Configurable select direction

src/components/fx/layout_attributes.js

@@ -101,5 +101,17 @@ module.exports = {
             ].join(' ')
         },
         editType: 'none'
+    },
+    selectdirection: {
+        valType: 'enumerated',
+        role: 'info',
+        values: ['h', 'v', 'd', 'any'],
+        dflt: 'any',
+        description: [
+            'When "dragmode" is set to "select", this limits the selection of the drag to',
+            'horizontal, vertical or diagonal. "h" only allows horizontal selection,',
+            '"v" only vertical, "d" only diagonal and "any" sets no limit.'
+        ].join(' '),
+        editType: 'none'
     }
 };

src/components/fx/layout_defaults.js

@@ -16,7 +16,8 @@ module.exports = function supplyLayoutDefaults(layoutIn, layoutOut, fullData) {
         return Lib.coerce(layoutIn, layoutOut, layoutAttributes, attr, dflt);
     }
 
-    coerce('dragmode');
+    var dragMode = coerce('dragmode');
+    if(dragMode === 'select') coerce('selectdirection');
 
     var hovermodeDflt;
     if(layoutOut._has('cartesian')) {

src/plots/cartesian/select.js

@@ -200,7 +200,18 @@ function prepSelect(e, startX, startY, dragOptions, mode) {
             dy = Math.abs(y1 - y0);
 
         if(mode === 'select') {
-            if(dy < Math.min(dx * 0.6, MINSELECT)) {
+            var direction = fullLayout.selectdirection;
+
+            if(fullLayout.selectdirection === 'any') {
+                if(dy < Math.min(dx * 0.6, MINSELECT)) direction = 'h';
+                else if(dx < Math.min(dy * 0.6, MINSELECT)) direction = 'v';
+                else direction = 'd';
+            }
+            else {
+                direction = fullLayout.selectdirection;
+            }
+
+            if(direction === 'h') {
                 // horizontal motion: make a vertical box
                 currentPolygon = [[x0, 0], [x0, ph], [x1, ph], [x1, 0]];
                 currentPolygon.xmin = Math.min(x0, x1);
@@ -214,7 +225,7 @@ function prepSelect(e, startX, startY, dragOptions, mode) {
                     'h4v' + (2 * MINSELECT) + 'h-4Z');
 
             }
-            else if(dx < Math.min(dy * 0.6, MINSELECT)) {
+            else if(direction === 'v') {
                 // vertical motion: make a horizontal box
                 currentPolygon = [[0, y0], [0, y1], [pw, y1], [pw, y0]];
                 currentPolygon.xmin = Math.min(0, pw);
@@ -226,7 +237,7 @@ function prepSelect(e, startX, startY, dragOptions, mode) {
                     'M' + (x0 - MINSELECT) + ',' + (currentPolygon.ymax - 1) +
                     'v4h' + (2 * MINSELECT) + 'v-4Z');
             }
-            else {
+            else if(direction === 'd') {
                 // diagonal motion
                 currentPolygon = [[x0, y0], [x0, y1], [x1, y1], [x1, y0]];
                 currentPolygon.xmin = Math.min(x0, x1);

test/jasmine/tests/select_test.js

@@ -552,6 +552,69 @@ describe('@flaky Test select box and lasso in general:', function() {
         .catch(failTest)
         .then(done);
     });
+
+    it('should select the right data with the corresponding select direction', function(done) {
+
+        var gd = createGraphDiv();
+
+        // drag around just the center point, but if we have a selectdirection we may
+        // get either the ones to the left and right or above and below
+        var selectPath = [[175, 175], [225, 225]];
+
+        function selectDrag() {
+            resetEvents(gd);
+            drag(selectPath);
+            return selectedPromise;
+        }
+
+        function assertSelectedPointNumbers(pointNumbers) {
+            var pts = selectedData.points;
+            expect(pts.length).toBe(pointNumbers.length);
+            pointNumbers.forEach(function(pointNumber, i) {
+                expect(pts[i].pointNumber).toBe(pointNumber);
+            });
+        }
+
+        Plotly.newPlot(gd, [{
+            x: [1, 1, 1, 2, 2, 2, 3, 3, 3],
+            y: [1, 2, 3, 1, 2, 3, 1, 2, 3],
+            mode: 'markers'
+        }], {
+            width: 400,
+            height: 400,
+            dragmode: 'select',
+            margin: {l: 100, r: 100, t: 100, b: 100},
+            xaxis: {range: [0, 4]},
+            yaxis: {range: [0, 4]}
+        })
+        .then(selectDrag)
+        .then(function() {
+            expect(gd._fullLayout.selectdirection).toBe('any');
+            assertSelectedPointNumbers([4]);
+
+            return Plotly.relayout(gd, {selectdirection: 'h'});
+        })
+        .then(selectDrag)
+        .then(function() {
+            assertSelectedPointNumbers([3, 4, 5]);
+
+            return Plotly.relayout(gd, {selectdirection: 'v'});
+        })
+        .then(selectDrag)
+        .then(function() {
+            assertSelectedPointNumbers([1, 4, 7]);
+
+            return Plotly.relayout(gd, {selectdirection: 'd'});
+        })
+        .then(selectDrag)
+        .then(function() {
+            assertSelectedPointNumbers([4]);
+        })
+        .catch(failTest)
+        .then(done);
+
+    });
+
 });
 
 describe('@flaky Test select box and lasso per trace:', function() {

test/jasmine/tests/shapes_test.js

@@ -1026,7 +1026,7 @@ describe('A fixed size shape', function() {
 
     var shapeAndResizeTypes = combinations(shapeTypes, resizeTypes);
     shapeAndResizeTypes.forEach(function(testCase) {
-        describe('of type ' + testCase.type + ' can be ' + testCase.resizeDisplayName, function() {
+        describe('@flaky of type ' + testCase.type + ' can be ' + testCase.resizeDisplayName, function() {
             resizeDirections.forEach(function(direction) {
                 it('over direction ' + direction, function(done) {
                     layout.shapes[0].type = testCase.type;