added order to iterPoints and iterClip

README.md

@@ -217,7 +217,12 @@ const result = iterClip({
     band: [2, 2], // 3rd band (blue), where band index starts at zero
     row: [55, 74], // from the 56th to the 75th row (counting from the top)
     column: [60, 62] // from the 61st to the 63rd column (counting from the left)
-  }
+  },
+
+  // optional
+  // order to return point values
+  // in left-to-right major order
+  order: ["band", "row", "column"]
 });
 ```
 result is an iterator object

src/xdim.js

@@ -162,10 +162,10 @@ function prepareUpdate({ useLayoutCache = true, data, layout, sizes = {} }) {
   };
 }
 
-function iterClip({ data, layout, rect = {}, sizes = {}, useLayoutCache = true }) {
+function iterClip({ data, layout, order, rect = {}, sizes = {}, useLayoutCache = true }) {
   if (!data) throw new Error("[xdim] must specify data");
   if (!layout) throw new Error("[xdim] must specify layout");
-  const points = iterPoints({ sizes, rect });
+  const points = iterPoints({ order, sizes, rect });
   return wrapNextFunction(function next() {
     const { value: point, done } = points.next();
     if (done) {
@@ -437,9 +437,9 @@ function iterRange({ start = 0, end = 100 }) {
 }
 
 // iterate over all the points, saving memory vs array
-function iterPoints({ sizes, rect = {} }) {
+function iterPoints({ order, sizes, rect = {} }) {
   // names sorted by shortest dimension to longest dimension
-  const names = Object.keys(sizes).sort((a, b) => sizes[a] - sizes[b]);
+  const names = Array.isArray(order) ? order : Object.keys(sizes).sort((a, b) => sizes[a] - sizes[b]);
 
   const iters = new Array(names.length);
   const current = {};

tests/test.iter-clip.js

@@ -3,18 +3,18 @@ const { iterClip } = require("../src/xdim");
 
 const range = ct => new Array(ct).fill(0).map((_, i) => i);
 
-test("iter clip with rect", ({ eq }) => {
-  // band row column
-  const pixelDepth = 4;
-  const height = 768;
-  const width = 1024;
-  const data = range(pixelDepth).map(band => {
-    return range(height).map(row => {
-      return range(width).map(column => {
-        return { b: band, r: row, c: column };
-      });
+const pixelDepth = 4;
+const height = 768;
+const width = 1024;
+const data = range(pixelDepth).map(band => {
+  return range(height).map(row => {
+    return range(width).map(column => {
+      return { b: band, r: row, c: column };
     });
   });
+});
+
+test("iter clip with rect", ({ eq }) => {
   const iter = iterClip({ data, layout: "[band][row][column]", sizes: { band: 4, row: 768, column: 1024 }, rect: { band: [1, 3] } });
   eq(iter.next().value, { b: 1, r: 0, c: 0 });
   eq(iter.next().value, { b: 1, r: 0, c: 1 });
@@ -26,3 +26,15 @@ test("iter clip with rect", ({ eq }) => {
   for (last of iter);
   eq(last, { b: 3, r: 767, c: 1023 });
 });
+
+test("iter clip with rect and order", ({ eq }) => {
+  const iter = iterClip({
+    data,
+    layout: "[band][row][column]",
+    order: ["row", "column", "band"],
+    sizes: { band: 4, row: 768, column: 1024 },
+    rect: { band: [1, 3] }
+  });
+  eq(iter.next().value, { b: 1, r: 0, c: 0 });
+  eq(iter.next().value, { b: 2, r: 0, c: 0 });
+});

tests/test.iter-points.js

@@ -26,3 +26,15 @@ test("iter points with rect", ({ eq }) => {
   for (last of iter);
   eq(last, { band: 3, row: 767, column: 1023 });
 });
+
+test("iter points with order", ({ eq }) => {
+  const iter = iterPoints({ order: ["band", "row", "column"], sizes: { band: 4, row: 101, column: 50 } });
+  eq(iter.next().value, { band: 0, row: 0, column: 0 });
+  eq(iter.next().value, { band: 0, row: 0, column: 1 });
+});
+
+test("iter points with rect and order", ({ eq }) => {
+  const iter = iterPoints({ order: ["row", "column", "band"], sizes: { band: 4, row: 101, column: 50 }, rect: { band: [1, 3] } });
+  eq(iter.next().value, { row: 0, column: 0, band: 1 });
+  eq(iter.next().value, { row: 0, column: 0, band: 2 });
+});