fix #2233 - smoothed coloring and hover data for nonuniform bricks

Author: alexcjohnson

src/traces/heatmap/calc.js

@@ -115,19 +115,27 @@ module.exports = function calc(gd, trace) {
     }
 
     // create arrays of brick boundaries, to be used by autorange and heatmap.plot
-    var xlen = maxRowLength(z),
-        xIn = trace.xtype === 'scaled' ? '' : x,
-        xArray = makeBoundArray(trace, xIn, x0, dx, xlen, xa),
-        yIn = trace.ytype === 'scaled' ? '' : y,
-        yArray = makeBoundArray(trace, yIn, y0, dy, z.length, ya);
+    var xlen = maxRowLength(z);
+    var xIn = trace.xtype === 'scaled' ? '' : x;
+    var xArray = makeBoundArray(trace, xIn, x0, dx, xlen, xa);
+    var yIn = trace.ytype === 'scaled' ? '' : y;
+    var yArray = makeBoundArray(trace, yIn, y0, dy, z.length, ya);
 
     // handled in gl2d convert step
     if(!isGL2D) {
         Axes.expand(xa, xArray);
         Axes.expand(ya, yArray);
     }
 
-    var cd0 = {x: xArray, y: yArray, z: z, text: trace.text};
+    var cd0 = {
+        x: xArray,
+        y: yArray,
+        z: z,
+        text: trace.text
+    };
+
+    if(xIn && xIn.length === xArray.length - 1) cd0.xCenter = xIn;
+    if(yIn && yIn.length === yArray.length - 1) cd0.yCenter = yIn;
 
     if(isHist) {
         cd0.xRanges = binned.xRanges;

src/traces/heatmap/hover.js

@@ -19,22 +19,22 @@ module.exports = function hoverPoints(pointData, xval, yval, hovermode, hoverLay
     // never let a heatmap override another type as closest point
     if(pointData.distance < MAXDIST) return;
 
-    var cd0 = pointData.cd[0],
-        trace = cd0.trace,
-        xa = pointData.xa,
-        ya = pointData.ya,
-        x = cd0.x,
-        y = cd0.y,
-        z = cd0.z,
-        zmask = cd0.zmask,
-        range = [trace.zmin, trace.zmax],
-        zhoverformat = trace.zhoverformat,
-        x2 = x,
-        y2 = y,
-        xl,
-        yl,
-        nx,
-        ny;
+    var cd0 = pointData.cd[0];
+    var trace = cd0.trace;
+    var xa = pointData.xa;
+    var ya = pointData.ya;
+    var x = cd0.x;
+    var y = cd0.y;
+    var z = cd0.z;
+    var xc = cd0.xCenter;
+    var yc = cd0.yCenter;
+    var zmask = cd0.zmask;
+    var range = [trace.zmin, trace.zmax];
+    var zhoverformat = trace.zhoverformat;
+    var x2 = x;
+    var y2 = y;
+
+    var xl, yl, nx, ny;
 
     if(pointData.index !== false) {
         try {
@@ -86,11 +86,11 @@ module.exports = function hoverPoints(pointData, xval, yval, hovermode, hoverLay
         yl = y[ny];
     }
     else {
-        xl = (x[nx] + x[nx + 1]) / 2;
-        yl = (y[ny] + y[ny + 1]) / 2;
+        xl = xc ? xc[nx] : ((x[nx] + x[nx + 1]) / 2);
+        yl = yc ? yc[ny] : ((y[ny] + y[ny + 1]) / 2);
         if(trace.zsmooth) {
-            x0 = x1 = (x0 + x1) / 2;
-            y0 = y1 = (y0 + y1) / 2;
+            x0 = x1 = xa.c2p(xl);
+            y0 = y1 = ya.c2p(yl);
         }
     }
 

src/traces/heatmap/plot.js

@@ -25,14 +25,14 @@ module.exports = function(gd, plotinfo, cdheatmaps) {
     }
 };
 
-// From http://www.xarg.org/2010/03/generate-client-side-png-files-using-javascript/
 function plotOne(gd, plotinfo, cd) {
-    var trace = cd[0].trace,
-        uid = trace.uid,
-        xa = plotinfo.xaxis,
-        ya = plotinfo.yaxis,
-        fullLayout = gd._fullLayout,
-        id = 'hm' + uid;
+    var cd0 = cd[0];
+    var trace = cd0.trace;
+    var uid = trace.uid;
+    var xa = plotinfo.xaxis;
+    var ya = plotinfo.yaxis;
+    var fullLayout = gd._fullLayout;
+    var id = 'hm' + uid;
 
     // in case this used to be a contour map
     fullLayout._paper.selectAll('.contour' + uid).remove();
@@ -45,23 +45,21 @@ function plotOne(gd, plotinfo, cd) {
         return;
     }
 
-    var z = cd[0].z,
-        x = cd[0].x,
-        y = cd[0].y,
-        isContour = Registry.traceIs(trace, 'contour'),
-        zsmooth = isContour ? 'best' : trace.zsmooth,
-
-        // get z dims
-        m = z.length,
-        n = maxRowLength(z),
-        xrev = false,
-        left,
-        right,
-        temp,
-        yrev = false,
-        top,
-        bottom,
-        i;
+    var z = cd0.z;
+    var x = cd0.x;
+    var y = cd0.y;
+    var xc = cd0.xCenter;
+    var yc = cd0.yCenter;
+    var isContour = Registry.traceIs(trace, 'contour');
+    var zsmooth = isContour ? 'best' : trace.zsmooth;
+
+    // get z dims
+    var m = z.length;
+    var n = maxRowLength(z);
+    var xrev = false;
+    var yrev = false;
+
+    var left, right, temp, top, bottom, i;
 
     // TODO: if there are multiple overlapping categorical heatmaps,
     // or if we allow category sorting, then the categories may not be
@@ -113,11 +111,10 @@ function plotOne(gd, plotinfo, cd) {
     // for contours with heatmap fill, we generate the boundaries based on
     // brick centers but then use the brick edges for drawing the bricks
     if(isContour) {
-        // TODO: for 'best' smoothing, we really should use the given brick
-        // centers as well as brick bounds in calculating values, in case of
-        // nonuniform brick sizes
-        x = cd[0].xfill;
-        y = cd[0].yfill;
+        xc = x;
+        yc = y;
+        x = cd0.xfill;
+        y = cd0.yfill;
     }
 
     // make an image that goes at most half a screen off either side, to keep
@@ -201,15 +198,15 @@ function plotOne(gd, plotinfo, cd) {
 
     // get interpolated bin value. Returns {bin0:closest bin, frac:fractional dist to next, bin1:next bin}
     function findInterp(pixel, pixArray) {
-        var maxbin = pixArray.length - 2,
-            bin = Lib.constrain(Lib.findBin(pixel, pixArray), 0, maxbin),
-            pix0 = pixArray[bin],
-            pix1 = pixArray[bin + 1],
-            interp = Lib.constrain(bin + (pixel - pix0) / (pix1 - pix0) - 0.5, 0, maxbin),
-            bin0 = Math.round(interp),
-            frac = Math.abs(interp - bin0);
-
-        if(!interp || interp === maxbin || !frac) {
+        var maxBin = pixArray.length - 2;
+        var bin = Lib.constrain(Lib.findBin(pixel, pixArray), 0, maxBin);
+        var pix0 = pixArray[bin];
+        var pix1 = pixArray[bin + 1];
+        var interp = Lib.constrain(bin + (pixel - pix0) / (pix1 - pix0) - 0.5, 0, maxBin);
+        var bin0 = Math.round(interp);
+        var frac = Math.abs(interp - bin0);
+
+        if(!interp || interp === maxBin || !frac) {
             return {
                 bin0: bin0,
                 bin1: bin0,
@@ -223,6 +220,36 @@ function plotOne(gd, plotinfo, cd) {
         };
     }
 
+    function findInterpFromCenters(pixel, centerPixArray) {
+        // if(pixel <= centerPixArray[0]) return {bin0: 0, bin1: 0, frac: 0};
+        var maxBin = centerPixArray.length - 1;
+        // if(pixel >= centerPixArray[lastCenter]) return {bin0: lastCenter, bin1: lastCenter, frac: 0};
+
+        var bin = Lib.constrain(Lib.findBin(pixel, centerPixArray), 0, maxBin);
+        var pix0 = centerPixArray[bin];
+        var pix1 = centerPixArray[bin + 1];
+        var frac = ((pixel - pix0) / (pix1 - pix0)) || 0;
+        if(frac <= 0) {
+            return {
+                bin0: bin,
+                bin1: bin,
+                frac: 0
+            };
+        }
+        if(frac < 0.5) {
+            return {
+                bin0: bin,
+                bin1: bin + 1,
+                frac: frac
+            };
+        }
+        return {
+            bin0: bin + 1,
+            bin1: bin,
+            frac: 1 - frac
+        };
+    }
+
     // build the pixel map brick-by-brick
     // cruise through z-matrix row-by-row
     // build a brick at each z-matrix value
@@ -303,24 +330,26 @@ function plotOne(gd, plotinfo, cd) {
         }
 
         if(zsmooth === 'best') {
-            var xPixArray = new Array(x.length),
-                yPixArray = new Array(y.length),
-                xinterpArray = new Array(imageWidth),
-                yinterp,
-                r0,
-                r1;
+            var xForPx = xc || x;
+            var yForPx = yc || y;
+            var xPixArray = new Array(xForPx.length);
+            var yPixArray = new Array(yForPx.length);
+            var xinterpArray = new Array(imageWidth);
+            var findInterpX = xc ? findInterpFromCenters : findInterp;
+            var findInterpY = yc ? findInterpFromCenters : findInterp;
+            var yinterp, r0, r1;
 
             // first make arrays of x and y pixel locations of brick boundaries
-            for(i = 0; i < x.length; i++) xPixArray[i] = Math.round(xa.c2p(x[i]) - left);
-            for(i = 0; i < y.length; i++) yPixArray[i] = Math.round(ya.c2p(y[i]) - top);
+            for(i = 0; i < xForPx.length; i++) xPixArray[i] = Math.round(xa.c2p(xForPx[i]) - left);
+            for(i = 0; i < yForPx.length; i++) yPixArray[i] = Math.round(ya.c2p(yForPx[i]) - top);
 
             // then make arrays of interpolations
             // (bin0=closest, bin1=next, frac=fractional dist.)
-            for(i = 0; i < imageWidth; i++) xinterpArray[i] = findInterp(i, xPixArray);
+            for(i = 0; i < imageWidth; i++) xinterpArray[i] = findInterpX(i, xPixArray);
 
             // now do the interpolations and fill the png
             for(j = 0; j < imageHeight; j++) {
-                yinterp = findInterp(j, yPixArray);
+                yinterp = findInterpY(j, yPixArray);
                 r0 = z[yinterp.bin0];
                 r1 = z[yinterp.bin1];
                 for(i = 0; i < imageWidth; i++, pxIndex += 4) {

test/image/baselines/heatmap_contour_irregular_bricks.png

@@ -0,0 +1,32 @@
+{
+    "data": [
+        {
+            "x": [0, 10, 12],
+            "y": [10, 12, 0],
+            "z": [1, 2, 3],
+            "zsmooth": "best",
+            "type": "heatmap",
+            "colorscale": "Cividis",
+            "colorbar": {"x": 0.42}
+        },
+        {
+            "x": [0, 10, 12],
+            "y": [10, 12, 0],
+            "z": [1, 2, 3],
+            "contours": {"coloring": "heatmap"},
+            "line": {"color": "#fff"},
+            "colorscale": "Cividis",
+            "type": "contour",
+            "xaxis": "x2",
+            "yaxis": "y2"
+        }
+    ],
+    "layout": {
+        "title": "heatmap and contour map with irregular bricks",
+        "xaxis": {"domain": [0, 0.4]},
+        "xaxis2": {"domain": [0.6, 1]},
+        "yaxis2": {"anchor": "x2"},
+        "height": 400,
+        "width": 800
+    }
+}

test/image/mocks/heatmap_contour_irregular_bricks.json

@@ -594,10 +594,10 @@ describe('heatmap hover', function() {
     }
 
     function assertLabels(hoverPoint, xLabel, yLabel, zLabel, text) {
-        expect(hoverPoint.xLabelVal).toEqual(xLabel, 'have correct x label');
-        expect(hoverPoint.yLabelVal).toEqual(yLabel, 'have correct y label');
-        expect(hoverPoint.zLabelVal).toEqual(zLabel, 'have correct z label');
-        expect(hoverPoint.text).toEqual(text, 'have correct text label');
+        expect(hoverPoint.xLabelVal).toBe(xLabel, 'have correct x label');
+        expect(hoverPoint.yLabelVal).toBe(yLabel, 'have correct y label');
+        expect(hoverPoint.zLabelVal).toBe(zLabel, 'have correct z label');
+        expect(hoverPoint.text).toBe(text, 'have correct text label');
     }
 
     describe('for `heatmap_multi-trace`', function() {
@@ -662,4 +662,39 @@ describe('heatmap hover', function() {
         });
 
     });
+
+    describe('nonuniform bricks', function() {
+
+        beforeAll(function(done) {
+            gd = createGraphDiv();
+
+            var mock = require('@mocks/heatmap_contour_irregular_bricks.json');
+            var mockCopy = Lib.extendDeep({}, mock);
+
+            Plotly.plot(gd, mockCopy.data, mockCopy.layout).then(done);
+        });
+
+        afterAll(destroyGraphDiv);
+
+        function checkData() {
+            var pt = _hover(gd, -4, 6)[0];
+            assertLabels(pt, 0, 10, 1);
+
+            pt = _hover(gd, 10.5, 12.5)[0];
+            assertLabels(pt, 10, 12, 2);
+
+            pt = _hover(gd, 11.5, 4)[0];
+            assertLabels(pt, 12, 0, 3);
+        }
+
+        it('gives data positions, not brick centers', function(done) {
+            checkData();
+
+            Plotly.restyle(gd, {zsmooth: 'none'}, [0])
+            .then(checkData)
+            .catch(failTest)
+            .then(done);
+        });
+
+    });
 });