New fill modes for lines (#3460)

New fill modes for lines allowing the user to customize where the fill goes to

docs/01-Chart-Configuration.md

@@ -392,7 +392,7 @@ borderDash | Array | `[]` | Default line dash. See [MDN](https://developer.mozil
 borderDashOffset | Number | 0.0 | Default line dash offset. See [MDN](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/lineDashOffset)
 borderJoinStyle | String | 'miter' | Default line join style. See [MDN](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/lineJoin)
 capBezierPoints | Boolean | true | If true, bezier control points are kept inside the chart. If false, no restriction is enforced.
-fill | Boolean | true | If true, the line is filled.
+fill | Boolean or String | true | If true, the fill is assumed to be to zero. String values are 'zero', 'top', and 'bottom' to fill to different locations. If `false`, no fill is added
 stepped | Boolean | false | If true, the line is shown as a stepped line and 'tension' will be ignored
 
 #### Point Configuration

src/elements/element.line.js

@@ -15,7 +15,7 @@ module.exports = function(Chart) {
 		borderDashOffset: 0.0,
 		borderJoinStyle: 'miter',
 		capBezierPoints: true,
-		fill: true // do we fill in the area between the line and its base axis
+		fill: true, // do we fill in the area between the line and its base axis
 	};
 
 	Chart.elements.Line = Chart.Element.extend({
@@ -23,9 +23,18 @@ module.exports = function(Chart) {
 			var me = this;
 			var vm = me._view;
 			var spanGaps = vm.spanGaps;
-			var scaleZero = vm.scaleZero;
+			var fillPoint = vm.scaleZero;
 			var loop = me._loop;
 
+			// Handle different fill modes for cartesian lines
+			if (!loop) {
+				if (vm.fill === 'top') {
+					fillPoint = vm.scaleTop;
+				} else if (vm.fill === 'bottom') {
+					fillPoint = vm.scaleBottom;
+				}
+			}
+
 			var ctx = me._chart.ctx;
 			ctx.save();
 
@@ -71,9 +80,9 @@ module.exports = function(Chart) {
 					// First point moves to it's starting position no matter what
 					if (index === 0) {
 						if (loop) {
-							ctx.moveTo(scaleZero.x, scaleZero.y);
+							ctx.moveTo(fillPoint.x, fillPoint.y);
 						} else {
-							ctx.moveTo(currentVM.x, scaleZero);
+							ctx.moveTo(currentVM.x, fillPoint);
 						}
 
 						if (!currentVM.skip) {
@@ -87,9 +96,9 @@ module.exports = function(Chart) {
 							// Only do this if this is the first point that is skipped
 							if (!spanGaps && lastDrawnIndex === (index - 1)) {
 								if (loop) {
-									ctx.lineTo(scaleZero.x, scaleZero.y);
+									ctx.lineTo(fillPoint.x, fillPoint.y);
 								} else {
-									ctx.lineTo(previous._view.x, scaleZero);
+									ctx.lineTo(previous._view.x, fillPoint);
 								}
 							}
 						} else {
@@ -102,7 +111,7 @@ module.exports = function(Chart) {
 								} else if (loop) {
 									ctx.lineTo(currentVM.x, currentVM.y);
 								} else {
-									ctx.lineTo(currentVM.x, scaleZero);
+									ctx.lineTo(currentVM.x, fillPoint);
 									ctx.lineTo(currentVM.x, currentVM.y);
 								}
 							} else {
@@ -115,7 +124,7 @@ module.exports = function(Chart) {
 				}
 
 				if (!loop && lastDrawnIndex !== -1) {
-					ctx.lineTo(points[lastDrawnIndex]._view.x, scaleZero);
+					ctx.lineTo(points[lastDrawnIndex]._view.x, fillPoint);
 				}
 
 				ctx.fillStyle = vm.backgroundColor || globalDefaults.defaultColor;

test/element.line.tests.js

@@ -527,6 +527,318 @@ describe('Line element tests', function() {
 		expect(mockContext.getCalls()).toEqual(expected);
 	});
 
+	it('should draw with fillMode top', function() {
+		var mockContext = window.createMockContext();
+
+		// Create our points
+		var points = [];
+		points.push(new Chart.elements.Point({
+			_datasetindex: 2,
+			_index: 0,
+			_view: {
+				x: 0,
+				y: 10,
+				controlPointNextX: 0,
+				controlPointNextY: 10
+			}
+		}));
+		points.push(new Chart.elements.Point({
+			_datasetindex: 2,
+			_index: 1,
+			_view: {
+				x: 5,
+				y: 0,
+				controlPointPreviousX: 5,
+				controlPointPreviousY: 0,
+				controlPointNextX: 5,
+				controlPointNextY: 0
+			}
+		}));
+		points.push(new Chart.elements.Point({
+			_datasetindex: 2,
+			_index: 2,
+			_view: {
+				x: 15,
+				y: -10,
+				controlPointPreviousX: 15,
+				controlPointPreviousY: -10,
+				controlPointNextX: 15,
+				controlPointNextY: -10
+			}
+		}));
+		points.push(new Chart.elements.Point({
+			_datasetindex: 2,
+			_index: 3,
+			_view: {
+				x: 19,
+				y: -5,
+				controlPointPreviousX: 19,
+				controlPointPreviousY: -5,
+				controlPointNextX: 19,
+				controlPointNextY: -5
+			}
+		}));
+
+		var line = new Chart.elements.Line({
+			_datasetindex: 2,
+			_chart: {
+				ctx: mockContext,
+			},
+			_children: points,
+			// Need to provide some settings
+			_view: {
+				fill: 'top',
+				scaleZero: 2, // for filling lines
+				scaleTop: -2,
+				scaleBottom: 10,
+				tension: 0.0, // no bezier curve for now
+
+				borderCapStyle: 'round',
+				borderColor: 'rgb(255, 255, 0)',
+				borderDash: [2, 2],
+				borderDashOffset: 1.5,
+				borderJoinStyle: 'bevel',
+				borderWidth: 4,
+				backgroundColor: 'rgb(0, 0, 0)'
+			}
+		});
+
+		line.draw();
+
+		var expected = [{
+			name: 'save',
+			args: []
+		}, {
+			name: 'beginPath',
+			args: []
+		}, {
+			name: 'moveTo',
+			args: [0, -2]
+		}, {
+			name: 'lineTo',
+			args: [0, 10]
+		}, {
+			name: 'bezierCurveTo',
+			args: [0, 10, 5, 0, 5, 0]
+		}, {
+			name: 'bezierCurveTo',
+			args: [5, 0, 15, -10, 15, -10]
+		}, {
+			name: 'bezierCurveTo',
+			args: [15, -10, 19, -5, 19, -5]
+		}, {
+			name: 'lineTo',
+			args: [19, -2]
+		}, {
+			name: 'setFillStyle',
+			args: ['rgb(0, 0, 0)']
+		}, {
+			name: 'closePath',
+			args: []
+		}, {
+			name: 'fill',
+			args: []
+		}, {
+			name: 'setLineCap',
+			args: ['round']
+		}, {
+			name: 'setLineDash',
+			args: [
+				[2, 2]
+			]
+		}, {
+			name: 'setLineDashOffset',
+			args: [1.5]
+		}, {
+			name: 'setLineJoin',
+			args: ['bevel']
+		}, {
+			name: 'setLineWidth',
+			args: [4]
+		}, {
+			name: 'setStrokeStyle',
+			args: ['rgb(255, 255, 0)']
+		}, {
+			name: 'beginPath',
+			args: []
+		}, {
+			name: 'moveTo',
+			args: [0, 10]
+		}, {
+			name: 'bezierCurveTo',
+			args: [0, 10, 5, 0, 5, 0]
+		}, {
+			name: 'bezierCurveTo',
+			args: [5, 0, 15, -10, 15, -10]
+		}, {
+			name: 'bezierCurveTo',
+			args: [15, -10, 19, -5, 19, -5]
+		}, {
+			name: 'stroke',
+			args: []
+		}, {
+			name: 'restore',
+			args: []
+		}];
+		expect(mockContext.getCalls()).toEqual(expected);
+	});
+
+	it('should draw with fillMode bottom', function() {
+		var mockContext = window.createMockContext();
+
+		// Create our points
+		var points = [];
+		points.push(new Chart.elements.Point({
+			_datasetindex: 2,
+			_index: 0,
+			_view: {
+				x: 0,
+				y: 10,
+				controlPointNextX: 0,
+				controlPointNextY: 10
+			}
+		}));
+		points.push(new Chart.elements.Point({
+			_datasetindex: 2,
+			_index: 1,
+			_view: {
+				x: 5,
+				y: 0,
+				controlPointPreviousX: 5,
+				controlPointPreviousY: 0,
+				controlPointNextX: 5,
+				controlPointNextY: 0
+			}
+		}));
+		points.push(new Chart.elements.Point({
+			_datasetindex: 2,
+			_index: 2,
+			_view: {
+				x: 15,
+				y: -10,
+				controlPointPreviousX: 15,
+				controlPointPreviousY: -10,
+				controlPointNextX: 15,
+				controlPointNextY: -10
+			}
+		}));
+		points.push(new Chart.elements.Point({
+			_datasetindex: 2,
+			_index: 3,
+			_view: {
+				x: 19,
+				y: -5,
+				controlPointPreviousX: 19,
+				controlPointPreviousY: -5,
+				controlPointNextX: 19,
+				controlPointNextY: -5
+			}
+		}));
+
+		var line = new Chart.elements.Line({
+			_datasetindex: 2,
+			_chart: {
+				ctx: mockContext,
+			},
+			_children: points,
+			// Need to provide some settings
+			_view: {
+				fill: 'bottom',
+				scaleZero: 2, // for filling lines
+				scaleTop: -2,
+				scaleBottom: 10,
+				tension: 0.0, // no bezier curve for now
+
+				borderCapStyle: 'round',
+				borderColor: 'rgb(255, 255, 0)',
+				borderDash: [2, 2],
+				borderDashOffset: 1.5,
+				borderJoinStyle: 'bevel',
+				borderWidth: 4,
+				backgroundColor: 'rgb(0, 0, 0)'
+			}
+		});
+
+		line.draw();
+
+		var expected = [{
+			name: 'save',
+			args: []
+		}, {
+			name: 'beginPath',
+			args: []
+		}, {
+			name: 'moveTo',
+			args: [0, 10]
+		}, {
+			name: 'lineTo',
+			args: [0, 10]
+		}, {
+			name: 'bezierCurveTo',
+			args: [0, 10, 5, 0, 5, 0]
+		}, {
+			name: 'bezierCurveTo',
+			args: [5, 0, 15, -10, 15, -10]
+		}, {
+			name: 'bezierCurveTo',
+			args: [15, -10, 19, -5, 19, -5]
+		}, {
+			name: 'lineTo',
+			args: [19, 10]
+		}, {
+			name: 'setFillStyle',
+			args: ['rgb(0, 0, 0)']
+		}, {
+			name: 'closePath',
+			args: []
+		}, {
+			name: 'fill',
+			args: []
+		}, {
+			name: 'setLineCap',
+			args: ['round']
+		}, {
+			name: 'setLineDash',
+			args: [
+				[2, 2]
+			]
+		}, {
+			name: 'setLineDashOffset',
+			args: [1.5]
+		}, {
+			name: 'setLineJoin',
+			args: ['bevel']
+		}, {
+			name: 'setLineWidth',
+			args: [4]
+		}, {
+			name: 'setStrokeStyle',
+			args: ['rgb(255, 255, 0)']
+		}, {
+			name: 'beginPath',
+			args: []
+		}, {
+			name: 'moveTo',
+			args: [0, 10]
+		}, {
+			name: 'bezierCurveTo',
+			args: [0, 10, 5, 0, 5, 0]
+		}, {
+			name: 'bezierCurveTo',
+			args: [5, 0, 15, -10, 15, -10]
+		}, {
+			name: 'bezierCurveTo',
+			args: [15, -10, 19, -5, 19, -5]
+		}, {
+			name: 'stroke',
+			args: []
+		}, {
+			name: 'restore',
+			args: []
+		}];
+		expect(mockContext.getCalls()).toEqual(expected);
+	});
+
 	it('should skip points correctly', function() {
 		var mockContext = window.createMockContext();