dlib/examples/image_ex.cpp

127 lines
3.5 KiB
C++

/*
This is an example illustrating the use of the GUI API as well as some
aspects of image manipulation from the dlib C++ Library.
This is a pretty simple example. It takes a BMP file on the command line
and opens it up, runs a simple edge detection algorithm on it, and
displays the results on the screen.
*/
#include "dlib/gui_widgets.h"
#include "dlib/image_io.h"
#include "dlib/image_transforms.h"
#include <fstream>
using namespace std;
using namespace dlib;
// ----------------------------------------------------------------------------
class win : public drawable_window
{
/*
Here we are making a GUI window that will be capable of displaying
an image.
*/
public:
template <typename image_type>
win(
const image_type& img
) :
gui_img(*this)
{
// set the size of this window to match the size of the input image
set_size(img.nc(),img.nr());
// Now load the image into the image widget so it has something to display.
gui_img.set_image(img);
set_title("image example");
// show this window on the screen
show();
}
~win(
)
{
// You should always call close_window() in the destructor of window
// objects to ensure that no events will be sent to this window while
// it is being destructed.
close_window();
}
private:
image_widget gui_img;
};
// ----------------------------------------------------------------------------
int main(int argc, char** argv)
{
try
{
// make sure the user entered an argument to this program
if (argc != 2)
{
cout << "error, you have to enter a BMP file as an argument to this program" << endl;
return 1;
}
ifstream fin(argv[1],ios::binary);
if (!fin)
{
cout << "error, can't find " << argv[1] << endl;
return 1;
}
// Here we declare an image object that can store rgb_pixels. Note that in
// dlib there is no explicit image object, just a 2D array and
// various pixel types.
array2d<rgb_pixel>::kernel_1a img;
// now load the bmp file into our image. If the file isn't really a BMP
// or is corrupted then load_bmp() will throw an exception.
load_bmp(img, fin);
// Now lets use some image functions. This example is going to perform
// simple edge detection on the image. First lets find the horizontal and
// vertical gradient images.
array2d<short>::kernel_1a horz_gradient, vert_gradient;
array2d<unsigned char>::kernel_1a edge_image;
sobel_edge_detector(img,horz_gradient, vert_gradient);
// now we do the non-maximum edge suppression step so that our edges are nice and thin
suppress_non_maximum_edges(horz_gradient, vert_gradient, edge_image);
// Now we would like to see what our images look like. So lets use our
// window to display them on the screen.
// create a window to display the edge image
win my_window(edge_image);
// also make a window to display the original image
win my_window2(img);
// wait until the user closes both windows before we let the program
// terminate.
my_window.wait_until_closed();
my_window2.wait_until_closed();
}
catch (exception& e)
{
cout << "exception thrown: " << e.what() << endl;
}
}
// ----------------------------------------------------------------------------