Chart.elements.Rectangle.prototype.draw = function() { var ctx = this._chart.ctx; var vm = this._view; var left, right, top, bottom, signX, signY, borderSkipped, radius; var borderWidth = vm.borderWidth; var cornerRadius = 20; 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 shold 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; } } ctx.beginPath(); ctx.fillStyle = vm.backgroundColor; ctx.strokeStyle = vm.borderColor; ctx.lineWidth = borderWidth; // Corner points, from bottom-left to bottom-right clockwise // | 1 2 | // | 0 3 | var corners = [ [left, bottom], [left, top], [right, top], [right, bottom] ]; // Find first (starting) corner with fallback to 'bottom' var borders = ['bottom', 'left', 'top', 'right']; var startCorner = borders.indexOf(borderSkipped, 0); if (startCorner === -1) { startCorner = 0; } function cornerAt(index) { return corners[(startCorner + index) % 4]; } // Draw rectangle from 'startCorner' var corner = cornerAt(0); ctx.moveTo(corner[0], corner[1]); for (var i = 1; i < 4; i++) { corner = cornerAt(i); nextCornerId = i+1; if(nextCornerId == 4){ nextCornerId = 0 } nextCorner = cornerAt(nextCornerId); width = corners[2][0] - corners[1][0]; height = corners[0][1] - corners[1][1]; x = corners[1][0]; y = corners[1][1]; var radius = cornerRadius; // Fix radius being too large if(radius > height/2){ radius = height/2; }if(radius > width/2){ radius = width/2; } ctx.moveTo(x + radius, y); ctx.lineTo(x + width - radius, y); ctx.quadraticCurveTo(x + width, y, x + width, y + radius); ctx.lineTo(x + width, y + height - radius); ctx.quadraticCurveTo(x + width, y + height, x + width - radius, y + height); ctx.lineTo(x + radius, y + height); ctx.quadraticCurveTo(x, y + height, x, y + height - radius); ctx.lineTo(x, y + radius); ctx.quadraticCurveTo(x, y, x + radius, y); } ctx.fill(); if (borderWidth) { ctx.stroke(); } };