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Essential tools for stock analysis: Learn the steps to draw candle charts with PHP and JS

王林

Dec 17, 2023 pm 06:55 PM

phpjsstepstock analysisCandlestick chart

Essential tools for stock analysis: Learn the steps to draw candle charts with PHP and JS

Essential Tools for Stock Analysis: Learn the steps to draw candle charts with PHP and JS, you need specific code examples

With the rapid development of the Internet and technology, stock trading has Become one of the important ways for many investors. Stock analysis is an important part of investor decision-making, and candle charts are widely used in technical analysis. Learning how to draw candle charts using PHP and JS will provide investors with more intuitive information to help them make better decisions.

Candlestick chart is a technical chart that displays stock prices in the form of candlesticks. It shows the opening, closing, high and low prices of stock prices and identifies market trends through changes in color. Among them, red means that the stock price has fallen, and green means that the stock price has increased. The method of drawing candle charts is relatively simple. You only need to know the daily opening price, closing price, highest price and lowest price.

First, we need to prepare the data. Suppose we have an array of stock data. Each element of the array contains information such as date, opening price, closing price, highest price, and lowest price.

$stocks = [
    ['date' => '2021/01/01', 'open' => 100, 'close' => 120, 'high' => 130, 'low' => 90],
    ['date' => '2021/01/02', 'open' => 130, 'close' => 150, 'high' => 160, 'low' => 120],
    // 更多股票数据...
];

Next, we can use PHP to draw candle charts. PHP provides many graphics libraries that can be used, such as gd, ImageMagick, etc. Here we use PHP's gd library to implement.

First, we create a blank canvas and set the width and height of the canvas.

$width = 800;
$height = 400;
$image = imagecreatetruecolor($width, $height);

Then, we set some basic colors, such as red and green, to represent rising and falling stock prices.

$red = imagecolorallocate($image, 255, 0, 0);
$green = imagecolorallocate($image, 0, 255, 0);

Next, we loop through the stock data array, calculate the position and size of each candle, and set the color according to the rise and fall of the stock price.

foreach ($stocks as $key => $stock) {
    $x = $key * ($width / count($stocks));
    $y1 = $height - ($stock['open'] - min($stock['low'], $stock['high'])) * ($height / (max($stock['high'], $stock['low']) - min($stock['low'], $stock['high'])));
    $y2 = $height - ($stock['close'] - min($stock['low'], $stock['high'])) * ($height / (max($stock['high'], $stock['low']) - min($stock['low'], $stock['high'])));
    $y3 = $height - ($stock['low'] - min($stock['low'], $stock['high'])) * ($height / (max($stock['high'], $stock['low']) - min($stock['low'], $stock['high'])));
    $y4 = $height - ($stock['high'] - min($stock['low'], $stock['high'])) * ($height / (max($stock['high'], $stock['low']) - min($stock['low'], $stock['high'])));

    if ($stock['close'] >= $stock['open']) {
        imagefilledrectangle($image, $x, $y2, $x + 10, $y1, $green);
        imageline($image, $x + 5, $y3, $x + 5, $y4, $green);
    } else {
        imagefilledrectangle($image, $x, $y1, $x + 10, $y2, $red);
        imageline($image, $x + 5, $y3, $x + 5, $y4, $red);
    }
}

Finally, we save the image to a file.

imagepng($image, 'candlestick.png');
imagedestroy($image);

At this point, we have successfully drawn the candle chart. By running the above code, an image file named candlestick.png will be generated in the current directory, which contains the drawing results of the candle chart.

In addition to PHP, we can also use JS to draw candle charts for dynamic display on the web page. Below is sample code for drawing a candle chart using HTML, CSS and JavaScript.

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Candlestick Chart</title>
    <style>
        #chart {
            width: 800px;
            height: 400px;
            border: 1px solid black;
        }
    </style>
</head>
<body>
    <div id="chart"></div>
    <script>
        var stocks = [
            {date: '2021/01/01', open: 100, close: 120, high: 130, low: 90},
            {date: '2021/01/02', open: 130, close: 150, high: 160, low: 120},
            // 更多股票数据...
        ];

        var chart = document.getElementById('chart');
        var ctx = chart.getContext('2d');
        var width = chart.width;
        var height = chart.height;

        stocks.forEach(function(stock, index) {
            var x = index * (width / stocks.length);
            var y1 = height - (stock.open - Math.min(stock.low, stock.high)) * (height / (Math.max(stock.high, stock.low) - Math.min(stock.low, stock.high)));
            var y2 = height - (stock.close - Math.min(stock.low, stock.high)) * (height / (Math.max(stock.high, stock.low) - Math.min(stock.low, stock.high)));
            var y3 = height - (stock.low - Math.min(stock.low, stock.high)) * (height / (Math.max(stock.high, stock.low) - Math.min(stock.low, stock.high)));
            var y4 = height - (stock.high - Math.min(stock.low, stock.high)) * (height / (Math.max(stock.high, stock.low) - Math.min(stock.low, stock.high)));

            if (stock.close >= stock.open) {
                ctx.fillStyle = 'green';
                ctx.fillRect(x, y2, 10, y1 - y2);
                ctx.strokeStyle = 'green';
                ctx.beginPath();
                ctx.moveTo(x + 5, y3);
                ctx.lineTo(x + 5, y4);
                ctx.stroke();
            } else {
                ctx.fillStyle = 'red';
                ctx.fillRect(x, y1, 10, y2 - y1);
                ctx.strokeStyle = 'red';
                ctx.beginPath();
                ctx.moveTo(x + 5, y3);
                ctx.lineTo(x + 5, y4);
                ctx.stroke();
            }
        });
    </script>
</body>
</html>

By opening the above code in the browser, we can see the results of the candle chart on the web page.

To sum up, mastering the steps of drawing candle charts using PHP and JS is essential for stock analysis. By learning these steps, combined with specific code examples, investors can better understand and analyze stock data and improve the accuracy and effectiveness of decision-making.

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