win32 - How to draw a rectangle around a text string?

Question

I am new to Win32 and trying to get a GDI based code in C++ ( for technical reasons don't want to use GDI+)

Edit: Simplied the question:

I need to draw a rectangle around the text that is drawn in the middle of the window. - How can I populate the rectangle co-ordinates? - Can any one help with the line - Rectangle(x1,y1,x2,y2)? - How to calculate these (x1,y1) & (x2,y2) values?

Thank you..

        hdc = BeginPaint(hWnd, &ps);
    GetClientRect(hWnd, &rcClient);
    SelectObject(hdc, GetStockObject(DEFAULT_GUI_FONT));
    SetTextColor(hdc, RGB(255, 0, 0));

    DrawText(hdc, wstring(s.begin(),s.end()).c_str(), -1, &rectResult, DT_SINGLELINE | DT_CALCRECT);

    DrawText(hdc, wstring(s.begin(),s.end()).c_str(), -1, &rcClient, DT_SINGLELINE | DT_CENTER | DT_VCENTER);

    // Here I need help - How to I place the rectangle around the Text - which is drawn in the middle of the window?
    // It looks like need to use - rectResult.bottom/top/left/right - but don't know how.. 
    Rectangle(hdc, 0,0,100,100);   

Answer 1

You don't actually have to center the text yourself. The GDI text output functions can do that for you if you pass the appropriate flags.

For example, if you call DrawText and pass the DT_CENTER flag, it will automatically draw the text in the middle of the specified rectangle (horizontally centered).

Assuming you have only a single line of text (which it sounds like you do), you can get it to automatically vertically center the text by passing the DT_SINGLELINE and DT_VCENTER flags.

So all you really have to do is write code to divide your window's client area up into 4 equal parts, and then pass those rectangles to the DrawText function. That's not terribly difficult. Put a pencil and paper to it if you can't visualize it in your head.

void PaintWindow(HWND hWnd)
{
   // Set up the device context for drawing.
   PAINTSTRUCT ps;
   HDC hDC = BeginPaint(hWnd, &ps);
   HPEN hpenOld = static_cast<HPEN>(SelectObject(hDC, GetStockObject(DC_PEN)));
   HBRUSH hbrushOld = static_cast<HBRUSH>(SelectObject(hDC, GetStockObject(NULL_BRUSH)));

   // Calculate the dimensions of the 4 equal rectangles.
   RECT rcWindow;
   GetClientRect(hWnd, &rcWindow);

   RECT rc1, rc2, rc3, rc4;
   rc1 = rc2 = rc3 = rc4 = rcWindow;

   rc1.right  -= (rcWindow.right - rcWindow.left) / 2;
   rc1.bottom -= (rcWindow.bottom - rcWindow.top) / 2;

   rc2.left   = rc1.right;
   rc2.bottom = rc1.bottom;

   rc3.top   = rc1.bottom;
   rc3.right = rc1.right;

   rc4.top  = rc1.bottom;
   rc4.left = rc1.right;

   // Optionally, deflate each of the rectangles by an arbitrary amount so that
   // they don't butt up right next to each other and we can distinguish them.
   InflateRect(&rc1, -5, -5);
   InflateRect(&rc2, -5, -5);
   InflateRect(&rc3, -5, -5);
   InflateRect(&rc4, -5, -5);

   // Draw (differently-colored) borders around these rectangles.
   SetDCPenColor(hDC, RGB(255, 0, 0));    // red
   Rectangle(hDC, rc1.left, rc1.top, rc1.right, rc1.bottom);
   SetDCPenColor(hDC, RGB(0, 255, 0));    // green
   Rectangle(hDC, rc2.left, rc2.top, rc2.right, rc2.bottom);
   SetDCPenColor(hDC, RGB(0, 0, 255));    // blue
   Rectangle(hDC, rc3.left, rc3.top, rc3.right, rc3.bottom);
   SetDCPenColor(hDC, RGB(255, 128, 0));  // orange
   Rectangle(hDC, rc4.left, rc4.top, rc4.right, rc4.bottom);

   // Draw the text into the center of each of the rectangles.
   SetBkMode(hDC, TRANSPARENT);
   SetBkColor(hDC, RGB(0, 0, 0));   // black
   // TODO: Optionally, set a nicer font than the default.
   DrawText(hDC, TEXT("Hello World!"), -1, &rc1, DT_CENTER | DT_SINGLELINE | DT_VCENTER);
   DrawText(hDC, TEXT("Hello World!"), -1, &rc2, DT_CENTER | DT_SINGLELINE | DT_VCENTER);
   DrawText(hDC, TEXT("Hello World!"), -1, &rc3, DT_CENTER | DT_SINGLELINE | DT_VCENTER);
   DrawText(hDC, TEXT("Hello World!"), -1, &rc4, DT_CENTER | DT_SINGLELINE | DT_VCENTER);

   // Clean up after ourselves.
   SelectObject(hDC, hpenOld);
   SelectObject(hDC, hbrushOld);
   EndPaint(hWnd, &ps);
}

 

Answer 2

RECT rect={0,0,0,0};
const char *str="Test Text";
DrawText(hDC, str, strlen(str), &rect, DT_CALCRECT | DT_NOCLIP);
Rectangle(hDC,rect.left,rect.top,rect.right,rect.bottom);
DrawText(hDC, str, strlen(str), &rect, DT_CENTER | DT_VCENTER | DT_SINGLELINE|DT_NOCLIP);