Fix zoom out of chart with cursor outside chart container

.changeset/honest-bananas-suffer.md

@@ -0,0 +1,5 @@
+---
+"victory-zoom-container": patch
+---
+
+Fix: #2761 zoom out zooming in if cursor outside chart container

packages/victory-zoom-container/src/zoom-helpers.test.ts

@@ -0,0 +1,88 @@
+import { RawZoomHelpers } from "./zoom-helpers";
+
+describe("RawZoomHelpers.getMinimumDomain", () => {
+  afterEach(() => {
+    jest.restoreAllMocks();
+  });
+  it("should be calculating the minimum domain", () => {
+    jest.spyOn(RawZoomHelpers, "getDomain").mockImplementation(() => ({
+      x: [0, 100],
+    }));
+    expect(
+      RawZoomHelpers.getMinimumDomain(30, { minimumZoom: true }, "x"),
+    ).toStrictEqual([29.95, 30.05]);
+  });
+});
+
+describe("RawZoomHelpers.getScaledDomain", () => {
+  it("should scale the domain correctly with a zoom in factor", () => {
+    expectToBeCloseToArray(
+      RawZoomHelpers.getScaledDomain([0, 100], 0.9, 0.5),
+      [5, 95],
+    );
+  });
+  it("should scale the domain correctly with a zoom out factor", () => {
+    expectToBeCloseToArray(
+      RawZoomHelpers.getScaledDomain([0, 100], 1.1, 0.5),
+      [-5, 105],
+    );
+  });
+});
+
+describe("RawZoomHelpers.scale", () => {
+  afterEach(() => {
+    jest.restoreAllMocks();
+  });
+
+  it("should get the correct domain", () => {
+    jest.spyOn(RawZoomHelpers, "getDomain").mockImplementation(() => ({
+      x: [0, 100],
+    }));
+    jest.spyOn(RawZoomHelpers, "getScalePercent").mockImplementation(() => 0.5);
+    jest
+      .spyOn(RawZoomHelpers, "getMinimumDomain")
+      .mockImplementation(() => [29.955, 30.045]);
+
+    expectToBeCloseToArray(
+      RawZoomHelpers.scale([0, 100], { deltaY: -1 }, {}, "x"),
+      [0.166, 99.833],
+    );
+  });
+
+  it("should't change the domain when zooming out with max zoom out", () => {
+    jest.spyOn(RawZoomHelpers, "getDomain").mockImplementation(() => ({
+      x: [0, 100],
+    }));
+    jest.spyOn(RawZoomHelpers, "getScalePercent").mockImplementation(() => 0.1);
+    jest
+      .spyOn(RawZoomHelpers, "getMinimumDomain")
+      .mockImplementation(() => [29.955, 30.045]);
+
+    expectToBeCloseToArray(
+      RawZoomHelpers.scale([0, 100], { deltaY: 1 }, {}, "x"),
+      [0, 100],
+    );
+  });
+
+  it("should't change the domain when zooming out with max zoom out with the cursor outside the container boundary", () => {
+    jest.spyOn(RawZoomHelpers, "getDomain").mockImplementation(() => ({
+      x: [0, 100],
+    }));
+    jest
+      .spyOn(RawZoomHelpers, "getScalePercent")
+      .mockImplementation(() => -0.1);
+    jest
+      .spyOn(RawZoomHelpers, "getMinimumDomain")
+      .mockImplementation(() => [29.955, 30.045]);
+
+    expectToBeCloseToArray(
+      RawZoomHelpers.scale([0, 100], { deltaY: 1 }, {}, "x"),
+      [0, 100],
+    );
+  });
+});
+
+function expectToBeCloseToArray(actual, expected) {
+  expect(actual.length).toBe(expected.length);
+  actual.forEach((x, i) => expect(x).toBeCloseTo(expected[i]));
+}

packages/victory-zoom-container/src/zoom-helpers.ts

@@ -64,8 +64,8 @@ export const RawZoomHelpers = {
     const [from, to] = currentDomain;
     const range = Math.abs(to - from);
     const diff = range - range * factor;
-    const newMin = Number(from) + diff * percent;
-    const newMax = Number(to) - diff * (1 - percent);
+    const newMin = Number(from) + diff * Math.max(percent, 0);
+    const newMax = Number(to) - diff * Math.max(1 - percent, 0);
     return [Math.min(newMin, newMax), Math.max(newMin, newMax)];
   },