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<html>
	<head>
		<title>dwm - dynamic window manager</title>
		<meta name="author" content="Anselm R. Garbe">
		<meta name="generator" content="ed">
		<meta name="copyright" content="(C)opyright 2006 by Anselm R. Garbe">
		<link rel="dwm icon" href="favicon.ico" type="image/x-icon" />
		<style type="text/css">
			body {
				color: #000000;
				font-family: sans-serif;
				margin: 20px 20px 20px 20px;
			}
		</style>
	</head>
	<body>
		<center>
			<img src="dwm.png"/><br />
			<h3>dynamic window manager</h3>
		</center>
		<h3>Description</h3>
		<p>
		dwm is a dynamic window manager for X11.
		</p>
		<h4>Background</h4>
		<p>
		As founder and main developer of wmii I came to the conclusion that
		wmii is too clunky for my needs. I don't need so many funky features
		and all this hype about remote control through a 9P service, I only
		want to manage my windows in a simple, but dynamic way. wmii never got
		finished because I listened to users, who proposed arbitrary ideas I
		considered useful. This resulted in an extreme <a
		href="http://www.jwz.org/doc/cadt.html">CADT</a> development model,
		which was a mistake. Thus the philosophy of dwm is simply <i>to fit my
		needs</i> (maybe yours as well). That's it.
		</p>
		<h4>Differences to ion, larswm, and wmii</h4>
		<p>
		In contrast to ion, larswm, and wmii, dwm is much smaller, faster and simpler.
		</p>
		<ul>
			<li>
			dwm has no Lua integration, no 9P support, no editable
			tagbars, no shell-based configuration, no remote control, and comes
			without any additional tools like printing the selection or warping
			the mouse.
			</li>
			<li>
			dwm is only a single binary, it's source code is intended to never
			exceed 2000 SLOC.
			</li>
			<li>
			dwm is based on tagging and dynamic window management (however
			simpler than ion, wmii or larswm). It manages windows in
			tiling and floating modes. Either mode can be applied dynamically,
			depending on the application in use and the task performed.
			</li>
			<li>
			dwm doesn't distinguishes between layers, there is no floating or
			tiled layer. Wether the clients of currently selected tag are in
			tiled mode or not, you can re-arrange all clients on the fly.
			Popup- and fixed-size windows are treated floating, however. 
			</li>
			<li>
			dwm is customized through editing its source code, that makes it
			extremely fast and secure - it does not process any input data
			which hasn't been known at compile time, except window title names
			and status text read from standard input. You don't have to learn
			Lua/sh/ruby or some weird configuration file format (like X
			resource files), beside C to customize it for your needs,
			you <b>only</b> have to learn C (at least editing header files).
			</li>
			<li>
			Because dwm is customized through editing its source code, it's
			pointless to make binary packages of it. This keeps its userbase
			small and elitist. No novices asking stupid questions.
			</li>
			<li>
			dwm uses 1-pixel borders to provide the maximum of screen real
			estate to clients. Small titlebars are only drawn in front of
			unfocused clients.
			</li>
			<li>
			dwm reads from standard input to print arbitrary status text (like
			the date, load, battery charge). That's much simpler than
			larsremote, wmiir and what not...
			</li>
			<li>
			It can be downloaded and distributed under the conditions
			of the <a href="http://10kloc.org/cgi-bin/hgwebdir.cgi/dwm?f=f10eb1139362;file=LICENSE;style=raw">MIT/X Consortium license</a>.
			</li>
			<li>
			Optionally you can install <b>dmenu</b> to extend dwm with a wmii-alike menu.
			</li>
		</ul>
		<h4>Links</h4>
		<ul>
			<li><a href="http://10kloc.org/cgi-bin/man/man2html?query=dwm">Man page</a></li>
			<li><a href="http://10kloc.org/shots/dwm-20060810a.png">Screenshot of tiled mode</a> (20060810)</li>
			<li><a href="http://10kloc.org/shots/dwm-20060810b.png">Screenshotof floating mode</a> (20060810)</li>
			<li><a href="http://10kloc.org/download/poster.ps">A4 poster (PostScript)</a></li>
			<li>Mailing List: <a href="http://10kloc.org/cgi-bin/mailman/listinfo/dwm">dwm at wmii dot de</a> <a href="http://10kloc.org/pipermail/dwm/">(Archives)</a>&nbsp;<a href="http://dir.gmane.org/gmane.comp.window-managers.dwm">(GMANE Archive)</a></li>
			<li>IRC channel: <code>#dwm</code> at <code>irc.oftc.net</code></li>
		</ul>
		<h3>Download</h3>
		<ul>
			<li><a href="http://10kloc.org/download/dwm-0.9.tar.gz">dwm 0.9</a> (15kb) (20060815)</li>
			<li><a href="http://10kloc.org/download/dmenu-0.4.tar.gz">dmenu 0.4</a> (7kb) (20060815)</li>
		</ul>
		<h3>Development</h3>
		<p>
		dwm is actively developed in parallel to wmii. You can <a href="http://10kloc.org/cgi-bin/hgwebdir.cgi/dwm">browse</a> its source code repository or get a copy using <a href="http://www.selenic.com/mercurial/">Mercurial</a> with following command:
		</p>
		<p>
		<code>hg clone http://10kloc.org/cgi-bin/hgwebdir.cgi/dwm</code>
		</p>
		<p>
		<code>hg clone http://10kloc.org/cgi-bin/hgwebdir.cgi/dmenu</code>
		</p>
		<h3>Miscellaneous</h3>
		<p>
		You can purchase this <a href="https://www.spreadshirt.net/shop.php?op=article&article_id=3298632&view=403">tricot</a>
		if you like dwm and the dwm logo, which has been designed by Anselm.
		</p>
		<p><small>--Anselm</small></p>
	</body>
</html>
/ .highlight .sx { color: #22bb22; background-color: #f0fff0 } /* Literal.String.Other */ .highlight .sr { color: #008800; background-color: #fff0ff } /* Literal.String.Regex */ .highlight .s1 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Single */ .highlight .ss { color: #aa6600; background-color: #fff0f0 } /* Literal.String.Symbol */ .highlight .bp { color: #003388 } /* Name.Builtin.Pseudo */ .highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */ .highlight .vc { color: #336699 } /* Name.Variable.Class */ .highlight .vg { color: #dd7700 } /* Name.Variable.Global */ .highlight .vi { color: #3333bb } /* Name.Variable.Instance */ .highlight .vm { color: #336699 } /* Name.Variable.Magic */ .highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */
-- primitives for editing drawings
Drawing = {}
geom = require 'geom'

-- All drawings span 100% of some conceptual 'page width' and divide it up
-- into 256 parts.
function Drawing.draw(line)
  local pmx,pmy = love.mouse.getX(), love.mouse.getY()
  if pmx < 16+Line_width and pmy > line.y and pmy < line.y+Drawing.pixels(line.h) then
    love.graphics.setColor(0.75,0.75,0.75)
    love.graphics.rectangle('line', 16,line.y, Line_width,Drawing.pixels(line.h))
    if icon[Current_drawing_mode] then
      icon[Current_drawing_mode](16+Line_width-20, line.y+4)
    else
      icon[Previous_drawing_mode](16+Line_width-20, line.y+4)
    end

    if love.mouse.isDown('1') and love.keyboard.isDown('h') then
      draw_help_with_mouse_pressed(line)
      return
    end
  end

  if line.show_help then
    draw_help_without_mouse_pressed(line)
    return
  end

  local mx,my = Drawing.coord(pmx-16), Drawing.coord(pmy-line.y)

  for _,shape in ipairs(line.shapes) do
    assert(shape)
    if geom.on_shape(mx,my, line, shape) then
      love.graphics.setColor(1,0,0)
    else
      love.graphics.setColor(0,0,0)
    end
    Drawing.draw_shape(16,line.y, line, shape)
  end
  for _,p in ipairs(line.points) do
    if p.deleted == nil then
      if Drawing.near(p, mx,my) then
        love.graphics.setColor(1,0,0)
        love.graphics.circle('line', Drawing.pixels(p.x)+16,Drawing.pixels(p.y)+line.y, 4)
      else
        love.graphics.setColor(0,0,0)
        love.graphics.circle('fill', Drawing.pixels(p.x)+16,Drawing.pixels(p.y)+line.y, 2)
      end
    end
  end
  love.graphics.setColor(0.75,0.75,0.75)
  Drawing.draw_pending_shape(16,line.y, line)
end

function Drawing.draw_shape(left,top, drawing, shape)
  if shape.mode == 'freehand' then
    local prev = nil
    for _,point in ipairs(shape.points) do
      if prev then
        love.graphics.line(Drawing.pixels(prev.x)+left,Drawing.pixels(prev.y)+top, Drawing.pixels(point.x)+left,Drawing.pixels(point.y)+top)
      end
      prev = point
    end
  elseif shape.mode == 'line' or shape.mode == 'manhattan' then
    local p1 = drawing.points[shape.p1]
    local p2 = drawing.points[shape.p2]
    love.graphics.line(Drawing.pixels(p1.x)+left,Drawing.pixels(p1.y)+top, Drawing.pixels(p2.x)+left,Drawing.pixels(p2.y)+top)
  elseif shape.mode == 'polygon' or shape.mode == 'rectangle' or shape.mode == 'square' then
    local prev = nil
    for _,point in ipairs(shape.vertices) do
      local curr = drawing.points[point]
      if prev then
        love.graphics.line(Drawing.pixels(prev.x)+left,Drawing.pixels(prev.y)+top, Drawing.pixels(curr.x)+left,Drawing.pixels(curr.y)+top)
      end
      prev = curr
    end
    -- close the loop
    local curr = drawing.points[shape.vertices[1]]
    love.graphics.line(Drawing.pixels(prev.x)+left,Drawing.pixels(prev.y)+top, Drawing.pixels(curr.x)+left,Drawing.pixels(curr.y)+top)
  elseif shape.mode == 'circle' then
    local center = drawing.points[shape.center]
    love.graphics.circle('line', Drawing.pixels(center.x)+left,Drawing.pixels(center.y)+top, Drawing.pixels(shape.radius))
  elseif shape.mode == 'arc' then
    local center = drawing.points[shape.center]
    love.graphics.arc('line', 'open', Drawing.pixels(center.x)+left,Drawing.pixels(center.y)+top, Drawing.pixels(shape.radius), shape.start_angle, shape.end_angle, 360)
  elseif shape.mode == 'deleted' then
    -- ignore
  else
    print(shape.mode)
    assert(false)
  end
end

function Drawing.draw_pending_shape(left,top, drawing)
  local shape = drawing.pending
  if shape.mode == nil then
    -- nothing pending
  elseif shape.mode == 'freehand' then
    Drawing.draw_shape(left,top, drawing, shape)
  elseif shape.mode == 'line' then
    local mx,my = Drawing.coord(love.mouse.getX()-left), Drawing.coord(love.mouse.getY()-top)
    if mx < 0 or mx >= 256 or my < 0 or my >= drawing.h then
      return
    end
    local p1 = drawing.points[shape.p1]
    love.graphics.line(Drawing.pixels(p1.x)+left,Drawing.pixels(p1.y)+top, Drawing.pixels(mx)+left,Drawing.pixels(my)+top)
  elseif shape.mode == 'manhattan' then
    local mx,my = Drawing.coord(love.mouse.getX()-left), Drawing.coord(love.mouse.getY()-top)
    if mx < 0 or mx >= 256 or my < 0 or my >= drawing.h then
      return
    end
    local p1 = drawing.points[shape.p1]
    if math.abs(mx-p1.x) > math.abs(my-p1.y) then
      love.graphics.line(Drawing.pixels(p1.x)+left,Drawing.pixels(p1.y)+top, Drawing.pixels(mx)+left,Drawing.pixels(p1.y)+top)
    else
      love.graphics.line(Drawing.pixels(p1.x)+left,Drawing.pixels(p1.y)+top, Drawing.pixels(p1.x)+left,Drawing.pixels(my)+top)
    end
  elseif shape.mode == 'polygon' then
    -- don't close the loop on a pending polygon
    local prev = nil
    for _,point in ipairs(shape.vertices) do
      local curr = drawing.points[point]
      if prev then
        love.graphics.line(Drawing.pixels(prev.x)+left,Drawing.pixels(prev.y)+top, Drawing.pixels(curr.x)+left,Drawing.pixels(curr.y)+top)
      end
      prev = curr
    end
    love.graphics.line(Drawing.pixels(prev.x)+left,Drawing.pixels(prev.y)+top, love.mouse.getX(),love.mouse.getY())
  elseif shape.mode == 'rectangle' then
    local pmx,pmy = love.mouse.getX(), love.mouse.getY()
    local first = drawing.points[shape.vertices[1]]
    if #shape.vertices == 1 then
      love.graphics.line(Drawing.pixels(first.x)+left,Drawing.pixels(first.y)+top, pmx,pmy)
      return
    end
    local second = drawing.points[shape.vertices[2]]
    local mx,my = Drawing.coord(pmx-left), Drawing.coord(pmy-top)
    local thirdx,thirdy, fourthx,fourthy = Drawing.complete_rectangle(first.x,first.y, second.x,second.y, mx,my)
    love.graphics.line(Drawing.pixels(first.x)+left,Drawing.pixels(first.y)+top, Drawing.pixels(second.x)+left,Drawing.pixels(second.y)+top)
    love.graphics.line(Drawing.pixels(second.x)+left,Drawing.pixels(second.y)+top, Drawing.pixels(thirdx)+left,Drawing.pixels(thirdy)+top)
    love.graphics.line(Drawing.pixels(thirdx)+left,Drawing.pixels(thirdy)+top, Drawing.pixels(fourthx)+left,Drawing.pixels(fourthy)+top)
    love.graphics.line(Drawing.pixels(fourthx)+left,Drawing.pixels(fourthy)+top, Drawing.pixels(first.x)+left,Drawing.pixels(first.y)+top)
  elseif shape.mode == 'square' then
    local pmx,pmy = love.mouse.getX(), love.mouse.getY()
    local first = drawing.points[shape.vertices[1]]
    if #shape.vertices == 1 then
      love.graphics.line(Drawing.pixels(first.x)+left,Drawing.pixels(first.y)+top, pmx,pmy)
      return
    end
    local second = drawing.points[shape.vertices[2]]
    local mx,my = Drawing.coord(pmx-left), Drawing.coord(pmy-top)
    local thirdx,thirdy, fourthx,fourthy = Drawing.complete_square(first.x,first.y, second.x,second.y, mx,my)
    love.graphics.line(Drawing.pixels(first.x)+left,Drawing.pixels(first.y)+top, Drawing.pixels(second.x)+left,Drawing.pixels(second.y)+top)
    love.graphics.line(Drawing.pixels(second.x)+left,Drawing.pixels(second.y)+top, Drawing.pixels(thirdx)+left,Drawing.pixels(thirdy)+top)
    love.graphics.line(Drawing.pixels(thirdx)+left,Drawing.pixels(thirdy)+top, Drawing.pixels(fourthx)+left,Drawing.pixels(fourthy)+top)
    love.graphics.line(Drawing.pixels(fourthx)+left,Drawing.pixels(fourthy)+top, Drawing.pixels(first.x)+left,Drawing.pixels(first.y)+top)
  elseif shape.mode == 'circle' then
    local center = drawing.points[shape.center]
    local mx,my = Drawing.coord(love.mouse.getX()-left), Drawing.coord(love.mouse.getY()-top)
    if mx < 0 or mx >= 256 or my < 0 or my >= drawing.h then
      return
    end
    local cx,cy = Drawing.pixels(center.x)+left, Drawing.pixels(center.y)+top
    love.graphics.circle('line', cx,cy, geom.dist(cx,cy, love.mouse.getX(),love.mouse.getY()))
  elseif shape.mode == 'arc' then
    local center = drawing.points[shape.center]
    local mx,my = Drawing.coord(love.mouse.getX()-left), Drawing.coord(love.mouse.getY()-top)
    if mx < 0 or mx >= 256 or my < 0 or my >= drawing.h then
      return
    end
    shape.end_angle = geom.angle_with_hint(center.x,center.y, mx,my, shape.end_angle)
    local cx,cy = Drawing.pixels(center.x)+left, Drawing.pixels(center.y)+top
    love.graphics.arc('line', 'open', cx,cy, Drawing.pixels(shape.radius), shape.start_angle, shape.end_angle, 360)
  elseif shape.mode == 'move' then
    -- nothing pending; changes are immediately committed
  else
    print(shape.mode)
    assert(false)
  end
end


function Drawing.in_drawing(drawing, x,y)
  if drawing.y == nil then return false end  -- outside current page
  return y >= drawing.y and y < drawing.y + Drawing.pixels(drawing.h) and x >= 16 and x < 16+Line_width
end

function Drawing.mouse_pressed(drawing, x,y, button)
  if Current_drawing_mode == 'freehand' then
    drawing.pending = {mode=Current_drawing_mode, points={{x=Drawing.coord(x-16), y=Drawing.coord(y-drawing.y)}}}
  elseif Current_drawing_mode == 'line' or Current_drawing_mode == 'manhattan' then
    local j = Drawing.insert_point(drawing.points, Drawing.coord(x-16), Drawing.coord(y-drawing.y))
    drawing.pending = {mode=Current_drawing_mode, p1=j}
  elseif Current_drawing_mode == 'polygon' or Current_drawing_mode == 'rectangle' or Current_drawing_mode == 'square' then
    local j = Drawing.insert_point(drawing.points, Drawing.coord(x-16), Drawing.coord(y-drawing.y))
    drawing.pending = {mode=Current_drawing_mode, vertices={j}}
  elseif Current_drawing_mode == 'circle' then
    local j = Drawing.insert_point(drawing.points, Drawing.coord(x-16), Drawing.coord(y-drawing.y))
    drawing.pending = {mode=Current_drawing_mode, center=j}
  elseif Current_drawing_mode == 'move' then
    -- all the action is in mouse_released
  else
    print(Current_drawing_mode)
    assert(false)
  end
  Lines.current = drawing
end

-- a couple of operations on drawings need to constantly check the state of the mouse
function Drawing.update()
  if Lines.current == nil then return end
  local drawing = Lines.current
  assert(drawing.mode == 'drawing')
  local x, y = love.mouse.getX(), love.mouse.getY()
  if love.mouse.isDown('1') then
    if Drawing.in_drawing(drawing, x,y) then
      if drawing.pending.mode == 'freehand' then
        table.insert(drawing.pending.points, {x=Drawing.coord(love.mouse.getX()-16), y=Drawing.coord(love.mouse.getY()-drawing.y)})
      elseif drawing.pending.mode == 'move' then
        local mx,my = Drawing.coord(x-16), Drawing.coord(y-drawing.y)
        drawing.pending.target_point.x = mx
        drawing.pending.target_point.y = my
      end
    end
  elseif Current_drawing_mode == 'move' then
    if Drawing.in_drawing(drawing, x, y) then
      local mx,my = Drawing.coord(x-16), Drawing.coord(y-drawing.y)
      drawing.pending.target_point.x = mx
      drawing.pending.target_point.y = my
    end
  else
    -- do nothing
  end
end

function Drawing.mouse_released(x,y, button)
  if Current_drawing_mode == 'move' then
    Current_drawing_mode = Previous_drawing_mode
    Previous_drawing_mode = nil
  elseif Lines.current then
    if Lines.current.pending then
      if Lines.current.pending.mode == 'freehand' then
        -- the last point added during update is good enough
        table.insert(Lines.current.shapes, Lines.current.pending)
      elseif Lines.current.pending.mode == 'line' then
        local mx,my = Drawing.coord(x-16), Drawing.coord(y-Lines.current.y)
        if mx >= 0 and mx < 256 and my >= 0 and my < Lines.current.h then
          local j = Drawing.insert_point(Lines.current.points, mx,my)
          Lines.current.pending.p2 = j
          table.insert(Lines.current.shapes, Lines.current.pending)
        end
      elseif Lines.current.pending.mode == 'manhattan' then
        local p1 = Lines.current.points[Lines.current.pending.p1]
        local mx,my = Drawing.coord(x-16), Drawing.coord(y-Lines.current.y)
        if mx >= 0 and mx < 256 and my >= 0 and my < Lines.current.h then
          if math.abs(mx-p1.x) > math.abs(my-p1.y) then
            local j = Drawing.insert_point(Lines.current.points, mx, p1.y)
            Lines.current.pending.p2 = j
          else
            local j = Drawing.insert_point(Lines.current.points, p1.x, my)
            Lines.current.pending.p2 = j
          end
          local p2 = Lines.current.points[Lines.current.pending.p2]
          love.mouse.setPosition(16+Drawing.pixels(p2.x), Lines.current.y+Drawing.pixels(p2.y))
          table.insert(Lines.current.shapes, Lines.current.pending)
        end
      elseif Lines.current.pending.mode == 'polygon' then
        local mx,my = Drawing.coord(x-16), Drawing.coord(y-Lines.current.y)
        if mx >= 0 and mx < 256 and my >= 0 and my < Lines.current.h then
          table.insert(Lines.current.pending.vertices, Drawing.insert_point(Lines.current.points, mx,my))
          table.insert(Lines.current.shapes, Lines.current.pending)
        end
      elseif Lines.current.pending.mode == 'rectangle' then
        assert(#Lines.current.pending.vertices <= 2)
        if #Lines.current.pending.vertices == 2 then
          local mx,my = Drawing.coord(x-16), Drawing.coord(y-Lines.current.y)
          if mx >= 0 and mx < 256 and my >= 0 and my < Lines.current.h then
            local first = Lines.current.points[Lines.current.pending.vertices[1]]
            local second = Lines.current.points[Lines.current.pending.vertices[2]]
            local thirdx,thirdy, fourthx,fourthy = Drawing.complete_rectangle(first.x,first.y, second.x,second.y, mx,my)
            table.insert(Lines.current.pending.vertices, Drawing.insert_point(Lines.current.points, thirdx,thirdy))
            table.insert(Lines.current.pending.vertices, Drawing.insert_point(Lines.current.points, fourthx,fourthy))
            table.insert(Lines.current.shapes, Lines.current.pending)
          end
        else
          -- too few points; draw nothing
        end
      elseif Lines.current.pending.mode == 'square' then
        assert(#Lines.current.pending.vertices <= 2)
        if #Lines.current.pending.vertices == 2 then
          local mx,my = Drawing.coord(x-16), Drawing.coord(y-Lines.current.y)
          if mx >= 0 and mx < 256 and my >= 0 and my < Lines.current.h then
            local first = Lines.current.points[Lines.current.pending.vertices[1]]
            local second = Lines.current.points[Lines.current.pending.vertices[2]]
            local thirdx,thirdy, fourthx,fourthy = Drawing.complete_square(first.x,first.y, second.x,second.y, mx,my)
            table.insert(Lines.current.pending.vertices, Drawing.insert_point(Lines.current.points, thirdx,thirdy))
            table.insert(Lines.current.pending.vertices, Drawing.insert_point(Lines.current.points, fourthx,fourthy))
            table.insert(Lines.current.shapes, Lines.current.pending)
          end
        end
      elseif Lines.current.pending.mode == 'circle' then
        local mx,my = Drawing.coord(x-16), Drawing.coord(y-Lines.current.y)
        if mx >= 0 and mx < 256 and my >= 0 and my < Lines.current.h then
          local center = Lines.current.points[Lines.current.pending.center]
          Lines.current.pending.radius = geom.dist(center.x,center.y, mx,my)
          table.insert(Lines.current.shapes, Lines.current.pending)
        end
      elseif Lines.current.pending.mode == 'arc' then
        local mx,my = Drawing.coord(x-16), Drawing.coord(y-Lines.current.y)
        if mx >= 0 and mx < 256 and my >= 0 and my < Lines.current.h then
          local center = Lines.current.points[Lines.current.pending.center]
          Lines.current.pending.end_angle = geom.angle_with_hint(center.x,center.y, mx,my, Lines.current.pending.end_angle)
          table.insert(Lines.current.shapes, Lines.current.pending)
        end
      else
        print(Lines.current.pending.mode)
        assert(false)
      end
      Lines.current.pending = {}
      Lines.current = nil
    end
  end
  save_to_disk(Lines, Filename)
end

function Drawing.keychord_pressed(chord)
  if chord == 'C-=' then
    Line_width = Line_width/Zoom
    Zoom = Zoom+0.5
    Line_width = Line_width*Zoom
  elseif chord == 'C--' then
    Line_width = Line_width/Zoom
    Zoom = Zoom-0.5
    Line_width = Line_width*Zoom
  elseif chord == 'C-0' then
    Line_width = Line_width/Zoom
    Zoom = 1.5
    Line_width = Line_width*Zoom
  elseif chord == 'C-f' and not love.mouse.isDown('1') then
    Current_drawing_mode = 'freehand'
  elseif chord == 'C-g' and not love.mouse.isDown('1') then
    Current_drawing_mode = 'polygon'
  elseif love.mouse.isDown('1') and chord == 'g' then
    Current_drawing_mode = 'polygon'
    local drawing = Drawing.current_drawing()
    if drawing.pending.mode == 'freehand' then
      drawing.pending.vertices = {Drawing.insert_point(drawing.points, drawing.pending.points[1].x, drawing.pending.points[1].y)}
    elseif drawing.pending.mode == 'line' or drawing.pending.mode == 'manhattan' then
      if drawing.pending.vertices == nil then
        drawing.pending.vertices = {drawing.pending.p1}
      end
    elseif drawing.pending.mode == 'square' or drawing.pending.mode == 'rectangle' then
      -- reuse existing vertices
    elseif drawing.pending.mode == 'circle' or drawing.pending.mode == 'arc' then
      drawing.pending.vertices = {drawing.pending.center}
    end
    drawing.pending.mode = 'polygon'
  elseif chord == 'C-r' and not love.mouse.isDown('1') then
    Current_drawing_mode = 'rectangle'
  elseif love.mouse.isDown('1') and chord == 'r' then
    Current_drawing_mode = 'rectangle'
    local drawing = Drawing.current_drawing()
    if drawing.pending.mode == 'freehand' then
      drawing.pending.vertices = {Drawing.insert_point(drawing.points, drawing.pending.points[1].x, drawing.pending.points[1].y)}
    elseif drawing.pending.mode == 'line' or drawing.pending.mode == 'manhattan' then
      if drawing.pending.vertices == nil then
        drawing.pending.vertices = {drawing.pending.p1}
      end
    elseif drawing.pending.mode == 'circle' or drawing.pending.mode == 'arc' then
      drawing.pending.vertices = {drawing.pending.center}
    end
    drawing.pending.mode = 'rectangle'
  elseif chord == 'C-s' and not love.mouse.isDown('1') then
    Current_drawing_mode = 'square'
  elseif love.mouse.isDown('1') and chord == 's' then
    Current_drawing_mode = 'square'
    local drawing = Drawing.current_drawing()
    if drawing.pending.mode == 'freehand' then
      drawing.pending.vertices = {Drawing.insert_point(drawing.points, drawing.pending.points[1].x, drawing.pending.points[1].y)}
    elseif drawing.pending.mode == 'line' or drawing.pending.mode == 'manhattan' then
      if drawing.pending.vertices == nil then
        drawing.pending.vertices = {drawing.pending.p1}
      end
    elseif drawing.pending.mode == 'circle' or drawing.pending.mode == 'arc' then
      drawing.pending.vertices = {drawing.pending.center}
    end
    drawing.pending.mode = 'square'
  elseif love.mouse.isDown('1') and chord == 'p' and (Current_drawing_mode == 'polygon' or Current_drawing_mode == 'rectangle' or Current_drawing_mode == 'square') then
    local drawing = Drawing.current_drawing()
    local mx,my = Drawing.coord(love.mouse.getX()-16), Drawing.coord(love.mouse.getY()-drawing.y)
    local j = Drawing.insert_point(drawing.points, mx,my)
    table.insert(drawing.pending.vertices, j)
  elseif chord == 'C-c' and not love.mouse.isDown('1') then
    Current_drawing_mode = 'circle'
  elseif love.mouse.isDown('1') and chord == 'a' and Current_drawing_mode == 'circle' then
    local drawing = Drawing.current_drawing()
    drawing.pending.mode = 'arc'
    local mx,my = Drawing.coord(love.mouse.getX()-16), Drawing.coord(love.mouse.getY()-drawing.y)
    local j = Drawing.insert_point(drawing.points, mx,my)
    local center = drawing.points[drawing.pending.center]
    drawing.pending.radius = geom.dist(center.x,center.y, mx,my)
    drawing.pending.start_angle = geom.angle(center.x,center.y, mx,my)
  elseif love.mouse.isDown('1') and chord == 'c' then
    Current_drawing_mode = 'circle'
    local drawing = Drawing.current_drawing()
    if drawing.pending.mode == 'freehand' then
      drawing.pending.center = Drawing.insert_point(drawing.points, drawing.pending.points[1].x, drawing.pending.points[1].y)
    elseif drawing.pending.mode == 'line' or drawing.pending.mode == 'manhattan' then
      drawing.pending.center = drawing.pending.p1
    elseif drawing.pending.mode == 'polygon' then
      drawing.pending.center = drawing.pending.vertices[1]
    end
    drawing.pending.mode = 'circle'
  elseif love.mouse.isDown('1') and chord == 'l' then
    Current_drawing_mode = 'line'
    local drawing = Drawing.current_drawing()
    if drawing.pending.mode == 'freehand' then
      drawing.pending.p1 = Drawing.insert_point(drawing.points, drawing.pending.points[1].x, drawing.pending.points[1].y)
    elseif drawing.pending.mode == 'circle' or drawing.pending.mode == 'arc' then
      drawing.pending.p1 = drawing.pending.center
    elseif drawing.pending.mode == 'polygon' or drawing.pending.mode == 'rectangle' or drawing.pending.mode == 'square' then
      drawing.pending.p1 = drawing.pending.vertices[1]
    end
    drawing.pending.mode = 'line'
  elseif chord == 'C-l' then
    Current_drawing_mode = 'line'
    local drawing,_,shape = Drawing.select_shape_at_mouse()
    if drawing then
      convert_line(drawing, shape)
    end
  elseif love.mouse.isDown('1') and chord == 'm' then
    Current_drawing_mode = 'manhattan'
    local drawing = Drawing.select_drawing_at_mouse()
    if drawing.pending.mode == 'freehand' then
      drawing.pending.p1 = Drawing.insert_point(drawing.points, drawing.pending.points[1].x, drawing.pending.points[1].y)
    elseif drawing.pending.mode == 'line' then
      -- do nothing
    elseif drawing.pending.mode == 'polygon' then
      drawing.pending.p1 = drawing.pending.vertices[1]
    elseif drawing.pending.mode == 'circle' or drawing.pending.mode == 'arc' then
      drawing.pending.p1 = drawing.pending.center
    end
    drawing.pending.mode = 'manhattan'
  elseif chord == 'C-m' and not love.mouse.isDown('1') then
    Current_drawing_mode = 'manhattan'
    local drawing,_,shape = Drawing.select_shape_at_mouse()
    if drawing then
      convert_horvert(drawing, shape)
    end
  elseif chord == 'C-s' and not love.mouse.isDown('1') then
    local drawing,_,shape = Drawing.select_shape_at_mouse()
    if drawing then
      smoothen(shape)
    end
  elseif chord == 'C-v' and not love.mouse.isDown('1') then
    local drawing,_,p = Drawing.select_point_at_mouse()
    if drawing then
      Previous_drawing_mode = Current_drawing_mode
      Current_drawing_mode = 'move'
      drawing.pending = {mode=Current_drawing_mode, target_point=p}
      Lines.current = drawing
    end
  elseif love.mouse.isDown('1') and chord == 'v' then
    local drawing,_,p = Drawing.select_point_at_mouse()
    if drawing then
      Previous_drawing_mode = Current_drawing_mode
      Current_drawing_mode = 'move'
      drawing.pending = {mode=Current_drawing_mode, target_point=p}
      Lines.current = drawing
    end
  elseif chord == 'C-d' and not love.mouse.isDown('1') then
    local drawing,i,p = Drawing.select_point_at_mouse()
    if drawing then
      for _,shape in ipairs(drawing.shapes) do
        if Drawing.contains_point(shape, i) then
          if shape.mode == 'polygon' then
            local idx = table.find(shape.vertices, i)
            assert(idx)
            table.remove(shape.vertices, idx)
            if #shape.vertices < 3 then
              shape.mode = 'deleted'
            end
          else
            shape.mode = 'deleted'
          end
        end
      end
      drawing.points[i].deleted = true
    end
    local drawing,_,shape = Drawing.select_shape_at_mouse()
    if drawing then
      shape.mode = 'deleted'
    end
  elseif chord == 'C-h' and not love.mouse.isDown('1') then
    local drawing = Drawing.select_drawing_at_mouse()
    if drawing then
      drawing.show_help = true
    end
  elseif chord == 'escape' and not love.mouse.isDown('1') then
    for _,line in ipairs(Lines) do
      if line.mode == 'drawing' then
        line.show_help = false
      end
    end
  end
end

function Drawing.complete_rectangle(firstx,firsty, secondx,secondy, x,y)
  if firstx == secondx then
    return x,secondy, x,firsty
  end
  if firsty == secondy then
    return secondx,y, firstx,y
  end
  local first_slope = (secondy-firsty)/(secondx-firstx)
  -- slope of second edge:
  --    -1/first_slope
  -- equation of line containing the second edge:
  --    y-secondy = -1/first_slope*(x-secondx)
  -- => 1/first_slope*x + y + (- secondy - secondx/first_slope) = 0
  -- now we want to find the point on this line that's closest to the mouse pointer.
  -- https://en.wikipedia.org/wiki/Distance_from_a_point_to_a_line#Line_defined_by_an_equation
  local a = 1/first_slope
  local c = -secondy - secondx/first_slope
  local thirdx = ((x-a*y) - a*c) / (a*a + 1)
  local thirdy = (a*(-x + a*y) - c) / (a*a + 1)
  -- slope of third edge = first_slope
  -- equation of line containing third edge:
  --     y - thirdy = first_slope*(x-thirdx)
  --  => -first_slope*x + y + (-thirdy + thirdx*first_slope) = 0
  -- now we want to find the point on this line that's closest to the first point
  local a = -first_slope
  local c = -thirdy + thirdx*first_slope
  local fourthx = ((firstx-a*firsty) - a*c) / (a*a + 1)
  local fourthy = (a*(-firstx + a*firsty) - c) / (a*a + 1)
  return thirdx,thirdy, fourthx,fourthy
end

function Drawing.complete_square(firstx,firsty, secondx,secondy, x,y)
  -- use x,y only to decide which side of the first edge to complete the square on
  local deltax = secondx-firstx
  local deltay = secondy-firsty
  local thirdx = secondx+deltay
  local thirdy = secondy-deltax
  if not geom.same_side(firstx,firsty, secondx,secondy, thirdx,thirdy, x,y) then
    deltax = -deltax
    deltay = -deltay
    thirdx = secondx+deltay
    thirdy = secondy-deltax
  end
  local fourthx = firstx+deltay
  local fourthy = firsty-deltax
  return thirdx,thirdy, fourthx,fourthy
end

function Drawing.current_drawing()
  local x, y = love.mouse.getX(), love.mouse.getY()
  for _,drawing in ipairs(Lines) do
    if drawing.mode == 'drawing' then
      if Drawing.in_drawing(drawing, x,y) then
        return drawing
      end
    end
  end
  return nil
end

function Drawing.select_shape_at_mouse()
  for _,drawing in ipairs(Lines) do
    if drawing.mode == 'drawing' then
      local x, y = love.mouse.getX(), love.mouse.getY()
      if Drawing.in_drawing(drawing, x,y) then
        local mx,my = Drawing.coord(x-16), Drawing.coord(y-drawing.y)
        for i,shape in ipairs(drawing.shapes) do
          assert(shape)
          if geom.on_shape(mx,my, drawing, shape) then
            return drawing,i,shape
          end
        end
      end
    end
  end
end

function Drawing.select_point_at_mouse()
  for _,drawing in ipairs(Lines) do
    if drawing.mode == 'drawing' then
      local x, y = love.mouse.getX(), love.mouse.getY()
      if Drawing.in_drawing(drawing, x,y) then
        local mx,my = Drawing.coord(x-16), Drawing.coord(y-drawing.y)
        for i,point in ipairs(drawing.points) do
          assert(point)
          if Drawing.near(point, mx,my) then
            return drawing,i,point
          end
        end
      end
    end
  end
end

function Drawing.select_drawing_at_mouse()
  for _,drawing in ipairs(Lines) do
    if drawing.mode == 'drawing' then
      local x, y = love.mouse.getX(), love.mouse.getY()
      if Drawing.in_drawing(drawing, x,y) then
        return drawing
      end
    end
  end
end

function Drawing.contains_point(shape, p)
  if shape.mode == 'freehand' then
    -- not supported
  elseif shape.mode == 'line' or shape.mode == 'manhattan' then
    return shape.p1 == p or shape.p2 == p
  elseif shape.mode == 'polygon' then
    return table.find(shape.vertices, p)
  elseif shape.mode == 'circle' then
    return shape.center == p
  elseif shape.mode == 'arc' then
    return shape.center == p
    -- ugh, how to support angles
  elseif shape.mode == 'deleted' then
    -- already done
  else
    print(shape.mode)
    assert(false)
  end
end

function Drawing.convert_line(drawing, shape)
  -- Perhaps we should do a more sophisticated "simple linear regression"
  -- here:
  --   https://en.wikipedia.org/wiki/Linear_regression#Simple_and_multiple_linear_regression
  -- But this works well enough for close-to-linear strokes.
  assert(shape.mode == 'freehand')
  shape.mode = 'line'
  shape.p1 = insert_point(drawing.points, shape.points[1].x, shape.points[1].y)
  local n = #shape.points
  shape.p2 = insert_point(drawing.points, shape.points[n].x, shape.points[n].y)
end

-- turn a line either horizontal or vertical
function Drawing.convert_horvert(drawing, shape)
  if shape.mode == 'freehand' then
    convert_line(shape)
  end
  assert(shape.mode == 'line')
  local p1 = drawing.points[shape.p1]
  local p2 = drawing.points[shape.p2]
  if math.abs(p1.x-p2.x) > math.abs(p1.y-p2.y) then
    p2.y = p1.y
  else
    p2.x = p1.x
  end
end

function Drawing.smoothen(shape)
  assert(shape.mode == 'freehand')
  for _=1,7 do
    for i=2,#shape.points-1 do
      local a = shape.points[i-1]
      local b = shape.points[i]
      local c = shape.points[i+1]
      b.x = (a.x + b.x + c.x)/3
      b.y = (a.y + b.y + c.y)/3
    end
  end
end

function Drawing.insert_point(points, x,y)
  for i,point in ipairs(points) do
    if Drawing.near(point, x,y) then
      return i
    end
  end
  table.insert(points, {x=x, y=y})
  return #points
end

function Drawing.near(point, x,y)
  local px,py = Drawing.pixels(x),Drawing.pixels(y)
  local cx,cy = Drawing.pixels(point.x), Drawing.pixels(point.y)
  return (cx-px)*(cx-px) + (cy-py)*(cy-py) < 16
end

function Drawing.pixels(n)  -- parts to pixels
  return math.floor(n*Line_width/256)
end
function Drawing.coord(n)  -- pixels to parts
  return math.floor(n*256/Line_width)
end

function table.find(h, x)
  for k,v in pairs(h) do
    if v == x then
      return k
    end
  end
end

return Drawing