GD Functions in PHP for managing graphics
We have to ensure that the support for all these graphics capabilities are available in our server and if not available then how to add them. We will learn all these along with script development here. First we will start with how to enable GD support in your server.
| Functions | Details |
| ImageRotate() | Rotate Image |
| ImageString() | Add text string to image |
| Imagettftext() | Add text of any font size to image |
| Imagerectangle() | Drawing rectangles |
| Imagearc() | Drawing Arc and circles |
| Imagefilledarc() | Drawing filled Arc and circles |
| Imageellipse() | Drawing ellipse and circles |
| Imagefilledellipse() | Drawing Filled ellipse and circles |
Checking GD support of PHP at your server
Learn how to check GD support availability at server and how to enable it at php.ini file.Displaying images by header control
To display images we have to have tell browser by header that we are sending one image and not a html page.Drawing lines in images
The first step to draw line chart or graphs is to draw lines of different length and reading the coordinates. We can change the gallery background or canvas colour also.Draw SIN & COS curve using imageline()
Draw Sin, Cos curve and then add both to draw a single image.Drawing graphs by using data from a mysql table
We can collect data from mysql table and plot a line graph by using this data. The image with the graph can have labels and data display on it.Adding grid to the line graph
How to add vertical grid to the ling graph drawn by taking data from a mysql table?Adding border to uploaded image
How to add border to an uploaded image by using gd support in PHP? WE can change the width of the border also.Watermarking of image by GD
We can add watermark images present in a directory or just uploaded by using GD support. The watermark can be added on the fly to the image while uploading.Generate Captcha
Generate Captcha for user to read the text and enter in a form. The text is generated as image by using GD functions.Adding Form entered text to Image template
User can enter name and grade through a form and submit. With this data and using a template, certificate can be generated by adding text to the image using ImageString().Generate certificate using data from MySQL student table
Using a standard template we can add data from MySQL table to generate certificates on the fly.Adding Student Photo, Logo and QR code to certificate
Along with the student data taken from MySQL table, we can add student photo, Logo and QR code while generating the certificates.Page hit counter
Generate a graphical page hit counter.Getting X,Y coordinates on click over an image.
Questions
- What is PHP GD, and what is its purpose?
- How can you check if GD support is enabled in your PHP installation?
- What are some commonly used GD functions in PHP?
- How do you create a new image using GD functions in PHP?
- How can you resize an image using GD functions?
- What is the difference between
imagecopy()andimagecopyresampled()functions? - How can you draw a rectangle on an image using GD functions?
- How do you add text to an image using GD functions?
- How can you apply image filters like grayscale or sepia using GD functions?
- How do you save an image created or modified using GD functions to a file?
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