To dynamically generate an image in GIF format should you notice? _php Foundation

Source: Internet
Author: User
Tags transparent color
If you use
int imagecreatefromgif (string filename);
To take a picture of a GIF format, when the background or basic canvas sample is used, draw a graphic on it, please note:
If there is no pigment in this file, you will not be able to use it.

Solution, you can use
int imagecreate (int x_size, int y_size);
Create a fully-empty graphic. Draw a graphic on it. Use black as a transparent color.
This new graphic will be the same size as the original graphic, absolute position is the same, put it above the original graphic, you can.

Original graphics file

Full-empty file photo.php

Code for photo.php:
Header ("Content-type:image/gif");
$im = Imagecreate (200,300);
$black = Imagecolorallocate ($im, 0,0,0);
$red = Imagecolorallocate ($im, 255,0,0);
$blue = Imagecolorallocate ($im, 0,0,255);

Imagerectangle ($im, 100,200,150,200, $red);
Imagestring ($im, 2,120,150, "aaaaaaaa", $blue);

Imagecolortransparent ($im, $black);
Use black as a transparent color

Imagegif ($im);
Imagedestroy ($im);


"This article copyright belongs to the author and the Osso net jointly owns, if needs to reprint, please indicate the author and the origin"

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.