Fix directional axis automargin anchors

Preserve anchor coordinates when filtering margin directions so enabled right and top margins can grow. Add regression coverage for anchored and free axes, disabled margins, and clipped labels. Refs #8073
FistOfMight · Sep 29, 2026 · Sep 29, 2026 · Sep 29, 2026 · 16d93d86c26cb9472b47b91cc0f53ded13d255b9
commit 16d93d86c26cb9472b47b91cc0f53ded13d255b9
diff --git a/draftlogs/LOCAL_PR_fix.md b/draftlogs/LOCAL_PR_fix.md
@@ -0,0 +1 @@
+- Fix directional axis automargins that discard anchor coordinates and clip labels [[#LOCAL_PR](https://github.com/plotly/plotly.js/pull/LOCAL_PR)]
diff --git a/src/plots/cartesian/axes.js b/src/plots/cartesian/axes.js
@@ -3015,12 +3015,13 @@ axes.drawOne = function(gd, ax, opts) {
 function filterPush(push, automargin) {
     if(!push) return;
 
-    var keepMargin = Object.keys(MARGIN_MAPPING).reduce(function(data, nextKey) {
+    // Anchor coordinates locate enabled margin constraints. They do not enable margin growth.
+    const keepMargin = Object.keys(MARGIN_MAPPING).reduce((data, nextKey) => {
         if(automargin.indexOf(nextKey) !== -1) {
             MARGIN_MAPPING[nextKey].forEach(function(key) { data[key] = 1;});
         }
         return data;
-    }, {});
+    }, { x: 1, y: 1 });
     Object.keys(push).forEach(function(key) {
         if(!keepMargin[key]) {
             if(key.length === 1) push[key] = 0;

diff --git a/test/jasmine/tests/axes_test.js b/test/jasmine/tests/axes_test.js
@@ -4687,6 +4687,73 @@ describe('Test axes', function() {
             .then(done, done.fail);
         });
 
+        ['right', 'left', 'top', 'bottom'].forEach((side) => {
+            [false, true].forEach((free) => {
+                it(`preserves ${side} anchors for ${free ? 'free' : 'anchored'} partial automargin`, async () => {
+                    const vertical = side === 'right' || side === 'left';
+                    const axis = vertical ? 'yaxis' : 'xaxis';
+                    const id = vertical ? 'y' : 'x';
+                    const edge = side[0];
+                    const fraction = side === 'right' || side === 'top' ? 1 : 0;
+                    const layout = {
+                        width: 500,
+                        height: 300,
+                        margin: { l: 0, r: 0, t: 0, b: 0 },
+                        xaxis: { range: [0, 4], visible: !vertical },
+                        yaxis: { range: [0, 4], visible: vertical }
+                    };
+                    layout[axis] = {
+                        range: [0, 4],
+                        side,
+                        automargin: true,
+                        tickvals: [1, 2, 3],
+                        ticktext: ['Long label', 'Long label', 'Long label'],
+                        tickangle: 0,
+                        ...(free ? { anchor: 'free', position: fraction } : {})
+                    };
+                    await Plotly.newPlot(gd, [{ x: [1, 2, 3], y: [1, 2, 3] }], layout);
+                    const automatic = gd._fullLayout._size[edge];
+                    expect(automatic).toBeGreaterThan(0);
+
+                    for (const flag of [side, vertical ? 'width' : 'height']) {
+                        await Plotly.relayout(gd, { [`${axis}.automargin`]: flag });
+                        expect(gd._fullLayout._size[edge]).toBe(automatic);
+                        expect(gd._fullLayout._pushmargin[`${id}.automargin`][edge].val).toBe(fraction);
+                        for (const other of ['l', 'r', 't', 'b'].filter((value) => value !== edge)) {
+                            expect(gd._fullLayout._size[other]).toBe(0);
+                        }
+                    }
+
+                    await Plotly.relayout(gd, { [`${axis}.automargin`]: vertical ? 'height' : 'width' });
+                    expect(gd._fullLayout._size[edge]).toBe(0);
+                    await Plotly.relayout(gd, { [`${axis}.automargin`]: true });
+                    expect(gd._fullLayout._size[edge]).toBe(automatic);
+                    await Plotly.relayout(gd, { [`${axis}.automargin`]: false });
+                    expect(gd._fullLayout._size[edge]).toBe(0);
+                });
+            });
+        });
+
+        it('keeps right-side labels inside the paper when left automargin is excluded', async () => {
+            await Plotly.newPlot(gd, [{ x: [0, 1, 2], y: [1000, 2000, 3000] }], {
+                width: 500,
+                height: 300,
+                margin: { l: 40, r: 0, t: 30, b: 40 },
+                yaxis: { side: 'right', automargin: 'right+top+bottom', tickformat: '.0f' }
+            });
+            const rightMargin = gd._fullLayout._size.r;
+            expect(rightMargin).toBeGreaterThan(0);
+            expect(gd._fullLayout._size.l).toBe(40);
+            const paper = gd.querySelector('.main-svg').getBoundingClientRect();
+            const labels = gd.querySelectorAll('.ytick text');
+            expect(labels.length).toBeGreaterThan(0);
+            labels.forEach((label) => {
+                expect(label.getBoundingClientRect().right).toBeLessThanOrEqual(paper.right + 0.5);
+            });
+            await Plotly.relayout(gd, { 'yaxis.automargin': true });
+            expect(gd._fullLayout._size.r).toBe(rightMargin);
+        });
+
         it('should handle partial automargin', function(done) {
             var initialSize;
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		- Fix directional axis automargins that discard anchor coordinates and clip labels [[#LOCAL_PR](https://github.com/plotly/plotly.js/pull/LOCAL_PR)]