图片品质前后对比 : var_dump(exif_read_data($img));查看 ,严重失真压缩比为 50%。 压缩前: array (size=18) 'FileName' = string '1367000585017724053.JPG' (length=23) 'FileDateTime' = int 1367029384 'FileSize' = int 67872 'FileType' = int 2 '
图片品质前后对比 : var_dump(exif_read_data($img));查看 ,严重失真压缩比为 50%。
<strong>压缩前:</strong>
<strong>array</strong> <em>(size=18)</em> 'FileName' <span>=></span> <small>string</small> <span>'1367000585017724053.JPG'</span> <em>(length=23)</em> 'FileDateTime' <span>=></span> <small>int</small> <span>1367029384</span> 'FileSize' <span>=></span> <small>int</small> <span>67872</span> 'FileType' <span>=></span> <small>int</small> <span>2</span> 'MimeType' <span>=></span> <small>string</small> <span>'image/jpeg'</span> <em>(length=10)</em> 'divsFound' <span>=></span> <small>string</small> <span>'ANY_TAG, IFD0, THUMBNAIL, EXIF'</span> <em>(length=30)</em> 'COMPUTED' <span>=></span> <strong>array</strong> <em>(size=7)</em> 'html' <span>=></span> <small>string</small> <span>'width="300" height="300"'</span> <em>(length=24)</em> 'Height' <span>=></span> <small>int</small> <span>300</span> 'Width' <span>=></span> <small>int</small> <span>300</span> 'IsColor' <span>=></span> <small>int</small> <span>1</span> 'ByteOrderMotorola' <span>=></span> <small>int</small> <span>1</span> 'Thumbnail.FileType' <span>=></span> <small>int</small> <span>2</span> 'Thumbnail.MimeType' <span>=></span> <small>string</small> <span>'image/jpeg'</span> <em>(length=10)</em> 'Orientation' <span>=></span> <small>int</small> <span>1</span> 'XResolution' <span>=></span> <small>string</small> <span>'72/1'</span> <em>(length=4)</em> 'YResolution' <span>=></span> <small>string</small> <span>'72/1'</span> <em>(length=4)</em> 'ResolutionUnit' <span>=></span> <small>int</small> <span>2</span> 'Software' <span>=></span> <small>string</small> <span>'Adobe Photoshop CS Windows'</span> <em>(length=26)</em> 'DateTime' <span>=></span> <small>string</small> <span>'2013:04:26 10:56:18'</span> <em>(length=19)</em> 'Exif_IFD_Pointer' <span>=></span> <small>int</small> <span>164</span> 'THUMBNAIL' <span>=></span> <strong>array</strong> <em>(size=6)</em> 'Compression' <span>=></span> <small>int</small> <span>6</span> 'XResolution' <span>=></span> <small>string</small> <span>'72/1'</span> <em>(length=4)</em> 'YResolution' <span>=></span> <small>string</small> <span>'72/1'</span> <em>(length=4)</em> 'ResolutionUnit' <span>=></span> <small>int</small> <span>2</span> 'JPEGInterchangeFormat' <span>=></span> <small>int</small> <span>302</span> 'JPEGInterchangeFormatLength' <span>=></span> <small>int</small> <span>5519</span> 'ColorSpace' <span>=></span> <small>int</small> <span>1</span> 'ExifImageWidth' <span>=></span> <small>int</small> <span>300</span> 'ExifImageLength' <span>=></span> <small>int</small> <span>300</span>
<strong>压缩之后:</strong>
<strong>array</strong> <em>(size=8)</em> 'FileName' <span>=></span> <small>string</small> <span>'1367000585108300044.jpg'</span> <em>(length=23)</em> 'FileDateTime' <span>=></span> <small>int</small> <span>1367029385</span> 'FileSize' <span>=></span> <small>int</small> <span>38802</span> 'FileType' <span>=></span> <small>int</small> <span>2</span> 'MimeType' <span>=></span> <small>string</small> <span>'image/jpeg'</span> <em>(length=10)</em> 'divsFound' <span>=></span> <small>string</small> <span>'COMMENT'</span> <em>(length=7)</em> 'COMPUTED' <span>=></span> <strong>array</strong> <em>(size=4)</em> 'html' <span>=></span> <small>string</small> <span>'width="300" height="300"'</span> <em>(length=24)</em> 'Height' <span>=></span> <small>int</small> <span>300</span> 'Width' <span>=></span> <small>int</small> <span>300</span> 'IsColor' <span>=></span> <small>int</small> <span>1</span> 'COMMENT' <span>=></span> <strong>array</strong> <em>(size=1)</em> 0 <span>=></span> <small>string</small> <span>'CREATOR: gd-jpeg v1.0 (using IJG JPEG v62), quality = 100 '</span> <em>(length=58)</em>
<?php $img_thumb = imagecreatetruecolor($thumb_width, $thumb_height); $bgcolor = trim($bgcolor,"#"); sscanf($bgcolor, "%2x%2x%2x", $red, $green, $blue); $clr = imagecolorallocate($img_thumb, $red, $green, $blue); imagefilledrectangle($img_thumb, 0, 0, $thumb_width, $thumb_height, $clr); imagecopyresampled($img_thumb, $img_org, $dst_x, $dst_y, 0, 0, $lessen_width, $lessen_height, $org_info[0], $org_info[1]);
图片只要经过那个函数的压缩,仍旧是失真的,图片文件大小压缩率为 50%。