1852 persistent click via select points

src/components/fx/layout_attributes.js

@@ -18,6 +18,29 @@ fontAttrs.family.dflt = constants.HOVERFONT;
 fontAttrs.size.dflt = constants.HOVERFONTSIZE;
 
 module.exports = {
+    clickmode: {
+        valType: 'flaglist',
+        role: 'info',
+        flags: ['event', 'select'],
+        dflt: 'event',
+        editType: 'plot',
+        extras: ['none'],
+        description: [
+            'Determines the mode of single click interactions.',
+            '*event* is the default value and emits the `plotly_click`',
+            'event. In addition this mode emits the `plotly_selected` event',
+            'in drag modes *lasso* and *select*, but with no event data attached',
+            '(kept for compatibility reasons).',
+            'The *select* flag enables selecting single',
+            'data points via click. This mode also supports persistent selections,',
+            'meaning that pressing Shift while clicking, adds to / subtracts from an',
+            'existing selection. *select* with `hovermode`: *x* can be confusing, consider',
+            'explicitly setting `hovermode`: *closest* when using this feature.',
+            'Selection events are sent accordingly as long as *event* flag is set as well.',
+            'When the *event* flag is missing, `plotly_click` and `plotly_selected`',
+            'events are not fired.'
+        ].join(' ')
+    },
     dragmode: {
         valType: 'enumerated',
         role: 'info',
@@ -36,7 +59,16 @@ module.exports = {
         role: 'info',
         values: ['x', 'y', 'closest', false],
         editType: 'modebar',
-        description: 'Determines the mode of hover interactions.'
+        description: [
+            'Determines the mode of hover interactions.',
+            'If `clickmode` includes the *select* flag,',
+            '`hovermode` defaults to *closest*.',
+            'If `clickmode` lacks the *select* flag,',
+            'it defaults to *x* or *y* (depending on the trace\'s',
+            '`orientation` value) for plots based on',
+            'cartesian coordinates. For anything else the default',
+            'value is *closest*.',
+        ].join(' ')
     },
     hoverdistance: {
         valType: 'integer',

src/components/fx/layout_defaults.js

@@ -16,15 +16,21 @@ module.exports = function supplyLayoutDefaults(layoutIn, layoutOut, fullData) {
         return Lib.coerce(layoutIn, layoutOut, layoutAttributes, attr, dflt);
     }
 
+    var clickmode = coerce('clickmode');
+
     var dragMode = coerce('dragmode');
     if(dragMode === 'select') coerce('selectdirection');
 
     var hovermodeDflt;
     if(layoutOut._has('cartesian')) {
-        // flag for 'horizontal' plots:
-        // determines the state of the mode bar 'compare' hovermode button
-        layoutOut._isHoriz = isHoriz(fullData);
-        hovermodeDflt = layoutOut._isHoriz ? 'y' : 'x';
+        if(clickmode.indexOf('select') > -1) {
+            hovermodeDflt = 'closest';
+        } else {
+            // flag for 'horizontal' plots:
+            // determines the state of the mode bar 'compare' hovermode button
+            layoutOut._isHoriz = isHoriz(fullData);
+            hovermodeDflt = layoutOut._isHoriz ? 'y' : 'x';
+        }
     }
     else hovermodeDflt = 'closest';
 

src/lib/polygon.js

@@ -31,7 +31,11 @@ var polygon = module.exports = {};
  *          returns boolean: is pt inside the polygon (including on its edges)
  */
 polygon.tester = function tester(ptsIn) {
-    if(Array.isArray(ptsIn[0][0])) return polygon.multitester(ptsIn);
+
+    // Throw an error if any code tries to pass this no
+    // longer supported argument shape. The local multitester became
+    // obsolete when introducing click-to-select in PR #2944.
+    if(Array.isArray(ptsIn[0][0])) throw new Error('multitester called!');
 
     var pts = ptsIn.slice(),
         xmin = pts[0][0],
@@ -174,50 +178,6 @@ polygon.tester = function tester(ptsIn) {
     };
 };
 
-/**
- * Test multiple polygons
- */
-polygon.multitester = function multitester(list) {
-    var testers = [],
-        xmin = list[0][0][0],
-        xmax = xmin,
-        ymin = list[0][0][1],
-        ymax = ymin;
-
-    for(var i = 0; i < list.length; i++) {
-        var tester = polygon.tester(list[i]);
-        tester.subtract = list[i].subtract;
-        testers.push(tester);
-        xmin = Math.min(xmin, tester.xmin);
-        xmax = Math.max(xmax, tester.xmax);
-        ymin = Math.min(ymin, tester.ymin);
-        ymax = Math.max(ymax, tester.ymax);
-    }
-
-    function contains(pt, arg) {
-        var yes = false;
-        for(var i = 0; i < testers.length; i++) {
-            if(testers[i].contains(pt, arg)) {
-                // if contained by subtract polygon - exclude the point
-                yes = testers[i].subtract === false;
-            }
-        }
-
-        return yes;
-    }
-
-    return {
-        xmin: xmin,
-        xmax: xmax,
-        ymin: ymin,
-        ymax: ymax,
-        pts: [],
-        contains: contains,
-        isRect: false,
-        degenerate: false
-    };
-};
-
 /**
  * Test if a segment of a points array is bent or straight
  *

src/plots/cartesian/dragbox.js

@@ -30,6 +30,7 @@ var doTicksSingle = require('./axes').doTicksSingle;
 var getFromId = require('./axis_ids').getFromId;
 var prepSelect = require('./select').prepSelect;
 var clearSelect = require('./select').clearSelect;
+var selectOnClick = require('./select').selectOnClick;
 var scaleZoom = require('./scale_zoom');
 
 var constants = require('./constants');
@@ -148,7 +149,11 @@ function makeDragBox(gd, plotinfo, x, y, w, h, ns, ew) {
     };
 
     dragOptions.prepFn = function(e, startX, startY) {
+        var dragModePrev = dragOptions.dragmode;
         var dragModeNow = gd._fullLayout.dragmode;
+        if(dragModeNow !== dragModePrev) {
+            dragOptions.dragmode = dragModeNow;
+        }
 
         recomputeAxisLists();
 
@@ -178,7 +183,19 @@ function makeDragBox(gd, plotinfo, x, y, w, h, ns, ew) {
             prepSelect(e, startX, startY, dragOptions, dragModeNow);
         } else {
             dragOptions.clickFn = clickFn;
-            clearAndResetSelect();
+            if(isSelectOrLasso(dragModePrev)) {
+                // TODO Fix potential bug
+                // Note: clearing / resetting selection state only happens, when user
+                // triggers at least one interaction in pan/zoom mode. Otherwise, the
+                // select/lasso outlines are deleted (in plots.js.cleanPlot) but the selection
+                // cache isn't cleared. So when the user switches back to select/lasso and
+                // 'adds to a selection' with Shift, the "old", seemingly removed outlines
+                // are redrawn again because the selection cache still holds their coordinates.
+                // However, this isn't easily solved, since plots.js would need
+                // to have a reference to the dragOptions object (which holds the
+                // selection cache).
+                clearAndResetSelect();
+            }
 
             if(!allFixedRanges) {
                 if(dragModeNow === 'zoom') {
@@ -207,12 +224,20 @@ function makeDragBox(gd, plotinfo, x, y, w, h, ns, ew) {
     }
 
     function clickFn(numClicks, evt) {
+        var clickmode = gd._fullLayout.clickmode;
+
         removeZoombox(gd);
 
         if(numClicks === 2 && !singleEnd) doubleClick();
 
         if(isMainDrag) {
-            Fx.click(gd, evt, plotinfo.id);
+            if(clickmode.indexOf('select') > -1) {
+                selectOnClick(evt, gd, xaxes, yaxes, plotinfo.id, dragOptions);
+            }
+
+            if(clickmode.indexOf('event') > -1) {
+                Fx.click(gd, evt, plotinfo.id);
+            }
         }
         else if(numClicks === 1 && singleEnd) {
             var ax = ns ? ya0 : xa0,