Examples of php drawing techniques

This article shares an example of PHP drawing to learn how to operate graphics technology in PHP, including drawing various graphics, writing text, copying canvas and other operations. Friends in need can refer to it.

1. Picture format: Common image formats include: gif, jpg/jpeg, png, etc.

Difference: 1) GIF images have a high compression rate, but can only display 256 colors, which may cause color loss, and animations can be displayed. 2). jpg/jpeg images have a high compression rate (lossy compression) and can be displayed with smaller files. 3), png This format combines the advantages of gif and jpg, but the disadvantage is that it cannot display animation.

2. PHP drawing example

<?php
//绘图技术 基本步骤 前提:在php.ini文件中启用gd库

//创建画布 默认背景是黑色的
$img=imagecreatetruecolor(400,300);

//绘制各种图形
//创建一个颜色
$background = imagecolorallocate($img, 255, 0, 0);
//画圆
//imageellipse($img,30,30,50,50,$background);
//椭圆
//imageellipse($img,30,30,50,30,$background);
//画直线
//imageline($img,0,0,400,300,$background);
//画矩形
//imagerectangle ($img, 50 , 20 , 100 , 40 , $background);
//填充矩形
//imagefilledrectangle ($img, 50 , 20 , 100 , 40 , $background);
//画弧线
//imagearc($img, 100, 100, 150, 150, 180, 270, $background);
//画扇型  IMG_ARC_CHORD直线连接了起始和结束点   IMG_ARC_PIE
//imagefilledarc($img, 100, 100, 150, 150, 180, 270, $background,IMG_ARC_PIE);

//拷贝图片到画布
/*$scrImg=imagecreatefromgif('http://www.baidu.com/img/shouye_b5486898c692066bd2cbaeda86d74448.gif');
$scrImgInfo=getimagesize('http://www.baidu.com/img/shouye_b5486898c692066bd2cbaeda86d74448.gif');
imagecopy ($img,$scrImg,10,10,0,0,$scrImgInfo[0],$scrImgInfo[1]);
*/
//imagecopy ($img,$scrImg,10,10,0,0,270,129);

//写字
//imagestring ($img , 5 , 20 , 20 , "hello,world", $background );
//写中文
$str="PHP绘画技术";
imagettftext ($img , 30 , 0 , 50 ,50, $background , "MSYHBD.TTF" , $str);

//输出图像到网页(或者另存为)
header("content-type: image/png");
imagepng($img);

//销毁该图片(释放内存)
imagedestroy($img);
?>