这篇文章主要介绍了php的图片处理实现代码，包括缩放、剪裁、缩放、翻转、旋转、透明、锐化等图片操作，需要的朋友可以参考下

一、创建图片资源

imagecreatetruecolor(width,height);
imagecreatefromgif(图片名称);
imagecreatefrompng(图片名称);
imagecreatefromjpeg(图片名称);画出各种图像 imagegif(图片资源,保存路径);
imagepng()
imagejpeg();

二、获取图片属性

imagesx(res//宽度
imagesy(res//高度
getimagesize(文件路径)
返回一个具有四个单元的数组。索引 0 包含图像宽度的像素值，索引 1 包含图像高度的像素值。索引 2 是图像类型的标记：1 = GIF，2 = JPG，3 = PNG，4 = SWF，5 = PSD，6 = BMP，7 = TIFF(intel byte order)，8 = TIFF(motorola byte order)，9 = JPC，10 = JP2，11 = JPX，12 = JB2，13 = SWC，14 = IFF，15 = WBMP，16 = XBM。这些标记与 PHP 4.3.0 新加的 IMAGETYPE 常量对应。索引 3 是文本字符串，内容为“height="yyy" width="xxx"”，可直接用于 IMG 标记。
销毁图像资源
imagedestroy(图片资源);

三、透明处理

PNG、jpeg透明色都正常，只有gif不正常

imagecolortransparent(resource image [,int color])//将某个颜色设置成透明色
imagecolorstotal()
imagecolorforindex();

四、图片的裁剪

imagecopyresized()
imagecopyresampled();

五、加水印（文字、图片）

字符串编码转换string iconv ( string $in_charset , string $out_charset , string $str )

六、图片旋转

imagerotate();//制定角度的图片翻转

七、图片的翻转

沿X轴   沿Y轴翻转

八、锐化

imagecolorsforindex()

imagecolorat()

在图片上画图形  $img=imagecreatefromgif("./images/map.gif");

 $red= imagecolorallocate($img, 255, 0, 0);
 imageline($img, 0, 0, 100, 100, $red);
 imageellipse($img, 200, 100, 100, 100, $red);
 imagegif($img, "./images/map2.gif");
 imagedestroy($img);

图片普通缩放

$filename="./images/hee.jpg";
 $per=0.3;
 list($width, $height)=getimagesize($filename);
 $n_w=$width*$per;
 $n_h=$width*$per;

 $new=imagecreatetruecolor($n_w, $n_h);
 $img=imagecreatefromjpeg($filename);
//拷贝部分图像并调整
 imagecopyresized($new, $img,0, 0,0, 0,$n_w, $n_h, $width, $height);
//图像输出新图片、另存为
 imagejpeg($new, "./images/hee2.jpg");
 imagedestroy($new);
 imagedestroy($img);

图片等比例缩放、没处理透明色

function thumn($background, $width, $height, $newfile) {
 list($s_w, $s_h)=getimagesize($background);//获取原图片高度、宽度

 if ($width && ($s_w < $s_h)) {
     $width = ($height / $s_h) * $s_w;
 } else {
     $height = ($width / $s_w) * $s_h;
 }
 $new=imagecreatetruecolor($width, $height);
 $img=imagecreatefromjpeg($background);
 imagecopyresampled($new, $img, 0, 0, 0, 0, $width, $height, $s_w, $s_h);
 imagejpeg($new, $newfile);
 imagedestroy($new);
 imagedestroy($img);
}
thumn("images/hee.jpg", 200, 200, "./images/hee3.jpg");

gif透明色处理

function thumn($background, $width, $height, $newfile) {
 list($s_w, $s_h)=getimagesize($background);

 if ($width && ($s_w < $s_h)) {
     $width = ($height / $s_h) * $s_w;
 } else {
     $height = ($width / $s_w) * $s_h;
 }
 $new=imagecreatetruecolor($width, $height);
 $img=imagecreatefromgif($background);
 $otsc=imagecolortransparent($img);
 if($otsc >=0 && $otst < imagecolorstotal($img)){//判断索引色
  $tran=imagecolorsforindex($img, $otsc);//索引颜色值
  $newt=imagecolorallocate($new, $tran["red"], $tran["green"], $tran["blue"]);
  imagefill($new, 0, 0, $newt);
  imagecolortransparent($new, $newt);
 }
 imagecopyresized($new, $img, 0, 0, 0, 0, $width, $height, $s_w, $s_h);
 imagegif($new, $newfile);
 imagedestroy($new);
 imagedestroy($img);
}
thumn("images/map.gif", 200, 200, "./images/map3.gif");

图片裁剪

function cut($background, $cut_x, $cut_y, $cut_width, $cut_height, $location){

 $back=imagecreatefromjpeg($background);
 $new=imagecreatetruecolor($cut_width, $cut_height);
 imagecopyresampled($new, $back, 0, 0, $cut_x, $cut_y, $cut_width, $cut_height,$cut_width,$cut_height);
 imagejpeg($new, $location);
 imagedestroy($new);
 imagedestroy($back);
}
cut("./images/hee.jpg", 440, 140, 117, 112, "./images/hee5.jpg");

图片加水印

文字水印

function mark_text($background, $text, $x, $y){
  $back=imagecreatefromjpeg($background);

  $color=imagecolorallocate($back, 0, 255, 0);
  imagettftext($back, 20, 0, $x, $y, $color, "simkai.ttf", $text);
  imagejpeg($back, "./images/hee7.jpg");
  imagedestroy($back);
 }
 mark_text("./images/hee.jpg", "细说PHP", 150, 250);
//图片水印
function mark_pic($background, $waterpic, $x, $y){
$back=imagecreatefromjpeg($background);
$water=imagecreatefromgif($waterpic);
$w_w=imagesx($water);
$w_h=imagesy($water);
imagecopy($back, $water, $x, $y, 0, 0, $w_w, $w_h);
imagejpeg($back,"./images/hee8.jpg");
imagedestroy($back);
imagedestroy($water);
}
mark_pic("./images/hee.jpg", "./images/gaolf.gif", 50, 200);

图片旋转

$back=imagecreatefromjpeg("./images/hee.jpg");
 $new=imagerotate($back, 45, 0);
 imagejpeg($new, "./images/hee9.jpg");

图片水平翻转垂直翻转

function turn_y($background, $newfile){
  $back=imagecreatefromjpeg($background);

  $width=imagesx($back);
  $height=imagesy($back);
  $new=imagecreatetruecolor($width, $height);
  for($x=0; $x < $width; $x++){
   imagecopy($new, $back, $width-$x-1, 0, $x, 0, 1, $height);
  }
  imagejpeg($new, $newfile);
  imagedestroy($back);
  imagedestroy($new);
 }
 function turn_x($background, $newfile){
  $back=imagecreatefromjpeg($background);
  $width=imagesx($back);
  $height=imagesy($back);
  $new=imagecreatetruecolor($width, $height);
  for($y=0; $y < $height; $y++){
   imagecopy($new, $back,0, $height-$y-1, 0, $y, $width, 1);
  }
  imagejpeg($new, $newfile);
  imagedestroy($back);
  imagedestroy($new);
 }
 turn_y("./images/hee.jpg", "./images/hee11.jpg");
 turn_x("./images/hee.jpg", "./images/hee12.jpg");

 图片锐化

function sharp($background, $degree, $save){
 $back=imagecreatefromjpeg($background);

 $b_x=imagesx($back);
 $b_y=imagesy($back);
 $dst=imagecreatefromjpeg($background);
 for($i=0; $i<$b_x; $i++){
  for($j=0; $j<$b_y; $j++){
   $b_clr1=imagecolorsforindex($back, imagecolorat($back, $i-1, $j-1));\\前一个像素颜色数组
   $b_clr2=imagecolorsforindex($back, imagecolorat($back, $i, $j));\\取出当前颜色数组
   $r=intval($b_clr2["red"]+$degree*($b_clr2["red"]-$b_clr1["red"]));\\加深
   $g=intval($b_clr2["green"]+$degree*($b_clr2["green"]-$b_clr1["green"]));
   $b=intval($b_clr2["blue"]+$degree*($b_clr2["blue"]-$b_clr1["blue"]));
   $r=min(255, max($r, 0));//限制r范围在0-255之间
   $g=min(255, max($g, 0));
   $b=min(255, max($b, 0));
   if(($d_clr=imagecolorexact($dst, $r, $g, $b))==-1){//等于1不在颜色范围内
    $d_clr=Imagecolorallocate($dst, $r, $g, $b);//创建一个颜色
   }
   imagesetpixel($dst, $i, $j, $d_clr);
  }
 }
 imagejpeg($dst, $save);
 imagedestroy($back);
 imagedestroy($dst);
}
sharp("./images/hee.jpg", 20, "./images/hee13.jpg");