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beginnings of support for multiple shapes

This commit is contained in:
Kartik K. Agaram 2022-05-14 13:08:33 -07:00
parent 422dd3c3b7
commit eaa3820241
1 changed files with 114 additions and 43 deletions
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157
main.lua
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@ -3,9 +3,39 @@ require 'button'
require 'repl'
local utf8 = require 'utf8'
-- lines is an array of lines
-- a line is either:
-- a string containing text
-- or a drawing
-- a drawing is a table with:
-- a (y) coord in pixels,
-- a (h)eight,
-- an array of points, and
-- an array of shapes
-- a shape is a table containing:
-- a mode
-- an array points for mode 'freehand' (raw x,y coords; freehand drawings don't pollute the points array of a drawing)
-- an array vertices for mode 'polygon', 'rectangle', 'square'
-- p1, p2 for mode 'line'
-- p1, p2, arrow-mode for mode 'arrow-line'
-- cx,cy, r for mode 'circle'
-- pc, r for mode 'circle'
-- pc, r, s, e for mode 'arc'
-- Unless otherwise specified, coord fields are normalized; a drawing is always 256 units wide
-- The field names are carefully chosen so that switching modes in midstream
-- remembers previously entered points where that makes sense.
--
-- Open question: how to maintain Sketchpad-style constraints? Answer for now:
-- we don't. Constraints operate only for the duration of a drawing operation.
-- We'll continue to persist them just to keep the option open to continue
-- solving for them. But for now, this is a program to create static drawings
-- once, and read them passively thereafter.
lines = {}
screenw, screenh, screenflags = 0, 0, nil
current_mode = 'freehand'
-- All drawings span 100% of some conceptual 'page width' and divide it up
-- into 256 parts. `drawingw` describes their width in pixels.
drawingw = 400 -- pixels
@ -57,26 +87,14 @@ function love.draw()
local mx,my = coord(love.mouse.getX()-12), coord(love.mouse.getY()-line.y)
for _,shape in ipairs(line.shapes) do
if on_freehand(mx,my, shape) then
if on_shape(mx,my, shape) then
love.graphics.setColor(1,0,0)
else
love.graphics.setColor(0,0,0)
end
prev = nil
for _,point in ipairs(shape) do
if prev then
love.graphics.line(pixels(prev.x)+12,pixels(prev.y)+line.y, pixels(point.x)+12,pixels(point.y)+line.y)
end
prev = point
end
end
prev = nil
for _,point in ipairs(line.pending) do
if prev then
love.graphics.line(pixels(prev.x)+12,pixels(prev.y)+line.y, pixels(point.x)+12,pixels(point.y)+line.y)
end
prev = point
draw_shape(12,line.y, shape)
end
draw_pending_shape(12,line.y, line.pending)
else
love.graphics.draw(text, 25,y, 0, 1.5)
end
@ -97,7 +115,9 @@ function love.update(dt)
if type(drawing) == 'table' then
local x, y = love.mouse.getX(), love.mouse.getY()
if y >= drawing.y and y < drawing.y + pixels(drawing.h) and x >= 12 and x < 12+drawingw then
table.insert(drawing.pending, {x=coord(love.mouse.getX()-12), y=coord(love.mouse.getY()-drawing.y)})
if drawing.pending.mode == 'freehand' then
table.insert(drawing.pending.points, {x=coord(love.mouse.getX()-12), y=coord(love.mouse.getY()-drawing.y)})
end
end
end
end
@ -109,20 +129,73 @@ function love.mousepressed(x,y, button)
propagate_to_drawings(x,y, button)
end
function love.mousereleased(x,y, button)
if lines.current then
if lines.current.pending then
if lines.current.pending.mode == 'freehand' then
-- the last point added during update is good enough
elseif lines.current.pending.mode == 'line' then
lines.current.pending.x2 = coord(x-12)
lines.current.pending.y2 = coord(y-lines.current.y)
end
table.insert(lines.current.shapes, lines.current.pending)
lines.current.pending = {}
lines.current = nil
end
end
end
function propagate_to_drawings(x,y, button)
for i,drawing in ipairs(lines) do
if type(drawing) == 'table' then
local x, y = love.mouse.getX(), love.mouse.getY()
if y >= drawing.y and y < drawing.y + pixels(drawing.h) and x >= 12 and x < 12+drawingw then
if current_mode == 'freehand' then
drawing.pending = {mode='freehand', points={x=coord(x-12), y=coord(y-drawing.y)}}
elseif current_mode == 'line' then
drawing.pending = {mode='line', x1=coord(x-12), y1=coord(y-drawing.y)}
end
lines.current = drawing
end
end
end
end
function draw_shape(left,top, shape)
if shape.mode == 'freehand' then
local prev = nil
for _,point in ipairs(shape.points) do
if prev then
love.graphics.line(pixels(prev.x)+left,pixels(prev.y)+top, pixels(point.x)+left,pixels(point.y)+top)
end
prev = point
end
elseif shape.mode == 'line' then
love.graphics.line(pixels(shape.x1)+left,pixels(shape.y1)+top, pixels(shape.x2)+left,pixels(shape.y2)+top)
end
end
function draw_pending_shape(left,top, shape)
if shape.mode == 'freehand' then
draw_shape(left,top, shape)
elseif shape.mode == 'line' then
love.graphics.line(pixels(line.pending.x1)+left,pixels(line.pending.y1)+top, love.mouse.getX(),love.mouse.getY())
end
end
function on_shape(x,y, shape)
if shape.mode == 'freehand' then
return on_freehand(x,y, shape)
elseif shape.mode == 'line' then
return on_line(x,y, shape)
else
assert(false)
end
end
function on_freehand(x,y, shape)
local prev
for _,p in ipairs(shape) do
for _,p in ipairs(shape.points) do
if prev then
if on_line(x,y, {x1=prev.x,y1=prev.y, x2=p.x,y2=p.y}) then
return true
@ -155,16 +228,6 @@ function on_line(x,y, shape)
return k > -0.05 and k < 1.05
end
function love.mousereleased(x,y, button)
if lines.current then
if lines.current.pending then
table.insert(lines.current.shapes, lines.current.pending)
lines.current.pending = {}
lines.current = nil
end
end
end
function love.textinput(t)
lines[#lines] = lines[#lines]..t
end
@ -190,12 +253,12 @@ function keychord_pressed(chord)
elseif chord == 'C-l' then
local drawing,i,shape = select_shape_at_mouse()
if drawing then
convert_line(drawing,i,shape)
convert_line(shape)
end
elseif chord == 'C-m' then
local drawing,i,shape = select_shape_at_mouse()
if drawing then
convert_horvert(drawing,i,shape)
convert_horvert(shape)
end
elseif chord == 'C-s' then
local drawing,i,shape = select_shape_at_mouse()
@ -212,7 +275,7 @@ function select_shape_at_mouse()
if y >= drawing.y and y < drawing.y + pixels(drawing.h) and x >= 12 and x < 12+drawingw then
local mx,my = coord(love.mouse.getX()-12), coord(love.mouse.getY()-drawing.y)
for i,shape in ipairs(drawing.shapes) do
if on_freehand(mx,my, shape) then
if on_shape(mx,my, shape) then
return drawing,i,shape
end
end
@ -221,31 +284,39 @@ function select_shape_at_mouse()
end
end
function convert_line(drawing, i, shape)
function convert_line(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.
drawing.shapes[i] = {shape[1], shape[#shape]}
assert(shape.mode == 'freehand')
shape.mode = 'line'
shape.x1 = shape.points[1].x
shape.y1 = shape.points[1].y
shape.x2 = shape.points[#shape.points].x
shape.y2 = shape.points[#shape.points].y
end
-- turn a stroke into either a horizontal or vertical line
function convert_horvert(drawing, i, shape)
local x1,y1 = shape[1].x, shape[1].y
local x2,y2 = shape[#shape].x, shape[#shape].y
if math.abs(x1-x2) > math.abs(y1-y2) then
drawing.shapes[i] = {{x=x1, y=y1}, {x=x2, y=y1}}
-- turn a line either horizontal or vertical
function convert_horvert(shape)
if shape.mode == 'freehand' then
convert_line(shape)
end
assert(shape.mode == 'line')
if math.abs(shape.x1-shape.x2) > math.abs(shape.y1-shape.y2) then
shape.y2 = shape.y1
else
drawing.shapes[i] = {{x=x1, y=y1}, {x=x1, y=y2}}
shape.x2 = shape.x1
end
end
function smoothen(shape)
assert(shape.mode == 'freehand')
for _=1,7 do
for i=2,#shape-1 do
local a = shape[i-1]
local b = shape[i]
local c = shape[i+1]
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