PHP利用GD库处理图片方法实现

这里写的是完成每个功能的函数，可以复制单个函数直接使用，这里的每个函数都是另外一篇PHP常用类------图片处理类Image当中的方法进行细化，可以参考一下

废话不多说，直接付代码吧！

添加水印(文字和图片）

<?php
/**
 * [创建图片文字水印]
 * @param  [string] $imagename [需要添加水印的值]
 * @param  [string] $string    [图片上添加的文字]
 * @param  [string] $locate    [水印位置，center,left_buttom,right_buttom三选一]
 * @return [null]            [description]
 */
function create_words_watermark($imagename,$string,$locate){
	list($width,$height,$type)=getimagesize($imagename);
	$types=array(1 => "GIF",2 => "JPEG",3 => "PNG",
		4 => "SWF",5 => "PSD",6 => "BMP",
		7 => "TIFF",8 => "TIFF",9 => "JPC",
		10 => "JP2",11 => "JPX",12 => "JB2",
		13 => "SWC",14 => "IFF",15 => "WBMP",16 => "XBM");
	$type=strtolower($types[$type]);
	$create="imagecreatefrom".$type;
	$img=$create($imagename);

	$string_color=imagecolorallocate($img,200, 200, 200);
	$fontsize=4;

	// 图片的宽和高也可用下面两个函数获得
	// $width=imagesx($img);
	// $height=imagesy($img);

	switch($locate){
		case ‘center‘:
			$x=($width-imagefontwidth($fontsize)*strlen($string))/2;
			$y=($height-imagefontheight($fontsize))/2;
			break;
		case ‘left_buttom‘:
			$x=5;
			$y=($height-imagefontheight($fontsize)-3);
			break;
		case ‘right_buttom‘:
			$x=($width-imagefontwidth($fontsize)*strlen($string)-3);
			$y=($height-imagefontheight($fontsize)-3);
 			break;
 		default:
 			die("未指定水印位置!");
 			break;
 	}

	imagestring($img,$fontsize,$x,$y,$string,$string_color);
	imagestring($img,$fontsize,$x+1,$y+1,$string,$string_color);

	$save="image".$type;
	//保存
	//$save($img,"new_".$imagename);

	//显示
	header("content-type:image/".$type);
	$save($img);
	imagedestroy($img);
}

// create_words_watermark("test.png","hello world","right_buttom");

/**
 * [create_pic_watermark 添加图片水印]
 * @param  [string] $dest_image [需要添加图片水印的图片名]
 * @param  [string] $watermark  [水印图片名]
 * @param  [string] $locate     [水印位置，center,left_buttom,right_buttom三选一]
 * @return [type]             [description]
 */
function create_pic_watermark($dest_image,$watermark,$locate){
	list($dwidth,$dheight,$dtype)=getimagesize($dest_image);
	list($wwidth,$wheight,$wtype)=getimagesize($watermark);

	$types=array(1 => "GIF",2 => "JPEG",3 => "PNG",
		4 => "SWF",5 => "PSD",6 => "BMP",
		7 => "TIFF",8 => "TIFF",9 => "JPC",
		10 => "JP2",11 => "JPX",12 => "JB2",
		13 => "SWC",14 => "IFF",15 => "WBMP",16 => "XBM");

	$dtype=strtolower($types[$dtype]);//原图类型
	$wtype=strtolower($types[$wtype]);//水印图片类型

	$created="imagecreatefrom".$dtype;
	$createw="imagecreatefrom".$wtype;

	$imgd=$created($dest_image);
	$imgw=$createw($watermark);

	switch($locate){
		case ‘center‘:
			$x=($dwidth-$wwidth)/2;
			$y=($dheight-$wheight)/2;
			break;
		case ‘left_buttom‘:
			$x=1;
			$y=($dheight-$wheight-2);
			break;
		case ‘right_buttom‘:
			$x=($dwidth-$wwidth-1);
			$y=($dheight-$wheight-2);
 			break;
 		default:
 			die("未指定水印位置!");
 			break;
 	}

 	imagecopy($imgd,$imgw,$x,$y,0,0, $wwidth,$wheight);

 	$save="image".$dtype;

 	//显示
 	header("content-type:image/".$dtype);
 	$save($imgd);

 	imagedestroy($imgw);
 	imagedestroy($imgd);
}

create_pic_watermark("ganlixin.jpg","test.png","left_buttom");
?>

剪切图片

<?php
/**
 * [cut_image]					从原图中剪切一部分
 * @param  [string] $old_imagename [需要剪切的图片名]
 * @param  [int] $start_width   [从原图片宽为的$start_width开始剪切]
 * @param  [int] $start_height  [从原图片高为的$start_height开始剪切]
 * @param  [int] $new_width     [从原图片中剪切$new_width的宽度]
 * @param  [int] $new_height    [从原图片中剪切$new_height的高度]
 * @return [null]                [null]
 */
function cut_image($old_imagename,$start_width,$start_height,$new_width,$new_height){
	list($old_width,$old_height,$type)=getimagesize($old_imagename);
	$types=array(1 => "GIF",2 => "JPEG",3 => "PNG",
		4 => "SWF",5 => "PSD",6 => "BMP",
		7 => "TIFF",8 => "TIFF",9 => "JPC",
		10 => "JP2",11 => "JPX",12 => "JB2",
		13 => "SWC",14 => "IFF",15 => "WBMP",16 => "XBM");
	$type=strtolower($types[$type]);
	$create="imagecreatefrom".$type;

	$old_img=$create($old_imagename);
	$new_img=imagecreatetruecolor($new_width, $new_height);

	imagecopyresampled($new_img,$old_img,0,0,$start_width,$start_height,$new_width,$new_height,$new_width,$new_height);
	$save="image".$type;

	//保存
	//$save($new_img,"new_".$old_imagename);

	//显示
	header("content-type:image/".$type);
	$save($new_img);

	//销毁
	imagedestroy($old_img);
	imagedestroy($new_img);
}

cut_image("ganlixin.jpg",0,0,200,200);
?>

翻转图片

<?php
/**
 * [rotate_image 图片旋转]
 * @param  [string] $imagename [要进行旋转的图片名]
 * @param  [string] $angle     [旋转的角度，逆时针为正]
 * @return [null]            [description]
 */
function rotate_image($imagename,$angle){
	list($width,$height,$type)=getimagesize($imagename);
	$types=array(1 => "GIF",2 => "JPEG",3 => "PNG",
		4 => "SWF",5 => "PSD",6 => "BMP",
		7 => "TIFF",8 => "TIFF",9 => "JPC",
		10 => "JP2",11 => "JPX",12 => "JB2",
		13 => "SWC",14 => "IFF",15 => "WBMP",16 => "XBM");
	$type=$types[$type];

	$create="imagecreatefrom".$type;
	$img=$create($imagename);
	$new_img=imagerotate($img,$angle,0);
	$save="image".$type;

	//显示
	header("content-type:image/".$type);
	$save($new_img);

	// 保存
	// $save($new_img,"new_".$imagename);

	imagedestroy($img);
	imagedestroy($new_img);
} 

rotate_image("ganlixin.jpg",-90);

?>

翻转图片

<?php
/**
 * [overturn_image 翻转图片]
 * @param  [string] $imagename [要反转的图片名]
 * @param  [char] $method    [按x轴或y轴翻转，只有x，y选项]
 * @return [type]            [description]
 */
function overturn_image($imagename,$method){
	$method=strtolower($method);
	list($width,$height,$type)=getimagesize($imagename);
	$types=array(1 => "GIF",2 => "JPEG",3 => "PNG",
		4 => "SWF",5 => "PSD",6 => "BMP",
		7 => "TIFF",8 => "TIFF",9 => "JPC",
		10 => "JP2",11 => "JPX",12 => "JB2",
		13 => "SWC",14 => "IFF",15 => "WBMP",16 => "XBM");
	$type=$types[$type];

	$create="imagecreatefrom".$type;
	$img=$create($imagename);//源图片
	$new_img=imagecreatetruecolor($width,$height);//翻转之后的图片

	if($method==‘y‘){
		for($i=0;$i<$width;$i++){
			imagecopy($new_img,$img,$width-$i-1,0,$i,0,1,$height);
		}
	} else if($method==‘x‘){
		for($i=0;$i<$height;$i++){
			imagecopy($new_img,$img,0,$height-$i-1,0,$i,$width,1);
		}
	}
	$save="image".$type;

	//显示
	header("content-type:image/".$type);
	$save($new_img);

	// 保存
	// $save($new_img,"new_".$imagename);

	imagedestroy($img);
	imagedestroy($new_img);
}
overturn_image("ganlixin.jpg","y");
?>