don’t allow margins or insets to invert range (#640)

Author: mbostock

src/scales.js

@@ -74,7 +74,9 @@ function autoScaleRangeX(scale, dimensions) {
   if (scale.range === undefined) {
     const {insetLeft, insetRight} = scale;
     const {width, marginLeft = 0, marginRight = 0} = dimensions;
-    scale.range = [marginLeft + insetLeft, width - marginRight - insetRight];
+    const left = marginLeft + insetLeft;
+    const right = width - marginRight - insetRight;
+    scale.range = [left, Math.max(left, right)];
     if (!isOrdinalScale(scale)) scale.range = piecewiseRange(scale);
     scale.scale.range(scale.range);
   }
@@ -85,7 +87,9 @@ function autoScaleRangeY(scale, dimensions) {
   if (scale.range === undefined) {
     const {insetTop, insetBottom} = scale;
     const {height, marginTop = 0, marginBottom = 0} = dimensions;
-    scale.range = [height - marginBottom - insetBottom, marginTop + insetTop];
+    const top = marginTop + insetTop;
+    const bottom = height - marginBottom - insetBottom;
+    scale.range = [Math.max(top, bottom), top];
     if (!isOrdinalScale(scale)) scale.range = piecewiseRange(scale);
     else scale.range.reverse();
     scale.scale.range(scale.range);

test/scales/scales-test.js

@@ -1091,6 +1091,16 @@ it("plot(…).scale('opacity') respects the percent option, affecting domain and
   });
 });
 
+it("plot({inset, …}).scale('x') does not allow insets or margins to invert the range", () => {
+  assert.deepStrictEqual(Plot.plot({x: {inset: 60}, width: 100}).scale("x").range, [80, 80]);
+  assert.deepStrictEqual(Plot.plot({x: {inset: 30}, margin: 30, width: 100}).scale("x").range, [60, 60]);
+});
+
+it("plot({inset, …}).scale('y') does not allow insets or margins to invert the range", () => {
+  assert.deepStrictEqual(Plot.plot({y: {inset: 60}, height: 100}).scale("y").range, [80, 80]);
+  assert.deepStrictEqual(Plot.plot({y: {inset: 30}, margin: 30, height: 100}).scale("y").range, [60, 60]);
+});
+
 it("plot({inset, …}).scale('x').range respects the given top-level inset", () => {
   assert.deepStrictEqual(Plot.dot([1, 2, 3], {x: d => d}).plot({inset: 0}).scale("x").range, [20, 620]);
   assert.deepStrictEqual(Plot.dot([1, 2, 3], {x: d => d}).plot({inset: 7}).scale("x").range, [27, 613]);