Question

求 php自动生成缩略图代码...

求 php自动生成缩略图代码... 找了好久也没找到合适的...

最好使带详细注释的... 这样能更容易懂一点 .... 先谢谢

我邮箱1182155534@QQ.COM

Answer 1

已经发你邮箱，下面给出源代码及调用方法，php需要安装GD库，并且安装相应的支持（如JPEG支持、GIF支持等等）：
$thumbnail = new ImageResize();
$thumbnail->resizeimage(源图片完整路径, 缩略图宽度, 缩略图高度, 是否剪裁（0或者1）, 新图片完整路径);

class ImageResize {

//图片类型
var $type;

//实际宽度
var $width;

//实际高度
var $height;

//改变后的宽度
var $resize_width;

//改变后的高度
var $resize_height;

//是否裁图
var $cut;

//源图象
var $srcimg;

//目标图象地址
var $dstimg;

//临时创建的图象
var $im;

function resizeimage($img, $wid, $hei,$c,$dstpath) {
$this->srcimg = $img;
$this->resize_width = $wid;
$this->resize_height = $hei;
$this->cut = $c;

//图片的类型
$this->type = strtolower(substr(strrchr($this->srcimg,"."),1));

//初始化图象
$this->initi_img();

//目标图象地址
$this -> dst_img($dstpath);

//--
$this->width = imagesx($this->im);
$this->height = imagesy($this->im);

//生成图象
$this->newimg();

ImageDestroy ($this->im);
}

function newimg() {

//改变后的图象的比例
$resize_ratio = ($this->resize_width)/($this->resize_height);

//实际图象的比例
$ratio = ($this->width)/($this->height);

if(($this->cut)=="1") {
//裁图 高度优先
if($ratio>=$resize_ratio){
$newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);
imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,$this->resize_height, (($this->height)*$resize_ratio), $this->height);
ImageJpeg ($newimg,$this->dstimg);
}

//裁图 宽度优先
if($ratio<$resize_ratio) {
$newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);
imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, $this->resize_height, $this->width, (($this->width)/$resize_ratio));
ImageJpeg ($newimg,$this->dstimg);
}
} else {
//不裁图
if($ratio>=$resize_ratio) {
$newimg = imagecreatetruecolor($this->resize_width,($this->resize_width)/$ratio);
imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, ($this->resize_width)/$ratio, $this->width, $this->height);
ImageJpeg ($newimg,$this->dstimg);
}
if($ratio<$resize_ratio) {
$newimg = imagecreatetruecolor(($this->resize_height)*$ratio,$this->resize_height);
imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, ($this->resize_height)*$ratio, $this->resize_height, $this->width, $this->height);
ImageJpeg ($newimg,$this->dstimg);
}
}
}

//初始化图象
function initi_img() {
if($this->type=="jpg") {
$this->im = imagecreatefromjpeg($this->srcimg);
}

if($this->type=="gif") {
$this->im = imagecreatefromgif($this->srcimg);
}

if($this->type=="png") {
$this->im = imagecreatefrompng($this->srcimg);
}

if($this->type=="bmp") {
$this->im = $this->imagecreatefrombmp($this->srcimg);
}
}

//图象目标地址
function dst_img($dstpath) {
$full_length = strlen($this->srcimg);
$type_length = strlen($this->type);
$name_length = $full_length-$type_length;
$name = substr($this->srcimg,0,$name_length-1);
$this->dstimg = $dstpath;
//echo $this->dstimg;
}

function ConvertBMP2GD($src, $dest = false) {
if(!($src_f = fopen($src, "rb"))) {
return false;
}
if(!($dest_f = fopen($dest, "wb"))) {
return false;
}
$header = unpack("vtype/Vsize/v2reserved/Voffset", fread($src_f,14));
$info = unpack("Vsize/Vwidth/Vheight/vplanes/vbits/Vcompression/Vimagesize/Vxres/Vyres/Vncolor/Vimportant", fread($src_f, 40));

extract($info);
extract($header);

if($type != 0x4D42) { // signature "BM"
return false;
}

$palette_size = $offset - 54;
$ncolor = $palette_size / 4;
$gd_header = "";
// true-color vs. palette
$gd_header .= ($palette_size == 0) ? "\xFF\xFE" : "\xFF\xFF";
$gd_header .= pack("n2", $width, $height);
$gd_header .= ($palette_size == 0) ? "\x01" : "\x00";
if($palette_size) {
$gd_header .= pack("n", $ncolor);
}
// no transparency
$gd_header .= "\xFF\xFF\xFF\xFF";

fwrite($dest_f, $gd_header);

if($palette_size) {
$palette = fread($src_f, $palette_size);
$gd_palette = "";
$j = 0;
while($j < $palette_size) {
$b = $palette{$j++};
$g = $palette{$j++};
$r = $palette{$j++};
$a = $palette{$j++};
$gd_palette .= "$r$g$b$a";
}
$gd_palette .= str_repeat("\x00\x00\x00\x00", 256 - $ncolor);
fwrite($dest_f, $gd_palette);
}

$scan_line_size = (($bits * $width) + 7) >> 3;
$scan_line_align = ($scan_line_size & 0x03) ? 4 - ($scan_line_size &
0x03) : 0;

for($i = 0, $l = $height - 1; $i < $height; $i++, $l--) {
// BMP stores scan lines starting from bottom
fseek($src_f, $offset + (($scan_line_size + $scan_line_align) * $l));
$scan_line = fread($src_f, $scan_line_size);
if($bits == 24) {
$gd_scan_line = "";
$j = 0;
while($j < $scan_line_size) {
$b = $scan_line{$j++};
$g = $scan_line{$j++};
$r = $scan_line{$j++};
$gd_scan_line .= "\x00$r$g$b";
}
}
else if($bits == 8) {
$gd_scan_line = $scan_line;
}
else if($bits == 4) {
$gd_scan_line = "";
$j = 0;
while($j < $scan_line_size) {
$byte = ord($scan_line{$j++});
$p1 = chr($byte >> 4);
$p2 = chr($byte & 0x0F);
$gd_scan_line .= "$p1$p2";
}
$gd_scan_line = substr($gd_scan_line, 0, $width);
}
else if($bits == 1) {
$gd_scan_line = "";
$j = 0;
while($j < $scan_line_size) {
$byte = ord($scan_line{$j++});
$p1 = chr((int) (($byte & 0x80) != 0));
$p2 = chr((int) (($byte & 0x40) != 0));
$p3 = chr((int) (($byte & 0x20) != 0));
$p4 = chr((int) (($byte & 0x10) != 0));
$p5 = chr((int) (($byte & 0x08) != 0));
$p6 = chr((int) (($byte & 0x04) != 0));
$p7 = chr((int) (($byte & 0x02) != 0));
$p8 = chr((int) (($byte & 0x01) != 0));
$gd_scan_line .= "$p1$p2$p3$p4$p5$p6$p7$p8";
}
$gd_scan_line = substr($gd_scan_line, 0, $width);
}
fwrite($dest_f, $gd_scan_line);
}
fclose($src_f);
fclose($dest_f);
return true;
}

function imagecreatefrombmp($filename) {
$tmp_name = tempnam("/tmp", "GD");
if($this->ConvertBMP2GD($filename, $tmp_name)) {
$img = imagecreatefromgd($tmp_name);
unlink($tmp_name);
return $img;
}
return false;
}

}