iss3917

src/core/core.ticks.js

@@ -116,7 +116,7 @@ module.exports = function(Chart) {
 
 				if (tickVal === 0) {
 					exp = Math.floor(helpers.log10(dataRange.minNotZero));
-					significand = Math.floor(dataRange.minNotZero / Math.pow(10, exp));
+					significand = 1;
 
 					ticks.push(tickVal);
 					tickVal = significand * Math.pow(10, exp);

src/scales/scale.logarithmic.js

@@ -178,63 +178,77 @@ module.exports = function(Chart) {
 		},
 		getPixelForValue: function(value) {
 			var me = this;
-			var innerDimension;
-			var pixel;
-
+			var innerDimension = me.isHorizontal() ? me.width : me.height;
 			var start = me.start;
+			var end = me.end;
 			var newVal = +me.getRightValue(value);
-			var range;
 			var opts = me.options;
 			var tickOpts = opts.ticks;
+			var zero = me.isHorizontal() ? (tickOpts.reverse ? me.right : me.left) : (tickOpts.reverse ? me.top : me.bottom);
 
-			if (me.isHorizontal()) {
-				range = helpers.log10(me.end) - helpers.log10(start); // todo: if start === 0
-				if (newVal === 0) {
-					pixel = me.left;
-				} else {
-					innerDimension = me.width;
-					pixel = me.left + (innerDimension / range * (helpers.log10(newVal) - helpers.log10(start)));
-				}
-			} else {
-				// Bottom - top since pixels increase downward on a screen
-				innerDimension = me.height;
-				if (start === 0 && !tickOpts.reverse) {
-					range = helpers.log10(me.end) - helpers.log10(me.minNotZero);
-					if (newVal === start) {
-						pixel = me.bottom;
-					} else if (newVal === me.minNotZero) {
-						pixel = me.bottom - innerDimension * 0.02;
-					} else {
-						pixel = me.bottom - innerDimension * 0.02 - (innerDimension * 0.98/ range * (helpers.log10(newVal)-helpers.log10(me.minNotZero)));
-					}
-				} else if (me.end === 0 && tickOpts.reverse) {
-					range = helpers.log10(me.start) - helpers.log10(me.minNotZero);
-					if (newVal === me.end) {
-						pixel = me.top;
-					} else if (newVal === me.minNotZero) {
-						pixel = me.top + innerDimension * 0.02;
-					} else {
-						pixel = me.top + innerDimension * 0.02 + (innerDimension * 0.98/ range * (helpers.log10(newVal)-helpers.log10(me.minNotZero)));
-					}
-				} else if (newVal === 0) {
-					pixel = tickOpts.reverse ? me.top : me.bottom;
-				} else {
-					range = helpers.log10(me.end) - helpers.log10(start);
-					innerDimension = me.height;
-					pixel = me.bottom - (innerDimension / range * (helpers.log10(newVal) - helpers.log10(start)));
+			var pixel, range, valueOffset;
+
+			if (start === 0 || end === 0) { // 0 is in range
+				var min = Math.pow(10, Math.floor(helpers.log10(me.minNotZero)));
+				var max = tickOpts.reverse ? start : end;
+				range = helpers.log10(max) - Math.floor(helpers.log10(me.minNotZero));
+				var fontSize = helpers.getValueOrDefault(tickOpts.fontSize, Chart.defaults.global.defaultFontSize);
+				var diff = fontSize;
+				innerDimension -= diff;
+
+				if (newVal === 0) { // 0
+					pixel = zero;
+				} else if (newVal === min) { // 0 in range, minNotZero
+					pixel = me.isHorizontal() ? (tickOpts.reverse ? zero - diff : zero + diff) : (tickOpts.reverse ? zero + diff : zero - diff);
+				} else { // 0 in range, common case
+					valueOffset = innerDimension / range * (helpers.log10(newVal) - Math.floor(helpers.log10(me.minNotZero)));
+					pixel = me.isHorizontal()
+						? (tickOpts.reverse ? zero - diff - valueOffset : zero + diff + valueOffset)
+						: (tickOpts.reverse ? zero + diff + valueOffset : zero - diff - valueOffset);
 				}
+			} else { // 0 is not in range
+				range = helpers.log10(end) - helpers.log10(start);
+				valueOffset = innerDimension / range * (helpers.log10(newVal) - helpers.log10(start));
+				pixel = me.isHorizontal() ? me.left + valueOffset : me.bottom - valueOffset;
 			}
 			return pixel;
 		},
 		getValueForPixel: function(pixel) {
 			var me = this;
 			var range = helpers.log10(me.end) - helpers.log10(me.start);
 			var value, innerDimension;
+			var tickOpts = me.options.ticks;
+			var reverse = tickOpts.reverse;
+
+			if (me.start === 0 || me.end === 0) {
+				var zeroPixel = me.isHorizontal() ? (reverse ? me.right : me.left) : (reverse ? me.top : me.bottom);
+				range = helpers.log10(reverse ? me.start : me.end) - Math.floor(helpers.log10(me.minNotZero));
+				var fontSize = helpers.getValueOrDefault(tickOpts.fontSize, Chart.defaults.global.defaultFontSize);
+				var diff = fontSize;
+				innerDimension -= diff;
+
+				//
+				var pixelMinNotZero;
+				if (me.isHorizontal()) {
+					pixelMinNotZero = reverse ? zeroPixel - diff : zeroPixel + diff;
+				} else {
+					pixelMinNotZero = reverse ? zeroPixel + diff : zeroPixel - diff;
+				}
 
-			if (me.isHorizontal()) {
+				if (pixel === zeroPixel) {
+					value = 0;
+				} else if (pixel === pixelMinNotZero) {
+					value = me.minNotZero;
+				} else {
+					var p = me.isHorizontal()
+						? (reverse ? zeroPixel - diff - pixel : zeroPixel + diff + pixel)
+						: (reverse ? zeroPixel + diff + pixel : zeroPixel - diff - pixel);
+					value = me.minNotZero * Math.pow(10, p * range / innerDimension);
+				}
+			} else if (me.isHorizontal()) {
 				innerDimension = me.width;
 				value = me.start * Math.pow(10, (pixel - me.left) * range / innerDimension);
-			} else {  // todo: if start === 0
+			} else {
 				innerDimension = me.height;
 				value = Math.pow(10, (me.bottom - pixel) * range / innerDimension) / me.start;
 			}

test/specs/scale.logarithmic.tests.js

@@ -514,7 +514,7 @@ describe('Logarithmic Scale tests', function() {
 			type: 'bar',
 			data: {
 				datasets: [{
-					data: [11, 0.8, 0, 28, 7]
+					data: [11, 76, 0, 28, 7]
 				}],
 				labels: []
 			},
@@ -535,9 +535,9 @@ describe('Logarithmic Scale tests', function() {
 
 		// Counts down because the lines are drawn top to bottom
 		expect(chart.scales.yScale).toEqual(jasmine.objectContaining({
-			ticks: [30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.9, 0.8, 0],
+			ticks: [80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0],
 			start: 0,
-			end: 30
+			end: 80
 		}));
 	});
 
@@ -602,7 +602,7 @@ describe('Logarithmic Scale tests', function() {
 
 		// Counts down because the lines are drawn top to bottom
 		expect(chart.scales.yScale).toEqual(jasmine.objectContaining({
-			ticks: [0, 9, 10, 20, 30],
+			ticks: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30],
 			start: 30,
 			end: 0
 		}));
@@ -735,7 +735,7 @@ describe('Logarithmic Scale tests', function() {
 		expect(yScale.getValueForPixel(246)).toBeCloseTo(10, 1e-4);
 	});
 
-	it('should get the correct pixel value for a point when 0 values are present', function() {
+	it('should get the correct pixel value for a point when 0 values are present (vertical)', function() {
 		var chart = window.acquireChart({
 			type: 'bar',
 			data: {
@@ -761,21 +761,76 @@ describe('Logarithmic Scale tests', function() {
 		var yScale = chart.scales.yScale;
 		expect(yScale.getPixelForValue(70, 0, 0)).toBeCloseToPixel(32);   // top + paddingTop
 		expect(yScale.getPixelForValue(0, 0, 0)).toBeCloseToPixel(484);  // bottom - paddingBottom
-		expect(yScale.getPixelForValue(0.063, 0, 0)).toBeCloseToPixel(475);  // minNotZero 2% from range
-		expect(yScale.getPixelForValue(0.5, 0, 0)).toBeCloseToPixel(344);
-		expect(yScale.getPixelForValue(4, 0, 0)).toBeCloseToPixel(213);
-		expect(yScale.getPixelForValue(10, 0, 0)).toBeCloseToPixel(155);
+		expect(yScale.getPixelForValue(0.01, 0, 0)).toBeCloseToPixel(472); // first possible tick
+		expect(yScale.getPixelForValue(0.063, 0, 0)).toBeCloseToPixel(381);  // minNotZero
+		expect(yScale.getPixelForValue(0.5, 0, 0)).toBeCloseToPixel(278);
+		expect(yScale.getPixelForValue(4, 0, 0)).toBeCloseToPixel(174);
+		expect(yScale.getPixelForValue(10, 0, 0)).toBeCloseToPixel(127);
 		expect(yScale.getPixelForValue(63, 0, 0)).toBeCloseToPixel(38.5);
 
 		chart.options.scales.yAxes[0].ticks.reverse = true;   // Reverse mode
 		chart.update();
 
 		expect(yScale.getPixelForValue(70, 0, 0)).toBeCloseToPixel(484); // bottom - paddingBottom
 		expect(yScale.getPixelForValue(0, 0, 0)).toBeCloseToPixel(32);  // top + paddingTop
-		expect(yScale.getPixelForValue(0.063, 0, 0)).toBeCloseToPixel(41);  // minNotZero 2% from range
-		expect(yScale.getPixelForValue(0.5, 0, 0)).toBeCloseToPixel(172);
-		expect(yScale.getPixelForValue(4, 0, 0)).toBeCloseToPixel(303);
-		expect(yScale.getPixelForValue(10, 0, 0)).toBeCloseToPixel(361);
+		expect(yScale.getPixelForValue(0.01, 0, 0)).toBeCloseToPixel(44);  // first possible tick
+		expect(yScale.getPixelForValue(0.063, 0, 0)).toBeCloseToPixel(135);  // minNotZero
+		expect(yScale.getPixelForValue(0.5, 0, 0)).toBeCloseToPixel(238);
+		expect(yScale.getPixelForValue(4, 0, 0)).toBeCloseToPixel(342);
+		expect(yScale.getPixelForValue(10, 0, 0)).toBeCloseToPixel(389);
 		expect(yScale.getPixelForValue(63, 0, 0)).toBeCloseToPixel(477);
 	});
+
+	it('should get the correct pixel value for a point when 0 values are present (horizontal)', function() {
+		var chart = window.acquireChart({
+			type: 'horizontalBar',
+			data: {
+				labels: ['data 1', 'data 2', 'data 3', 'data 4', 'data 5', 'data 6'],
+				datasets: [{
+					xAxisID: 'xScale',
+					yAxisID: 'yScale',
+					data: [0.063, 4, 0, 63, 10, 0.5],
+				}],
+			},
+			options: {
+				scales: {
+					xAxes: [{
+						id: 'xScale',
+						type: 'logarithmic',
+						display: true,
+						ticks: {
+							reverse: false,
+						},
+					}],
+					yAxes: [{
+						id: 'yScale',
+						type: 'category',
+						display: true,
+					}]
+				}
+			}
+		});
+
+		var xScale = chart.scales.xScale;
+		expect(xScale.getPixelForValue(70, 0, 0)).toBeCloseToPixel(505);
+		expect(xScale.getPixelForValue(0, 0, 0)).toBeCloseToPixel(44);
+		expect(xScale.getPixelForValue(0.01, 0, 0)).toBeCloseToPixel(56);
+		expect(xScale.getPixelForValue(0.063, 0, 0)).toBeCloseToPixel(149);
+		expect(xScale.getPixelForValue(0.5, 0, 0)).toBeCloseToPixel(254);
+		expect(xScale.getPixelForValue(4, 0, 0)).toBeCloseToPixel(360);
+		expect(xScale.getPixelForValue(10, 0, 0)).toBeCloseToPixel(406);
+		expect(xScale.getPixelForValue(63, 0, 0)).toBeCloseToPixel(500);
+
+		chart.options.scales.xAxes[0].ticks.reverse = true;   // Reverse mode
+		chart.update();
+
+		expect(xScale.getPixelForValue(70, 0, 0)).toBeCloseToPixel(44);
+		expect(xScale.getPixelForValue(0, 0, 0)).toBeCloseToPixel(505);
+		expect(xScale.getPixelForValue(0.01, 0, 0)).toBeCloseToPixel(493);
+		expect(xScale.getPixelForValue(0.063, 0, 0)).toBeCloseToPixel(400);
+		expect(xScale.getPixelForValue(0.5, 0, 0)).toBeCloseToPixel(295);
+		expect(xScale.getPixelForValue(4, 0, 0)).toBeCloseToPixel(189);
+		expect(xScale.getPixelForValue(10, 0, 0)).toBeCloseToPixel(143);
+		expect(xScale.getPixelForValue(63, 0, 0)).toBeCloseToPixel(49);
+	});
 });