Polar better angular tick label placement

src/components/colorbar/draw.js

@@ -434,7 +434,6 @@ module.exports = function draw(gd, id) {
 
                     var vals = Axes.calcTicks(cbAxisOut);
                     var transFn = Axes.makeTransFn(cbAxisOut);
-                    var labelFns = Axes.makeLabelFns(cbAxisOut, shift);
                     var tickSign = Axes.getTickSigns(cbAxisOut)[2];
 
                     Axes.drawTicks(gd, cbAxisOut, {
@@ -448,9 +447,7 @@ module.exports = function draw(gd, id) {
                         vals: vals,
                         layer: axisLayer,
                         transFn: transFn,
-                        labelXFn: labelFns.labelXFn,
-                        labelYFn: labelFns.labelYFn,
-                        labelAnchorFn: labelFns.labelAnchorFn
+                        labelFns: Axes.makeLabelFns(cbAxisOut, shift)
                     });
                 },
                 function() {

src/plots/cartesian/axes.js

@@ -1802,14 +1802,11 @@ axes.drawOne = function(gd, ax, opts) {
     // TODO: mirror labels, esp for subplots
 
     seq.push(function() {
-        var labelFns = axes.makeLabelFns(ax, mainLinePosition);
         return axes.drawLabels(gd, ax, {
             vals: vals,
             layer: mainAxLayer,
             transFn: transFn,
-            labelXFn: labelFns.labelXFn,
-            labelYFn: labelFns.labelYFn,
-            labelAnchorFn: labelFns.labelAnchorFn,
+            labelFns: axes.makeLabelFns(ax, mainLinePosition)
         });
     });
 
@@ -1821,8 +1818,6 @@ axes.drawOne = function(gd, ax, opts) {
         seq.push(function() {
             labelLength += getLabelLevelSpan(ax, axId + 'tick') + pad;
             labelLength += ax._tickAngles[axId + 'tick'] ? ax.tickfont.size * LINE_SPACING : 0;
-            var secondaryPosition = mainLinePosition + labelLength * sgn;
-            var secondaryLabelFns = axes.makeLabelFns(ax, secondaryPosition);
 
             return axes.drawLabels(gd, ax, {
                 vals: getSecondaryLabelVals(ax, vals),
@@ -1831,9 +1826,7 @@ axes.drawOne = function(gd, ax, opts) {
                 repositionOnUpdate: true,
                 secondary: true,
                 transFn: transFn,
-                labelXFn: secondaryLabelFns.labelXFn,
-                labelYFn: secondaryLabelFns.labelYFn,
-                labelAnchorFn: secondaryLabelFns.labelAnchorFn,
+                labelFns: axes.makeLabelFns(ax, mainLinePosition + labelLength * sgn)
             });
         });
 
@@ -2178,66 +2171,79 @@ axes.makeTickPath = function(ax, shift, sgn, len) {
  * @param {number} shift
  * @param {number} angle [in degrees] ...
  * @return {object}
- *  - {fn} labelXFn
- *  - {fn} labelYFn
- *  - {fn} labelAnchorFn
- *  - {number} labelStandoff
- *  - {number} labelShift
+ *  - {fn} xFn
+ *  - {fn} yFn
+ *  - {fn} anchorFn
+ *  - {fn} heightFn
+ *  - {number} labelStandoff (gap parallel to ticks)
+ *  - {number} labelShift (gap perpendicular to ticks)
  */
 axes.makeLabelFns = function(ax, shift, angle) {
     var axLetter = ax._id.charAt(0);
-    var pad = (ax.linewidth || 1) / 2;
     var ticksOnOutsideLabels = ax.tickson !== 'boundaries' && ax.ticks === 'outside';
 
-    var labelStandoff = ticksOnOutsideLabels ? ax.ticklen : 0;
+    var labelStandoff = 0;
     var labelShift = 0;
 
+    if(ticksOnOutsideLabels) {
+        labelStandoff += ax.ticklen;
+    }
     if(angle && ax.ticks === 'outside') {
         var rad = Lib.deg2rad(angle);
         labelStandoff = ax.ticklen * Math.cos(rad) + 1;
         labelShift = ax.ticklen * Math.sin(rad);
     }
-
     if(ax.showticklabels && (ticksOnOutsideLabels || ax.showline)) {
         labelStandoff += 0.2 * ax.tickfont.size;
     }
+    labelStandoff += (ax.linewidth || 1) / 2;
 
-    // Used in polar angular label x/y functions
-    // TODO generalize makeLabelFns so that it just work for angular axes
     var out = {
         labelStandoff: labelStandoff,
         labelShift: labelShift
     };
 
     var x0, y0, ff, flipIt;
+
     if(axLetter === 'x') {
         flipIt = ax.side === 'bottom' ? 1 : -1;
         x0 = labelShift * flipIt;
-        y0 = shift + (labelStandoff + pad) * flipIt;
+        y0 = shift + labelStandoff * flipIt;
         ff = ax.side === 'bottom' ? 1 : -0.2;
 
-        out.labelXFn = function(d) { return d.dx + x0; };
-        out.labelYFn = function(d) { return d.dy + y0 + d.fontSize * ff; };
-        out.labelAnchorFn = function(a) {
+        out.xFn = function(d) { return d.dx + x0; };
+        out.yFn = function(d) { return d.dy + y0 + d.fontSize * ff; };
+        out.anchorFn = function(d, a) {
             if(!isNumeric(a) || a === 0 || a === 180) {
                 return 'middle';
             }
             return (a * flipIt < 0) ? 'end' : 'start';
         };
+        out.heightFn = function(d, a, h) {
+            return (a < -60 || a > 60) ? -0.5 * h :
+                ax.side === 'top' ? -h :
+                0;
+        };
     } else if(axLetter === 'y') {
         flipIt = ax.side === 'right' ? 1 : -1;
-        x0 = labelStandoff + pad;
+        x0 = labelStandoff;
         y0 = -labelShift * flipIt;
         ff = Math.abs(ax.tickangle) === 90 ? 0.5 : 0;
 
-        out.labelXFn = function(d) { return d.dx + shift + (x0 + d.fontSize * ff) * flipIt; };
-        out.labelYFn = function(d) { return d.dy + y0 + d.fontSize * MID_SHIFT; };
-        out.labelAnchorFn = function(a) {
+        out.xFn = function(d) { return d.dx + shift + (x0 + d.fontSize * ff) * flipIt; };
+        out.yFn = function(d) { return d.dy + y0 + d.fontSize * MID_SHIFT; };
+        out.anchorFn = function(d, a) {
             if(isNumeric(a) && Math.abs(a) === 90) {
                 return 'middle';
             }
             return ax.side === 'right' ? 'start' : 'end';
         };
+        out.heightFn = function(d, a, h) {
+            a *= ax.side === 'left' ? 1 : -1;
+            return a < -30 ? -h :
+                a < 30 ? -0.5 * h :
+                0;
+        };
     }
 
     return out;
@@ -2412,9 +2418,11 @@ axes.drawZeroLine = function(gd, ax, opts) {
  * - {boolean} repositionOnUpdate (set to true to reposition update selection)
  * - {boolean} secondary
  * - {fn} transFn
- * - {fn} labelXFn
- * - {fn} labelYFn
- * - {fn} labelAnchorFn
+ * - {object} labelFns
+ *  + {fn} xFn
+ *  + {fn} yFn
+ *  + {fn} anchorFn
+ *  + {fn} heightFn
  */
 axes.drawLabels = function(gd, ax, opts) {
     opts = opts || {};
@@ -2423,9 +2431,7 @@ axes.drawLabels = function(gd, ax, opts) {
     var axLetter = axId.charAt(0);
     var cls = opts.cls || axId + 'tick';
     var vals = opts.vals;
-    var labelXFn = opts.labelXFn;
-    var labelYFn = opts.labelYFn;
-    var labelAnchorFn = opts.labelAnchorFn;
+    var labelFns = opts.labelFns;
     var tickAngle = opts.secondary ? 0 : ax.tickangle;
     var lastAngle = (ax._tickAngles || {})[cls];
 
@@ -2445,7 +2451,7 @@ axes.drawLabels = function(gd, ax, opts) {
                 var newPromise = gd._promises.length;
 
                 thisLabel
-                    .call(svgTextUtils.positionText, labelXFn(d), labelYFn(d))
+                    .call(svgTextUtils.positionText, labelFns.xFn(d), labelFns.yFn(d))
                     .call(Drawing.font, d.font, d.fontSize, d.fontColor)
                     .text(d.text)
                     .call(svgTextUtils.convertToTspans, gd);
@@ -2469,47 +2475,26 @@ axes.drawLabels = function(gd, ax, opts) {
     if(opts.repositionOnUpdate) {
         tickLabels.each(function(d) {
             d3.select(this).select('text')
-                .call(svgTextUtils.positionText, labelXFn(d), labelYFn(d));
+                .call(svgTextUtils.positionText, labelFns.xFn(d), labelFns.yFn(d));
         });
     }
 
-    // How much to shift a multi-line label to center it vertically.
-    function getAnchorHeight(lineCount, lineHeight, angle) {
-        var h = (lineCount - 1) * lineHeight;
-        if(axLetter === 'x') {
-            if(angle < -60 || 60 < angle) {
-                return -0.5 * h;
-            } else if(ax.side === 'top') {
-                return -h;
-            }
-        } else {
-            angle *= ax.side === 'left' ? 1 : -1;
-            if(angle < -30) {
-                return -h;
-            } else if(angle < 30) {
-                return -0.5 * h;
-            }
-        }
-        return 0;
-    }
-
     function positionLabels(s, angle) {
         s.each(function(d) {
             var thisLabel = d3.select(this);
             var mathjaxGroup = thisLabel.select('.text-math-group');
-            var anchor = labelAnchorFn(angle, d);
+            var anchor = labelFns.anchorFn(d, angle);
 
             var transform = opts.transFn.call(thisLabel.node(), d) +
                 ((isNumeric(angle) && +angle !== 0) ?
-                (' rotate(' + angle + ',' + labelXFn(d) + ',' +
-                    (labelYFn(d) - d.fontSize / 2) + ')') :
+                (' rotate(' + angle + ',' + labelFns.xFn(d) + ',' +
+                    (labelFns.yFn(d) - d.fontSize / 2) + ')') :
                 '');
 
-            var anchorHeight = getAnchorHeight(
-                svgTextUtils.lineCount(thisLabel),
-                LINE_SPACING * d.fontSize,
-                isNumeric(angle) ? +angle : 0
-            );
+            // how much to shift a multi-line label to center it vertically.
+            var nLines = svgTextUtils.lineCount(thisLabel);
+            var lineHeight = LINE_SPACING * d.fontSize;
+            var anchorHeight = labelFns.heightFn(d, isNumeric(angle) ? +angle : 0, (nLines - 1) * lineHeight);
 
             if(anchorHeight) {
                 transform += ' translate(0, ' + anchorHeight + ')';

src/plots/polar/polar.js

@@ -404,7 +404,6 @@ proto.updateRadialAxis = function(fullLayout, polarLayout) {
 
         var vals = Axes.calcTicks(ax);
         var valsClipped = Axes.clipEnds(ax, vals);
-        var labelFns = Axes.makeLabelFns(ax, 0);
         var tickSign = Axes.getTickSigns(ax)[2];
 
         Axes.drawTicks(gd, ax, {
@@ -427,9 +426,7 @@ proto.updateRadialAxis = function(fullLayout, polarLayout) {
             vals: vals,
             layer: layers['radial-axis'],
             transFn: transFn,
-            labelXFn: labelFns.labelXFn,
-            labelYFn: labelFns.labelYFn,
-            labelAnchorFn: labelFns.labelAnchorFn
+            labelFns: Axes.makeLabelFns(ax, 0)
         });
     }
 
@@ -556,36 +553,31 @@ proto.updateAngularAxis = function(fullLayout, polarLayout) {
 
     var out = Axes.makeLabelFns(ax, 0);
     var labelStandoff = out.labelStandoff;
-    var labelShift = out.labelShift;
-    var offset4fontsize = (angularLayout.ticks !== 'outside' ? 0.7 : 0.5);
-    var pad = (ax.linewidth || 1) / 2;
+    var labelFns = {};
 
-    var labelXFn = function(d) {
+    labelFns.xFn = function(d) {
         var rad = t2g(d);
-
-        var offset4tx = signSin(rad) === 0 ?
-            0 :
-            Math.cos(rad) * (labelStandoff + pad + offset4fontsize * d.fontSize);
-        var offset4tick = signCos(rad) * (d.dx + labelStandoff + pad);
-
-        return offset4tx + offset4tick;
+        return Math.cos(rad) * labelStandoff;
     };
 
-    var labelYFn = function(d) {
+    labelFns.yFn = function(d) {
         var rad = t2g(d);
+        var ff = Math.sin(rad) > 0 ? 0.2 : 1;
+        return -Math.sin(rad) * (labelStandoff + d.fontSize * ff) +
+            Math.abs(Math.cos(rad)) * (d.fontSize * MID_SHIFT);
+    };
 
-        var offset4tx = d.dy + d.fontSize * MID_SHIFT - labelShift;
-        var offset4tick = -Math.sin(rad) * (labelStandoff + pad + offset4fontsize * d.fontSize);
-
-        return offset4tx + offset4tick;
+    labelFns.anchorFn = function(d) {
+        var rad = t2g(d);
+        var cos = Math.cos(rad);
+        return Math.abs(cos) < 0.1 ?
+            'middle' :
+            (cos > 0 ? 'start' : 'end');
     };
 
-    // TODO maybe switch angle, d ordering ??
-    var labelAnchorFn = function(angle, d) {
+    labelFns.heightFn = function(d, a, h) {
         var rad = t2g(d);
-        return signSin(rad) === 0 ?
-            (signCos(rad) > 0 ? 'start' : 'end') :
-            'middle';
+        return -0.5 * (1 + Math.sin(rad)) * h;
     };
 
     var newTickLayout = strTickLayout(angularLayout);
@@ -623,6 +615,7 @@ proto.updateAngularAxis = function(fullLayout, polarLayout) {
 
     if(ax.visible) {
         var tickSign = ax.ticks === 'inside' ? -1 : 1;
+        var pad = (ax.linewidth || 1) / 2;
 
         Axes.drawTicks(gd, ax, {
             vals: vals,
@@ -645,9 +638,7 @@ proto.updateAngularAxis = function(fullLayout, polarLayout) {
             layer: layers['angular-axis'],
             repositionOnUpdate: true,
             transFn: transFn,
-            labelXFn: labelXFn,
-            labelYFn: labelYFn,
-            labelAnchorFn: labelAnchorFn
+            labelFns: labelFns
         });
     }
 
@@ -1413,18 +1404,3 @@ function strTranslate(x, y) {
 function strRotate(angle) {
     return 'rotate(' + angle + ')';
 }
-
-// because Math.sign(Math.cos(Math.PI / 2)) === 1
-// oh javascript ;)
-function sign(v) {
-    return Math.abs(v) < 1e-10 ? 0 :
-        v > 0 ? 1 : -1;
-}
-
-function signCos(v) {
-    return sign(Math.cos(v));
-}
-
-function signSin(v) {
-    return sign(Math.sin(v));
-}

src/plots/ternary/ternary.js

@@ -459,15 +459,11 @@ proto.drawAx = function(ax) {
         crisp: false
     });
 
-    var labelFns = Axes.makeLabelFns(ax, 0, counterAngle);
-
     Axes.drawLabels(gd, ax, {
         vals: vals,
         layer: axLayer,
         transFn: transFn,
-        labelXFn: labelFns.labelXFn,
-        labelYFn: labelFns.labelYFn,
-        labelAnchorFn: labelFns.labelAnchorFn
+        labelFns: Axes.makeLabelFns(ax, 0, counterAngle)
     });
 };