PHP利用GD库处理图片方法实现

<?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");
?>

<?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);
?>

<?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);

?>

<?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");
?>