- Qt 5.15
- Qt Quick Demo - StocQt
- Qt 5.15.16 Reference Documentation

# Qt Quick Demo - StocQt

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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(stockModel.newest);
             if (chart.activeChart === "month") {
                 chart.startDate = new Date(stockModel.newest.getFullYear(),
                                            stockModel.newest.getMonth() - 1,
                                            stockModel.newest.getDate());
                 gridSize = 4;
             }
             else if (chart.activeChart === "quarter") {
                 chart.startDate = new Date(stockModel.newest.getFullYear(),
                                            stockModel.newest.getMonth() - 3,
                                            stockModel.newest.getDate());
                 gridSize = 3;
             }
             else if (chart.activeChart === "halfyear") {
                 chart.startDate = new Date(stockModel.newest.getFullYear(),
                                            stockModel.newest.getMonth() - 6,
                                            stockModel.newest.getDate());
                 gridSize = 6;
             }
             else {
                 chart.startDate = new Date(stockModel.newest.getFullYear(),
                                            stockModel.newest.getMonth(),
                                            stockModel.newest.getDate() - 7);
                 gridSize = 0;
             }

             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: "3 Months"
                 buttonEnabled: chart.activeChart === "quarter"
                 onClicked: {
                     chart.activeChart = "quarter";
                     chart.update();
                 }
             }

             Button {
                 id: halfYearlyButton
                 text: "6 Months"
                 buttonEnabled: chart.activeChart === "halfyear"
                 onClicked: {
                     chart.activeChart = "halfyear";
                     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() + " |"
             }
         }
     }