Add .map() method to Playfield.
catseye
12 years ago
| 187 | 187 | }; |
| 188 | 188 | |
| 189 | 189 | /* |
| 190 | * Analogous to (monoid) map in functional languages, | |
| 191 | * iterate over this Playfield, transform each value using | |
| 192 | * a supplied function, and write the transformed value into | |
| 193 | * a destination Playfield. | |
| 194 | * | |
| 195 | * Supplied function should take a Playfield (this Playfield), | |
| 196 | * x, and y, and return a value. | |
| 197 | * | |
| 198 | * The map source may extend beyond the internal bounds of | |
| 199 | * the Playfield, by giving the min/max Dx/Dy arguments | |
| 200 | * (which work like margin offsets.) | |
| 201 | * | |
| 202 | * Useful for evolving a cellular automaton playfield. In this | |
| 203 | * case, min/max Dx/Dy should be computed from the neighbourhood. | |
| 204 | */ | |
| 205 | this.map = function(destPf, fun, minDx, minDy, maxDx, maxDy) { | |
| 206 | if (minDx === undefined) minDx = 0; | |
| 207 | if (minDy === undefined) minDy = 0; | |
| 208 | if (maxDx === undefined) maxDx = 0; | |
| 209 | if (maxDy === undefined) maxDy = 0; | |
| 210 | for (var y = this.minY + minDy; y <= this.maxY + maxDy; y++) { | |
| 211 | for (var x = this.minX + minDx; x <= this.maxX + maxDx; x++) { | |
| 212 | destPf.putDirty(x, y, fun(pf, x, y)); | |
| 213 | } | |
| 214 | } | |
| 215 | destPf.recalculateBounds(); | |
| 216 | }; | |
| 217 | ||
| 218 | /* | |
| 190 | 219 | * Draws elements of the Playfield in a drawing context. |
| 191 | 220 | * x and y are canvas coordinates, and width and height |
| 192 | 221 | * are canvas units of measure. |