Here is link for png++ :http://savannah.nongnu.org/projects/pngpp/
What I'm doing wrong?
I installed opencv for OS X by command in terminal:"brew install opencv" and I have problems with using library png++.
#include <iostream>
#include "png++/png.hpp"
using namespace std;
int main(int argc, const char * argv[])
{
png::image< png::rgb_pixel > image("74");
for(int i=0;i<image.get_width();i++)
{
for(int j=0;j<image.get_height();j++)
{
image[i][j]=png::rgb_pixel(255-image[i][j].red, 255-image[i][j].green, 255-image[i][j].blue);
}
}
image.write("output.png");
return 0;
}
And I have next errors:
error messages
Problem was, that I install opencv with brew, which I installed on Yosemite. When I updated brew on ElCapitan and reinstalled opencv, errors disappeared.
Related
I run KDE Neon 20.04 and whenever i try to run this command block in Sublime Text i get this error.
#include "SDL2.h"
#include "SDL2_image"
#include <iostream.h>
int main(int argc, char* args[])
{
std::cout << "Yay" << std::endl;
return 0;
}
SDL2.h there is no such file or directory
You have to install SDL development libraries first. You can install it using the command sudo apt-get install libsdl2-dev.
You are also including sdl headers wrong.
This is the correct way.
#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
I have installed OpenCv with Homebrew on my MacOs. I have added libopencv 4.0.1.dylib in Xcode. When I try to build, Xcode cannot find the files. Any suggestions?
I changed my path but still have problems.
Main code:
#include <iostream>
#include <opencv4/opencv2/opencv.hpp>
int main(int argc, const char * argv[]) {
// insert code here...
std::cout << "Hello, World!\n";
return 0;
}
Build settings including path:
Error messages:
I'm trying to run MIT MEEP on ubuntu through its C++ lib but I've been widely unsuccessful. I have meep and g++ installed properly. I can run Scheme ctrl file but not the c++ libs.
I am trying the simple code from MEEP c++ tutorial. The meep.hpp is located where I have given. I am new to c++.
Could anyone give me a hint of what can be wrong?
These are the first lines of errors I get:
Building target: test2
Invoking: GCC C++ Linker
g++ -o "test2" ./src/test2.o
./src/test2.o: In function `main':
/home/mad/clipse_workspace/test2/Debug/../src/test2.cpp:20: undefined reference to `meep::initialize::initialize(int&, char**&)'
/home/mad/clipse_workspace/test2/Debug/../src/test2.cpp:22: undefined reference to `meep::vol2d(double, double, double)'
Here is the code I run:
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include </usr/include/meep/meep.hpp>
using namespace meep;
using namespace std;
double eps(const vec &p);
int main(int argc, char **argv) {
initialize mpi(argc, argv); // do this even for non-MPI Meep
double resolution = 10; // pixels per distance
grid_volume v = vol2d(5,10, resolution); // 5x10 2d cell
structure s(v, eps, pml(1.0));
fields f(&s);
f.output_hdf5(Dielectric, v.surroundings());
double freq = 0.3, fwidth = 0.1;
gaussian_src_time src(freq, fwidth);
f.add_point_source(Ey, src, vec(1.1, 2.3));
while (f.time() < f.last_source_time()) {
f.step();
}
f.output_hdf5(Hz, v.surroundings());
return 0;
}
double eps(const vec &p) {
if (p.x() < 2 && p.y() < 3)
return 12.0;
return 1.0;
}
You have to link the MEEP library. I compiled your app like this:
g++ -o test2 test2.cpp -lmeep
MEEP development files can be installed like this on Ubuntu:
sudo apt-get install libmeep-dev
Also modify the include statement like this now:
#include <meep.hpp>
I tested this on Ubuntu 15.10 and your app worked fine.
I've been writing a program that needs a wine version of 2.6 or later. I'd like to get it as a boolean, so I've been trying to use the code below:
#include <string>
#include <iostream>
#include "WineCheck.h"
#include <cstdlib>
using namespace std;
bool checkForWine()
{
// Create variables for checking wine state
bool wineIsThere = false;
bool wineIsVersion = false;
// Check dpkg if wine is there
if (string(system("dpkg -l | cut -c 4-9 | grep \\ wine\\ ")) == " wine ")
{
wineIsThere = true;
// Check version
if (double(system("wine --version | cut -c 6-8")) >= 2.6)
wineIsVersion = true;
}
// Return
if (wineIsThere && wineIsVersion)
return true;
else
return false;
}
First, it's my opinion you shouldn't bother with this. Wine 2.6 should just be included as a dependency in your configuration script, and/or your package file. Targeting a specific package management system in your program source code is not a good idea if you want to maintain portability to other GNU/Linux distributions that don't use that packager.
To answer your question though. There are two ways I found you can do this. You can check /var/lib/dpkg/status. Read through the file line by line until you get to this section. If you don't find the section, or the Status: ... line doesn't say installed then wine is not installed. The Version: ... line will tell you what version is installed. I verified this method works by installing and uninstalling Wine on Debian Wheezy. You didn't say what distro you're working with, but it's obvious you're using the Debian Packaging system, so this should work on Ubuntu and other Debian based distributions as well.
$cat /var/lib/dpkg/status
...
Package: wine
Status: install ok installed
Priority: optional
Section: otherosf
Installed-Size: 80
Maintainer: Debian Wine Party <pkg-wine-party#lists.alioth.debian.org>
Architecture: amd64
Version: 1.4.1-4
...
The other option is use libdpkg. I found an example that lists all installed packages.
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <dpkg/dpkg.h>
#include <dpkg/dpkg-db.h>
#include <dpkg/pkg-array.h>
#include "filesdb.h"
const char thisname[] = "example1";
int
main(int argc, const char *const *argv)
{
struct pkg_array array;
struct pkginfo *pkg;
int i;
enum modstatdb_rw msdb_status;
standard_startup();
filesdbinit();
msdb_status = modstatdb_open(msdbrw_readonly);
pkg_infodb_init(msdb_status);
pkg_array_init_from_db(&array);
pkg_array_sort(&array, pkg_sorter_by_name);
for (i = 0; i < array.n_pkgs; i++) {
pkg = array.pkgs[i];
if (pkg->status == stat_notinstalled)
continue;
printf("Package --> %s\n", pkg->set->name);
}
pkg_array_destroy(&array);
modstatdb_shutdown();
standard_shutdown();
}
The following code fails to open a VideoWriter object:
#include <iostream>
#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>
using namespace cv;
using namespace std;
int main() {
VideoWriter oVideo;
oVideo.open ("381.avi", -1, 30, Size(640,480), true);
if (!oVideo.isOpened()) {
cout << "Could not open the output video for write" << endl;
return -1;
}
return 0;
}
I'm running OpenCV 2.4.9 pre-built with Code::Blocks on Ubuntu 12.04. I've written a number of images using imwrite() on the same location without issue, so I doubt it has to do with permissions. Also I tried CV_FOURCC('X','V','I','D') which did not work.
What am I missing here?
Any help is greatly appreciated.
I reinstalled OpenCV using this amazing script: https://help.ubuntu.com/community/OpenCV
Solved.
Make sure specific codec is installed in your machine.