diff options
Diffstat (limited to 'node_modules/color-convert/route.js')
-rw-r--r-- | node_modules/color-convert/route.js | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/node_modules/color-convert/route.js b/node_modules/color-convert/route.js new file mode 100644 index 0000000..0a1fdea --- /dev/null +++ b/node_modules/color-convert/route.js @@ -0,0 +1,97 @@ +var conversions = require('./conversions'); + +/* + this function routes a model to all other models. + + all functions that are routed have a property `.conversion` attached + to the returned synthetic function. This property is an array + of strings, each with the steps in between the 'from' and 'to' + color models (inclusive). + + conversions that are not possible simply are not included. +*/ + +function buildGraph() { + var graph = {}; + // https://jsperf.com/object-keys-vs-for-in-with-closure/3 + var models = Object.keys(conversions); + + for (var len = models.length, i = 0; i < len; i++) { + graph[models[i]] = { + // http://jsperf.com/1-vs-infinity + // micro-opt, but this is simple. + distance: -1, + parent: null + }; + } + + return graph; +} + +// https://en.wikipedia.org/wiki/Breadth-first_search +function deriveBFS(fromModel) { + var graph = buildGraph(); + var queue = [fromModel]; // unshift -> queue -> pop + + graph[fromModel].distance = 0; + + while (queue.length) { + var current = queue.pop(); + var adjacents = Object.keys(conversions[current]); + + for (var len = adjacents.length, i = 0; i < len; i++) { + var adjacent = adjacents[i]; + var node = graph[adjacent]; + + if (node.distance === -1) { + node.distance = graph[current].distance + 1; + node.parent = current; + queue.unshift(adjacent); + } + } + } + + return graph; +} + +function link(from, to) { + return function (args) { + return to(from(args)); + }; +} + +function wrapConversion(toModel, graph) { + var path = [graph[toModel].parent, toModel]; + var fn = conversions[graph[toModel].parent][toModel]; + + var cur = graph[toModel].parent; + while (graph[cur].parent) { + path.unshift(graph[cur].parent); + fn = link(conversions[graph[cur].parent][cur], fn); + cur = graph[cur].parent; + } + + fn.conversion = path; + return fn; +} + +module.exports = function (fromModel) { + var graph = deriveBFS(fromModel); + var conversion = {}; + + var models = Object.keys(graph); + for (var len = models.length, i = 0; i < len; i++) { + var toModel = models[i]; + var node = graph[toModel]; + + if (node.parent === null) { + // no possible conversion, or this node is the source model. + continue; + } + + conversion[toModel] = wrapConversion(toModel, graph); + } + + return conversion; +}; + |