C ++和Xlib-中心窗口 [英] C++ and Xlib - center window

问题描述

我已经开始研究直接基于XLib的GUI应用程序编程，并且我试图在屏幕上创建一个居中的窗口。我不知道用于实现此目的的常用技术。我的代码（无效）是（我使用CodeBlocks）

I have started to study GUI applications programming based on XLib directly and I am trying to create a centered window on the screen. I don't know the usual technique used to achieve this. My code (which doesn't work) is this (I use CodeBlocks)

#include <stdio.h>
#include <stdlib.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/Xos.h>
#include <X11/Xatom.h>
#include <X11/keysym.h>
#include <GL/glew.h>
#include <GL/freeglut.h>

int screen;
Display *display;
XSetWindowAttributes window_attributes;
Window mainwindow;
XEvent events;

int main(int argc, char** argv) {
    display = XOpenDisplay(NULL);screen = DefaultScreen(display);
    window_attributes.background_pixel = XWhitePixel(display, screen);
    window_attributes.border_pixel = XBlackPixel(display, screen);
    window_attributes.win_gravity = SouthWestGravity;

    mainwindow = XCreateWindow(display,
                             RootWindow(display, screen),
                             1, 1,
                             600, 400,
                             0,
                             CopyFromParent,
                             InputOutput,
                             CopyFromParent,
                             CWBackPixel|CWBorderPixel,
                             &window_attributes
                            );
    XMapWindow(display, mainwindow);
    XFlush(display);
    XSelectInput(display, mainwindow, ExposureMask|KeyPressMask|ButtonPressMask);
    while (1)  {
        XNextEvent(display, &events);
        switch  (events.type) {
            case Expose:
                // Lots of code that doesn't matter for my problem
            break;
        }
    }
    return 0;
}

所以，我认为 window_attributes.win_gravity 可以解决问题，但似乎我做错了，或者肯定是与操作系统相关的问题。

感谢您的帮助！

So, I thought that window_attributes.win_gravity would do the trick but it seems like I'm doing something wrong or it must be an OS related issue.
Thanks for your help!

更新

我已经将X（左侧位置）更改为100，将y（顶部位置）更改为100，但窗口的位置未更改。因此，我的问题是，无论窗口的位置如何，都无法更改。

UPDATE
I have changed X (left position) by 100 and y (top position) by 100 but the window's position doesn't change. So, my problem is that the window's position can't be changed, no matter what it is.

推荐答案

1. 引力适用于窗口自身的内容和子元素，而不适用于其在父窗口中的位置。


2. 窗口管理器可以并且确实会覆盖顶级窗口位置请求。在 XMapWindow 调用之后，使用 XMoveWindow 。

1. Gravity applies to the window's own content and children, not to its position in the parent window.
2. Window managers can and do override top-level window position requests. Use XMoveWindow after the XMapWindow call.

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