my compiler says: destroyWindow isn't an element of cv. (hope i translated it correctly)
i included opencv/highgui.h and actually there exists:
destroy window and all the trackers associated with it
CVAPI(void) cvDestroyWindow( const char* name );
I am using the latest version of opencv.
Yes, this function exists within the namespace cv as:
void destroyWindow(const string& winname)
And you should include:
#include "opencv2/highgui/highgui.hpp"
which is the appropriate header to add when working with the C++ interface of OpenCV. If you need samples, check samples/cpp/ffilldemo.cpp (can be found inside OpenCV's source code).
Related
I'm trying to find out if a window belongs to the current virtual desktop.
I found the VirtualDesktopManager class form the winapi, but even though it is supposed to be in the "shobjidl.h" header according to here, when I compile the code it throws this error:
85:5: error: 'VirtualDesktopManager' was not declared in this scope
important piece of my code:
#include <shobjidl.h>
...
BOOL is_on_current_desktop = FALSE;
VirtualDesktopManager g_pvdm;
g_pvdm.IsWindowOnCurrentVirtualDesktop(hwnd, &is_on_current_desktop); // hwnd is a window handle acquired previously
g_pvdm.Release();
How could I make this work?
Apparently this interface was not included in the "shobjidl.h" header in mingw64 which I was using, running it in Visual Studio it finds it. So the issue was in the header.
I am trying to compile and run this GUI code
#include "Graph.h" // get access to our graphics library facilities
int main()
{
using namespace Graph_lib; // our graphics facilities are in Graph_lib
Point tl{ 100,100 }; // to become top left corner of window
Simple_window win{ tl,600,400,"Canvas" }; // make a simple window
Polygon poly; // make a shape (a polygon)
poly.add(Point{ 300,200 }); // add a point
poly.add(Point{ 350,100 }); // add another point
poly.add(Point{ 400,200 }); // add a third point
poly.set_color(Color::red); // adjust properties of poly
win.attach(poly); // connect poly to the window
win.wait_for_button(); // give control to the display engine
}
source of headers and code files: http://www.stroustrup.com/Programming/PPP2code/
I get the hash_map error
Error (active) E0035 #error directive: <hash_map> is deprecated and will be REMOVED. Please use <unordered_map>. You can define _SILENCE_STDEXT_HASH_DEPRECATION_WARNINGS to acknowledge that you have received this warning. ConsoleApplication1 C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.24.28314\include\hash_map 21
What causes an hash_map error and how can I fix it?
hash_map is an old API pre-dating the c++11 spec, where they decided the name for that container was unordered_map. You need to switch to using that name instead.
It's exactly what it says.
The header <hash_map> is not standard, but came from the actual STL. Though it currently remains available on your platform, it's "deprecated and will be REMOVED".
You should do what the message says and switch to modern tools like std::unordered_map. Unfortunately that means straying from your source material.
I'm guessing the error itself comes from within fltk (none of Bjarne's code seems to include that header, though I only scanned through it quickly). These examples are very, very old.
You can learn C++ from a modern book, instead.
In the meantime, and again as the error message says, you can define _SILENCE_STDEXT_HASH_DEPRECATION_WARNINGS (in your project settings under "Preprocessor Definitions") to acknowledge this for now.
Similar question:
```hash_map``` Error with Stroustrup's GUI examples from chapter 12 of his book Programming Principles and Practices Using C++
I've been trying to make a simple wxWidgets program with just a button with a picture on it. I've been able to make the button with the image on it easily enough, but my problem arises when including it.
So far, I've only been able to fetch the image during run-time (the image has to be in the same folder as the .exe file; otherwise, I get error 2: the system cannot find the file specified). With this method, I have no problems -- the program works just fine. What I'm trying to do, however, is to #include the file so that it is embedded during compile-time, so that it doesn't need to be available during run-time.
I've tried #including the file (both as .png and as .xpm), and I've also tried adding it to the resource includes (this is on Visual Studio 2017). Neither of these worked -- the first method still required the image to be in the same folder, and the second failed during compilation (as far as I can tell, it wasn't able to read the .xpm file).
Here is the relevant code, if it helps:
/*relevant includes*/
#include "happyFace.png" //this isn't working. the file is still needed
||
#include "happyFace.xpm" //ditto
/*I have also tried putting these lines in the resource includes.*/
/*code*/
wxInitAllImageHandlers();
wxBitmap bitmap("happyFace.xpm", wxBITMAP_TYPE_XPM); //only works in same directory at run-time
||
wxBitmap bitmap("happyFace.png", wxBITMAP_TYPE_PNG); //ditto
wxButton *button = new wxButton(this, ID_BMP_BUTTON);
button->SetBitmap(bitmap);
//the rest of the button programming and stuff
Sorry if I haven't provided enough information; I can provide more if necessary. I would really appreciate any help. Thanks!
Two possibilities... Number 1 is simplest. It's been a long time since I wrote the code I'm looking at, so the details are fuzzy.
In Visual Studio, Solution Explorer, add the image into the resource files. Assume the name of the resourse is sample.rc. Then it can be used like so to set the main icon...
SetIcon(wxICON(sample));
Method 1 must be used in order for MS Windows Explorer to display the main icon. I do not remember how to use .rc resources for other things, but it should be easy to figure out.
I did it this way before I discovered VS resource (.rc) files. Compile the file-image into the program "by hand." In other words, write a program that will read an image file and produce bit-for-bit copy in a .cpp file. Then compile that .cpp into the program. Here I have the file-image in memory as an object named dj::main_cursor. Note that the in-memory version is a bit-for-bit copy of a .cur file.
dj::captured_file &c1file(dj::main_cursor);
wxMemoryInputStream cistr(c1file.contents, c1file.size);
cursor1 = wxCursor(wxImage(cistr, wxBITMAP_TYPE_CUR));
FYI, I defined the structure dj::captured_file like so:
struct captured_file {
const char *name;
const unsigned long size;
const void *contents;
captured_file(const char*fn, size_t sz, const void*c)
: name(fn)
, contents(c)
, size(sz)
{}
};
See also, Embedding PNG Images into Windows RC Files
I found some other documentation.
Resources and Application Icon All applications using wxMSW should
have a Windows resource file (.rc extension) and this file should
include include/wx/msw/wx.rc file which defines resources used by
wxWidgets itself.
Among other things, wx.rc defines some standard icons, all of which
have names starting with the "wx" prefix. This normally ensures that
any icons defined in the application's own resource file come before
them in alphabetical order which is important because Explorer
(Windows shell) selects the first icon in alphabetical order to use as
the application icon which is displayed when viewing its file in the
file manager. So if all the icons defined in your application start
with "x", "y" or "z", they won't be used by Explorer. To avoid this,
ensure that the icon which is meant to be used as the main application
icon has a name preceding "wxICON" in alphabetical order.
http://docs.wxwidgets.org/3.1.0/page_port.html
Here is how you should do it:
#include "happyFace.xpm"
wxBitmap bitmap = wxBitmap( happyFace ); // assuming the variable name is "happyFace" inside the xpm
Then you will use bitmap object just like usual. Assuming that the file happyFace.xpm is available for compilation.
So I am reading up on some OpenGL and I want to use the QOpenGLWidget for drawing to maybe create some other helpful UI elements later. I am using glad for resolving the function pointers to OpenGL but I have no idea how to use Qt's getProcAddress function!
Inside my QOpenGLWidget subclass' initializeGL() function I have tried:
if(gladLoadGLloader((GLADloadproc) currentContext()->getProcAddress) {}
but that did not work out since Qt's function is overloaded. When I use
if(gladLoadGL()) {}
it doesn't work either. My includes are:
#include <glad\glad.h>
#include "OpenGLViewport.h"
#include <QDebug>
#include <QOpenGLContext>
I have searched Mr. Google and I've had a diligent look through the Qt documentation and found nothing. I want to use GLAD just so my rendering code is not bound to Qt too tightly, in case I want to switch later.
EDIT: I am aiming to use the noninstanced OpenGL functions with Qt (though the documentation recommends otherwise if I recall correctly). Because then I'd be able to seemlessly switch to GLFW for providing a window etc.
Moved solution from question to answer:
ANSWER: So it turns out I just had some things mixed up, this is how I got it to work, in case anyone has the same problem:
add glad.c in your project
add the necessary headers to your include directory
the .cpp file of your QOpenGLWidget subclass should have following components:
// Subclass.cpp
#include <glad/glad.h>
// important, subclass header file after glad!!
// otherwise glad won't "hook"
#include "Subclass.h"
void Subclass::initializeGL()
{
if(gladLoadGL()) initialized = true; // initialized is a class member here
else; // handle errors
}
void Subclass::paintGL()
{
if(initialized); // render here
}
First: sorry for my English from Google
The question:
I'm changing the IDE, I'm migrating from Borland to QT with QT Creator.
In Borland I used a class contained in a type library (APuma.dll). The prototype was:
BOOL XOpen (long hDIB, LPCTSTR FileName) / / OpenOCR - Cuneiform
hDIB is a pointer to global memory of an image.This version Not Work with files.
To pass a pointer to global memory of an image, I used GDI+, but in QT can not find anything similar, and the inclusion of Gdiplus.h and GdiPlusInit.h generates too many errors.
How do I give access to global memory where I host the image to XOpen?
Thank you very much.
OK, I think i understand what you need. You need a pointer to the pixels of the image so you can pass it. Your simplest option in Qt is using a QImage object and using its bits() member.
Something like this:
QImage image(filename);
uchar* p = image.bits();
XOpen(reinterpret_cast<long>(p), whatever);
just be sure that XOpen somehow knows the dimmensions of the image. And that you have it in the right format (See QImage::convertToFormat). For more overall information check the Qt documentation at http://doc.qt.io/qt-4.8/qimage.html