c++ - C++: Magick++: Resize breaks PixelPacket, and causes to return a nullptr

Question

#include <Magick++.h>
using namespace std;
using namespace Magick;

int main(int argc,char **argv) 
{
  InitializeMagick(*argv);
  Thumbnail.read(argv[1]);
  Thumbnail.resize(Geometry(50, 50));

  Pixels viewThumbnail(ResizedThumbnail);
  PixelPacket *ThumbnailPixels = viewThumbnail.get(0, 0, 50, 50);
}

Info:

#define MagickPackageName "ImageMagick"
#define MagickCopyright  "Copyright (C) 1999-2012 ImageMagick Studio LLC"
#define MagickSVNRevision  "8535"
#define MagickLibVersion  0x677
#define MagickLibVersionText  "6.7.7"
#define MagickLibVersionNumber  5,0,0
#define MagickLibAddendum  "-10"
#define MagickLibInterface  5
#define MagickLibMinInterface  5
#define MagickReleaseDate  "2013-09-10"
#define MagickChangeDate   "20120628"
#define MagickAuthoritativeURL  "http://www.imagemagick.org"

g++ --version
g++ (Ubuntu/Linaro 4.7.3-1ubuntu1) 4.7.3
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

uname -r && lsb_release  -rd
3.8.0-26-generic
Description:    Linux Mint 15 Olivia
Release:        15

When I resize Thumbnail it makes PixelPacket return nullptr regardless of what size I chose, and using Image ResizedThumbnail = Thumbnail does not fix the issue. Crop does not cause an issue but scale and resize do. Also if I put Thumbnail.write("test.jpg"); before Pixels viewThumbnail(...) test.jpg is a valid jpeg image

Answer 1

使用以下解决问题：

Geometry Size = Geometry(twidth, theight);
Size.aspect(true);
Thumbnail.resize(Size);