||Plustcharts||
How to create a Spline Chart using PHP and JavaScript
Spline charts are created in the same way as line charts, only here instead of lines, curves are used. Following are the steps to form a spline chart using PHP and JavaScript with Pluscharts, a JavaScript charting library to build charts.
Step 1: Creating the MySQL table
For this, consider a table of data, consisting of seven data entries. The columns are labeled id, month and sales. This table can be created using the following code.
CREATE TABLE shop (
id INT NOT NULL,
month VARCHAR(30) NOT NULL,
sales INT NOT NULL,
PRIMARY KEY (id),
UNIQUE (month)
);
INSERT INTO shop
(id, month, sales)
VALUES
(1, “Jan”, 50),
(2, “Feb”, 10),
(3, “Mar”, 20),
(4, “Apr”, 20),
(5, “May”, 30),
(6, “Jun”, 10),
(7, “Jul”, 20);
Also read: Pie Chart Using PHP And JS
Step 2: Connecting to the database file
Once you have entered the data in the database, you can start with creating your project folder and the main file. But before you begin with the main code, don’t forget to create a subfolder (optional), to hold the secondary files that need to be included in the main code.
Now, let us move to create a new file, that will contain a PHP code to fetch the data from the database.
<?php
$dbservername = “localhost”;
$dbusername = “”;
$dbpassword = “”;
$dbname = “test”;
$conn = mysqli_connect($dbservername, $dbusername, $dbpassword, $dbname);
if (!$conn) {
die(“Connection failed: “. mysqli_connect_error());
}
?>
Include the file, in the main file and in order to check the connection establishment, run the code in the browser, preferably Chrome. Store both sets of data, months and sales in two arrays.
<?php
include_once ‘dbh.php’;
$sql= “SELECT*FROM shop”;
$result= mysqli_query($conn, $sql);
$shops= array();
if (mysqli_num_rows($result) >0)
{
while ($row= mysqli_fetch_assoc($result)) {
$shops[]= $row;
}
}
$a= array();
foreach ($shops as $shop) {
$a[]= $shop[‘sales’];
}
$b= array();
foreach ($shops as $shop) {
$b[]= $shop[‘month’];
}
?>
Also Read: Donut Chart Using PHP And JS
Step 3: Writing the Line Chart example code
Create an element, where you want to render your chart, using the following code.
For example, here we create an element with id, ‘spline-chart-example’.
<div id=”spline-chart-example”></div>
Now, since the pluscharts library is built upon d3, we load d3 first and then pluscharts, using the following scripts.
<script src=”https://d3js.org/d3.v5.min.js”></script>
<script src=”path-to/src/pluscharts.js”></script>
Then we assign the data from PHP variables to JS variables, using the following code.
<script type=”text/javascript”>
var sales= <?php echo json_encode($a ); ?>;
var months= <?php echo json_encode($b ); ?>;
The next step will be to write a JavaScript code to set up a spline chart.
pluscharts.draw({
drawOn : “#spline-chart-example”,
type: “spline”,
dataset : {
data: [
{
x: sales,
y: months
}
],
lineColor: “#e46161”,
lineWidth: 2,
legendLabel: “visitors”
},
options: {
text: {
display: true,
color: “#6c478c”
},
points: {
display: true,
color: “#e46161”,
radius: 3
},
axes: {
x: {
display: true,
scale: 1,
min: 0,
max: 160
},
y: {
display: true,
scale: 3,
min: 0,
max: 100
}
},
legends: {
display: true,
width: 20,
height: 20
},
size: {
width: ‘container’, //give ‘container’ if you want width and height of initiated container
height: ‘400’
}
}
})
</script>
For better understanding let us break this code into parts.
pluscharts.draw
({ })
This function is used to initiate the chart. Under this draw function, we pass the details of the chart including the data and options as the argument to the draw() function.
drawOn : ‘#spline-chart-example’,
The drawOn element is used to indicate the element where the chart is to be generated.
type: “spline”,
The type of chart to be drawn is specified in the type element.
dataset: {
data: [
{
x: sales,
y: months
}
],
lineColor: “#e46161”,
lineWidth: 2,
legendLabel: “visitors”
},
The dataset is used to insert data values, background color, border color, border width, label and legend labels. Note that here, instead of specifying the data values in data and labels, we have given the name of the array where the data is stored, which is “sales” and “labels” respectively.
options: {
text: {
display: true,
color: “#6c478c”
},
points: {
display: true,
color: “#e46161”,
radius: 3
},
axes: {
x: {
display: true,
scale: 1,
min: 0,
max: 160
},
y: {
display: true,
scale: 3,
min: 0,
max: 100
}
},
legends: {
display: true,
width: 20,
height: 20
},
size: {
width: ‘container’, //give ‘container’ if you want the width and height of the initiated container
height: ‘400’
}
}
})
Options are used for customization of the chart. The text and points radius and color is assigned, along with a display option. The x and y-axis minimum and maximum points on the scale are set. The visibility and dimension of legends are set. The size of the chart can be adjusted by adjusting the height and width. ‘Container’ can be set in as value when the dimension of the chart needs to be the same as that of its initiated container.
