PHP draw a line segment

php editor Xinyi introduces you how to use PHP code to draw a line segment. In PHP, you can draw line segments through the functions provided by the GD library. First, you need to create a canvas, then set the starting and ending coordinates of the line segment, select the color and thickness of the line segment, and finally use the corresponding function on the canvas. Just draw the line segment. With a few simple lines of code, you can draw line segments and add more vivid visual effects to web pages.

Steps to draw a line segment in PHP

1. Create canvas

$im = imagecreatetruecolor(width, height);

• width and height specify the width and height of the canvas in pixels.

2. Set color

$color = imagecolorallocate($im, red, green, blue);

• imagecolorallocate() The function creates the specified color and returns a color index .
• red, green and blue specify the red, green and blue components of the color (0-255).

3. Draw line segments

imageline($im, x1, y1, x2, y2, $color);

• $im is the canvas image resource.
• x1, y1 and x2, y2 specify the coordinates of the start and end points of the line segment.
• $color is the color index of the line segment.

Sample code:

<?php
//Create a 500x500 canvas
$im = imagecreatetruecolor(500, 500);

// assign blue
$blue = imagecolorallocate($im, 0, 0, 255);

// Draw a blue line segment from (100, 100) to (400, 400)
imageline($im, 100, 100, 400, 400, $blue);

//output image
header("Content-Type: image/png");
imagepng($im);
imagedestroy($im);
?>

hint:

• Make sure the values ​​of x1, y1, x2 and y2 are within the canvas range.
• You can use the imagedashedline() function to draw a dotted line segment.
• Use the imagecolortransparent() function to set the background to transparent.
• Use the imagefilledpoly<strong class="keylink">Go</strong>n() function to draw filled graphics.
• Use the imagestring() function to draw text on the image.

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