px;height:<%= t_height %>px;border-left: 1px solid #c0c0c0;" class="m_bg"></div>
<%
#
# Tasks subjects
#
top = headers_heigth + 8
@issues.each do |i| %>
	<div style="position: absolute;line-height:1em;height:16px;top:<%= top %>px;left:4px;width:<%= subject_width - 5 %>px;overflow:hidden;">
	<small><%= link_to "#{i.tracker.name} ##{i.id}", :controller => 'issues', :action => 'show', :id => i %>:
	<%= i.subject.sub(/^(.{30}[^\s]*\s).*$/, '\1 (...)') %></small>
	</div>
<% top = top + 20
end %>
</div>
</td>
<td>

<div style="position:relative;height:<%= t_height + 24 %>px;width:<%= subject_width %>;overflow:auto;">
<div style="width:<%= g_width-1 %>px;height:<%= headers_heigth %>px;" class="m_bg">&nbsp;</div>
<% 
#
# Months headers
#
month_f = @date_from
left = 0
height = (show_weeks ? header_heigth : header_heigth + g_height)
@months.times do 
	width = ((month_f >> 1) - month_f) * zoom - 1
	%>
	<div style="left:<%= left %>px;width:<%= width %>px;height:<%= height %>px;" class="m_bg">
	<%= link_to "#{month_f.year}-#{month_f.month}", :year => month_f.year, :month => month_f.month, :zoom => @zoom, :months => @months %>
	</div>
	<% 
	left = left + width + 1
	month_f = month_f >> 1
end %>

<% 
#
# Weeks headers
#
if show_weeks
	left = 0
	height = (show_days ? header_heigth-1 : header_heigth-1 + g_height)
	if @date_from.cwday == 1
	    # @date_from is monday
        week_f = @date_from
	else
	    # find next monday after @date_from
		week_f = @date_from + (7 - @date_from.cwday + 1)
		width = (7 - @date_from.cwday + 1) * zoom-1
		%>
		<div style="left:<%= left %>px;top:19px;width:<%= width %>px;height:<%= height %>px;" class="m_bg">&nbsp;</div>
		<% 
		left = left + width+1
	end %>
	<%
	while week_f < @date_to
		width = (week_f + 6 <= @date_to) ? 7 * zoom -1 : (@date_to - week_f + 1) * zoom-1
		%>
		<div style="left:<%= left %>px;top:19px;width:<%= width %>px;height:<%= height %>px;" class="m_bg">
		<small><%= week_f.cweek %></small>
		</div>
		<% 
		left = left + width+1
		week_f = week_f+7
	end
end %>

<% 
#
# Days headers
#
if show_days
	left = 0
	height = g_height + header_heigth - 1
	wday = @date_from.cwday
	(@date_to - @date_from + 1).to_i.times do 
	width =  zoom - 1
	%>
	<div style="left:<%= left %>px;top:37px;width:<%= width %>px;height:<%= height %>px;font-size:0.7em;<%= "background:#f1f1f1;" if wday > 5 %>" class="m_bg">
	<%= day_name(wday)[0,1] %>
	</div>
	<% 
	left = left + width+1
	wday = wday + 1
	wday = 1 if wday > 7
	end
end %>

<%
#
# Today red line
#
if Date.today >= @date_from and Date.today <= @date_to %>
    <div style="position: absolute;height:<%= g_height %>px;top:<%= headers_heigth + 1 %>px;left:<%= ((Date.today-@date_from+1)*zoom).floor()-1 %>px;width:10px;border-left: 1px dashed red;">&nbsp;</div>
<% end %>

<%
#
# Tasks
#
top = headers_heigth + 12
@issues.each do |i| %>
	<%
	i_start_date = (i.start_date >= @date_from ? i.start_date : @date_from )
	i_end_date = (i.due_date <= @date_to ? i.due_date : @date_to )
	
	i_done_date = i.start_date + ((i.due_date - i.start_date+1)*i.done_ratio/100).floor
	i_done_date = (i_done_date <= @date_from ? @date_from : i_done_date )
	i_done_date = (i_done_date >= @date_to ? @date_to : i_done_date )
	
	i_late_date = [i_end_date, Date.today].min if i_start_date < Date.today
	
	i_left = ((i_start_date - @date_from)*zoom).floor 
	i_width = ((i_end_date - i_start_date + 1)*zoom).floor
	d_width = ((i_done_date - i_start_date)*zoom).floor
	l_width = ((i_late_date - i_start_date+1)*zoom).floor if i_late_date
	l_width ||= 0
	%>	
	<div style="top:<%= top %>px;left:<%= i_left %>px;width:<%= i_width %>px;" class="task">&nbsp;</div>
	<% if l_width > 0 %>
	    <div style="top:<%= top %>px;left:<%= i_left %>px;width:<%= l_width %>px;" class="task task_late">&nbsp;</div>
	<% end %>
	<% if d_width > 0 %>
	    <div style="top:<%= top %>px;left:<%= i_left %>px;width:<%= d_width %>px;" class="task task_done">&nbsp;</div>
	<% end %>
	<div style="top:<%= top %>px;left:<%= i_left + i_width + 5 %>px;background:#fff;" class="task">
	<%= i.status.name %>
	<%= (i.done_ratio).to_i %>%
	</div>	
	<% top = top + 20
end %>
</div>
</td>
</tr>
</table>

<table width="100%">
<tr>
<td align="left"><%= link_to ('&#171; ' + l(:label_previous)), :year => (@date_from << @months).year, :month => (@date_from << @months).month, :zoom => @zoom, :months => @months %></td>
<td>
<td align="right"><%= link_to (l(:label_next) + ' &#187;'), :year => (@date_from >> @months).year, :month => (@date_from >> @months).month, :zoom => @zoom, :months => @months %></td>
</tr>
</table>