将图像放入 x11 中的 Window

Question

我有一个.JPG 格式的二维码。我使用 OpenCV 3.4.4 加载它。现在，我使用 XCreateSimpleWindow() 创建了一个新的 X11 window。然后，我会将 QR 图像调整为这个新 window 的大小。

接下来，我想将这个调整大小的二维码放入window。我尝试使用 XPutImage()，但没有成功，可能是因为我不知道用法。

为了使用 XPutImage()，我首先使用 XGetImage() 拍摄了 X11 window 的图像；然后获取QR图像的像素值，然后将其赋值给通过XGetImage获取的图像的像素值。

获得此 XImage 后，我尝试使用 XPutImage 将其放入 window。但是，它仍然显示黑色 window。终端没有错误，但结果不尽如人意

这个问题有什么解决办法吗？例如，如何更改 window (X11) w.r.t 示例图像的背景，并使用 XPutImage()?

代码是这样的...

// Written by Ch. Tronche (http://tronche.lri.fr:8000/)
// Copyright by the author. This is unmaintained, no-warranty free software. 
// Please use freely. It is appreciated (but by no means mandatory) to
// acknowledge the author's contribution. Thank you.
// Started on Thu Jun 26 23:29:03 1997

//
// Xlib tutorial: 2nd program
// Make a window appear on the screen and draw a line inside.
// If you don't understand this program, go to
// http://tronche.lri.fr:8000/gui/x/xlib-tutorial/2nd-program-anatomy.html
//

//  compilation:
//              g++ -o go qrinX11.cpp `pkg-config --cflags --libs opencv` -lX11
//

#include <opencv2/opencv.hpp>
#include "opencv2/opencv.hpp"   // FOR OpenCV
#include <opencv2/core.hpp>     // Basic OpenCV structures (cv::Mat)
#include <opencv2/videoio.hpp>  
#include <opencv2/imgproc.hpp>
#include <opencv2/highgui.hpp>

#include <bits/stdc++.h>
#include <X11/Xlib.h> // Every Xlib program must include this
#include <assert.h>   // I include this to test return values the lazy way
#include <unistd.h>   // So we got the profile for 10 seconds
#include <X11/Xutil.h>
#include <X11/keysym.h>
#include <X11/Xlib.h> // Every Xlib program must include this
#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/extensions/Xcomposite.h>
#include <X11/extensions/Xfixes.h>
#include <X11/extensions/shape.h>
#define NIL (0)       // A name for the void pointer

using namespace cv;
using namespace std;

int main()
{

      XGCValues gr_values;
      //GC gc;
      XColor    color, dummy;


      Display *dpy = XOpenDisplay(NIL);
      //assert(dpy);
      //int screen = DefaultScreen(dpy);
      // Get some colors

      int blackColor = BlackPixel(dpy, DefaultScreen(dpy));
      int whiteColor = WhitePixel(dpy, DefaultScreen(dpy));

      // Create the window

      Window w = XCreateSimpleWindow(dpy, DefaultRootWindow(dpy), 0, 0, 
                     200, 100, 0, whiteColor, blackColor);

      // We want to get MapNotify events

      XSelectInput(dpy, w, StructureNotifyMask);

      XMapWindow(dpy, w);

      // Wait for the MapNotify event

      for(;;) {
        XEvent e;
        XNextEvent(dpy, &e);
        if (e.type == MapNotify)
          break;
      }

    Window focal = w;

    XWindowAttributes gwa;
    XGetWindowAttributes(dpy, w, &gwa); 
    int wd1 = gwa.width;
    int ht1 = gwa.height;



    XImage *image = XGetImage(dpy, w, 0, 0 , wd1, ht1, AllPlanes, ZPixmap);
    unsigned long rm = image->red_mask;
    unsigned long gm = image->green_mask;
    unsigned long bm = image->blue_mask;

    Mat img(ht1, wd1, CV_8UC3);             // OpenCV Mat object is initilaized
    Mat scrap = imread("qr.jpg");//(wid, ht, CV_8UC3);      
    resize(scrap, img, img.size(), CV_INTER_AREA);

    for (int x = 0; x < wd1; x++)
        for (int y = 0; y < ht1 ; y++)
        {
            unsigned long pixel = XGetPixel(image,x,y);     
            unsigned char blue = pixel & bm;                // Applying the red/blue/green mask to obtain the indiv channel values
            unsigned char green = (pixel & gm) >> 8;
            unsigned char red = (pixel & rm) >> 16;     

            Vec3b color = img.at<Vec3b>(Point(x,y));        // Store RGB values in the OpenCV image


            //color[0] = blue;
            //color[1] = green;
            //color[2] = red;
            //img.at<Vec3b>(Point(x,y)) = color;


            pixel = color[0];//&color[1]&color[2];

        }   

        namedWindow("QR", CV_WINDOW_NORMAL);
        imshow("QR", img);

        cout << "herererere\n";
        GC gc = XCreateGC(dpy, w, 0, NIL);
        XPutImage(dpy, w, gc, image, 0, 0, wd1, ht1, wd1, ht1);

    waitKey(0);
//sleep(3);
    return 0;
}

Answer 1

好的，我自己解决了。更改像素值并将其更新为实际图像然后将其放入 window 的背景时出现了一个愚蠢的错误。

先用XPutPixel()，再用XPutImage()

这是最终正确的方法：

//  compilation:
//              g++ -o go qrinX11.cpp `pkg-config --cflags --libs opencv` -lX11
//

#include <opencv2/opencv.hpp>
#include "opencv2/opencv.hpp"   // FOR OpenCV
#include <opencv2/core.hpp>     // Basic OpenCV structures (cv::Mat)
#include <opencv2/videoio.hpp>  
#include <opencv2/imgproc.hpp>
#include <opencv2/highgui.hpp>

#include <bits/stdc++.h>
#include <X11/Xlib.h> // Every Xlib program must include this
#include <assert.h>   // I include this to test return values the lazy way
#include <unistd.h>   // So we got the profile for 10 seconds
#include <X11/Xutil.h>
#include <X11/keysym.h>
#include <X11/Xlib.h> // Every Xlib program must include this
#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/extensions/Xcomposite.h>
#include <X11/extensions/Xfixes.h>
#include <X11/extensions/shape.h>
#define NIL (0)       // A name for the void pointer

using namespace cv;
using namespace std;

int main()
{

      XGCValues gr_values;
      //GC gc;
      XColor    color, dummy;


      Display *dpy = XOpenDisplay(NIL);
      //assert(dpy);
      //int screen = DefaultScreen(dpy);
      // Get some colors

      int blackColor = BlackPixel(dpy, DefaultScreen(dpy));
      int whiteColor = WhitePixel(dpy, DefaultScreen(dpy));

      // Create the window

      Window w = XCreateSimpleWindow(dpy, DefaultRootWindow(dpy), 0, 0, 
                     200, 100, 0, whiteColor, blackColor);

      // We want to get MapNotify events

      XSelectInput(dpy, w, StructureNotifyMask);

      XMapWindow(dpy, w);

      // Wait for the MapNotify event

      for(;;) {
        XEvent e;
        XNextEvent(dpy, &e);
        if (e.type == MapNotify)
          break;
      }

    Window focal = w;

    XWindowAttributes gwa;
    XGetWindowAttributes(dpy, w, &gwa); 
    int wd1 = gwa.width;
    int ht1 = gwa.height;



    XImage *image = XGetImage(dpy, w, 0, 0 , wd1, ht1, AllPlanes, ZPixmap);
    unsigned long rm = image->red_mask;
    unsigned long gm = image->green_mask;
    unsigned long bm = image->blue_mask;

    Mat img(ht1, wd1, CV_8UC3);     // OpenCV Mat object is initilaized
    Mat scrap = imread("qr.jpg");//(wid, ht, CV_8UC3);      
    resize(scrap, img, img.size(), CV_INTER_AREA);

    for (int x = 0; x < wd1; x++)
        for (int y = 0; y < ht1 ; y++)
        {
            unsigned long pixel = XGetPixel(image,x,y);     

            Vec3b color = img.at<Vec3b>(Point(x,y));



            pixel = 65536 * color[2] + 256 * color[1] + color[0];               

            XPutPixel(image, x, y, pixel);                  
        }   

    namedWindow("QR", CV_WINDOW_NORMAL);
    imshow("QR", img);


    GC gc = XCreateGC(dpy, w, 0, NIL);
    XPutImage(dpy, w, gc, image, 0, 0, 0, 0, wd1, ht1);

    waitKey(0);    
    return 0;
}

Answer 2

简单是关键，可以提高性能（在本例中）：

//.. 

// Mat img(ht1, wd1, CV_8UC3);     // OpenCV Mat object is initilaized
cv::Mat img(ht1, wd1, CV_8UC4, image->data);  // initilaize with existing mem
Mat scrap = imread("qr.jpg");//(wid, ht, CV_8UC3); 
cv::cvtColor(scrap,scrap,cv::COLOR_BGR2BGRA);
resize(scrap, img, img.size(), cv::INTER_AREA);    

// .. and we can skip the for loops 

namedWindow("QR", CV_WINDOW_NORMAL);
imshow("QR", img);

// .. etc

将图像放入 x11 中的 Window

Putting image into a Window in x11

x11

image

c++14

opencv3.0