📐 using earcut for triangulation, implementing own Canvas

README.md

@@ -27,7 +27,6 @@ No web browser around? No worries - discover the planet in your console!
 ## Behind the scenes
 ### Libraries
 #### Mastering the console
-  * [`drawille-canvas-blessed-contrib`](https://github.com/yaronn/drawille-canvas-blessed-contrib/) for [braille](http://www.fileformat.info/info/unicode/block/braille_patterns/utf8test.htm) rendering
   * [`x256`](https://github.com/substack/node-x256) for finding nearest xterm-256 [color codes](https://en.wikipedia.org/wiki/File:Xterm_256color_chart.svg)
   * [`term-mouse`](https://github.com/CoderPuppy/term-mouse) for mouse handling
   * [`keypress`](https://github.com/TooTallNate/keypress) for input handling
@@ -38,9 +37,10 @@ No web browser around? No worries - discover the planet in your console!
 * [`vector-tile-js`](https://github.com/mapbox/vector-tile-js) for [VectorTile](https://github.com/mapbox/vector-tile-spec/tree/master/2.1) parsing
 
 #### Juggling the vectors and numbers
-* [`pnltri`](https://github.com/jahting/pnltri.js) for polygon triangulation to draw 'em filled
+* [`earcut`](https://github.com/mapbox/earcut) for polygon triangulation
 * [`rbush`](https://github.com/mourner/rbush) for 2D spatial indexing based label and mouse collision detection
 * [`gl-matrix`](https://github.com/toji/gl-matrix) for vector and matrix operations
+* [`breseham`](https://github.com/madbence/node-bresenham) for line calculations
 * [`sphericalmercator`](https://github.com/mapbox/node-sphericalmercator) for [EPSG:3857](http://spatialreference.org/ref/sr-org/6864/) <> [WGS84](http://spatialreference.org/ref/epsg/wgs-84/) conversions
 
 ### TODOs

package.json

@@ -20,12 +20,12 @@
   "author": "Michael Straßburger <codepoet@cpan.org>",
   "license": "MIT",
   "dependencies": {
+    "bresenham": "0.0.4",
     "coffee-script": "^1.10.0",
-    "drawille-canvas-blessed-contrib": "git+https://github.com/rastapasta/drawille-canvas-blessed-contrib.git",
+    "earcut": "^2.1.1",
     "gl-matrix": "^2.3.2",
     "keypress": "^0.2.1",
     "pbf": "^3.0.0",
-    "pnltri": "^2.1.1",
     "rbush": "^2.0.1",
     "sphericalmercator": "^1.0.5",
     "term-mouse": "^0.1.1",

src/BrailleBuffer.coffee

@@ -5,8 +5,9 @@
   Simple pixel to barille character mapper
 
   Implementation inspired by node-drawille (https://github.com/madbence/node-drawille)
-  * added written text support
   * added color support
+  * added support for filled polygons
+  * added text label support
   * general optimizations
     -> more bit shifting/operations, less Math.floors
 
@@ -78,12 +79,5 @@ module.exports = class BrailleBuffer
     @colorBuffer[idx] = @termColor color
 
   writeText: (text, x, y, color, center = true) ->
-    x -= text.length/2 if center
+    x -= text.length/2+1 if center
     @setChar text.charAt(i), x+i*2, y, color for i in [0...text.length]
-
-# buffer = new BrailleBuffer 100, 16
-# for i in [0...255]
-#   buffer.setPixel i, 8+8*Math.cos(i/10*Math.PI/2), i
-#
-# buffer.writeText "ruth", 10, 0, 111
-# console.log buffer.frame()

src/Canvas.coffee

@@ -2,40 +2,107 @@
   termap - Terminal Map Viewer
   by Michael Strassburger <codepoet@cpan.org>
 
-  Extends drawille-canvas to add additional drawing functions.
+  Simple pixel to barille character mapper
-  To be PRed up the tree at some point.
+
+  Implementation inspired by node-drawille-canvas (https://github.com/madbence/node-drawille-canvas)
+  * added support for filled polygons
+  * improved text rendering
+
+  Will most likely be turned into a stand alone module at some point
 ###
 
-BlessedCanvas = require 'drawille-canvas-blessed-contrib'
+bresenham = require 'bresenham'
-vec2 = require('gl-matrix').vec2
+glMatrix = require 'gl-matrix'
+earcut = require 'earcut'
 
-module.exports = class Canvas extends BlessedCanvas
+BrailleBuffer = require './BrailleBuffer'
 
-  # bresenham: (from, to) ->
+vec2 = glMatrix.vec2
-  #   points = []
+mat2d = glMatrix.mat2d
-  #   adx = Math.abs dx = to.x - from.x
+
-  #   ady = Math.abs dy = to.y - from.y
+module.exports = class Canvas
-  #   eps = 0
+  matrix: null
-  #   sx = if dx > 0 then 1 else -1
+
-  #   sy = if dy > 0 then 1 else -1
+  constructor: (@width, @height) ->
-  #
+    @buffer = new BrailleBuffer @width, @height
-  #   [x, y] = from
+    @reset()
-  #   if adx > ady
+
-  #     while if sx < 0 then x >= x1 else x <= x1
+  reset: ->
-  #       points.add x:, y: y
+    @matrix = mat2d.create()
-  #       eps += ady
+
-  #       if eps<<1 >= adx
+  print: ->
-  #         y += sy
+    process.stdout.write @buffer.frame()
-  #         eps -= adx
+
-  #
+  translate: (x, y) ->
-  #       x += sx
+    mat2d.translate @matrix, @matrix, vec2.fromValues(x, y)
-  #   else
+
-  #     while if sy < 0 then y >= y1 else y <= y1
+  clear: ->
-  #       fn(x, y);
+    @buffer.clear()
-  #       eps += adx;
+
-  #       if eps<<1 >= ady
+  text: (text, x, y, color, center = true) ->
-  #         x += sx;
+    @buffer.writeText text, x, y, color, center
-  #         eps -= ady;
+
-  #
+  polyline: (points, color) ->
-  #       y += sy
+    projected = (@_project point[0], point[1] for point in points)
-  #   arr
+    for i in [1...projected.length]
+      bresenham projected[i-1]..., projected[i]...,
+        (x, y) => @buffer.setPixel x, y, color
+
+  # TODO: support for polygon holes
+  polygon: (points, color) ->
+    vertices = []
+    for point in points
+      vertices = vertices.concat @_project point[0], point[1]
+
+    triangles = earcut vertices
+    extract = (pointId) ->
+      [vertices[pointId*2], vertices[pointId*2+1]]
+
+    for i in [0...triangles.length] by 3
+      @_filledTriangle extract(triangles[i]), extract(triangles[i+1]), extract(triangles[i+2]), color
+
+  _bresenham: (pointA, pointB) ->
+    bresenham pointA[0], pointA[1],
+              pointB[0], pointB[1]
+
+  _project: (x, y) ->
+    point = vec2.transformMat2d vec2.create(), vec2.fromValues(x, y), @matrix
+    [Math.floor(point[0]), Math.floor(point[1])]
+
+  _filledRectangle: (x, y, width, height, color) ->
+    pointA = @_project x, y
+    pointB = @_project x+width, y
+    pointC = @_project x, y+height
+    pointD = @_project x+width, y+height
+
+    @_filledTriangle pointA, pointB, pointC, color
+    @_filledTriangle pointC, pointB, pointD, color
+
+  # Draws a filled triangle
+  _filledTriangle: (pointA, pointB, pointC, color) ->
+    a = @_bresenham pointB, pointC
+    b = @_bresenham pointA, pointC
+    c = @_bresenham pointA, pointB
+
+    # Filter out any points outside of the visible area
+    # TODO: benchmark - is it more effective to filter double points, or does
+    # it req more computing time than actually setting points multiple times?
+
+    last = null
+    points = a.concat(b).concat(c)
+    .filter (point) => 0 <= point.y < @height
+    .sort (a, b) -> if a.y is b.y then a.x - b.x else a.y-b.y
+    .filter (point) ->
+      [lastPoint, last] = [last, point]
+      not lastPoint or lastPoint.x isnt point.x or lastPoint.y isnt point.y
+
+    for i, point of points
+      next = points[i*1+1]
+
+      if point.y is next?.y
+        left = Math.max 0, point.x
+        right = Math.min @width, next?.x
+        @buffer.setPixel x, point.y, color for x in [left..right]
+
+      else
+        @buffer.setPixel point.x, point.y, color

src/Renderer.coffee

@@ -5,7 +5,6 @@
   The Console Vector Tile renderer - bäm!
 ###
 x256 = require 'x256'
-triangulator = new (require('pnltri')).Triangulator()
 
 Canvas = require './Canvas'
 LabelBuffer = require './LabelBuffer'
@@ -17,7 +16,8 @@ module.exports = class Renderer
     fillPolygons: true
     language: 'de'
 
-    drawOrder: ["admin", "building", "road", "water", "poi_label", "place_label", "housenum_label"]
+    #"poi_label", "housenum_label", "water",
+    drawOrder: ["admin", "building", "road", "place_label"]
 
     icons:
       car: "🚗"
@@ -77,14 +77,13 @@ module.exports = class Renderer
     #   @canvas.strokeStyle = x256 utils.hex2rgb(color)...
     #   @canvas.fillRect 0, 0, @width, @height
     # else
-    @canvas.clearRect 0, 0, @width, @height
+    @canvas.clear()
+    @canvas.reset()
 
-    @canvas.save()
     @canvas.translate @view[0], @view[1]
     @_drawLayers()
-    @canvas.restore()
 
-    @_write @canvas._canvas.frame()
+    @canvas.print()
 
     @isDrawing = false
 
@@ -114,9 +113,7 @@ module.exports = class Renderer
       return false
 
     toDraw = for points in feature.points
-      for point in points
+      [point.x/scale, point.y/scale] for point in points
-        x: point.x/scale
-        y: point.y/scale
 
     color = style.paint['line-color'] or style.paint['fill-color'] or style.paint['text-color']
 
@@ -124,16 +121,15 @@ module.exports = class Renderer
     if color instanceof Object
       color = color.stops[0][1]
 
-    @canvas.fillStyle = @canvas.strokeStyle = x256 utils.hex2rgb color
+    colorCode = x256 utils.hex2rgb color
 
     switch feature.type
       when "LineString"
-        @_drawWithLines points for points in toDraw
+        @canvas.polyline points, colorCode for points in toDraw
         true
 
       when "Polygon"
-        unless @config.fillPolygons and @_drawWithTriangles toDraw
+        @canvas.polygon toDraw[0], colorCode
-          @_drawWithLines points for points in toDraw
         true
 
       when "Point"
@@ -150,37 +146,11 @@ module.exports = class Renderer
             x = point.x - text.length
             #continue if x-@view[0] < 0
             if @labelBuffer.writeIfPossible text, x, point.y
-              @canvas.fillText text, x, point.y
+              @canvas.text text, x, point.y, colorCode
               wasDrawn = true
 
         wasDrawn
 
-  _drawWithTriangles: (points) ->
-    try
-      triangles = triangulator.triangulate_polygon points
-    catch
-      return false
-
-    return false unless triangles.length
-
-    # TODO: triangles are returned as vertex references to a flattened input.
-    #       optimize it!
-
-    arr = points.reduce (a, b) -> a.concat b
-    for triangle in triangles
-      try
-        @canvas.fillTriangle arr[triangle[0]], arr[triangle[1]], arr[triangle[2]]
-      catch
-        return false
-    true
-
-  _drawWithLines: (points) ->
-    @canvas.beginPath()
-    first = points.shift()
-    @canvas.moveTo first.x, first.y
-    @canvas.lineTo point.x, point.y for point in points
-    @canvas.stroke()
-
   _isOnScreen: (point) ->
     point.x+@view[0]>=4 and
     point.x+@view[0]<@width-4 and