在窗口中垂直居中多行文本，纯 winapi 和 C++ [英] Center multiline text vertically in a window, pure winapi and c++

问题描述

我有一个需要根据需要重绘多行文本的窗口，文本可以是可变长度的.那么如何去做呢?

I have a window that needs redrawing multiline text on demand, text could be of variable length. So how to go about doing this ?

这是我现在所拥有的，但不起作用.

This is what I have for now and it doesn't work.

               RECT rc;

               GetWindowRect ( hwnd, &rc );



               int rectHeight = DrawText( hMemDc, text.c_str(), text.size(), &rc, DT_CALCRECT );                    // Get formating rectangle height


               int windowHight = rc.bottom - rc.top;
               int windowWidth = rc.right - rc.left;


               int yTop = rc.top + (  ( windowHight - rectHeight ) / 2  );
               int yBottom = yTop + rectHeight;

               int xLeft = rc.left + 20;
               int xRight = rc.right - 20;


               rc.top       = yTop;
               rc.bottom    = yBottom;
               rc.left      = xLeft;
               rc.right     = xRight;


               DrawText( hMemDc, text.c_str(), text.size(), &rc, DT_LEFT | DT_WORDBREAK );

推荐答案

您的代码中有两个问题.首先，您需要在 DT_CALCRECT 调用中指定 DT_WORDBREAK 否则它不会包装文本以适应可用宽度.

There are two problems in your code. First, you need to specify DT_WORDBREAK in the DT_CALCRECT call otherwise it won't wrap the text to fit the available width.

int rectHeight = DrawText( hMemDc, text.c_str(), text.size(), &rc,
  DT_CALCRECT|DT_WORDBREAK );

其次，DT_CALCRECT 调用将使用计算出的矩形覆盖 rc 变量，因此您的窗口高度将是错误的，并且您的居中将不起作用.在 DT_CALCRECT 调用之前保存 rc 变量，或者之后再次调用 GetWindowRect.

Second, the DT_CALCRECT call will override the rc variable with calculated rect, so your window height will be wrong and your centering won't work. Either save the rc variable before the DT_CALCRECT call, or call GetWindowRect again afterwards.

GetWindowRect ( hwnd, &rc );

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