SAK-41400 remove rounding on gradebook charts (sakaiproject#6605)

* #3432 Make sure mapped grades are not null when they are collected.

Mapped grades will be null if the student doesn't have a course grade yet.

* SAK-41400 Remove custom chart drawing as we no longer want rounded corners

gradebookng/tool/src/webapp/scripts/gradebook-chart.js

@@ -6,109 +6,6 @@
  * Draws charts using ChartJS.
  */
 
-
-/**
- * Custom chart drawing, to enable us to have rounded corners
- * 
- * Based on code by Jed Trow
- * https://github.com/jedtrow/Chart.js-Rounded-Bar-Charts/blob/master/Chart.roundedBarCharts.js
- * 
- * Updated to remove unnecessary code and only round the top corners
- * 
- * NOTE: This code should be removed as soon as rounded corners are added as a feature to Chartjs. 
- * It is only a stopgap solution.
- */
-
-Chart.elements.Rectangle.prototype.draw = function() {
-
-    var ctx = this._chart.ctx;
-    var vm = this._view;
-    var left, right, top, bottom, signX, signY, borderSkipped, cornerRadius;
-    var borderWidth = vm.borderWidth;
-
-    if (!vm.horizontal) {
-        // bar
-        left = vm.x - vm.width / 2;
-        right = vm.x + vm.width / 2;
-        top = vm.y;
-        bottom = vm.base;
-        signX = 1;
-        signY = bottom > top? 1: -1;
-        borderSkipped = vm.borderSkipped || 'bottom';
-    } else {
-        // horizontal bar
-        left = vm.base;
-        right = vm.x;
-        top = vm.y - vm.height / 2;
-        bottom = vm.y + vm.height / 2;
-        signX = right > left? 1: -1;
-        signY = 1;
-        borderSkipped = vm.borderSkipped || 'left';
-    }
-
-    // Canvas doesn't allow us to stroke inside the width so we can
-    // adjust the sizes to fit if we're setting a stroke on the line
-    if (borderWidth) {
-        // borderWidth should be less than bar width and bar height.
-        var barSize = Math.min(Math.abs(left - right), Math.abs(top - bottom));
-        borderWidth = borderWidth > barSize? barSize: borderWidth;
-        var halfStroke = borderWidth / 2;
-        // Adjust borderWidth when bar top position is near vm.base (zero)
-        var borderLeft = left + (borderSkipped !== 'left'? halfStroke * signX: 0);
-        var borderRight = right + (borderSkipped !== 'right'? -halfStroke * signX: 0);
-        var borderTop = top + (borderSkipped !== 'top'? halfStroke * signY: 0);
-        var borderBottom = bottom + (borderSkipped !== 'bottom'? -halfStroke * signY: 0);
-        // not become a vertical line?
-        if (borderLeft !== borderRight) {
-            top = borderTop;
-            bottom = borderBottom;
-        }
-        // not become a horizontal line?
-        if (borderTop !== borderBottom) {
-            left = borderLeft;
-            right = borderRight;
-        }
-    }
-
-    width = right - left;
-    height = bottom - top;
-
-    // Set the corner radius to be half the width or height (whichever is smaller)
-    if (this._chart.config.options.roundedCorners) {
-    	cornerRadius = (Math.abs(height) < Math.abs(width)) ? Math.floor(Math.abs(height)/2) : Math.floor(Math.abs(width)/2);
-    } else {
-    	cornerRadius = 0;
-    }
-
-    // Draw the rectangle
-    ctx.beginPath();
-    ctx.fillStyle = vm.backgroundColor;
-    ctx.strokeStyle = vm.borderColor;
-    ctx.lineWidth = borderWidth;
-    var x = left, y = top;
-    if (!vm.horizontal) {
-    	ctx.moveTo(x, y + height);
-    	ctx.lineTo(x, y + cornerRadius);
-        ctx.quadraticCurveTo(x, y, x + cornerRadius, y);
-        ctx.lineTo(x + width - cornerRadius, y);
-        ctx.quadraticCurveTo(x + width, y, x + width, y + cornerRadius);
-        ctx.lineTo(x + width, y + height);
-        ctx.lineTo(x, y + height);
-    } else {
-    	ctx.moveTo(x, y);
-    	ctx.lineTo(x + width - cornerRadius, y);
-    	ctx.quadraticCurveTo(x + width, y, x + width, y + cornerRadius);
-    	ctx.lineTo(x + width, y + height - cornerRadius);
-    	ctx.quadraticCurveTo(x + width, y + height, x + width - cornerRadius, y + height);
-    	ctx.lineTo(x, y + height);
-    	ctx.lineTo(x, y);
-    }
-    ctx.fill();
-    if (borderWidth) {
-        ctx.stroke();
-    }
-};
-
 /**
  * Render the chart from the given dataset.
  * @param gbChartData the data for the chart. Must be a GbChartData object serialised to JSON.
@@ -147,7 +44,6 @@ function renderChart(gbChartData) {
 			}]
 		},
 		options: {
-			roundedCorners: true,
 			title: {
 				display: true,
 				text: chartTitle,