【发布时间】：2019-02-04 09:41:39
【问题描述】：
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() 创建一个新的 X11 窗口。然后，我会将 QR 图像的大小调整为这个新窗口的大小。
接下来，我想把这个调整大小的二维码放到窗口中。我尝试使用 XPutImage()，但没有任何成功，可能是因为我不知道用法。
为了使用 XPutImage()，我首先使用 XGetImage() 获取 X11 窗口的图像；然后获取QR图像的像素值，然后将其分配给通过XGetImage获得的图像的像素值。
一旦我有了这个 XImage，我尝试使用 XPutImage 将它放到窗口中。但是，它仍然显示一个黑色窗口。 终端没有错误，但结果不理想。
这个问题有什么解决办法吗？比如，如何改变窗口的背景（X11）w.r.t 一个示例图像，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;
}
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