http://blog.csdn.net/xiaozhun07/article/details/49865785
png使用过程问题小结：
(1) libpng “png_set_longjmp_fn” not found
解决方法
In my case, I have the old png 1.2 came with my ubuntu installed in /usr. I installed the 1.6.x in /usr/local. In my make system, the default include /usr/include and linking /usr/lib were picked up. When compiling any software that rely on the new interface, you need to add
CPPFLAGS="-I/usr/local/include $CPPFLAGS"
LDFLAGS="-L/usr/local/lib $LDFLAGS"this will pick up
grep png_set_longjmp_fn png.h
PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
(*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
In my case, I have the old png 1.2 came with my ubuntu installed in /usr. I installed the 1.6.x in /usr/local. In my make system,
the default include /usr/include and linking /usr/lib were picked up. When compiling any software that rely on the new interface, you need to add
CPPFLAGS="-I/usr/local/include $CPPFLAGS"
LDFLAGS="-L/usr/local/lib $LDFLAGS"
this will pick up
grep png_set_longjmp_fn png.h
PNG_EXPORT(8, jmp_buf*, png_set_longjmp_fn, (png_structrp png_ptr,
(*png_set_longjmp_fn((png_ptr), longjmp, (sizeof (jmp_buf))))
Then
libpng12.so.0 => /lib/x86_64-linux-gnu/libpng12.so.0 (0x00007f8ac214e000)
change to
libpng16.so.16 => /usr/local/lib/libpng16.so.16 (0x00007fc9c273f000)
5.PNG++安装
我们首先安装libpng和zlib
5.1安装libpng和zlib
由于PNG++是基于libpng-1.2.x的版本，所以这里我们下载1.2.53版本
下载地址：
http://sourceforge.net/projects/libpng/files/libpng12/1.2.53/libpng-1.2.53.tar.xz/download
解压后进入文件夹，编译
./configure
make check
sudo make install
make check
sudo ldconfig
5.2安装png++
首先，下载png++0.2.5版本
http://download.savannah.gnu.org/releases/pngpp/
解压后进入文件夹
Issue make to test how it's doing:
$ make
This will compile examples in the example directory. If everything goes well, try
$ make test
(or make check which is the same as above) to run the test suite. If tests do not produce error messages then probably all is OK.
Now you can create documentation (optional). Use
$ make docs
to run doxygen in the sources directory.
Now it is time to become root and install png++ into your system. It's OK to issue make install under ordinary user permissions if you want to install png++ into your home directory. Run the following command:
$ make install PREFIX=$HOME
to copy png++ header files to ~/include/png++ and documentation files to ~/share/doc/png++-0.2.x. Without a PREFIX png++ installs to /usr/local.
随后可以根据http://www.nongnu.org/pngpp/doc/0.2.5/
测试是否安装成功：
#include <png++/png.hpp>
//...
int main()
{
png::image< png::rgb_pixel > image(128, 128);
for (png::uint_32 y = 0; y < image.get_height(); ++y)
{
for (png::uint_32 x = 0; x < image.get_width(); ++x)
{
image[y][x] = png::rgb_pixel(x, y, x + y);
// non-checking equivalent of image.set_pixel(x, y, ...);
}
}
image.write("rgb.png");
return 0;
}
Use the following command to compile your program:
$ g++ -c example.cpp `libpng-config --cflags`
and the following to link it:
$ g++ -o example example.o `libpng-config --ldflags`
运行 example文件
./example
如果能够生成一张图片，说明png++安装成功
相关文档
Main Page
Namespaces
Classes
Files
png++ Documentation
0.2.1
Introduction
This is the documentation for png++ the C++ wrapper for libpng. This page documents png++ version 0.2.1.
Png++ aims to provide simple yet powerful C++ interface to libpng, the PNG reference implementation library. Png++ is free software distributed under a modified variant of BSD license.
News
Added support for tRNS chunk.
Added non-std IO streams support.
Fixed 16-bit endianness problems.
Improved test script.
Getting started
The following code demonstrates how to read and write PNG images using png++:
png::image< png::rgb_pixel > image("input.png");
image.write("output.png");
The code reads an image from the file named input.png, then writes the image to a file named output.png. The image class template allows you to specify the desired pixel type for the image data. The available pixel types include: RGB, Grayscale and Indexed pixels. Some of the pixel types can have an alpha channel.
The png++ naturally supports reading PNG images of any color type into RGB or Grayscale pixel buffers (with optional alpha channel). This is particularly useful for an image viewer if it needs to display the PNG image on, for example, RGB device regardless of the image color type.
On the other hand one might want to read only images of particular type. With png++ you can specify it this way:
png::image< png::rgb_pixel > image("rgb.png", png::require_color_space< png::rgb_pixel >());
Installing
Png++ comes as a set of header files and does not require compilation to be installed. For the same reason there are no binary packages for png++.
Prerequisites
png++ works with libpng-1.2.x.
png++ compiles with g++-4.1 and g++-4.2. Other version should work well too.
png++ relies on GNU make for compiling tests and examples; in particular it uses "remaking makefiles" feature
Documentation is produced using doxygen. See the bottom of this page for doxygen version used to compile these docs.
Installing png++
Follow these instructions in order to install png++:
Unpack source package:
$ tar -zxf png++-0.2.x.tar.gz -C ~/src
Go to your brand new png++ sources directory:
$ cd ~/src/png++-0.2.x
Issue make to test how it's doing:
$ make
This will compile examples in the example directory. If everything goes well, try
$ make test
(or make check which is the same as above) to run the test suite. If tests do not produce error messages then probably all is OK.
Now you can create documentation (optional). Use
$ make docs
to run doxygen in the sources directory.
Now it is time to become root and install png++ into your system. It's OK to issue make install under ordinary user permissions if you want to install png++ into your home directory. Run the following command:
$ make install PREFIX=$HOME
to copy png++ header files to ~/include/png++ and documentation files to ~/share/doc/png++-0.2.x. Without a PREFIX png++ installs to /usr/local.
Working with images
In png++ you can create new images like this:
#include <png++/png.hpp>
//...
png::image< png::rgb_pixel > image(128, 128);
for (size_t y = 0; y < image.get_height(); ++y)
{
for (size_t x = 0; x < image.get_width(); ++x)
{
image[y][x] = png::rgb_pixel(x, y, x + y);
// non-checking equivalent of image.set_pixel(x, y, ...);
}
}
image.write("rgb.png");
Optionally, you may specify
image.set_interlace_type(png::interlace_adam7)
to produce an interlaced image.
If you are writing an indexed colors image, you should provide a palette (colormap). One of the ways to do this is the following:
#include <png++/png.hpp>
//...
png::image< png::index_pixel > image;
png::palette pal(256);
for (size_t i = 0; i < pal.size(); ++i)
{
pal[i] = png::color(i, 255 - i, i);
}
image.set_palette(pal);
...
image.write("palette.png");
It is not absolutely necessary to have the whole image data in memory in order to write a PNG file. You can use generator class template to write the image row-by-row. An example of this is provided in example/pixel_generator.cpp bundled with the sources package.
The same holds for reading images too. You can use consumer class template in order to read the image data row-by-row. This might help in applications which have to deal with large PNG images but do not want to read the entire image into memory.
You can read or write images from/to generic IO stream, not only file on disk. Check out image::read(std::istream&), image::write(std::ostream&) overloads in the reference manual.
Compiling your programs
Use the following command to compile your program:
$ g++ -c example.cpp `libpng-config --cflags`
and the following to link it:
$ g++ -o example example.o `libpng-config --ldflags`
When compiling you should add -I $PREFIX/include if you have installed png++ to non-standard location, like your home directory.
In your program, the line
#include <png++/png.hpp>
brings in all the header files in png++ which should be suitable for the most of the applications. You may include only the headers you really use, for example:
#include <png++/image.hpp>
#include <png++/rgb_pixel.hpp>
If do not want to install png++ headers you still can compile your programs. Just create a subdirectory named png++ somewhere in your project tree and copy all of the .hpp files in png++ distribution there. Then use appropriate compiler options to add this directory into the header search path.
Further reading
To get information about specific features, use reference (can be reached from the top of this page).
If you are looking for more example code, please go to the example/ directory of the source distribution. You may also find sources in the test/ directory insightful (well, somewhat).
Have a question? Check out Getting help section below.
Of course, your ultimate source for learning is the source code. :-)
Download
The project is hosted at Savannah: http://savannah.nongnu.org/projects/pngpp/
Released source packages can be found here: http://download.savannah.nongnu.org/releases/pngpp/
Also, you can check out sources directly from SVN repository: svn://svn.sv.nongnu.org/pngpp/trunk/ or http://svn.sv.nongnu.org/pngpp/trunk/ (for people w/o outgoing svn).
Online version of this documentation can be found here: http://www.nongnu.org/pngpp/doc/0.2.1/index.html
Bugs
The following is a list of known bugs and limitations:
Lacks support for output transformations
Lacks support for optional/unknown chunks in PNG data stream
Documentation sucks ;-)
To report bugs, please use Savannah bug tracker: http://savannah.nongnu.org/bugs/?group=pngpp&func=additem
Do not forget to check if the bug was already filed. :-)
Getting help
There is a mailing list for developers: http://lists.nongnu.org/mailman/listinfo/pngpp-devel
You can also contact me by dropping a mail to <alex.shulgin@gmail.com>.
Happy hacking!
Alex Shulgin
Generated on Sat Dec 8 13:43:56 2007 for png++ by doxygen 1.5.3-20071008