function.imagecopyresampled.html

来自「php的帮助文档,涉及到PHP的案例和基本语法,以及实际应用内容」· HTML 代码 · 共 308 行 · 第 1/2 页

       y-coordinate of source point.
      </p>
     </dd>

    </dt>

    <dt>

     <span class="term"><i><tt class="parameter">dst_w</tt></i>
</span>

     <dd>

      <p class="para">
       Destination width.
      </p>
     </dd>

    </dt>

    <dt>

     <span class="term"><i><tt class="parameter">dst_h</tt></i>
</span>

     <dd>

      <p class="para">
       Destination height.
      </p>
     </dd>

    </dt>

    <dt>

     <span class="term"><i><tt class="parameter">src_w</tt></i>
</span>

     <dd>

      <p class="para">
       Source width.
      </p>
     </dd>

    </dt>

    <dt>

     <span class="term"><i><tt class="parameter">src_h</tt></i>
</span>

     <dd>

      <p class="para">
       Source height.
      </p>
     </dd>

    </dt>

   </dl>

  </p>
 </div>

 <div class="refsect1 returnvalues">
  <h3 class="title">Return Values</h3>
  <p class="para">
   Returns <b><tt>TRUE</tt></b> on success or <b><tt>FALSE</tt></b> on failure.
  </p>
 </div>

 <div class="refsect1 examples">
  <h3 class="title">Examples</h3>
  <p class="para">
   <div class="example">
    <p><b>Example #1 Simple example</b></p>
    <div class="example-contents"><p>
     This example will resample an image to half its original size.
    </p></div>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #FF8000">//&nbsp;The&nbsp;file<br /></span><span style="color: #0000BB">$filename&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'test.jpg'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$percent&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">0.5</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">//&nbsp;Content&nbsp;type<br /></span><span style="color: #0000BB">header</span><span style="color: #007700">(</span><span style="color: #DD0000">'Content-type:&nbsp;image/jpeg'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">//&nbsp;Get&nbsp;new&nbsp;dimensions<br /></span><span style="color: #007700">list(</span><span style="color: #0000BB">$width</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$height</span><span style="color: #007700">)&nbsp;=&nbsp;</span><span style="color: #0000BB">getimagesize</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$new_width&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$width&nbsp;</span><span style="color: #007700">*&nbsp;</span><span style="color: #0000BB">$percent</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$new_height&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$height&nbsp;</span><span style="color: #007700">*&nbsp;</span><span style="color: #0000BB">$percent</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">//&nbsp;Resample<br /></span><span style="color: #0000BB">$image_p&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">imagecreatetruecolor</span><span style="color: #007700">(</span><span style="color: #0000BB">$new_width</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$new_height</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$image&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">imagecreatefromjpeg</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">imagecopyresampled</span><span style="color: #007700">(</span><span style="color: #0000BB">$image_p</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$image</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$new_width</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$new_height</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$width</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$height</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">//&nbsp;Output<br /></span><span style="color: #0000BB">imagejpeg</span><span style="color: #007700">(</span><span style="color: #0000BB">$image_p</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">null</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">100</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>The above example will output 
something similar to:</p></div>
    <div class="mediaobject">
     <div class="imageobject">
      <img src="figures/image.imagecopyresampled.jpg" />
     </div>
    </div>
   </div>
  </p>
  <p class="para">
   <div class="example">
    <p><b>Example #2 Resampling an image proportionally</b></p>
    <div class="example-contents"><p>
     This example will display an image with the maximum width,
     or height, of 200 pixels.
    </p></div>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #FF8000">//&nbsp;The&nbsp;file<br /></span><span style="color: #0000BB">$filename&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'test.jpg'</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">//&nbsp;Set&nbsp;a&nbsp;maximum&nbsp;height&nbsp;and&nbsp;width<br /></span><span style="color: #0000BB">$width&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">200</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$height&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">200</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">//&nbsp;Content&nbsp;type<br /></span><span style="color: #0000BB">header</span><span style="color: #007700">(</span><span style="color: #DD0000">'Content-type:&nbsp;image/jpeg'</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">//&nbsp;Get&nbsp;new&nbsp;dimensions<br /></span><span style="color: #007700">list(</span><span style="color: #0000BB">$width_orig</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$height_orig</span><span style="color: #007700">)&nbsp;=&nbsp;</span><span style="color: #0000BB">getimagesize</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$ratio_orig&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$width_orig</span><span style="color: #007700">/</span><span style="color: #0000BB">$height_orig</span><span style="color: #007700">;<br /><br />if&nbsp;(</span><span style="color: #0000BB">$width</span><span style="color: #007700">/</span><span style="color: #0000BB">$height&nbsp;</span><span style="color: #007700">&gt;&nbsp;</span><span style="color: #0000BB">$ratio_orig</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$width&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$height</span><span style="color: #007700">*</span><span style="color: #0000BB">$ratio_orig</span><span style="color: #007700">;<br />}&nbsp;else&nbsp;{<br />&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$height&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$width</span><span style="color: #007700">/</span><span style="color: #0000BB">$ratio_orig</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #FF8000">//&nbsp;Resample<br /></span><span style="color: #0000BB">$image_p&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">imagecreatetruecolor</span><span style="color: #007700">(</span><span style="color: #0000BB">$width</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$height</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$image&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">imagecreatefromjpeg</span><span style="color: #007700">(</span><span style="color: #0000BB">$filename</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">imagecopyresampled</span><span style="color: #007700">(</span><span style="color: #0000BB">$image_p</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$image</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">0</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$width</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$height</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$width_orig</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$height_orig</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">//&nbsp;Output<br /></span><span style="color: #0000BB">imagejpeg</span><span style="color: #007700">(</span><span style="color: #0000BB">$image_p</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">null</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">100</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>The above example will output 
something similar to:</p></div>
    <div class="mediaobject">
     <div class="imageobject">
      <img src="figures/image.imagecopyresampled_2.jpg" />
     </div>
    </div>
   </div>
  </p>
 </div>

 <div class="refsect1 notes">
  <h3 class="title">Notes</h3>
  <blockquote><p><b class="note">Note</b>: 
   
    There is a problem due to palette image limitations (255+1 colors).
    Resampling or filtering an image commonly needs more colors than 255, a
    kind of approximation is used to calculate the new resampled pixel and its
    color.  With a palette image we try to allocate a new color, if that
    failed, we choose the closest (in theory) computed color.  This is
    not always the closest visual color. That may produce a weird result, like
    blank (or visually blank) images.  To skip this problem, please use a
    truecolor image as a destination image, such as one created by
    <a href="function.imagecreatetruecolor.html" class="function">imagecreatetruecolor()</a>.
   <br />
  </p></blockquote>
 </div>

 <div class="refsect1 seealso">
  <h3 class="title">See Also</h3>
  <p class="para">
   <a href="function.imagecopyresized.html" class="function" rel="rdfs-seeAlso">imagecopyresized()</a>
  </p>
 </div>

</div><hr /><div style="text-align: center;">
 <div class="prev" style="text-align: left; float: left;"><a href="function.imagecopymergegray.html">imagecopymergegray</a></div>
 <div class="next" style="text-align: right; float: right;"><a href="function.imagecopyresized.html">imagecopyresized</a></div>
 <div class="up"><a href="ref.image.html">GD Functions</a></div>
 <div class="home"><a href="index.html">PHP Manual</a></div>
</div></body></html>