try to generate at least one tick

d3 · Jan 18, 2023 · cc9ac02 · cc9ac02
1 parent 191aa03
commit cc9ac02
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Showing 2 changed files with 25 additions and 7 deletions.
diff --git a/src/ticks.js b/src/ticks.js
@@ -6,7 +6,7 @@ export default function ticks(start, stop, count) {
   var reverse,
       i = -1,
       n,
-      ticks,
+      t,
       step;
 
   stop = +stop, start = +start, count = +count;
@@ -18,20 +18,22 @@ export default function ticks(start, stop, count) {
     let r0 = Math.round(start / step), r1 = Math.round(stop / step);
     if (r0 * step < start) ++r0;
     if (r1 * step > stop) --r1;
-    ticks = new Array(n = r1 - r0 + 1);
-    while (++i < n) ticks[i] = (r0 + i) * step;
+    if (r1 < r0 && 0.5 <= count && count < 2) return ticks(start, stop, count * 2);
+    t = new Array(n = r1 - r0 + 1);
+    while (++i < n) t[i] = (r0 + i) * step;
   } else {
     step = -step;
     let r0 = Math.round(start * step), r1 = Math.round(stop * step);
     if (r0 / step < start) ++r0;
     if (r1 / step > stop) --r1;
-    ticks = new Array(n = r1 - r0 + 1);
-    while (++i < n) ticks[i] = (r0 + i) / step;
+    if (r1 < r0 && 0.5 <= count && count < 2) return ticks(start, stop, count * 2);
+    t = new Array(n = r1 - r0 + 1);
+    while (++i < n) t[i] = (r0 + i) / step;
   }
 
-  if (reverse) ticks.reverse();
+  if (reverse) t.reverse();
 
-  return ticks;
+  return t;
 }
 
 export function tickIncrement(start, stop, count) {

diff --git a/test/ticks-test.js b/test/ticks-test.js
@@ -109,3 +109,19 @@ it("ticks(start, stop, count) returns the reverse of ticks(stop, start, count)",
 it("ticks(start, stop, count) handles precision problems", () => {
   assert.deepStrictEqual(ticks(0.98, 1.14, 10), [0.98, 1, 1.02, 1.04, 1.06, 1.08, 1.1, 1.12, 1.14]);
 });
+
+it("ticks(start, stop, count) tries to return at least one tick if count >= 0.5", () => {
+  assert.deepStrictEqual(ticks(1, 364, 0.1), []);
+  assert.deepStrictEqual(ticks(1, 364, 0.499), []);
+  assert.deepStrictEqual(ticks(1, 364, 0.5), [200]);
+  assert.deepStrictEqual(ticks(1, 364, 1), [200]);
+  assert.deepStrictEqual(ticks(1, 364, 1.5), [200]);
+  assert.deepStrictEqual(ticks(1, 499, 1), [200, 400]);
+  assert.deepStrictEqual(ticks(364, 1, 0.5), [200]);
+  assert.deepStrictEqual(ticks(0.001, 0.364, 0.5), [0.2]);
+  assert.deepStrictEqual(ticks(0.364, 0.001, 0.5), [0.2]);
+  assert.deepStrictEqual(ticks(-1, -364, 0.5), [-200]);
+  assert.deepStrictEqual(ticks(-364, -1, 0.5), [-200]);
+  assert.deepStrictEqual(ticks(-0.001, -0.364, 0.5), [-0.2]);
+  assert.deepStrictEqual(ticks(-0.364, -0.001, 0.5), [-0.2]);
+});