Linux X11 波火屏幕 窗口

#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/Xutil.h>

//获取窗口图片后，在QListWidget中显示，图片缩放大小为210*100
const QSize IMAGE_SIZE(210, 100);
const QSize ITEM_SIZE(210, 120);

static Display *xdisplay = 0;

Display *disp()
{
    if (!xdisplay)
        xdisplay = XOpenDisplay(NULL);

    return xdisplay;
}

void cleanupDisplay()
{
    if (!xdisplay)
        return;

    XCloseDisplay(xdisplay);
    xdisplay = 0;
}

bool ewmhIsSupported()
{
    Display *display = disp();
    Atom netSupportingWmCheck = XInternAtom(display, "_NET_SUPPORTING_WM_CHECK", true);
    Atom actualType;
    int format = 0;
    unsigned long num = 0, bytes = 0;
    unsigned char *data = NULL;
    Window ewmh_window = 0;

    int status = XGetWindowProperty(display, DefaultRootWindow(display),
                    netSupportingWmCheck, 0L, 1L, false,
                    XA_WINDOW, &actualType, &format, &num,
                    &bytes, &data);

    if (status == Success) {
        if (num > 0) {
            ewmh_window = ((Window *)data)[0];
        }
        if (data) {
            XFree(data);
            data = NULL;
        }
    }

    if (ewmh_window) {
        status = XGetWindowProperty(display, ewmh_window,
                        netSupportingWmCheck, 0L, 1L, false,
                        XA_WINDOW, &actualType, &format,
                        &num, &bytes, &data);
        if (status != Success || num == 0 ||
            ewmh_window != ((Window *)data)[0]) {
            ewmh_window = 0;
        }
        if (status == Success && data) {
            XFree(data);
        }
    }

    return ewmh_window != 0;
}
//枚举所有窗口
std::list<Window> getTopLevelWindows()
{
    std::list<Window> res;

    if (!ewmhIsSupported()) {
        qDebug("Unable to query window list "
                  "because window manager "
                  "does not support extended "
                  "window manager Hints");
        return res;
    }

    Atom netClList = XInternAtom(disp(), "_NET_CLIENT_LIST", true);
    Atom actualType;
    int format;
    unsigned long num, bytes;
    Window *data = 0;

    for (int i = 0; i < ScreenCount(disp()); ++i) {
        Window rootWin = RootWindow(disp(), i);

        int status = XGetWindowProperty(disp(), rootWin, netClList, 0L,
                        ~0L, false, AnyPropertyType,
                        &actualType, &format, &num,
                        &bytes, (uint8_t **)&data);

        if (status != Success) {
            qDebug("Failed getting root "
                      "window properties");
            continue;
        }

        for (unsigned long i = 0; i < num; ++i)
            res.push_back(data[i]);

        XFree(data);
    }

    return res;
}

std::string getWindowAtom(Window win, const char *atom)
{
    Atom netWmName = XInternAtom(disp(), atom, false);
    int n;
    char **list = 0;
    XTextProperty tp;
    std::string res = "unknown";

    XGetTextProperty(disp(), win, &tp, netWmName);

    if (!tp.nitems)
        XGetWMName(disp(), win, &tp);

    if (!tp.nitems)
        return "error";

    if (tp.encoding == XA_STRING) {
        res = (char *)tp.value;
    } else {
        int ret = XmbTextPropertyToTextList(disp(), &tp, &list, &n);

        if (ret >= Success && n > 0 && *list) {
            res = *list;
            XFreeStringList(list);
        }
    }

    XFree(tp.value);

    return res;
}

inline std::string getWindowName(Window win)
{
    return getWindowAtom(win, "_NET_WM_NAME");
}

将窗口显示到QListWidget中

int index = 0;
for (Window win : getTopLevelWindows()) {
    //获取窗口属性
    XWindowAttributes attrs;
    XGetWindowAttributes(disp(), win, &attrs);

    //XGetImage获取XImage，并通过转换得到QPixmap
    XImage * pImage = XGetImage(disp(), win, 0, 0, attrs.width, attrs.height, AllPlanes, ZPixmap);
    QImage image = QImage((const uchar *)(pImage->data), pImage->width, pImage->height, pImage->bytes_per_line, QImage::Format_RGB32);
    QPixmap pixmap = QPixmap::fromImage(image);

　　 //将QPixmap和窗口名添加到QListWidgetItem中，并将item添加到QListWidget中
    QListWidgetItem *listWidgetItemScreen = new QListWidgetItem(QIcon(pixmap.scaled(IMAGE_SIZE)), getWindowName(win).c_str());
    listWidgetItemScreen->setSizeHint(ITEM_SIZE);
    ui->listWidget->insertItem(index++, listWidgetItemScreen);
}

获取整个屏幕图像并显示到QListWidget中

//获取屏幕Window属性使用RootWindow函数获取
Window rootwin = RootWindow(disp(),0);

XWindowAttributes attrs;
XGetWindowAttributes(disp(), rootwin, &attrs);
XImage * pImage = XGetImage(disp(), rootwin, 0, 0, attrs.width, attrs.height, AllPlanes, ZPixmap);
QImage image = QImage((const uchar *)(pImage->data), pImage->width, pImage->height, pImage->bytes_per_line, QImage::Format_RGB32);
QPixmap pixmap = QPixmap::fromImage(image);
QListWidgetItem *listWidgetItemScreen = new QListWidgetItem(QIcon(pixmap.scaled(IMAGE_SIZE)), "Screen");
listWidgetItemScreen->setSizeHint(ITEM_SIZE);
ui->listWidget->insertItem(index++, listWidgetItemScreen);