php生成高清縮略圖實例
php生成高清縮略圖的方法,較為詳細的分析了php生成縮略圖時出現失真的解決方法,并給出了完整實例進行總結分析,需要的朋友可以參考下。
在使用php的函數生成縮略圖的使用，縮略圖很多情況下都會失真，這個時候需要有一些對應的解決方法。
1.用imagecreatetruecolor和imageCopyreSampled函數分別取代imagecreate和imagecopyresized
2.給imagejpeg的第三個參數帶上100(例:imagejpeg($ni,$toFile,100))
下面是具體的函數
function CreateSmallImage( $OldImagePath, $NewImagePath, $NewWidth=154, $NewHeight=134)
{
/pic/2jpg/3png),3(width="638" height="340")
$OldImageInfo = getimagesize($OldImagePath);
if ( $OldImageInfo[2] == 1 ) $OldImg = @imagecreatefromgif($OldImagePath);
elseif ( $OldImageInfo[2] == 2 ) $OldImg = @imagecreatefromjpeg($OldImagePath);
else $OldImg = @imagecreatefrompng($OldImagePath);
/pic/p>
$NewImg = imagecreatetruecolor( $NewWidth, $NewHeight );
/pic/p>
$black = ImageColorAllocate( $NewImg, 0, 0, 0 ); /pic/p>
$white = ImageColorAllocate( $NewImg, 255, 255, 255 ); /pic/p>
$red = ImageColorAllocate( $NewImg, 255, 0, 0 ); /pic/p>
$blue = ImageColorAllocate( $NewImg, 0, 0, 255 ); /pic/p>
$other = ImageColorAllocate( $NewImg, 0, 255, 0 );
/pic/p>
$WriteNewWidth = $NewHeight*($OldImageInfo[0] / $OldImageInfo[1]); /pic/p>
$WriteNewHeight = $NewWidth*($OldImageInfo[1] / $OldImageInfo[0]); /pic/p>
/pic/p>
if ($OldImageInfo[0] / $NewWidth > $org_info[1] / $NewHeight) {
$WriteNewWidth = $NewWidth;
$WriteNewHeight = $NewWidth / ($OldImageInfo[0] / $OldImageInfo[1]);
} else {
$WriteNewWidth = $NewHeight * ($OldImageInfo[0] / $OldImageInfo[1]);
$WriteNewHeight = $NewHeight;
}
/pic/p>
if ( $WriteNewWidth <= $NewWidth ) {
$WriteNewWidth = $WriteNewWidth; /pic/p>
$WriteNewHeight = $NewHeight; /pic/p>
$WriteX = floor( ($NewWidth-$WriteNewWidth) / 2 ); /pic/p>
$WriteY = 0;
} else {
$WriteNewWidth = $NewWidth; /pic/p>
$WriteNewHeight = $WriteNewHeight; /pic/p>
$WriteX = 0;
$WriteY = floor( ($NewHeight-$WriteNewHeight) / 2 ); /pic/p>
}
/pic/p>
@imageCopyreSampled( $NewImg, $OldImg, $WriteX, $WriteY, 0, 0, $WriteNewWidth, $WriteNewHeight, $OldImageInfo[0], $OldImageInfo[1] );
/pic/p>
/pic/p>
@imagejpeg($NewImg, $NewImagePath, 100);
/pic/p>
@imagedestroy($NewImg);
}
CreateSmallImage("./images/jiexie.jpg","./images/jiexie.small.jpg",200,300);
CreateSmallImage("./images/jiexie.jpg","./images/jiexie.middle.jpg",400,500);
希望本文所述對大家php程序設計有所幫助。
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