magick-wand.html - Android社区 - https://www.androidos.net.cn/




<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8"  />
  <meta name="viewport" content="width=device-width,minimum-scale=1,initial-scale=1,shrink-to-fit=no"  />
  <title>MagickWand, C API @ ImageMagick</title>
  <meta name="application-name" content="ImageMagick" />
  <meta name="description" content="Use ImageMagick® to create, edit, compose, or convert bitmap images. You can resize your image, crop it, change its shades and colors, add captions, among other operations." />
  <meta name="application-url" content="https://imagemagick.org" />
  <meta name="generator" content="PHP" />
  <meta name="keywords" content="magickwc, api, ImageMagick, PerlMagick, image processing, image, photo, software, Magick++, OpenMP, convert" />
  <meta name="rating" content="GENERAL" />
  <meta name="robots" content="INDEX, FOLLOW" />
  <meta name="generator" content="ImageMagick Studio LLC" />
  <meta name="author" content="ImageMagick Studio LLC" />
  <meta name="revisit-after" content="2 DAYS" />
  <meta name="resource-type" content="document" />
  <meta name="copyright" content="Copyright (c) 1999-2019 ImageMagick Studio LLC" />
  <meta name="distribution" content="Global" />
  <meta name="magick-serial" content="P131-S030410-R485315270133-P82224-A6668-G1245-1" />
  <meta name="google-site-verification" content="_bMOCDpkx9ZAzBwb2kF3PRHbfUUdFj2uO8Jd1AXArz4" />
  <link href="magick-wand.html" rel="canonical" />
  <link href="../images/wand.png" rel="icon" />
  <link href="../images/wand.ico" rel="shortcut icon" />
  <link href="assets/magick.css" rel="stylesheet" />
</head>
<body>
  <header>
  <nav class="navbar navbar-expand-md navbar-dark fixed-top bg-dark">
    <a class="navbar-brand" href="../"><img class="d-block" id="icon" alt="ImageMagick" width="32" height="32" src="../images/wand.ico"/></a>
    <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarsMagick" aria-controls="navbarsMagick" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>

    <div class="navbar-collapse collapse" id="navbarsMagick" style="">
    <ul class="navbar-nav mr-auto">
      <li class="nav-item ">
        <a class="nav-link" href="api/quantize.html">Home <span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item ">
        <a class="nav-link" href="../www/download.html">Download</a>
      </li>
      <li class="nav-item ">
        <a class="nav-link" href="../www/command-line-tools.html">Tools</a>
      </li>
      <li class="nav-item ">
        <a class="nav-link" href="../www/command-line-processing.html">Command-line</a>
      </li>
      <li class="nav-item ">
        <a class="nav-link" href="../www/resources.html">Resources</a>
      </li>
      <li class="nav-item ">
        <a class="nav-link" href="../www/develop.html">Develop</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" target="_blank" href="https://imagemagick.org/discourse-server/">Community</a>
      </li>
    </ul>
    <form class="form-inline my-2 my-lg-0" action="https://imagemagick.org/script/search.php">
      <input class="form-control mr-sm-2" type="text" name="q" placeholder="Search" aria-label="Search">
      <button class="btn btn-outline-success my-2 my-sm-0" type="submit" name="sa">Search</button>
    </form>
    </div>
  </nav>
  <div class="container">
   <script async="async" src="https://localhost/pagead/js/adsbygoogle.js"></script>    <ins class="adsbygoogle"
         style="display:block"
         data-ad-client="ca-pub-3129977114552745"
         data-ad-slot="6345125851"
         data-ad-format="auto"></ins>
    <script>
      (adsbygoogle = window.adsbygoogle || []).push({});
    </script>

  </div>
  </header>
  <main class="container">
    <div class="magick-template">
<div class="magick-header">

<p class="lead magick-description">The <a href="api/MagickWand/index.html">MagickWand API</a> is the recommended interface between the C programming language and the ImageMagick image processing libraries.  Unlike the <a href="magick-core.html">MagickCore</a> C API, MagickWand uses only a few opaque types.  Accessors are available to set or get important wand properties.  A description of the MagickWand public methods are found here:</p>

<ul>
  <li><a href="api/magick-wand.html">Magick Wand Methods</a></li>
  <li><a href="api/magick-property.html">Set or Get Magick Wand Properties</a></li>
  <li><a href="api/magick-image.html">Magick Wand Image Methods</a></li>
  <li><a href="api/pixel-iterator.html">Pixel Iterator Methods</a></li>
  <li><a href="api/pixel-wand.html">Pixel Wand Methods</a></li>
  <li><a href="api/drawing-wand.html">Image Vector Drawing</a></li>
  <li><a href="api/mogrify.html">Command-line Interface</a></li>
  <li><a href="api/wand-view.html">Wand View Methods</a></li>
  <li><a href="api/magick-deprecate.html">Deprecated Methods</a></li>
  <li><a href="exception.html">Error and Warning Codes</a></li>
</ul>

<p>After you write your MagickWand program, compile it like this:</p>

<pre class="highlight"><code>cc -o wand wand.c `pkg-config --cflags --libs MagickWand`
</code></pre>

<p>Set the <code>PKG_CONFIG_PATH</code> environment variable if ImageMagick is not in your default system path:</p>

<pre class="highlight"><code>export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig
</code></pre>

<p>Here is a example program that utilizes the MagickWand API to get you started, <a href="https://imagemagick.org/source/wand.c">wand.c</a>. It reads an image, creates a thumbnail, and writes the result to disk.</p>

<pre class="pre-scrollable"><code>#include &lt;stdio.h>
#include &lt;stdlib.h>
#include &lt;wand/MagickWand.h>

int main(int argc,char **argv)
{
#define ThrowWandException(wand) \
{ \
  char \
    *description; \
 \
  ExceptionType \
    severity; \
 \
  description=MagickGetException(wand,&amp;severity); \
  (void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \
  description=(char *) MagickRelinquishMemory(description); \
  exit(-1); \
}

  MagickBooleanType
    status;

  MagickWand
    *magick_wand;

  if (argc != 3)
    {
      (void) fprintf(stdout,"Usage: %s image thumbnail\n",argv[0]);
      exit(0);
    }
  /*
    Read an image.
  */
  MagickWandGenesis();
  magick_wand=NewMagickWand();
  status=MagickReadImage(magick_wand,argv[1]);
  if (status == MagickFalse)
    ThrowWandException(magick_wand);
  /*
    Turn the images into a thumbnail sequence.
  */
  MagickResetIterator(magick_wand);
  while (MagickNextImage(magick_wand) != MagickFalse)
    MagickResizeImage(magick_wand,106,80,LanczosFilter,1.0);
  /*
    Write the image then destroy it.
  */
  status=MagickWriteImages(magick_wand,argv[2],MagickTrue);
  if (status == MagickFalse)
    ThrowWandException(magick_wand);
  magick_wand=DestroyMagickWand(magick_wand);
  MagickWandTerminus();
  return(0);
}
</code></pre>

<p>Here is another program that shows one way to get and set image pixels with the MagickWand API, <a href="https://imagemagick.org/source/contrast.c">contrast.c</a>. It reads an image, applies sigmoidal non-linearity contrast control, and writes the result to disk.</p>

<pre class="pre-scrollable"><code>#include &lt;stdio.h>
#include &lt;stdlib.h>
#include &lt;math.h>
#include &lt;wand/MagickWand.h>

int main(int argc,char **argv)
{
#define QuantumScale  ((MagickRealType) 1.0/(MagickRealType) QuantumRange)
#define SigmoidalContrast(x) \
  (QuantumRange*(1.0/(1+exp(10.0*(0.5-QuantumScale*x)))-0.0066928509)*1.0092503)
#define ThrowWandException(wand) \
{ \
  char \
    *description; \
 \
  ExceptionType \
    severity; \
 \
  description=MagickGetException(wand,&amp;severity); \
  (void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \
  description=(char *) MagickRelinquishMemory(description); \
  exit(-1); \
}

  long
    y;

  MagickBooleanType
    status;

  MagickPixelPacket
    pixel;

  MagickWand
    *contrast_wand,
    *image_wand;

  PixelIterator
    *contrast_iterator,
    *iterator;

  PixelWand
    **contrast_pixels,
    **pixels;

  register long
    x;

  unsigned long
    width;

  if (argc != 3)
    {
      (void) fprintf(stdout,"Usage: %s image sigmoidal-image\n",argv[0]);
      exit(0);
    }
  /*
    Read an image.
  */
  MagickWandGenesis();
  image_wand=NewMagickWand();
  status=MagickReadImage(image_wand,argv[1]);
  if (status == MagickFalse)
    ThrowWandException(image_wand);
  contrast_wand=CloneMagickWand(image_wand);
  /*
    Sigmoidal non-linearity contrast control.
  */
  iterator=NewPixelIterator(image_wand);
  contrast_iterator=NewPixelIterator(contrast_wand);
  if ((iterator == (PixelIterator *) NULL) ||
      (contrast_iterator == (PixelIterator *) NULL))
    ThrowWandException(image_wand);
  for (y=0; y &lt; (long) MagickGetImageHeight(image_wand); y++)
  {
    pixels=PixelGetNextIteratorRow(iterator,&amp;width);
    contrast_pixels=PixelGetNextIteratorRow(contrast_iterator,&amp;width);
    if ((pixels == (PixelWand **) NULL) ||
        (contrast_pixels == (PixelWand **) NULL))
      break;
    for (x=0; x &lt; (long) width; x++)
    {
      PixelGetMagickColor(pixels[x],&amp;pixel);
      pixel.red=SigmoidalContrast(pixel.red);
      pixel.green=SigmoidalContrast(pixel.green);
      pixel.blue=SigmoidalContrast(pixel.blue);
      pixel.index=SigmoidalContrast(pixel.index);
      PixelSetMagickColor(contrast_pixels[x],&amp;pixel);
    }
    (void) PixelSyncIterator(contrast_iterator);
  }
  if (y &lt; (long) MagickGetImageHeight(image_wand))
    ThrowWandException(image_wand);
  contrast_iterator=DestroyPixelIterator(contrast_iterator);
  iterator=DestroyPixelIterator(iterator);
  image_wand=DestroyMagickWand(image_wand);
  /*
    Write the image then destroy it.
  */
  status=MagickWriteImages(contrast_wand,argv[2],MagickTrue);
  if (status == MagickFalse)
    ThrowWandException(image_wand);
  contrast_wand=DestroyMagickWand(contrast_wand);
  MagickWandTerminus();
  return(0);
}
</code></pre>
<p><a class="anchor" id="wand-view"></a>Now lets perform the same contrast enhancement while taking advantage of our dual or quad-core processing system by running the algorithm in parallel utilizing wand views.  The <a href="https://imagemagick.org/source/wand/sigmoidal-contrast.c">sigmoidal-contrast.c</a> module reads an image, applies sigmoidal non-linearity contrast control, and writes the result to disk just like the previous contrast enhancement program, but now it does its work in parallel (assumes ImageMagick is built with OpenMP support).</p>

<pre class="pre-scrollable"><code>#include &lt;stdio.h>
#include &lt;stdlib.h>
#include &lt;math.h>
#include &lt;wand/MagickWand.h>

static MagickBooleanType SigmoidalContrast(WandView *pixel_view,
  const ssize_t y,const int id,void *context)
{
#define QuantumScale  ((MagickRealType) 1.0/(MagickRealType) QuantumRange)
#define SigmoidalContrast(x) \
  (QuantumRange*(1.0/(1+exp(10.0*(0.5-QuantumScale*x)))-0.0066928509)*1.0092503)

  RectangleInfo
    extent;

  MagickPixelPacket
    pixel;

  PixelWand
    **pixels;

  register long
    x;

  extent=GetWandViewExtent(contrast_view);
  pixels=GetWandViewPixels(contrast_view);
  for (x=0; x &lt; (long) (extent.width-extent.height); x++)
  {
    PixelGetMagickColor(pixels[x],&amp;pixel);
    pixel.red=SigmoidalContrast(pixel.red);
    pixel.green=SigmoidalContrast(pixel.green);
    pixel.blue=SigmoidalContrast(pixel.blue);
    pixel.index=SigmoidalContrast(pixel.index);
    PixelSetMagickColor(contrast_pixels[x],&amp;pixel);
  }
  return(MagickTrue);
}

int main(int argc,char **argv)
{
#define ThrowViewException(view) \
{ \
  description=GetWandViewException(view,&amp;severity); \
  (void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \
  description=(char *) MagickRelinquishMemory(description); \
  exit(-1); \
}
#define ThrowWandException(wand) \
{ \
  description=MagickGetException(wand,&amp;severity); \
  (void) fprintf(stderr,"%s %s %lu %s\n",GetMagickModule(),description); \
  description=(char *) MagickRelinquishMemory(description); \
  exit(-1); \
}

  char
    *description;

  ExceptionType
    severity;

  MagickBooleanType
    status;

  MagickPixelPacket
    pixel;

  MagickWand
    *contrast_wand;

  WandView
    *contrast_view;

  if (argc != 3)
    {
      (void) fprintf(stdout,"Usage: %s image sigmoidal-image\n",argv[0]);
      exit(0);
    }
  /*
    Read an image.
  */
  MagickWandGenesis();
  contrast_wand=NewMagickWand();
  status=MagickReadImage(contrast_wand,argv[1]);
  if (status == MagickFalse)
    ThrowWandException(contrast_wand);
  /*
    Sigmoidal non-linearity contrast control.
  */
  contrast_view=NewWandView(contrast_wand);
  if (contrast_view == (WandView *) NULL)
    ThrowWandException(contrast_wand);
  status=UpdateWandViewIterator(contrast_view,SigmoidalContrast,(void *) NULL);
  if (status == MagickFalse)
    ThrowWandException(contrast_wand);
  contrast_view=DestroyWandView(contrast_view);
  /*
    Write the image then destroy it.
  */
  status=MagickWriteImages(contrast_wand,argv[2],MagickTrue);
  if (status == MagickFalse)
    ThrowWandException(contrast_wand);
  contrast_wand=DestroyMagickWand(contrast_wand);
  MagickWandTerminus();
  return(0);
}
</code></pre>
<p><a href="../MagickWand/index.html">MagickWand Examples in C</a> illustrates how to use the ImageMagick MagickWand API. Each example is presented as a C function, complete with headers, so that it can be copied to a file and then included in your own C project.</p>
</div>
    </div>
  </main><!-- /.container -->
  <footer class="magick-footer">
    <p><a href="../www/security-policy.html">Security</a> •
    <a href="../www/architecture.html">Architecture</a> •
    <a href="../www/links.html">Related</a> •
     <a href="../www/sitemap.html">Sitemap</a>
       
    <a href="magick-wand.html#"><img class="d-inline" id="wand" alt="And Now a Touch of Magick" width="16" height="16" src="../images/wand.ico"/></a>
       
    <a href="http://pgp.mit.edu/pks/lookup?op=get&amp;search=0x89AB63D48277377A">Public Key</a> •
    <a href="../www/support.html">Donate</a> •
    <a href="../www/https://imagemagick.org/script/contact.php">Contact Us</a>
    <br/>
    <small>© 1999-2019 ImageMagick Studio LLC</small></p>
  </footer>

  <!-- Javascript assets -->
  <script src="assets/magick.js" crossorigin="anonymous"></script>
  <script>window.jQuery || document.write('<script src="https://localhost/ajax/libs/jquery/3.3.1/jquery.min.js"><\/script>')</script>
</body>
</html>