PHP output GD2 image to browser or file

php Editor Xiaoxin will introduce to you how to use PHP to output GD2 images to a browser or file. The GD library is a graphics library for PHP that can be used to create and process images. Through the GD library, we can generate verification codes, thumbnails, watermarks, etc. Output images using the GD library can be displayed directly in the browser or saved as a file. Next, we will introduce in detail how to use PHP combined with the GD library to implement this function.

PHP Output GD2 image to browser or file

The GD2 library in

php provides rich functionality for creating, editing and outputting images. Here's how to output a GD2 image to a browser or file:

Output to browser

1. Create an image: Create a new canvas using the imagecreate() function.
2. Drawing content: Use imagestring(), imageline() and other functions to draw text, line segments and other content.
3. Set header information: Use the header() function to set the correct MIME type, for example Content-Type: image/png.
4. Output image: Use imagepng(), imagejpeg() and other functions to output the image to the browser.

Code example:

<?php
// create image
$image = imagecreate(200, 100);

//Set background color
$white = imagecolorallocate($image, 255, 255, 255);
imagefill($image, 0, 0, $white);

// draw text
$black = imagecolorallocate($image, 0, 0, 0);
imagestring($image, 5, 50, 50, "Hello World!", $black);

//Output the image to the browser
header("Content-Type: image/png");
imagepng($image);

// Release image resources
imagedestroy($image);
?>

Output to file

1. Create image: Same as output to browser.
2. Save the image: Use functions such as imagepng(), imagejpeg() to save the image to a file.

Code example:

<?php
// create image
$image = imagecreate(200, 100);

//Set background color
$white = imagecolorallocate($image, 255, 255, 255);
imagefill($image, 0, 0, $white);

// draw text
$black = imagecolorallocate($image, 0, 0, 0);
imagestring($image, 5, 50, 50, "Hello World!", $black);

//Save image to file
imagepng($image, "image.png");

// Release image resources
imagedestroy($image);
?>

Other notes

• GD2 supports multiple image formats, including PNG, JPEG, GIF, etc.
• Use the imageinterlace() function to enable progressive display of images.
• You can adjust the image size through the imagescale() function.
• PHP 5.5 and higher versions support using the gd_info() function to query GD library information.

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