php图片处理

一、创建图片资源

      imagecreatetruecolor(width,height)

      imagecreatefromgif(图片名称);

      imagecreatefromgif(图片名称);

      imagecreatefromgif(图片名称); 

      画出各种图形（圆形、矩形、线段、文字）

      imagegif(，图片位置)；//此时是保存图片，不输出到浏览器

     imagepng(,);

      imagejpeg(,);

      imagedestroy(图片资源)

二、获取图片的属性

     imagesx(res)

     imagesy(res)

     getimagesize(图片名称);//返回数组，0==width   1==height  2==type

三、透明处理

     png jpeg透明色都正常，只有gif不正常

     imagecolortransparent();

     imagecolorstotal();

     imagecolorsforindex();

例如：

<?php
function thumn($background,$width,$height,$newfile){
 list($s_w,$s_h)=getimagesize($background);
    if($width && $s_w<$s_h){
  $width=$s_w/$s_h*$height;
 }else{
  $height=$s_h/$s_w*$width;
 }
    $new=imagecreatetruecolor($width,$height);
 $img=imagecreatefromgif($background);
 $otsc=imagecolortransparent($img);
 if($otsc>=0 && $otsc<imagecolorstotal($img)){
     $tran=imagecolorsforindex($img,$otsc);
     $newt=imagecolorallocate($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("1.gif",200,200,"demo4.gif");
 
?>

四、图片裁剪

      imagecopyresized()

      imagecopyresampled()

<?php
function cut($background,$cut_x,$cut_y,$cut_width,$cut_height,$location){
    $back=imagecreatefromgif($background);
 $new=imagecreatetruecolor($cut_width,$cut_height);
 imagecopyresampled($new,$back,0,0,$cut_x,$cut_y,$cut_width,$cut_height,$cut_width,$cut_width);
 imagegif($new,$location);
 imagedestroy($new);
 imagedestroy($back);
}
cut("./demo.gif",10,20,100,100,"./demo7.gif");
?>

五、加水印（文字、图片）

<?php
   function mark_text($background,$test,$x,$y){
       $back=imagecreatefromgif($background);
    $color=imagecolorallocate($back,0,255,0);
    //iconv("utf-8","gb2312",$text);  下面的函数只能输出utf-8字体，如果编辑器不是的话，需要使用此函数
    imagettftext($back,20,0,$x,$y,$color,"simkai.ttf",$test);
       imagegif($back,"./demo33.gif");
    imagedestroy($back);
}
   mark_text("./demo.gif","细说PHP",100,150);
   function mark_pic($background,$waterpic,$x,$y){
       $back=imagecreatefromgif($background);
    $water=imagecreatefromgif($waterpic);
       $w_w=imagesx($water);
    $w_h=imagesy($water);
    imagecopy($back,$water,$x,$y,0,0,$w_w,$w_h);
    imagegif($back,"demo32.gif");
       imagedestroy($back);
   }
   mark_pic("./2.gif","./demo33.gif",0,0);
?>

六、图片旋转

imagerotate--用给定角度旋转图像

<?php
   $back=imagecreatefromgif("./demo.gif");
   //$color=imagecolorallocate($back,255,20,10);通过自己理解，此变量可放在下面那个函数当作第三个参数用
   $new=imagerotate($back,25,0);
   imagegif($new,"./demo9.gif");
?>

七、图片翻转

沿X轴

沿Y轴

<?php
   function turn_y($background,$newfile){
    $back=imagecreatefromgif($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,$height);
    }
    imagegif($new,$newfile);
    imagedestroy($new);
    imagedestroy($back);
   }
   function turn_x($background,$newfile){
    $back=imagecreatefromgif($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,$width,1);
    }
    imagegif($new,$newfile);
    imagedestroy($new);
    imagedestroy($back);
   }
   turn_y("./demo.gif","./demo10.gif");
   turn_x("./demo.gif","./demo20.gif");
?>

八、图片锐化

<?php
    function sharp($background,$degree,$save){
        $back=imagecreatefromgif($background);
  $b_x=imagesx($back);
  $b_y=imagesy($back);
  $dst=imagecreatefromgif($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));
      $b_clr2=imagecolorsforindex($back,imagecolorat($back,$i,$j));
      $r=intval($b_clr2["red"]+$degree*($b_clr2["red"]-$b_clr1["red"]));
      $g=intval($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));
      $g=min(255,max($g,0));
      $b=min(255,max($b,0));
               if(($d_clr=imagecolorexact($dst,$r,$g,$b))==-1){
       $d_clr=imagecolorallocate($dst,$r,$g,$b);
      }
      imagesetpixel($dst,$i,$j,$d_clr);
     }
  }
               imagejpeg($dst,$save);
         imagedestroy($back);
      imagedestroy($dst);
}
    sharp("./demo.gif",0.5,"./rh.gif");
 
?>