PHP圖片壓縮類,部分來源於網絡(侵則刪),部分自己改寫拼湊成一個類。該類封裝了了PHP7沒有的imagecreatefrombmp等的相關方法(7.2有提供這個方法)
<?php
/**
* Created by PhpStorm.
* User: Administrator
* Date: 2019/12/18
* Time: 9:56
*/
namespace App\Service\ImageDeal;
/**
* 圖片壓縮類:通過縮放來壓縮。如果要保持源圖比例,把參數$percent保持爲1即可。
* 即使原比例壓縮,也可大幅度縮小。數碼相機4M圖片。也可以縮爲700KB左右。如果縮小比例,則體積會更小。
* 結果:可保存、可直接顯示。
*
* 使用方法
* $dst_img = './ss.bmp'; //可加存放路徑
$source = './ss.bmp'; //可加存放路徑(可以直接保留回原圖)
$percent = 1; #原圖壓縮,不縮放
$image = (new ImageCompressService($source,$percent))->compressImg($dst_img); //調用示例
*/
Class ImageCompressService{
private $src;
public $image;
private $imageinfo;
private $percent = 0.5;
/**
* 圖片壓縮
* @param $src 源圖
* @param float $percent 壓縮比例
*/
public function __construct($src, $percent=1)
{
$this->src = $src;
$this->percent = $percent;
}
/** 高清壓縮圖片
* @param string $saveName 提供圖片名(可不帶擴展名,用源圖擴展名)用於保存。或不提供文件名直接顯示
*/
public function compressImg($saveName='')
{
$this->_openImage();
if(!empty($saveName)) $this->_saveImage($saveName); //保存
else $this->_showImage();
}
/**
* 內部:打開圖片
*/
private function _openImage()
{
list($width, $height, $type, $attr) = getimagesize($this->src);
$this->imageinfo = array(
'width'=>$width,
'height'=>$height,
'type'=>image_type_to_extension($type,false),
'attr'=>$attr
);
if($this->imageinfo['type'] == 'bmp'){
$this->image = $this->imagecreatefrombmp($this->src); // 自己編寫的bmp處理方法
}else{
$fun = "imagecreatefrom".$this->imageinfo['type']; //調用php方法
$this->image = $fun($this->src);
}
$this->_thumpImage();
}
/**
* 內部:操作圖片
*/
private function _thumpImage()
{
$new_width = $this->imageinfo['width'] * $this->percent;
$new_height = $this->imageinfo['height'] * $this->percent;
$image_thump = imagecreatetruecolor($new_width,$new_height);
//將原圖複製帶圖片載體上面,並且按照一定比例壓縮,極大的保持了清晰度
imagecopyresampled($image_thump,$this->image,0,0,0,0,$new_width,$new_height,$this->imageinfo['width'],$this->imageinfo['height']);
imagedestroy($this->image);
$this->image = $image_thump;
}
/**
* 輸出圖片:保存圖片則用saveImage()
*/
private function _showImage()
{
header('Content-Type: image/'.$this->imageinfo['type']);
$funcs = "image".$this->imageinfo['type'];
$funcs($this->image);
}
/**
* 保存圖片到硬盤:
* @param string $dstImgName 1、可指定字符串不帶後綴的名稱,使用源圖擴展名 。2、直接指定目標圖片名帶擴展名。
*/
private function _saveImage($dstImgName)
{
if(empty($dstImgName)) return false;
$allowImgs = ['.jpg', '.jpeg', '.png', '.bmp', '.wbmp','.gif']; //如果目標圖片名有後綴就用目標圖片擴展名 後綴,如果沒有,則用源圖的擴展名
$dstExt = strrchr($dstImgName ,".");
$sourseExt = strrchr($this->src ,".");
if(!empty($dstExt)) $dstExt =strtolower($dstExt);
if(!empty($sourseExt)) $sourseExt =strtolower($sourseExt);
//有指定目標名擴展名
if(!empty($dstExt) && in_array($dstExt,$allowImgs)){
$dstName = $dstImgName;
}elseif(!empty($sourseExt) && in_array($sourseExt,$allowImgs)){
$dstName = $dstImgName.$sourseExt;
}else{
$dstName = $dstImgName.$this->imageinfo['type'];
}
if($this->imageinfo['type'] == 'bmp'){
$this->imagebmp($this->image,$dstName); //調用外部方法
}else{
$funcs = "image".$this->imageinfo['type'];
$funcs($this->image,$dstName);
}
}
/**
* 銷燬圖片
*/
public function __destruct(){
if(is_resource($this->image)){
imagedestroy($this->image);
}
}
/**
* 補全bmp相關的方法(函數)
*/
function imagecreatefrombmp($file)
{
global $CurrentBit, $echoMode;
$f=fopen($file,"r");
$Header=fread($f,2);
if($Header=="BM")
{
$Size=$this->freaddword($f);
$Reserved1=$this->freadword($f);
$Reserved2=$this->freadword($f);
$FirstByteOfImage=$this->freaddword($f);
$SizeBITMAPINFOHEADER=$this->freaddword($f);
$Width=$this->freaddword($f);
$Height=$this->freaddword($f);
$biPlanes=$this->freadword($f);
$biBitCount=$this->freadword($f);
$RLECompression=$this->freaddword($f);
$WidthxHeight=$this->freaddword($f);
$biXPelsPerMeter=$this->freaddword($f);
$biYPelsPerMeter=$this->freaddword($f);
$NumberOfPalettesUsed=$this->freaddword($f);
$NumberOfImportantColors=$this->freaddword($f);
if($biBitCount<24)
{
$img=imagecreate($Width,$Height);
$Colors=pow(2,$biBitCount);
for($p=0;$p<$Colors;$p++)
{
$B=$this->freadbyte($f);
$G=$this->freadbyte($f);
$R=$this->freadbyte($f);
$Reserved=$this->freadbyte($f);
$Palette[]=imagecolorallocate($img,$R,$G,$B);
}
if($RLECompression==0)
{
$Zbytek=(4-ceil(($Width/(8/$biBitCount)))%4)%4;
for($y=$Height-1;$y>=0;$y--)
{
$CurrentBit=0;
for($x=0;$x<$Width;$x++)
{
$C=$this->freadbits($f,$biBitCount);
imagesetpixel($img,$x,$y,$Palette[$C]);
}
if($CurrentBit!=0) {$this->freadbyte($f);}
for($g=0;$g<$Zbytek;$g++)
$this->freadbyte($f);
}
}
}
if($RLECompression==1) //$BI_RLE8
{
$y=$Height;
$pocetb=0;
while(true)
{
$y--;
$prefix=$this->freadbyte($f);
$suffix=$this->freadbyte($f);
$pocetb+=2;
$echoit=false;
if($echoit)echo "Prefix: $prefix Suffix: $suffix<BR>";
if(($prefix==0)and($suffix==1)) break;
if(feof($f)) break;
while(!(($prefix==0)and($suffix==0)))
{
if($prefix==0)
{
$pocet=$suffix;
$Data.=fread($f,$pocet);
$pocetb+=$pocet;
if($pocetb%2==1) {$this->freadbyte($f); $pocetb++;}
}
if($prefix>0)
{
$pocet=$prefix;
for($r=0;$r<$pocet;$r++)
$Data.=chr($suffix);
}
$prefix=$this->freadbyte($f);
$suffix=$this->freadbyte($f);
$pocetb+=2;
if($echoit) echo "Prefix: $prefix Suffix: $suffix<BR>";
}
for($x=0;$x<strlen($Data);$x++)
{
imagesetpixel($img,$x,$y,$Palette[ord($Data[$x])]);
}
$Data="";
}
}
if($RLECompression==2) //$BI_RLE4
{
$y=$Height;
$pocetb=0;
/*while(!feof($f))
echo freadbyte($f)."_".freadbyte($f)."<BR>";*/
while(true)
{
//break;
$y--;
$prefix=$this->freadbyte($f);
$suffix=$this->freadbyte($f);
$pocetb+=2;
$echoit=false;
if($echoit)echo "Prefix: $prefix Suffix: $suffix<BR>";
if(($prefix==0)and($suffix==1)) break;
if(feof($f)) break;
while(!(($prefix==0)and($suffix==0)))
{
if($prefix==0)
{
$pocet=$suffix;
$CurrentBit=0;
for($h=0;$h<$pocet;$h++)
$Data.=chr($this->freadbits($f,4));
if($CurrentBit!=0) $this->freadbits($f,4);
$pocetb+=ceil(($pocet/2));
if($pocetb%2==1) {$this->freadbyte($f); $pocetb++;}
}
if($prefix>0)
{
$pocet=$prefix;
$i=0;
for($r=0;$r<$pocet;$r++)
{
if($i%2==0)
{
$Data.=chr($suffix%16);
}
else
{
$Data.=chr(floor($suffix/16));
}
$i++;
}
}
$prefix=$this->freadbyte($f);
$suffix=$this->freadbyte($f);
$pocetb+=2;
if($echoit) echo "Prefix: $prefix Suffix: $suffix<BR>";
}
for($x=0;$x<strlen($Data);$x++)
{
imagesetpixel($img,$x,$y,$Palette[ord($Data[$x])]);
}
$Data="";
}
}
if($biBitCount==24)
{
$img=imagecreatetruecolor($Width,$Height);
$Zbytek=$Width%4;
for($y=$Height-1;$y>=0;$y--)
{
for($x=0;$x<$Width;$x++)
{
$B=$this->freadbyte($f);
$G=$this->freadbyte($f);
$R=$this->freadbyte($f);
$color=imagecolorexact($img,$R,$G,$B);
if($color==-1) $color=imagecolorallocate($img,$R,$G,$B);
imagesetpixel($img,$x,$y,$color);
}
for($z=0;$z<$Zbytek;$z++)
$this->freadbyte($f);
}
}
return $img;
}
fclose($f);
}
function freadbits($f, $biBitCount,&$echoMode='')
{ $str='';
if($biBitCount==4){
if($echoMode==false){
$echoMode=true;
$str = $this->freadbyte($f);
fseek($f, -1,SEEK_CUR);
$str = $str >> 4;
return $str & 0x0f;
}else{
$str = $this->freadbyte($f);
$echoMode = false;
return $str & 0x0f;
}
}
if($biBitCount == 8){
$str=$this->freadbyte($f);
return $str & 0xff;
}
}
function freadbyte($f)
{
return ord(fread($f,1));
}
function freadword($f)
{
$b1=$this->freadbyte($f);
$b2=$this->freadbyte($f);
return $b2*256+$b1;
}
function freaddword($f)
{
$b1=$this->freadword($f);
$b2=$this->freadword($f);
return $b2*65536+$b1;
}
/*格式組成典型的BMP圖像文件由四部分組成:
1:位圖頭文件數據結構,它包含BMP圖像文件的類型、顯示內容等信息;
2:位圖信息數據結構,它包含有BMP圖像的寬、高、壓縮方法,以及定義顏色等信息;
3:調色板,這個部分是可選的,有些位圖需要調色板,有些位圖,比如真彩色圖(24位的BMP)就不需要調色板;
4:位圖數據,這部分的內容根據BMP位圖使用的位數不同而不同,在24位圖中直接使用RGB,而其他的小於24位的使用調色板中顏色索引值。
*/
function imagebmp(&$im, $filename = '', $bit = 8, $compression = 0)
{
if (!in_array($bit, array(1, 4, 8, 16, 24, 32)))
{
$bit = 8; //記錄每個像素所佔計算機字節的位數,默認爲8位
}
else if ($bit == 32) // todo:32 bit
{
$bit = 24;
}
$bits = pow(2, $bit); //表示待創建的圖像一共由$bits種顏色組成
// 將圖像調整爲調色板圖像,便於以後繪圖,如果是24位BMP位圖,那麼就不需要這一步
/*調色板是被保存在一個RGBQUAD結構的數組中,該結構指出了每一種顏色的紅、綠、藍的分量值。
*位數組中的每一個索引都對應於一個調色板項(即一個RGBQUAD結構),應用程序將根據這種對
*應關係,將像素索引值轉換爲像素RGB值(真實的像素顏色)
* */
imagetruecolortopalette($im, true, $bits);
$width = imagesx($im);
$height = imagesy($im);
$colors_num = imagecolorstotal($im); //返回的一般都是256
// 顏色索引
$rgb_quad = '';
if ($bit <= 8)//僅針對1,4,8位BMP位圖建立顏色索引
{
for ($i = 0; $i < $colors_num; $i ++)
{
$colors = imagecolorsforindex($im, $i);//每一幅圖的索引表都是不一樣的!
$rgb_quad .= chr($colors['blue']) . chr($colors['green']) . chr($colors['red']) . "\0";
}
// 位圖數據
$bmp_data = '';
// 非壓縮,即對RGB值不進行壓縮,讀取時順序爲BGR,高位在前,低位在後
if ($compression == 0 || $bit < 8)
{
$compression = 0;
// 每行字節數必須爲4的倍數,補齊。
$extra = '';
$padding = 32 - ( $width * $bit ) % 32 ;
if ($padding % 32 != 0)
{
$extra = str_repeat("\0", $padding);
}
for ($j = $height - 1; $j >= 0; $j --)
{
$i = 0;
while ($i < $width)
{
$bin = 0;
$limit = $width - $i < 8 / $bit ? (8 / $bit - $width + $i) * $bit : 0;
for ($k = 8 - $bit; $k >= $limit; $k -= $bit)
{
$index = imagecolorat($im, $i, $j);
$bin |= $index << $k;
$i ++;
}
$bmp_data .= chr($bin);
}
$bmp_data .= $extra;
}
}
// RLE8 壓縮
else if ($compression == 1 && $bit == 8)
{
for ($j = $height - 1; $j >= 0; $j --)
{
$last_index = "\0";
$same_num = 0;
for ($i = 0; $i <= $width; $i ++)
{
$index = imagecolorat($im, $i, $j);
if ($index !== $last_index || $same_num > 255)
{
if ($same_num != 0)
{
$bmp_data .= chr($same_num) . chr($last_index);
}
$last_index = $index;
$same_num = 1;
}
else
{
$same_num ++;
}
}
$bmp_data .= "\0\0";
}
$bmp_data .= "\0\1";
}
$size_quad = strlen($rgb_quad);
$size_data = strlen($bmp_data);
}
else
{
// 每行字節數必須爲4的倍數,補齊。
$extra = '';
$padding = 4 - ($width * ($bit / 8)) % 4;
if ($padding % 4 != 0)
{
$extra = str_repeat("\0", $padding);
}
// 位圖數據
$bmp_data = '';
for ($j = $height - 1; $j >= 0; $j --)
{
for ($i = 0; $i < $width; $i ++)
{
$index = imagecolorat($im, $i, $j);
$colors = imagecolorsforindex($im, $index);
if ($bit == 16)
{
$bin = 0 << $bit;
$bin |= ($colors['red'] >> 3) << 10;
$bin |= ($colors['green'] >> 3) << 5;
$bin |= $colors['blue'] >> 3;
$bmp_data .= pack("v", $bin);
}
else
{
$bmp_data .= pack("c*", $colors['blue'], $colors['green'], $colors['red']);
}
// todo: 32bit;
}
$bmp_data .= $extra;
}
$size_quad = 0;
$size_data = strlen($bmp_data);
$colors_num = 0;
}
// 位圖文件頭
$file_header = "BM" . pack("V3", 54 + $size_quad + $size_data, 0, 54 + $size_quad);
// 位圖信息頭
$info_header = pack("V3v2V*", 0x28, $width, $height, 1, $bit, $compression, $size_data, 0, 0, $colors_num, 0);
// 寫入文件
if ($filename != '')
{
$fp = fopen($filename, "wb");
fwrite($fp, $file_header);
fwrite($fp, $info_header);
if($rgb_quad!=='')
fwrite($fp, $rgb_quad);
fwrite($fp, $bmp_data);
fclose($fp);
return true;
}
// 瀏覽器輸出
header("Content-Type: image/bmp");
echo $file_header . $info_header;
echo $rgb_quad;
echo $bmp_data;
return true;
}
}