drawing.lua

   1 -- primitives for editing drawings
   2 Drawing = {}
   3 require 'drawing_tests'
   4
   5 -- All drawings span 100% of some conceptual 'page width' and divide it up
   6 -- into 256 parts.
   7 function Drawing.draw(State, line_index, y)
   8   local line = State.lines[line_index]
   9   local pmx,pmy = App.mouse_x(), App.mouse_y()
  10   local starty = Text.starty(State, line_index)
  11   if pmx < State.right and pmy > starty and pmy < starty+Drawing.pixels(line.h, State.width) then
  12     App.color(Icon_color)
  13     love.graphics.rectangle('line', State.left,starty, State.width,Drawing.pixels(line.h, State.width))
  14     if icon[State.current_drawing_mode] then
  15       icon[State.current_drawing_mode](State.right-22, starty+4)
  16     else
  17       icon[State.previous_drawing_mode](State.right-22, starty+4)
  18     end
  19
  20     if App.mouse_down(1) and love.keyboard.isDown('h') then
  21       draw_help_with_mouse_pressed(State, line_index)
  22       return
  23     end
  24   end
  25
  26   if line.show_help then
  27     draw_help_without_mouse_pressed(State, line_index)
  28     return
  29   end
  30
  31   local mx = Drawing.coord(pmx-State.left, State.width)
  32   local my = Drawing.coord(pmy-starty, State.width)
  33
  34   for _,shape in ipairs(line.shapes) do
  35     if geom.on_shape(mx,my, line, shape) then
  36       App.color(Focus_stroke_color)
  37     else
  38       App.color(Stroke_color)
  39     end
  40     Drawing.draw_shape(line, shape, starty, State.left,State.right)
  41   end
  42
  43   local function px(x) return Drawing.pixels(x, State.width)+State.left end
  44   local function py(y) return Drawing.pixels(y, State.width)+starty end
  45   for i,p in ipairs(line.points) do
  46     if p.deleted == nil then
  47       if Drawing.near(p, mx,my, State.width) then
  48         App.color(Focus_stroke_color)
  49         love.graphics.circle('line', px(p.x),py(p.y), Same_point_distance)
  50       else
  51         App.color(Stroke_color)
  52         love.graphics.circle('fill', px(p.x),py(p.y), 2)
  53       end
  54       if p.name then
  55         -- TODO: clip
  56         local x,y = px(p.x)+5, py(p.y)+5
  57         love.graphics.print(p.name, x,y)
  58         if State.current_drawing_mode == 'name' and i == line.pending.target_point then
  59           -- create a faint red box for the name
  60           App.color(Current_name_background_color)
  61           local name_width
  62           if p.name == '' then
  63             name_width = State.font:getWidth('m')
  64           else
  65             name_width = State.font:getWidth(p.name)
  66           end
  67           love.graphics.rectangle('fill', x,y, name_width, State.line_height)
  68         end
  69       end
  70     end
  71   end
  72   App.color(Current_stroke_color)
  73   Drawing.draw_pending_shape(line, starty, State.left,State.right)
  74 end
  75
  76 function Drawing.draw_shape(drawing, shape, top, left,right)
  77   local width = right-left
  78   local function px(x) return Drawing.pixels(x, width)+left end
  79   local function py(y) return Drawing.pixels(y, width)+top end
  80   if shape.mode == 'freehand' then
  81     local prev = nil
  82     for _,point in ipairs(shape.points) do
  83       if prev then
  84         love.graphics.line(px(prev.x),py(prev.y), px(point.x),py(point.y))
  85       end
  86       prev = point
  87     end
  88   elseif shape.mode == 'line' or shape.mode == 'manhattan' then
  89     local p1 = drawing.points[shape.p1]
  90     local p2 = drawing.points[shape.p2]
  91     love.graphics.line(px(p1.x),py(p1.y), px(p2.x),py(p2.y))
  92   elseif shape.mode == 'polygon' or shape.mode == 'rectangle' or shape.mode == 'square' then
  93     local prev = nil
  94     for _,point in ipairs(shape.vertices) do
  95       local curr = drawing.points[point]
  96       if prev then
  97         love.graphics.line(px(prev.x),py(prev.y), px(curr.x),py(curr.y))
  98       end
  99       prev = curr
 100     end
 101     -- close the loop
 102     local curr = drawing.points[shape.vertices[1]]
 103     love.graphics.line(px(prev.x),py(prev.y), px(curr.x),py(curr.y))
 104   elseif shape.mode == 'circle' then
 105     -- TODO: clip
 106     local center = drawing.points[shape.center]
 107     love.graphics.circle('line', px(center.x),py(center.y), Drawing.pixels(shape.radius, width))
 108   elseif shape.mode == 'arc' then
 109     local center = drawing.points[shape.center]
 110     love.graphics.arc('line', 'open', px(center.x),py(center.y), Drawing.pixels(shape.radius, width), shape.start_angle, shape.end_angle, 360)
 111   elseif shape.mode == 'deleted' then
 112     -- ignore
 113   else
 114     assert(false, ('unknown drawing mode %s'):format(shape.mode))
 115   end
 116 end
 117
 118 function Drawing.draw_pending_shape(drawing, top, left,right)
 119   local width = right-left
 120   local pmx,pmy = App.mouse_x(), App.mouse_y()
 121   local function px(x) return Drawing.pixels(x, width)+left end
 122   local function py(y) return Drawing.pixels(y, width)+top end
 123   local mx = Drawing.coord(pmx-left, width)
 124   local my = Drawing.coord(pmy-top, width)
 125   -- recreate pixels from coords to precisely mimic how the drawing will look
 126   -- after mouse_release
 127   pmx,pmy = px(mx), py(my)
 128   local shape = drawing.pending
 129   if shape.mode == nil then
 130     -- nothing pending
 131   elseif shape.mode == 'freehand' then
 132     local shape_copy = deepcopy(shape)
 133     Drawing.smoothen(shape_copy)
 134     Drawing.draw_shape(drawing, shape_copy, top, left,right)
 135   elseif shape.mode == 'line' then
 136     if mx < 0 or mx >= 256 or my < 0 or my >= drawing.h then
 137       return
 138     end
 139     local p1 = drawing.points[shape.p1]
 140     love.graphics.line(px(p1.x),py(p1.y), pmx,pmy)
 141   elseif shape.mode == 'manhattan' then
 142     if mx < 0 or mx >= 256 or my < 0 or my >= drawing.h then
 143       return
 144     end
 145     local p1 = drawing.points[shape.p1]
 146     if math.abs(mx-p1.x) > math.abs(my-p1.y) then
 147       love.graphics.line(px(p1.x),py(p1.y), pmx,     py(p1.y))
 148     else
 149       love.graphics.line(px(p1.x),py(p1.y), px(p1.x),pmy)
 150     end
 151   elseif shape.mode == 'polygon' then
 152     -- don't close the loop on a pending polygon
 153     local prev = nil
 154     for _,point in ipairs(shape.vertices) do
 155       local curr = drawing.points[point]
 156       if prev then
 157         love.graphics.line(px(prev.x),py(prev.y), px(curr.x),py(curr.y))
 158       end
 159       prev = curr
 160     end
 161     love.graphics.line(px(prev.x),py(prev.y), pmx,pmy)
 162   elseif shape.mode == 'rectangle' then
 163     local first = drawing.points[shape.vertices[1]]
 164     if #shape.vertices == 1 then
 165       love.graphics.line(px(first.x),py(first.y), pmx,pmy)
 166       return
 167     end
 168     local second = drawing.points[shape.vertices[2]]
 169     local thirdx,thirdy, fourthx,fourthy = Drawing.complete_rectangle(first.x,first.y, second.x,second.y, mx,my)
 170     love.graphics.line(px(first.x),py(first.y), px(second.x),py(second.y))
 171     love.graphics.line(px(second.x),py(second.y), px(thirdx),py(thirdy))
 172     love.graphics.line(px(thirdx),py(thirdy), px(fourthx),py(fourthy))
 173     love.graphics.line(px(fourthx),py(fourthy), px(first.x),py(first.y))
 174   elseif shape.mode == 'square' then
 175     local first = drawing.points[shape.vertices[1]]
 176     if #shape.vertices == 1 then
 177       love.graphics.line(px(first.x),py(first.y), pmx,pmy)
 178       return
 179     end
 180     local second = drawing.points[shape.vertices[2]]
 181     local thirdx,thirdy, fourthx,fourthy = Drawing.complete_square(first.x,first.y, second.x,second.y, mx,my)
 182     love.graphics.line(px(first.x),py(first.y), px(second.x),py(second.y))
 183     love.graphics.line(px(second.x),py(second.y), px(thirdx),py(thirdy))
 184     love.graphics.line(px(thirdx),py(thirdy), px(fourthx),py(fourthy))
 185     love.graphics.line(px(fourthx),py(fourthy), px(first.x),py(first.y))
 186   elseif shape.mode == 'circle' then
 187     local center = drawing.points[shape.center]
 188     if mx < 0 or mx >= 256 or my < 0 or my >= drawing.h then
 189       return
 190     end
 191     local r = round(geom.dist(center.x, center.y, mx, my))
 192     local cx,cy = px(center.x), py(center.y)
 193     love.graphics.circle('line', cx,cy, Drawing.pixels(r, width))
 194   elseif shape.mode == 'arc' then
 195     local center = drawing.points[shape.center]
 196     if mx < 0 or mx >= 256 or my < 0 or my >= drawing.h then
 197       return
 198     end
 199     shape.end_angle = geom.angle_with_hint(center.x,center.y, mx,my, shape.end_angle)
 200     local cx,cy = px(center.x), py(center.y)
 201     love.graphics.arc('line', 'open', cx,cy, Drawing.pixels(shape.radius, width), shape.start_angle, shape.end_angle, 360)
 202   elseif shape.mode == 'move' then
 203     -- nothing pending; changes are immediately committed
 204   elseif shape.mode == 'name' then
 205     -- nothing pending; changes are immediately committed
 206   else
 207     assert(false, ('unknown drawing mode %s'):format(shape.mode))
 208   end
 209 end
 210
 211 function Drawing.in_current_drawing(State, x,y, left,right)
 212   return Drawing.in_drawing(State, State.lines.current_drawing_index, x,y, left,right)
 213 end
 214
 215 function Drawing.in_drawing(State, line_index, x,y, left,right)
 216   assert(State.lines[line_index].mode == 'drawing')
 217   local starty = Text.starty(State, line_index)
 218   if starty == nil then return false end  -- outside current page
 219   local drawing = State.lines[line_index]
 220   local width = right-left
 221   return y >= starty and y < starty + Drawing.pixels(drawing.h, width) and x >= left and x < right
 222 end
 223
 224 function Drawing.mouse_press(State, drawing_index, x,y, mouse_button)
 225   local drawing = State.lines[drawing_index]
 226   local starty = Text.starty(State, drawing_index)
 227   local cx = Drawing.coord(x-State.left, State.width)
 228   local cy = Drawing.coord(y-starty, State.width)
 229   if State.current_drawing_mode == 'freehand' then
 230     drawing.pending = {mode=State.current_drawing_mode, points={{x=cx, y=cy}}}
 231   elseif State.current_drawing_mode == 'line' or State.current_drawing_mode == 'manhattan' then
 232     local j = Drawing.find_or_insert_point(drawing.points, cx, cy, State.width)
 233     drawing.pending = {mode=State.current_drawing_mode, p1=j}
 234   elseif State.current_drawing_mode == 'polygon' or State.current_drawing_mode == 'rectangle' or State.current_drawing_mode == 'square' then
 235     local j = Drawing.find_or_insert_point(drawing.points, cx, cy, State.width)
 236     drawing.pending = {mode=State.current_drawing_mode, vertices={j}}
 237   elseif State.current_drawing_mode == 'circle' then
 238     local j = Drawing.find_or_insert_point(drawing.points, cx, cy, State.width)
 239     drawing.pending = {mode=State.current_drawing_mode, center=j}
 240   elseif State.current_drawing_mode == 'move' then
 241     -- all the action is in mouse_release
 242   elseif State.current_drawing_mode == 'name' then
 243     -- nothing
 244   else
 245     assert(false, ('unknown drawing mode %s'):format(State.current_drawing_mode))
 246   end
 247 end
 248
 249 -- a couple of operations on drawings need to constantly check the state of the mouse
 250 function Drawing.update(State)
 251   if State.lines.current_drawing == nil then return end
 252   local drawing = State.lines.current_drawing
 253   local starty = Text.starty(State, State.lines.current_drawing_index)
 254   if starty == nil then
 255     -- some event cleared starty just this frame
 256     -- draw in this frame will soon set starty
 257     -- just skip this frame
 258     return
 259   end
 260   assert(drawing.mode == 'drawing', 'Drawing.update: line is not a drawing')
 261   local pmx, pmy = App.mouse_x(), App.mouse_y()
 262   local mx = Drawing.coord(pmx-State.left, State.width)
 263   local my = Drawing.coord(pmy-starty, State.width)
 264   if App.mouse_down(1) then
 265     if Drawing.in_current_drawing(State, pmx,pmy, State.left,State.right) then
 266       if drawing.pending.mode == 'freehand' then
 267         table.insert(drawing.pending.points, {x=mx, y=my})
 268       elseif drawing.pending.mode == 'move' then
 269         drawing.pending.target_point.x = mx
 270         drawing.pending.target_point.y = my
 271         Drawing.relax_constraints(drawing, drawing.pending.target_point_index)
 272       end
 273     end
 274   elseif State.current_drawing_mode == 'move' then
 275     if Drawing.in_current_drawing(State, pmx, pmy, State.left,State.right) then
 276       drawing.pending.target_point.x = mx
 277       drawing.pending.target_point.y = my
 278       Drawing.relax_constraints(drawing, drawing.pending.target_point_index)
 279     end
 280   else
 281     -- do nothing
 282   end
 283 end
 284
 285 function Drawing.relax_constraints(drawing, p)
 286   for _,shape in ipairs(drawing.shapes) do
 287     if shape.mode == 'manhattan' then
 288       if shape.p1 == p then
 289         shape.mode = 'line'
 290       elseif shape.p2 == p then
 291         shape.mode = 'line'
 292       end
 293     elseif shape.mode == 'rectangle' or shape.mode == 'square' then
 294       for _,v in ipairs(shape.vertices) do
 295         if v == p then
 296           shape.mode = 'polygon'
 297         end
 298       end
 299     end
 300   end
 301 end
 302
 303 function Drawing.mouse_release(State, x,y, mouse_button)
 304   if State.current_drawing_mode == 'move' then
 305     State.current_drawing_mode = State.previous_drawing_mode
 306     State.previous_drawing_mode = nil
 307     if State.lines.current_drawing then
 308       State.lines.current_drawing.pending = {}
 309       State.lines.current_drawing = nil
 310     end
 311   elseif State.lines.current_drawing then
 312     local drawing = State.lines.current_drawing
 313     local starty = Text.starty(State, State.lines.current_drawing_index)
 314     if drawing.pending then
 315       if drawing.pending.mode == nil then
 316         -- nothing pending
 317       elseif drawing.pending.mode == 'freehand' then
 318         -- the last point added during update is good enough
 319         Drawing.smoothen(drawing.pending)
 320         table.insert(drawing.shapes, drawing.pending)
 321       elseif drawing.pending.mode == 'line' then
 322         local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
 323         if mx >= 0 and mx < 256 and my >= 0 and my < drawing.h then
 324           drawing.pending.p2 = Drawing.find_or_insert_point(drawing.points, mx,my, State.width)
 325           table.insert(drawing.shapes, drawing.pending)
 326         end
 327       elseif drawing.pending.mode == 'manhattan' then
 328         local p1 = drawing.points[drawing.pending.p1]
 329         local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
 330         if mx >= 0 and mx < 256 and my >= 0 and my < drawing.h then
 331           if math.abs(mx-p1.x) > math.abs(my-p1.y) then
 332             drawing.pending.p2 = Drawing.find_or_insert_point(drawing.points, mx, p1.y, State.width)
 333           else
 334             drawing.pending.p2 = Drawing.find_or_insert_point(drawing.points, p1.x, my, State.width)
 335           end
 336           local p2 = drawing.points[drawing.pending.p2]
 337           App.mouse_move(State.left+Drawing.pixels(p2.x, State.width), starty+Drawing.pixels(p2.y, State.width))
 338           table.insert(drawing.shapes, drawing.pending)
 339         end
 340       elseif drawing.pending.mode == 'polygon' then
 341         local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
 342         if mx >= 0 and mx < 256 and my >= 0 and my < drawing.h then
 343           table.insert(drawing.pending.vertices, Drawing.find_or_insert_point(drawing.points, mx,my, State.width))
 344           table.insert(drawing.shapes, drawing.pending)
 345         end
 346       elseif drawing.pending.mode == 'rectangle' then
 347         assert(#drawing.pending.vertices <= 2, 'Drawing.mouse_release: rectangle has too many pending vertices')
 348         if #drawing.pending.vertices == 2 then
 349           local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
 350           if mx >= 0 and mx < 256 and my >= 0 and my < drawing.h then
 351             local first = drawing.points[drawing.pending.vertices[1]]
 352             local second = drawing.points[drawing.pending.vertices[2]]
 353             local thirdx,thirdy, fourthx,fourthy = Drawing.complete_rectangle(first.x,first.y, second.x,second.y, mx,my)
 354             table.insert(drawing.pending.vertices, Drawing.find_or_insert_point(drawing.points, thirdx,thirdy, State.width))
 355             table.insert(drawing.pending.vertices, Drawing.find_or_insert_point(drawing.points, fourthx,fourthy, State.width))
 356             table.insert(drawing.shapes, drawing.pending)
 357           end
 358         else
 359           -- too few points; draw nothing
 360         end
 361       elseif drawing.pending.mode == 'square' then
 362         assert(#drawing.pending.vertices <= 2, 'Drawing.mouse_release: square has too many pending vertices')
 363         if #drawing.pending.vertices == 2 then
 364           local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
 365           if mx >= 0 and mx < 256 and my >= 0 and my < drawing.h then
 366             local first = drawing.points[drawing.pending.vertices[1]]
 367             local second = drawing.points[drawing.pending.vertices[2]]
 368             local thirdx,thirdy, fourthx,fourthy = Drawing.complete_square(first.x,first.y, second.x,second.y, mx,my)
 369             table.insert(drawing.pending.vertices, Drawing.find_or_insert_point(drawing.points, thirdx,thirdy, State.width))
 370             table.insert(drawing.pending.vertices, Drawing.find_or_insert_point(drawing.points, fourthx,fourthy, State.width))
 371             table.insert(drawing.shapes, drawing.pending)
 372           end
 373         end
 374       elseif drawing.pending.mode == 'circle' then
 375         local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
 376         if mx >= 0 and mx < 256 and my >= 0 and my < drawing.h then
 377           local center = drawing.points[drawing.pending.center]
 378           drawing.pending.radius = round(geom.dist(center.x,center.y, mx,my))
 379           table.insert(drawing.shapes, drawing.pending)
 380         end
 381       elseif drawing.pending.mode == 'arc' then
 382         local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
 383         if mx >= 0 and mx < 256 and my >= 0 and my < drawing.h then
 384           local center = drawing.points[drawing.pending.center]
 385           drawing.pending.end_angle = geom.angle_with_hint(center.x,center.y, mx,my, drawing.pending.end_angle)
 386           table.insert(drawing.shapes, drawing.pending)
 387         end
 388       elseif drawing.pending.mode == 'name' then
 389         -- drop it
 390       else
 391         assert(false, ('unknown drawing mode %s'):format(drawing.pending.mode))
 392       end
 393       State.lines.current_drawing.pending = {}
 394       State.lines.current_drawing = nil
 395     end
 396   end
 397 end
 398
 399 function Drawing.keychord_press(State, chord)
 400   if chord == 'C-p' and not App.mouse_down(1) then
 401     State.current_drawing_mode = 'freehand'
 402   elseif App.mouse_down(1) and chord == 'l' then
 403     State.current_drawing_mode = 'line'
 404     local _,drawing = Drawing.current_drawing(State)
 405     if drawing.pending.mode == 'freehand' then
 406       drawing.pending.p1 = Drawing.find_or_insert_point(drawing.points, drawing.pending.points[1].x, drawing.pending.points[1].y, State.width)
 407     elseif drawing.pending.mode == 'polygon' or drawing.pending.mode == 'rectangle' or drawing.pending.mode == 'square' then
 408       drawing.pending.p1 = drawing.pending.vertices[1]
 409     elseif drawing.pending.mode == 'circle' or drawing.pending.mode == 'arc' then
 410       drawing.pending.p1 = drawing.pending.center
 411     end
 412     drawing.pending.mode = 'line'
 413   elseif chord == 'C-l' and not App.mouse_down(1) then
 414     State.current_drawing_mode = 'line'
 415   elseif App.mouse_down(1) and chord == 'm' then
 416     State.current_drawing_mode = 'manhattan'
 417     local drawing = Drawing.select_drawing_at_mouse(State)
 418     if drawing.pending.mode == 'freehand' then
 419       drawing.pending.p1 = Drawing.find_or_insert_point(drawing.points, drawing.pending.points[1].x, drawing.pending.points[1].y, State.width)
 420     elseif drawing.pending.mode == 'line' then
 421       -- do nothing
 422     elseif drawing.pending.mode == 'polygon' or drawing.pending.mode == 'rectangle' or drawing.pending.mode == 'square' then
 423       drawing.pending.p1 = drawing.pending.vertices[1]
 424     elseif drawing.pending.mode == 'circle' or drawing.pending.mode == 'arc' then
 425       drawing.pending.p1 = drawing.pending.center
 426     end
 427     drawing.pending.mode = 'manhattan'
 428   elseif chord == 'C-m' and not App.mouse_down(1) then
 429     State.current_drawing_mode = 'manhattan'
 430   elseif chord == 'C-g' and not App.mouse_down(1) then
 431     State.current_drawing_mode = 'polygon'
 432   elseif App.mouse_down(1) and chord == 'g' then
 433     State.current_drawing_mode = 'polygon'
 434     local _,drawing = Drawing.current_drawing(State)
 435     if drawing.pending.mode == 'freehand' then
 436       drawing.pending.vertices = {Drawing.find_or_insert_point(drawing.points, drawing.pending.points[1].x, drawing.pending.points[1].y, State.width)}
 437     elseif drawing.pending.mode == 'line' or drawing.pending.mode == 'manhattan' then
 438       if drawing.pending.vertices == nil then
 439         drawing.pending.vertices = {drawing.pending.p1}
 440       end
 441     elseif drawing.pending.mode == 'rectangle' or drawing.pending.mode == 'square' then
 442       -- reuse existing vertices
 443     elseif drawing.pending.mode == 'circle' or drawing.pending.mode == 'arc' then
 444       drawing.pending.vertices = {drawing.pending.center}
 445     end
 446     drawing.pending.mode = 'polygon'
 447   elseif chord == 'C-r' and not App.mouse_down(1) then
 448     State.current_drawing_mode = 'rectangle'
 449   elseif App.mouse_down(1) and chord == 'r' then
 450     State.current_drawing_mode = 'rectangle'
 451     local _,drawing = Drawing.current_drawing(State)
 452     if drawing.pending.mode == 'freehand' then
 453       drawing.pending.vertices = {Drawing.find_or_insert_point(drawing.points, drawing.pending.points[1].x, drawing.pending.points[1].y, State.width)}
 454     elseif drawing.pending.mode == 'line' or drawing.pending.mode == 'manhattan' then
 455       if drawing.pending.vertices == nil then
 456         drawing.pending.vertices = {drawing.pending.p1}
 457       end
 458     elseif drawing.pending.mode == 'polygon' or drawing.pending.mode == 'square' then
 459       -- reuse existing (1-2) vertices
 460     elseif drawing.pending.mode == 'circle' or drawing.pending.mode == 'arc' then
 461       drawing.pending.vertices = {drawing.pending.center}
 462     end
 463     drawing.pending.mode = 'rectangle'
 464   elseif chord == 'C-s' and not App.mouse_down(1) then
 465     State.current_drawing_mode = 'square'
 466   elseif App.mouse_down(1) and chord == 's' then
 467     State.current_drawing_mode = 'square'
 468     local _,drawing = Drawing.current_drawing(State)
 469     if drawing.pending.mode == 'freehand' then
 470       drawing.pending.vertices = {Drawing.find_or_insert_point(drawing.points, drawing.pending.points[1].x, drawing.pending.points[1].y, State.width)}
 471     elseif drawing.pending.mode == 'line' or drawing.pending.mode == 'manhattan' then
 472       if drawing.pending.vertices == nil then
 473         drawing.pending.vertices = {drawing.pending.p1}
 474       end
 475     elseif drawing.pending.mode == 'polygon' then
 476       while #drawing.pending.vertices > 2 do
 477         table.remove(drawing.pending.vertices)
 478       end
 479     elseif drawing.pending.mode == 'rectangle' then
 480       -- reuse existing (1-2) vertices
 481     elseif drawing.pending.mode == 'circle' or drawing.pending.mode == 'arc' then
 482       drawing.pending.vertices = {drawing.pending.center}
 483     end
 484     drawing.pending.mode = 'square'
 485   elseif App.mouse_down(1) and chord == 'p' and State.current_drawing_mode == 'polygon' then
 486     local drawing_index,drawing = Drawing.current_drawing(State)
 487     local starty = Text.starty(State, drawing_index)
 488     local mx,my = Drawing.coord(App.mouse_x()-State.left, State.width), Drawing.coord(App.mouse_y()-starty, State.width)
 489     local j = Drawing.find_or_insert_point(drawing.points, mx,my, State.width)
 490     table.insert(drawing.pending.vertices, j)
 491   elseif App.mouse_down(1) and chord == 'p' and (State.current_drawing_mode == 'rectangle' or State.current_drawing_mode == 'square') then
 492     local drawing_index,drawing = Drawing.current_drawing(State)
 493     local starty = Text.starty(State, drawing_index)
 494     local mx,my = Drawing.coord(App.mouse_x()-State.left, State.width), Drawing.coord(App.mouse_y()-starty, State.width)
 495     local j = Drawing.find_or_insert_point(drawing.points, mx,my, State.width)
 496     while #drawing.pending.vertices >= 2 do
 497       table.remove(drawing.pending.vertices)
 498     end
 499     table.insert(drawing.pending.vertices, j)
 500   elseif chord == 'C-o' and not App.mouse_down(1) then
 501     State.current_drawing_mode = 'circle'
 502   elseif App.mouse_down(1) and chord == 'a' and State.current_drawing_mode == 'circle' then
 503     local drawing_index,drawing = Drawing.current_drawing(State)
 504     local starty = Text.starty(State, drawing_index)
 505     drawing.pending.mode = 'arc'
 506     local mx,my = Drawing.coord(App.mouse_x()-State.left, State.width), Drawing.coord(App.mouse_y()-starty, State.width)
 507     local center = drawing.points[drawing.pending.center]
 508     drawing.pending.radius = round(geom.dist(center.x,center.y, mx,my))
 509     drawing.pending.start_angle = geom.angle(center.x,center.y, mx,my)
 510   elseif App.mouse_down(1) and chord == 'o' then
 511     State.current_drawing_mode = 'circle'
 512     local _,drawing = Drawing.current_drawing(State)
 513     if drawing.pending.mode == 'freehand' then
 514       drawing.pending.center = Drawing.find_or_insert_point(drawing.points, drawing.pending.points[1].x, drawing.pending.points[1].y, State.width)
 515     elseif drawing.pending.mode == 'line' or drawing.pending.mode == 'manhattan' then
 516       drawing.pending.center = drawing.pending.p1
 517     elseif drawing.pending.mode == 'polygon' or drawing.pending.mode == 'rectangle' or drawing.pending.mode == 'square' then
 518       drawing.pending.center = drawing.pending.vertices[1]
 519     end
 520     drawing.pending.mode = 'circle'
 521   elseif chord == 'C-u' and not App.mouse_down(1) then
 522     local drawing_index,drawing,_,i,p = Drawing.select_point_at_mouse(State)
 523     if drawing then
 524       if State.previous_drawing_mode == nil then
 525         State.previous_drawing_mode = State.current_drawing_mode
 526       end
 527       State.current_drawing_mode = 'move'
 528       drawing.pending = {mode=State.current_drawing_mode, target_point=p, target_point_index=i}
 529       State.lines.current_drawing_index = drawing_index
 530       State.lines.current_drawing = drawing
 531     end
 532   elseif chord == 'C-n' and not App.mouse_down(1) then
 533     local drawing_index,drawing,_,point_index,p = Drawing.select_point_at_mouse(State)
 534     if drawing then
 535       if State.previous_drawing_mode == nil then
 536         -- don't clobber
 537         State.previous_drawing_mode = State.current_drawing_mode
 538       end
 539       State.current_drawing_mode = 'name'
 540       p.name = ''
 541       drawing.pending = {mode=State.current_drawing_mode, target_point=point_index}
 542       State.lines.current_drawing_index = drawing_index
 543       State.lines.current_drawing = drawing
 544     end
 545   elseif chord == 'C-d' and not App.mouse_down(1) then
 546     local _,drawing,_,i,p = Drawing.select_point_at_mouse(State)
 547     if drawing then
 548       for _,shape in ipairs(drawing.shapes) do
 549         if Drawing.contains_point(shape, i) then
 550           if shape.mode == 'polygon' then
 551             local idx = table.find(shape.vertices, i)
 552             assert(idx, 'point to delete is not in vertices')
 553             table.remove(shape.vertices, idx)
 554             if #shape.vertices < 3 then
 555               shape.mode = 'deleted'
 556             end
 557           else
 558             shape.mode = 'deleted'
 559           end
 560         end
 561       end
 562       drawing.points[i].deleted = true
 563     end
 564     local drawing,_,_,shape = Drawing.select_shape_at_mouse(State)
 565     if drawing then
 566       shape.mode = 'deleted'
 567     end
 568   elseif chord == 'C-h' and not App.mouse_down(1) then
 569     local drawing = Drawing.select_drawing_at_mouse(State)
 570     if drawing then
 571       drawing.show_help = true
 572     end
 573   elseif chord == 'escape' and App.mouse_down(1) then
 574     local _,drawing = Drawing.current_drawing(State)
 575     drawing.pending = {}
 576   end
 577 end
 578
 579 function Drawing.complete_rectangle(firstx,firsty, secondx,secondy, x,y)
 580   if firstx == secondx then
 581     return x,secondy, x,firsty
 582   end
 583   if firsty == secondy then
 584     return secondx,y, firstx,y
 585   end
 586   local first_slope = (secondy-firsty)/(secondx-firstx)
 587   -- slope of second edge:
 588   --    -1/first_slope
 589   -- equation of line containing the second edge:
 590   --    y-secondy = -1/first_slope*(x-secondx)
 591   -- => 1/first_slope*x + y + (- secondy - secondx/first_slope) = 0
 592   -- now we want to find the point on this line that's closest to the mouse pointer.
 593   -- https://en.wikipedia.org/wiki/Distance_from_a_point_to_a_line#Line_defined_by_an_equation
 594   local a = 1/first_slope
 595   local c = -secondy - secondx/first_slope
 596   local thirdx = round(((x-a*y) - a*c) / (a*a + 1))
 597   local thirdy = round((a*(-x + a*y) - c) / (a*a + 1))
 598   -- slope of third edge = first_slope
 599   -- equation of line containing third edge:
 600   --     y - thirdy = first_slope*(x-thirdx)
 601   --  => -first_slope*x + y + (-thirdy + thirdx*first_slope) = 0
 602   -- now we want to find the point on this line that's closest to the first point
 603   local a = -first_slope
 604   local c = -thirdy + thirdx*first_slope
 605   local fourthx = round(((firstx-a*firsty) - a*c) / (a*a + 1))
 606   local fourthy = round((a*(-firstx + a*firsty) - c) / (a*a + 1))
 607   return thirdx,thirdy, fourthx,fourthy
 608 end
 609
 610 function Drawing.complete_square(firstx,firsty, secondx,secondy, x,y)
 611   -- use x,y only to decide which side of the first edge to complete the square on
 612   local deltax = secondx-firstx
 613   local deltay = secondy-firsty
 614   local thirdx = secondx+deltay
 615   local thirdy = secondy-deltax
 616   if not geom.same_side(firstx,firsty, secondx,secondy, thirdx,thirdy, x,y) then
 617     deltax = -deltax
 618     deltay = -deltay
 619     thirdx = secondx+deltay
 620     thirdy = secondy-deltax
 621   end
 622   local fourthx = firstx+deltay
 623   local fourthy = firsty-deltax
 624   return thirdx,thirdy, fourthx,fourthy
 625 end
 626
 627 function Drawing.current_drawing(State)
 628   local x, y = App.mouse_x(), App.mouse_y()
 629   for drawing_index,drawing in ipairs(State.lines) do
 630     if drawing.mode == 'drawing' then
 631       if Drawing.in_drawing(State, drawing_index, x,y, State.left,State.right) then
 632         return drawing_index,drawing
 633       end
 634     end
 635   end
 636   return nil
 637 end
 638
 639 function Drawing.select_shape_at_mouse(State)
 640   for drawing_index,drawing in ipairs(State.lines) do
 641     if drawing.mode == 'drawing' then
 642       local x, y = App.mouse_x(), App.mouse_y()
 643       local starty = Text.starty(State, drawing_index)
 644       if Drawing.in_drawing(State, drawing_index, x,y, State.left,State.right) then
 645         local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
 646         for i,shape in ipairs(drawing.shapes) do
 647           if geom.on_shape(mx,my, drawing, shape) then
 648             return drawing,starty,i,shape
 649           end
 650         end
 651       end
 652     end
 653   end
 654 end
 655
 656 function Drawing.select_point_at_mouse(State)
 657   for drawing_index,drawing in ipairs(State.lines) do
 658     if drawing.mode == 'drawing' then
 659       local x, y = App.mouse_x(), App.mouse_y()
 660       local starty = Text.starty(State, drawing_index)
 661       if Drawing.in_drawing(State, drawing_index, x,y, State.left,State.right) then
 662         local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
 663         for i,point in ipairs(drawing.points) do
 664           if Drawing.near(point, mx,my, State.width) then
 665             return drawing_index,drawing,starty,i,point
 666           end
 667         end
 668       end
 669     end
 670   end
 671 end
 672
 673 function Drawing.select_drawing_at_mouse(State)
 674   for drawing_index,drawing in ipairs(State.lines) do
 675     if drawing.mode == 'drawing' then
 676       local x, y = App.mouse_x(), App.mouse_y()
 677       if Drawing.in_drawing(State, drawing_index, x,y, State.left,State.right) then
 678         return drawing
 679       end
 680     end
 681   end
 682 end
 683
 684 function Drawing.contains_point(shape, p)
 685   if shape.mode == 'freehand' then
 686     -- not supported
 687   elseif shape.mode == 'line' or shape.mode == 'manhattan' then
 688     return shape.p1 == p or shape.p2 == p
 689   elseif shape.mode == 'polygon' or shape.mode == 'rectangle' or shape.mode == 'square' then
 690     return table.find(shape.vertices, p)
 691   elseif shape.mode == 'circle' then
 692     return shape.center == p
 693   elseif shape.mode == 'arc' then
 694     return shape.center == p
 695     -- ugh, how to support angles
 696   elseif shape.mode == 'deleted' then
 697     -- already done
 698   else
 699     assert(false, ('unknown drawing mode %s'):format(shape.mode))
 700   end
 701 end
 702
 703 function Drawing.smoothen(shape)
 704   assert(shape.mode == 'freehand', 'can only smoothen freehand shapes')
 705   for _=1,7 do
 706     for i=2,#shape.points-1 do
 707       local a = shape.points[i-1]
 708       local b = shape.points[i]
 709       local c = shape.points[i+1]
 710       b.x = round((a.x + b.x + c.x)/3)
 711       b.y = round((a.y + b.y + c.y)/3)
 712     end
 713   end
 714 end
 715
 716 function round(num)
 717   return math.floor(num+.5)
 718 end
 719
 720 function Drawing.find_or_insert_point(points, x,y, width)
 721   -- check if UI would snap the two points together
 722   for i,point in ipairs(points) do
 723     if Drawing.near(point, x,y, width) then
 724       return i
 725     end
 726   end
 727   table.insert(points, {x=x, y=y})
 728   return #points
 729 end
 730
 731 function Drawing.near(point, x,y, width)
 732   local px,py = Drawing.pixels(x, width),Drawing.pixels(y, width)
 733   local cx,cy = Drawing.pixels(point.x, width), Drawing.pixels(point.y, width)
 734   return (cx-px)*(cx-px) + (cy-py)*(cy-py) < Same_point_distance*Same_point_distance
 735 end
 736
 737 function Drawing.pixels(n, width)  -- parts to pixels
 738   return math.floor(n*width/256)
 739 end
 740 function Drawing.coord(n, width)  -- pixels to parts
 741   return math.floor(n*256/width)
 742 end
 743
 744 function table.find(h, x)
 745   for k,v in pairs(h) do
 746     if v == x then
 747       return k
 748     end
 749   end
 750 end