diff --git a/.vscode/settings.json b/.vscode/settings.json new file mode 100644 index 0000000..ad94bc7 --- /dev/null +++ b/.vscode/settings.json @@ -0,0 +1,3 @@ +{ + "npm.packageManager": "yarn" +} diff --git a/.vscode/tasks.json b/.vscode/tasks.json new file mode 100644 index 0000000..bfd6d50 --- /dev/null +++ b/.vscode/tasks.json @@ -0,0 +1,16 @@ +{ + "version": "2.0.0", + "tasks": [ + { + "type": "npm", + "script": "test", + "group": { + "kind": "build", + "isDefault": true + }, + "problemMatcher": [], + "label": "yarn: test", + "detail": "tape 'test/**/*-test.js' && eslint src" + } + ] +} diff --git a/README.md b/README.md index 5abb632..04bc6df 100644 --- a/README.md +++ b/README.md @@ -98,7 +98,62 @@ If *size* is specified, sets the expected size of the input *values* grid to the # contours.smooth([smooth]) · [Source](https://github.com/d3/d3-contour/blob/master/src/contours.js), [Examples](https://observablehq.com/@d3/contours-smooth) -If *smooth* is specified, sets whether or not the generated contour polygons are smoothed using linear interpolation. If *smooth* is not specified, returns the current smoothing flag, which defaults to true. +If *smooth* is specified, sets the smoothing method to use when generating the contour polygons. If *smooth* is not specified, returns the current smoothing method, which defaults to true. + +The available *smooth* options are: + +- `false`: Smoothing is disabled. +- `true` or `"linear"` (Default): Linear interpolation smoothing, as described in the original [Marching Squares algorithm](https://en.wikipedia.org/wiki/Marching_squares). +- `"linearDual"`: Dual linear interpolation smoothing, as described in the [Dual Marching Squares algorithm](https://ieeexplore.ieee.org/document/7459173). + +In general, the quality of each smoothing method is inversely proportional to its runtime performance. + +Additionally, the density of the source data impacts contour smoothness: the differences between the smoothing methods are more noticeable with low-density data than they are with high-density data. With _very_ high-density data, there is no discernible quality difference between the three methods. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
Low-density dataHigh-density data
Smoothing methodContour
quality		Performance
cost*		Contour
quality		Performance
cost*
NonefalsePoor+0%Good+0%
Linear (Default)true or
"linear"		Good+2.40%Best+1.55%
Dual linear"linearDual"Best+2.70%Best+2.00%
+ +\* Estimated performance cost based on 2 sample datasets. # contours.thresholds([thresholds]) · [Source](https://github.com/d3/d3-contour/blob/master/src/contours.js), [Examples](https://observablehq.com/@d3/volcano-contours) diff --git a/src/contours.js b/src/contours.js index 614e9ec..6b7b6fb 100644 --- a/src/contours.js +++ b/src/contours.js @@ -182,6 +182,39 @@ export default function() { }); } + /** + * Applies smoothing to an iso-ring according to the Dual Marching Squares algorithm. + * @param {[number, number][]} ring The sorted list of (x,y) coordinates of points for a given iso-ring. + * @param {number[]} values The underlying grid values. + * @param {number} value The iso-value for this iso-ring. + */ + function smoothLinearDual(ring, values, value) { + var point, x, y, x1, y1; + + // The first step in Dual Marching Squares smoothing is linear interpolation. + smoothLinear(ring, values, value); + + for (var i = 0; i < ring.length; i++) { + point = ring[i]; + x = point[0]; + y = point[1]; + + if (i < ring.length - 1) { + // Next point + x1 = ring[i + 1][0]; + y1 = ring[i + 1][1]; + + // Set the current point to the midpoint between it and the next point. + point[0] = x + (x1 - x) / 2; + point[1] = y + (y1 - y) / 2; + } else { + // This is the last point, complete the ring by matching the first point + point[0] = ring[0][0]; + point[1] = ring[0][1]; + } + } + } + contours.contour = contour; contours.size = function(_) { @@ -196,7 +229,7 @@ export default function() { }; contours.smooth = function(_) { - return arguments.length ? (smooth = _ ? smoothLinear : noop, contours) : smooth === smoothLinear; + return arguments.length ? (smooth = _ === 'linearDual' ? smoothLinearDual : _ ? smoothLinear : noop, contours) : smooth === smoothLinear || smooth === smoothLinearDual; }; return contours; diff --git a/test/contours-test.js b/test/contours-test.js index 650c5e7..8cc92fa 100644 --- a/test/contours-test.js +++ b/test/contours-test.js @@ -24,6 +24,31 @@ tape("contours(values) returns the expected result for an empty polygon", functi test.end(); }); +tape("contours.smooth('linearDual')(values) returns the expected result for an empty polygon", function(test) { + var contours = d3.contours().smooth('linearDual').size([10, 10]).thresholds([0.5]); + test.deepEqual(contours([ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 + ]), [ + { + "type": "MultiPolygon", + "value": 0.5, + "coordinates": [] + } + ]); + test.end(); +}); + + + tape("contours(values) returns the expected result for a simple polygon", function(test) { var contours = d3.contours().size([10, 10]).thresholds([0.5]); test.deepEqual(contours([ @@ -53,6 +78,105 @@ tape("contours(values) returns the expected result for a simple polygon", functi test.end(); }); +tape("contours.smooth(false)(values) returns the expected result for a simple polygon", function(test) { + var contours = d3.contours().smooth(false).size([10, 10]).thresholds([0.5]); + test.deepEqual(contours([ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 + ]), [ + { + "type": "MultiPolygon", + "value": 0.5, + "coordinates": [ + [ + [ + [6, 7.5], [6, 6.5], [6, 5.5], [6, 4.5], [6, 3.5], // Right edge + [5.5, 3], [4.5, 3], [3.5, 3], // Top edge + [3, 3.5], [3, 4.5], [3, 5.5], [3, 6.5], [3, 7.5], // Left edge + [3.5, 8], [4.5, 8], [5.5, 8], // Bottom edge + [6, 7.5] + ] + ] + ] + } + ]); + test.end(); +}); + +tape("contours.smooth(true)(values) returns the expected result for a simple polygon", function(test) { + var contours = d3.contours().smooth(true).size([10, 10]).thresholds([0.5]); + test.deepEqual(contours([ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 + ]), [ + { + "type": "MultiPolygon", + "value": 0.5, + "coordinates": [ + [ + [ + [6, 7.5], [6, 6.5], [6, 5.5], [6, 4.5], [6, 3.5], // Right edge + [5.5, 3], [4.5, 3], [3.5, 3], // Top edge + [3, 3.5], [3, 4.5], [3, 5.5], [3, 6.5], [3, 7.5], // Left edge + [3.5, 8], [4.5, 8], [5.5, 8], // Bottom edge + [6, 7.5] + ] + ] + ] + } + ]); + test.end(); +}); + +tape("contours.smooth('linearDual')(values) returns the expected result for a simple polygon", function(test) { + var contours = d3.contours().smooth('linearDual').size([10, 10]).thresholds([0.5]); + test.deepEqual(contours([ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 + ]), [ + { + "type": "MultiPolygon", + "value": 0.5, + "coordinates": [ + [ + [ + [6, 7], [6, 6], [6, 5], [6, 4], [5.75, 3.25], // Right edge + [5, 3], [4, 3], [3.25, 3.25], // Top edge + [3, 4], [3, 5], [3, 6], [3, 7], [3.25, 7.75], // Left edge + [4, 8], [5, 8], [5.75, 7.75], // Bottom edge + [6, 7] + ] + ] + ] + } + ]); + test.end(); +}); + tape("contours(values).contour(value) returns the expected result for a simple polygon", function(test) { var contours = d3.contours().size([10, 10]); test.deepEqual(contours.contour([ @@ -80,7 +204,106 @@ tape("contours(values).contour(value) returns the expected result for a simple p test.end(); }); -tape("contours.smooth(false)(values) returns the expected result for a simple polygon", function(test) { +tape("contours(values) returns the expected result for a corner polygon", function(test) { + var contours = d3.contours().size([10, 10]).thresholds([0.5]); + test.deepEqual(contours([ + 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 + ]), [ + { + "type": "MultiPolygon", + "value": 0.5, + "coordinates": [ + [ + [ + [2, 1.5], [2, 0.5], // Right edge + [1.5, 0], [0.5, 0], // Top edge + [0, 0.5], [0, 1.5], // Left edge + [0.5, 2], [1.5, 2], // Bottom edge + [2, 1.5] + ] + ] + ] + } + ]); + test.end(); +}); + +tape("contours.smooth(false)(values) returns the expected result for a polygon in the corner", function(test) { + var contours = d3.contours().smooth(false).size([10, 10]).thresholds([0.5]); + test.deepEqual(contours([ + 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 + ]), [ + { + "type": "MultiPolygon", + "value": 0.5, + "coordinates": [ + [ + [ + [2, 1.5], [2, 0.5], // Right edge + [1.5, 0], [0.5, 0], // Top edge + [0, 0.5], [0, 1.5], // Left edge + [0.5, 2], [1.5, 2], // Bottom edge + [2, 1.5] + ] + ] + ] + } + ]); + test.end(); +}); + +tape("contours.smooth('linearDual')(values) returns the expected result for polygon in the corner", function(test) { + var contours = d3.contours().smooth('linearDual').size([10, 10]).thresholds([0.5]); + test.deepEqual(contours([ + 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, + 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 + ]), [ + { + "type": "MultiPolygon", + "value": 0.5, + "coordinates": [ + [ + [ + [2, 1], [1.75, 0.25], // Right edge + [1, 0], [0.25, 0.25], // Top edge + [0, 1], [0.25, 1.75], // Left edge + [1, 2], [1.75, 1.75], // Bottom edge + [2, 1] + ] + ] + ] + } + ]); + test.end(); +}); + +tape("contours.smooth(false)(values) returns the expected result for a complex polygon", function(test) { var contours = d3.contours().smooth(false).size([10, 10]).thresholds([0.5]); test.deepEqual(contours([ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, @@ -109,6 +332,72 @@ tape("contours.smooth(false)(values) returns the expected result for a simple po test.end(); }); +tape("contours.smooth(true)(values) returns the expected result for a complex polygon", function(test) { + var contours = d3.contours().smooth(true).size([10, 10]).thresholds([0.5]); + test.deepEqual(contours([ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 2, 1, 2, 0, 0, 0, 0, + 0, 0, 0, 2, 2, 2, 0, 0, 0, 0, + 0, 0, 0, 1, 2, 1, 0, 0, 0, 0, + 0, 0, 0, 2, 2, 2, 0, 0, 0, 0, + 0, 0, 0, 2, 1, 2, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 + ]), [ + { + "type": "MultiPolygon", + "value": 0.5, + "coordinates": [ + [ + [ + [6.25, 7.5], [6.25, 6.5], [6, 5.5], [6.25, 4.5], [6.25, 3.5], // Right edge + [5.5, 2.75], [4.5, 3], [3.5, 2.75], // Top edge + [2.75, 3.5], [2.75, 4.5], [3, 5.5], [2.75, 6.5], [2.75, 7.5], // Left edge + [3.5, 8.25], [4.5, 8], [5.5, 8.25], // Bottom edge + [6.25, 7.5] + ] + ] + ] + } + ]); + test.end(); +}); + +tape("contours.smooth('linearDual')(values) returns the expected result for a complex polygon", function(test) { + var contours = d3.contours().smooth('linearDual').size([10, 10]).thresholds([0.5]); + test.deepEqual(contours([ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 2, 1, 2, 0, 0, 0, 0, + 0, 0, 0, 2, 2, 2, 0, 0, 0, 0, + 0, 0, 0, 1, 2, 1, 0, 0, 0, 0, + 0, 0, 0, 2, 2, 2, 0, 0, 0, 0, + 0, 0, 0, 2, 1, 2, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 + ]), [ + { + "type": "MultiPolygon", + "value": 0.5, + "coordinates": [ + [ + [ + [6.25, 7], [6.125, 6], [6.125, 5], [6.25, 4], [5.875, 3.125], // Right edge + [5, 2.875], [4, 2.875], [3.125, 3.125], // Top edge + [2.75, 4], [2.875, 5], [2.875, 6], [2.75, 7], [3.125, 7.875], // Left edge + [4, 8.125], [5, 8.125], [5.875, 7.875], // Bottom edge + [6.25, 7] + ] + ] + ] + } + ]); + test.end(); +}); + tape("contours(values) returns the expected result for a polygon with a hole", function(test) { var contours = d3.contours().size([10, 10]).thresholds([0.5]); test.deepEqual(contours([ @@ -140,6 +429,90 @@ tape("contours(values) returns the expected result for a polygon with a hole", f test.end(); }); +tape("contours.smooth(true)(values) returns the expected result for a polygon with a hole", function(test) { + var contours = d3.contours().smooth(true).size([10, 10]).thresholds([0.5]); + test.deepEqual(contours([ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 + ]), [ + { + "type": "MultiPolygon", + "value": 0.5, + "coordinates": [ + [ + [ + // Outer polygon, counter-clockwise path + [6, 7.5], [6, 6.5], [6, 5.5], [6, 4.5], [6, 3.5], // Right edge + [5.5, 3], [4.5, 3], [3.5, 3], // Top edge + [3, 3.5], [3, 4.5], [3, 5.5], [3, 6.5], [3, 7.5], // Left edge + [3.5, 8], [4.5, 8], [5.5, 8], // Bottom edge + [6, 7.5] + ], + [ + // Inner polygon, clockwise path + [4.5, 7], // Bottom point + [4, 6.5], [4, 5.5], [4, 4.5], // Left edge + [4.5, 4], // Top point + [5, 4.5], [5, 5.5], [5, 6.5], // Right edge + [4.5, 7] + ] + ] + ] + } + ]); + test.end(); +}); + +tape("contours.smooth('linearDual')(values) returns the expected result for a polygon with a hole", function(test) { + var contours = d3.contours().smooth('linearDual').size([10, 10]).thresholds([0.5]); + test.deepEqual(contours([ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, + 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 + ]), [ + { + "type": "MultiPolygon", + "value": 0.5, + "coordinates": [ + [ + [ + // Outer polygon, counter-clockwise path + [6, 7], [6, 6], [6, 5], [6, 4], [5.75, 3.25], // Right edge + [5, 3], [4, 3], [3.25, 3.25], // Top edge + [3, 4], [3, 5], [3, 6], [3, 7], [3.25, 7.75], // Left edge + [4, 8], [5, 8], [5.75, 7.75], // Bottom edge + [6, 7] + ], + [ + // Inner polygon, clockwise path + [4.25, 6.75], // Bottom edge + [4, 6], [4, 5], // Left edge + [4.25, 4.25], [4.75, 4.25], // Top edge + [5, 5], [5, 6], // Right edge + [4.75, 6.75], [4.25, 6.75] // Bottom edge + ] + ] + ] + } + ]); + test.end(); +}); + tape("contours(values) returns the expected result for a multipolygon", function(test) { var contours = d3.contours().size([10, 10]).thresholds([0.5]); test.deepEqual(contours([ @@ -207,6 +580,126 @@ tape("contours(values) returns the expected result for a multipolygon with holes test.end(); }); +tape("contours.smooth(false)(values) returns the expected result for a multipolygon with holes", function(test) { + var contours = d3.contours().smooth(false).size([10, 10]).thresholds([0.5]); + test.deepEqual(contours([ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, + 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, + 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 + ]), [ + { + "type": "MultiPolygon", + "value": 0.5, + "coordinates": [ + [ + [ + // Outer left polygon, counter-clockwise path + [4, 5.5], [4, 4.5], [4, 3.5], // Right edge + [3.5, 3], [2.5, 3], [1.5, 3], // Top edge + [1, 3.5], [1, 4.5], [1, 5.5], // Left edge + [1.5, 6], [2.5, 6], [3.5, 6], // Bottom edge + [4,5.5] + ], + [ + // Inner left polygon, clockwise path + [2.5, 5], // Bottom + [2, 4.5], // Left + [2.5, 4], // Top + [3, 4.5], // Right + [2.5, 5] + ] + ], + [ + [ + // Outer right polygon, counter-clockwise path + [8, 5.5], [8, 4.5], [8, 3.5], // Right edge + [7.5, 3], [6.5, 3], [5.5, 3], // Top edge + [5, 3.5], [5, 4.5], [5, 5.5], // Left edge + [5.5, 6], [6.5, 6], [7.5, 6], // Bottom edge + [8, 5.5] + ], + [ + // Inner right polygon, clockwise path + [6.5, 5], // Bottom + [6, 4.5], // Left + [6.5, 4], // Top + [7, 4.5], // Right + [6.5, 5] + ] + ] + ] + } + ]); + test.end(); +}); + +tape("contours.smooth('linearDual')(values) returns the expected result for a multipolygon with holes", function(test) { + var contours = d3.contours().smooth('linearDual').size([10, 10]).thresholds([0.5]); + test.deepEqual(contours([ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, + 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, + 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 + ]), [ + { + "type": "MultiPolygon", + "value": 0.5, + "coordinates": [ + [ + [ + // Outer left polygon, counter-clockwise path + [4, 5], [4, 4], // Right edge + [3.75, 3.25], [3, 3], [2, 3], [1.25, 3.25], // Top edge + [1, 4], [1, 5], // Left edge + [1.25, 5.75], [2, 6], [3, 6], [3.75, 5.75], // Bottom edge + [4, 5] + ], + [ + // Inner left polygon, clockwise path + [2.25, 4.75], // Bottom-left + [2.25, 4.25], // Top-left + [2.75, 4.25], // Top-right + [2.75, 4.75], // Bottom-right + [2.25, 4.75] + ] + ], + [ + [ + // Outer right polygon, counter-clockwise path + [8, 5], [8, 4], // Right edge + [7.75, 3.25], [7, 3], [6, 3], [5.25, 3.25], // Top edge + [5, 4], [5, 5], // Left edge + [5.25, 5.75], [6, 6], [7, 6], [7.75, 5.75], // Bottom edge + [8, 5] + ], + [ + // Inner right polygon, clockwise path + [6.25, 4.75], // Bottom-left + [6.25, 4.25], // Top-left + [6.75, 4.25], // Top-right + [6.75, 4.75], // Bottom-right + [6.25, 4.75] + ] + ] + ] + } + ]); + test.end(); +}); + tape("contours.size(…) validates the specified size", function(test) { test.deepEqual(d3.contours().size([1, 2]).size(), [1, 2]); test.deepEqual(d3.contours().size([0, 0]).size(), [0, 0]);