Hyperlinks.cpp

// Hyperlinks.cpp
//
// Copyright 2002 Neal Stublen
// All rights reserved.
//
// http://www.awesoftware.com
//

#include <windows.h>

#include "Hyperlinks.h"


#define PROP_ORIGINAL_FONT		TEXT("_Hyperlink_Original_Font_")
#define PROP_ORIGINAL_PROC		TEXT("_Hyperlink_Original_Proc_")
#define PROP_STATIC_HYPERLINK	TEXT("_Hyperlink_From_Static_")
#define PROP_UNDERLINE_FONT		TEXT("_Hyperlink_Underline_Font_")


LRESULT CALLBACK _HyperlinkParentProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	WNDPROC pfnOrigProc = (WNDPROC) GetProp(hwnd, PROP_ORIGINAL_PROC);

	switch (message)
	{
        case WM_CTLCOLORSTATIC:
		{
			HDC hdc = (HDC) wParam;
			HWND hwndCtl = (HWND) lParam;

			BOOL fHyperlink = (NULL != GetProp(hwndCtl, PROP_STATIC_HYPERLINK));
			if (fHyperlink)
			{
				LRESULT lr = CallWindowProc(pfnOrigProc, hwnd, message, wParam, lParam);
				SetTextColor(hdc, RGB(0, 0, 192));
				return lr;
			}
		}
		break;
		
        case WM_DESTROY:
		{
			SetWindowLong(hwnd, GWL_WNDPROC, (LONG) pfnOrigProc);
			RemoveProp(hwnd, PROP_ORIGINAL_PROC);
		}
		break;
	}
	
	return CallWindowProc(pfnOrigProc, hwnd, message, wParam, lParam);
}

LRESULT CALLBACK _HyperlinkProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	WNDPROC pfnOrigProc = (WNDPROC) GetProp(hwnd, PROP_ORIGINAL_PROC);

	switch (message)
	{
	case WM_DESTROY:
		{
			SetWindowLong(hwnd, GWL_WNDPROC, (LONG) pfnOrigProc);
			RemoveProp(hwnd, PROP_ORIGINAL_PROC);

			HFONT hOrigFont = (HFONT) GetProp(hwnd, PROP_ORIGINAL_FONT);
			SendMessage(hwnd, WM_SETFONT, (WPARAM) hOrigFont, 0);
			RemoveProp(hwnd, PROP_ORIGINAL_FONT);

			HFONT hFont = (HFONT) GetProp(hwnd, PROP_UNDERLINE_FONT);
			DeleteObject(hFont);
			RemoveProp(hwnd, PROP_UNDERLINE_FONT);

			RemoveProp(hwnd, PROP_STATIC_HYPERLINK);

			break;
		}
	case WM_MOUSEMOVE:
		{
			if (GetCapture() != hwnd)
			{
				HFONT hFont = (HFONT) GetProp(hwnd, PROP_UNDERLINE_FONT);
				SendMessage(hwnd, WM_SETFONT, (WPARAM) hFont, FALSE);
				InvalidateRect(hwnd, NULL, FALSE);
				SetCapture(hwnd);
			}
			else
			{
				RECT rect;
				GetWindowRect(hwnd, &rect);

				POINT pt = { LOWORD(lParam), HIWORD(lParam) };
				ClientToScreen(hwnd, &pt);

				if (!PtInRect(&rect, pt))
				{
					HFONT hFont = (HFONT) GetProp(hwnd, PROP_ORIGINAL_FONT);
					SendMessage(hwnd, WM_SETFONT, (WPARAM) hFont, FALSE);
					InvalidateRect(hwnd, NULL, FALSE);
					ReleaseCapture();
				}
			}
			break;
		}
	case WM_SETCURSOR:
		{
			// Since IDC_HAND is not available on all operating systems,
			// we will load the arrow cursor if IDC_HAND is not present.
			HCURSOR hCursor = LoadCursor(NULL, IDC_HAND);
			if (NULL == hCursor)
			{
				hCursor = LoadCursor(NULL, IDC_ARROW);
			}
			SetCursor(hCursor);
			return TRUE;
		}
	}

	return CallWindowProc(pfnOrigProc, hwnd, message, wParam, lParam);
}

BOOL ConvertStaticToHyperlink(HWND hwndCtl)
{
	// Subclass the parent so we can color the controls as we desire.

	HWND hwndParent = GetParent(hwndCtl);
	if (NULL != hwndParent)
	{
		WNDPROC pfnOrigProc = (WNDPROC) GetWindowLong(hwndParent, GWL_WNDPROC);
		if (pfnOrigProc != _HyperlinkParentProc)
		{
			SetProp(hwndParent, PROP_ORIGINAL_PROC, (HANDLE) pfnOrigProc);
			SetWindowLong(hwndParent, GWL_WNDPROC, (LONG) (WNDPROC) _HyperlinkParentProc);
		}
	}

	// Make sure the control will send notifications.

	DWORD dwStyle = GetWindowLong(hwndCtl, GWL_STYLE);
	SetWindowLong(hwndCtl, GWL_STYLE, dwStyle | SS_NOTIFY);

	// Subclass the existing control.

	WNDPROC pfnOrigProc = (WNDPROC) GetWindowLong(hwndCtl, GWL_WNDPROC);
	SetProp(hwndCtl, PROP_ORIGINAL_PROC, (HANDLE) pfnOrigProc);
	SetWindowLong(hwndCtl, GWL_WNDPROC, (LONG) (WNDPROC) _HyperlinkProc);

	// Create an updated font by adding an underline.

	HFONT hOrigFont = (HFONT) SendMessage(hwndCtl, WM_GETFONT, 0, 0);
	SetProp(hwndCtl, PROP_ORIGINAL_FONT, (HANDLE) hOrigFont);

	LOGFONT lf;
	GetObject(hOrigFont, sizeof(lf), &lf);
	lf.lfUnderline = TRUE;

	HFONT hFont = CreateFontIndirect(&lf);
	SetProp(hwndCtl, PROP_UNDERLINE_FONT, (HANDLE) hFont);

	// Set a flag on the control so we know what color it should be.

	SetProp(hwndCtl, PROP_STATIC_HYPERLINK, (HANDLE) 1);

	return TRUE;
}

BOOL ConvertStaticToHyperlink(HWND hwndParent, UINT uiCtlId)
{
	return ConvertStaticToHyperlink(GetDlgItem(hwndParent, uiCtlId));
}