php生成图片缩略图类程序
缩略图用得最多的是我们上传图片时生成一张小图,这样就可以很好的解决图片大小或影响网站整体美观的问题了,下面介绍的生成图片缩略图类都不支持图片上传,我们要先上传再调用此类来操作.
使用如下类就可以生成图片缩略图,代码如下:
<?php
class resizeimage {
//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
{
if ($ratio >= $resize_ratio)
//高度优先
{
$newimg = imagecreatetruecolor($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, $this->dstimg);
}
if ($ratio < $resize_ratio)
//宽度优先
{
$newimg = imagecreatetruecolor($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,
//开源代码phprm.com
$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);
}
}
//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;
}
}
?>类的调用方法:
$resizeimage = new resizeimage("图片源文件地址", "200", "100", "0","缩略图地址");
就只用上面的一句话,就能生成缩略图,其中,源文件和缩略图地址可以相同,200,100分别代表宽和高.
实例2:PHP缩略图 等比例无损压缩,可填充空白区域补充色,代码如下:
<?php
error_reporting(E_ALL);
// 测试
imagezoom('1.jpg', '2.jpg', 400, 300, '#FFFFFF');
/*
php缩略图函数：
等比例无损压缩，可填充补充色 author: 华仔
主持格式：
bmp 、jpg 、gif、png
param:
@srcimage : 要缩小的图片
@dstimage : 要保存的图片
@dst_width: 缩小宽
@dst_height: 缩小高
@backgroundcolor: 补充色 如：#FFFFFF 支持 6位 不支持3位
*/
function imagezoom($srcimage, $dstimage, $dst_width, $dst_height, $backgroundcolor) {
// 中文件名乱码
if (PHP_OS == 'WINNT') {
$srcimage = iconv('UTF-8', 'GBK', $srcimage);
$dstimage = iconv('UTF-8', 'GBK', $dstimage);
}
$dstimg = imagecreatetruecolor($dst_width, $dst_height);
$color = imagecolorallocate($dstimg, hexdec(substr($backgroundcolor, 1, 2)) , hexdec(substr($backgroundcolor, 3, 2)) , hexdec(substr($backgroundcolor, 5, 2)));
imagefill($dstimg, 0, 0, $color);
if (!$arr = getimagesize($srcimage)) {
echo "要生成缩略图的文件不存在";
exit;
}
$src_width = $arr[0];
$src_height = $arr[1];
$srcimg = null;
$method = getcreatemethod($srcimage);
if ($method) {
eval('$srcimg = ' . $method . ';');
}
$dst_x = 0;
$dst_y = 0;
$dst_w = $dst_width;
$dst_h = $dst_height;
if (($dst_width / $dst_height - $src_width / $src_height) > 0) {
$dst_w = $src_width * ($dst_height / $src_height);
$dst_x = ($dst_width - $dst_w) / 2;
} elseif (($dst_width / $dst_height - $src_width / $src_height) < 0) {
$dst_h = $src_height * ($dst_width / $src_width);
$dst_y = ($dst_height - $dst_h) / 2;
}
imagecopyresampled($dstimg, $srcimg, $dst_x, $dst_y, 0, 0, $dst_w, $dst_h, $src_width, $src_height);
// 保存格式
$arr = array(
'jpg' => 'imagejpeg',
'jpeg' => 'imagejpeg',
'png' => 'imagepng',
'gif' => 'imagegif',
'bmp' => 'imagebmp'
);
$suffix = strtolower(array_pop(explode('.', $dstimage)));
if (!in_array($suffix, array_keys($arr))) {
echo "保存的文件名错误";
exit;
} else {
eval($arr[$suffix] . '($dstimg, "' . $dstimage . '");');
}
imagejpeg($dstimg, $dstimage);
imagedestroy($dstimg);
imagedestroy($srcimg);
}
function getcreatemethod($file) {
$arr = array(
'474946' => "imagecreatefromgif('$file')",
'FFD8FF' => "imagecreatefromjpeg('$file')",
'424D' => "imagecreatefrombmp('$file')",
'89504E' => "imagecreatefrompng('$file')"
);
$fd = fopen($file, "rb");
$data = fread($fd, 3);
$data = str2hex($data);
if (array_key_exists($data, $arr)) {
return $arr[$data];
} elseif (array_key_exists(substr($data, 0, 4) , $arr)) {
return $arr[substr($data, 0, 4) ];
} else {
return false;
}
}
function str2hex($str) {
$ret = "";
for ($i = 0; $i < strlen($str); $i++) {
$ret.= ord($str[$i]) >= 16 ? strval(dechex(ord($str[$i]))) : '0' . strval(dechex(ord($str[$i])));
}
return strtoupper($ret);
}
// BMP 创建函数 php本身无
function imagecreatefrombmp($filename) {
if (!$f1 = fopen($filename, "rb")) return FALSE;
$FILE = unpack("vfile_type/Vfile_size/Vreserved/Vbitmap_offset", fread($f1, 14));
if ($FILE['file_type'] != 19778) return FALSE;
$BMP = unpack('Vheader_size/Vwidth/Vheight/vplanes/vbits_per_pixel' . '/Vcompression/Vsize_bitmap/Vhoriz_resolution' . '/Vvert_resolution/Vcolors_used/Vcolors_important', fread($f1, 40));
$BMP['colors'] = pow(2, $BMP['bits_per_pixel']);
if ($BMP['size_bitmap'] == 0) $BMP['size_bitmap'] = $FILE['file_size'] - $FILE['bitmap_offset'];
$BMP['bytes_per_pixel'] = $BMP['bits_per_pixel'] / 8;
$BMP['bytes_per_pixel2'] = ceil($BMP['bytes_per_pixel']);
$BMP['decal'] = ($BMP['width'] * $BMP['bytes_per_pixel'] / 4);
$BMP['decal']-= floor($BMP['width'] * $BMP['bytes_per_pixel'] / 4);
$BMP['decal'] = 4 - (4 * $BMP['decal']);
if ($BMP['decal'] == 4) $BMP['decal'] = 0;
$PALETTE = array();
if ($BMP['colors'] < 16777216) {
$PALETTE = unpack('V' . $BMP['colors'], fread($f1, $BMP['colors'] * 4));
}
$IMG = fread($f1, $BMP['size_bitmap']);
$VIDE = chr(0);
$res = imagecreatetruecolor($BMP['width'], $BMP['height']);
$P = 0;
$Y = $BMP['height'] - 1;
while ($Y >= 0) {
$X = 0;
while ($X < $BMP['width']) {
if ($BMP['bits_per_pixel'] == 24) $COLOR = unpack("V", substr($IMG, $P, 3) . $VIDE);
elseif ($BMP['bits_per_pixel'] == 16) {
$COLOR = unpack("n", substr($IMG, $P, 2));
$COLOR[1] = $PALETTE[$COLOR[1] + 1];
} elseif ($BMP['bits_per_pixel'] == 8) {
$COLOR = unpack("n", $VIDE . substr($IMG, $P, 1));
$COLOR[1] = $PALETTE[$COLOR[1] + 1];
} elseif ($BMP['bits_per_pixel'] == 4) {
$COLOR = unpack("n", $VIDE . substr($IMG, floor($P) , 1));
if (($P * 2) % 2 == 0) $COLOR[1] = ($COLOR[1] >> 4);
else $COLOR[1] = ($COLOR[1] & 0x0F);
$COLOR[1] = $PALETTE[$COLOR[1] + 1];
} elseif ($BMP['bits_per_pixel'] == 1) {
$COLOR = unpack("n", $VIDE . substr($IMG, floor($P) , 1));
if (($P * 8) % 8 == 0) $COLOR[1] = $COLOR[1] >> 7;
elseif (($P * 8) % 8 == 1) $COLOR[1] = ($COLOR[1] & 0x40) >> 6;
elseif (($P * 8) % 8 == 2) $COLOR[1] = ($COLOR[1] & 0x20) >> 5;
elseif (($P * 8) % 8 == 3) $COLOR[1] = ($COLOR[1] & 0x10) >> 4;
elseif (($P * 8) % 8 == 4) $COLOR[1] = ($COLOR[1] & 0x8) >> 3;
elseif (($P * 8) % 8 == 5) $COLOR[1] = ($COLOR[1] & 0x4) >> 2;
elseif (($P * 8) % 8 == 6) $COLOR[1] = ($COLOR[1] & 0x2) >> 1;
elseif (($P * 8) % 8 == 7) $COLOR[1] = ($COLOR[1] & 0x1);
$COLOR[1] = $PALETTE[$COLOR[1] + 1];
} else return FALSE;
imagesetpixel($res, $X, $Y, $COLOR[1]);
$X++;
$P+= $BMP['bytes_per_pixel'];
}
$Y--;
$P+= $BMP['decal'];
}
fclose($f1);
return $res;
}
// BMP 保存函数，php本身无
function imagebmp($im, $fn = false) {
if (!$im) return false;
if ($fn === false) $fn = 'php://output';
$f = fopen($fn, "w");
if (!$f) return false;
$biWidth = imagesx($im);
$biHeight = imagesy($im);
$biBPLine = $biWidth * 3;
$biStride = ($biBPLine + 3) & ~3;
$biSizeImage = $biStride * $biHeight;
$bfOffBits = 54;
$bfSize = $bfOffBits + $biSizeImage;
fwrite($f, 'BM', 2);
fwrite($f, pack('VvvV', $bfSize, 0, 0, $bfOffBits));
fwrite($f, pack('VVVvvVVVVVV', 40, $biWidth, $biHeight, 1, 24, 0, $biSizeImage, 0, 0, 0, 0));
$numpad = $biStride - $biBPLine;
for ($y = $biHeight - 1; $y >= 0; --$y) {
for ($x = 0; $x < $biWidth; ++$x) {
$col = imagecolorat($im, $x, $y);
fwrite($f, pack('V', $col) , 3);
}
for ($i = 0; $i < $numpad; ++$i) fwrite($f, pack('C', 0));
}
fclose($f);
return true;
}
?>总结,第一个类文件不如第二个好,因为第一个生成图之后图片会有点变模糊,后面这个生成类是高质量的.
本文地址：http://www.phprm.com/tuxiang/fs4416.html
转载随意，但请附上文章地址:-)