StockChart.qml Example File

demos/stocqt/content/StockChart.qml
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import QtQuick 2.0 import QtQuick.Layouts 1.1 import "." Rectangle { id: chart property var stockModel: null property var startDate: new Date() property var endDate: new Date() property string activeChart: "week" property var settings property int gridSize: 4 property real gridStep: gridSize ? (canvas.width - canvas.tickMargin) / gridSize : canvas.xGridStep function update() { endDate = new Date(); if (chart.activeChart === "year") { chart.startDate = new Date(chart.endDate.getFullYear() - 1, chart.endDate.getMonth(), chart.endDate.getDate()); chart.gridSize = 12; } else if (chart.activeChart === "month") { chart.startDate = new Date(chart.endDate.getFullYear(), chart.endDate.getMonth() - 1, chart.endDate.getDate()); gridSize = 4; } else if (chart.activeChart === "week") { chart.startDate = new Date(chart.endDate.getFullYear(), chart.endDate.getMonth(), chart.endDate.getDate() - 7); gridSize = 0; } else if (chart.activeChart === "halfyear") { chart.startDate = new Date(chart.endDate.getFullYear(), chart.endDate.getMonth() - 6, chart.endDate.getDate()); gridSize = 6; } else if (chart.activeChart === "quarter") { chart.startDate = new Date(chart.endDate.getFullYear(), chart.endDate.getMonth() - 3, chart.endDate.getDate()); gridSize = 3; } else { chart.startDate = new Date(2005, 3, 25); gridSize = 4; } canvas.requestPaint(); } GridLayout { anchors.fill: parent columns: 6 rows: 3 columnSpacing: 4 Button { id: weekButton text: "Week" buttonEnabled: chart.activeChart === "week" onClicked: { chart.activeChart = "week"; chart.update(); } } Button { id: monthButton text: "Month" buttonEnabled: chart.activeChart === "month" onClicked: { chart.activeChart = "month"; chart.update(); } } Button { id: quarterlyButton text: "3M" buttonEnabled: chart.activeChart === "quarter" onClicked: { chart.activeChart = "quarter"; chart.update(); } } Button { id: halfYearlyButton text: "6M" buttonEnabled: chart.activeChart === "halfyear" onClicked: { chart.activeChart = "halfyear"; chart.update(); } } Button { id: yearButton text: "Year" buttonEnabled: chart.activeChart === "year" onClicked: { chart.activeChart = "year"; chart.update(); } } Button { id: maxButton text: "Max" buttonEnabled: chart.activeChart === "max" onClicked: { chart.activeChart = "max"; chart.update(); } } Canvas { id: canvas Layout.fillWidth: true Layout.fillHeight: true Layout.columnSpan: 6 // Uncomment below lines to use OpenGL hardware accelerated rendering. // See Canvas documentation for available options. // renderTarget: Canvas.FramebufferObject // renderStrategy: Canvas.Threaded property int pixelSkip: 1 property int numPoints: 1 property int tickMargin: 34 property real xGridStep: (canvas.width - tickMargin) / numPoints property real yGridOffset: canvas.height / 26 property real yGridStep: canvas.height / 12 function drawBackground(ctx) { ctx.save(); ctx.fillStyle = "#ffffff"; ctx.fillRect(0, 0, canvas.width, canvas.height); ctx.strokeStyle = "#d7d7d7"; ctx.beginPath(); // Horizontal grid lines for (var i = 0; i < 12; i++) { ctx.moveTo(0, canvas.yGridOffset + i * canvas.yGridStep); ctx.lineTo(canvas.width, canvas.yGridOffset + i * canvas.yGridStep); } // Vertical grid lines var height = 35 * canvas.height / 36; var yOffset = canvas.height - height; var xOffset = 0; for (i = 0; i < chart.gridSize; i++) { ctx.moveTo(xOffset + i * chart.gridStep, yOffset); ctx.lineTo(xOffset + i * chart.gridStep, height); } ctx.stroke(); // Right ticks ctx.strokeStyle = "#666666"; ctx.beginPath(); var xStart = canvas.width - tickMargin; ctx.moveTo(xStart, 0); ctx.lineTo(xStart, canvas.height); for (i = 0; i < 12; i++) { ctx.moveTo(xStart, canvas.yGridOffset + i * canvas.yGridStep); ctx.lineTo(canvas.width, canvas.yGridOffset + i * canvas.yGridStep); } ctx.moveTo(0, canvas.yGridOffset + 9 * canvas.yGridStep); ctx.lineTo(canvas.width, canvas.yGridOffset + 9 * canvas.yGridStep); ctx.closePath(); ctx.stroke(); ctx.restore(); } // Returns a shortened, readable version of the potentially // large volume number. function volumeToString(value) { if (value < 1000) return value; var exponent = parseInt(Math.log(value) / Math.log(1000)); var shortVal = parseFloat(parseFloat(value) / Math.pow(1000, exponent)).toFixed(1); // Drop the decimal point on 3-digit values to make it fit if (shortVal >= 100.0) { shortVal = parseFloat(shortVal).toFixed(0); } return shortVal + "KMBTG".charAt(exponent - 1); } function drawScales(ctx, high, low, vol) { ctx.save(); ctx.strokeStyle = "#888888"; ctx.font = "10px Open Sans" ctx.beginPath(); // prices on y-axis var x = canvas.width - tickMargin + 3; var priceStep = (high - low) / 9.0; for (var i = 0; i < 10; i += 2) { var price = parseFloat(high - i * priceStep).toFixed(1); ctx.text(price, x, canvas.yGridOffset + i * yGridStep - 2); } // volume scale for (i = 0; i < 3; i++) { var volume = volumeToString(vol - (i * (vol/3))); ctx.text(volume, x, canvas.yGridOffset + (i + 9) * yGridStep + 10); } ctx.closePath(); ctx.stroke(); ctx.restore(); } function drawPrice(ctx, from, to, color, price, points, highest, lowest) { ctx.save(); ctx.globalAlpha = 0.7; ctx.strokeStyle = color; ctx.lineWidth = numPoints > 200 ? 1 : 3 ctx.beginPath(); var end = points.length; var range = highest - lowest; if (range == 0) { range = 1; } for (var i = 0; i < end; i += pixelSkip) { var x = points[i].x; var y = points[i][price]; var h = 9 * yGridStep; y = h * (lowest - y)/range + h + yGridOffset; if (i == 0) { ctx.moveTo(x, y); } else { ctx.lineTo(x, y); } } ctx.stroke(); ctx.restore(); } function drawVolume(ctx, from, to, color, price, points, highest) { ctx.save(); ctx.fillStyle = color; ctx.globalAlpha = 0.8; ctx.lineWidth = 0; ctx.beginPath(); var end = points.length; var margin = 0; if (chart.activeChart === "month" || chart.activeChart === "week") { margin = 8; ctx.shadowOffsetX = 4; ctx.shadowBlur = 3.5; ctx.shadowColor = Qt.darker(color); } // To match the volume graph with price grid, skip drawing the initial // volume of the first day on chart. for (var i = 1; i < end; i += pixelSkip) { var x = points[i - 1].x; var y = points[i][price]; y = canvas.height * (y / highest); y = 3 * y / 12; ctx.fillRect(x, canvas.height - y + yGridOffset, canvas.xGridStep - margin, y); } ctx.stroke(); ctx.restore(); } function drawError(ctx, msg) { ctx.save(); ctx.strokeStyle = "#888888"; ctx.font = "24px Open Sans" ctx.textAlign = "center" ctx.shadowOffsetX = 4; ctx.shadowOffsetY = 4; ctx.shadowBlur = 1.5; ctx.shadowColor = "#aaaaaa"; ctx.beginPath(); ctx.fillText(msg, (canvas.width - tickMargin) / 2, (canvas.height - yGridOffset - yGridStep) / 2); ctx.closePath(); ctx.stroke(); ctx.restore(); } onPaint: { numPoints = stockModel.indexOf(chart.startDate); if (chart.gridSize == 0) chart.gridSize = numPoints var ctx = canvas.getContext("2d"); ctx.globalCompositeOperation = "source-over"; ctx.lineWidth = 1; drawBackground(ctx); if (!stockModel.ready) { drawError(ctx, "No data available."); return; } var highestPrice = 0; var highestVolume = 0; var lowestPrice = -1; var points = []; for (var i = numPoints, j = 0; i >= 0 ; i -= pixelSkip, j += pixelSkip) { var price = stockModel.get(i); if (parseFloat(highestPrice) < parseFloat(price.high)) highestPrice = price.high; if (parseInt(highestVolume, 10) < parseInt(price.volume, 10)) highestVolume = price.volume; if (lowestPrice < 0 || parseFloat(lowestPrice) > parseFloat(price.low)) lowestPrice = price.low; points.push({ x: j * xGridStep, open: price.open, close: price.close, high: price.high, low: price.low, volume: price.volume }); } if (settings.drawHighPrice) drawPrice(ctx, 0, numPoints, settings.highColor, "high", points, highestPrice, lowestPrice); if (settings.drawLowPrice) drawPrice(ctx, 0, numPoints, settings.lowColor, "low", points, highestPrice, lowestPrice); if (settings.drawOpenPrice) drawPrice(ctx, 0, numPoints,settings.openColor, "open", points, highestPrice, lowestPrice); if (settings.drawClosePrice) drawPrice(ctx, 0, numPoints, settings.closeColor, "close", points, highestPrice, lowestPrice); drawVolume(ctx, 0, numPoints, settings.volumeColor, "volume", points, highestVolume); drawScales(ctx, highestPrice, lowestPrice, highestVolume); } } Text { id: fromDate color: "#000000" font.family: Settings.fontFamily font.pointSize: 8 Layout.alignment: Qt.AlignLeft text: "| " + startDate.toDateString() } Text { id: toDate color: "#000000" font.family: Settings.fontFamily font.pointSize: 8 Layout.alignment: Qt.AlignRight Layout.rightMargin: canvas.tickMargin Layout.columnSpan: 5 text: endDate.toDateString() + " |" } } }