/// <summary>
/// Attempt to enumerate all dead keys available on the current keyboard
/// layout and cache the results in <see cref="m_possible_dead_keys"/>.
/// </summary>
private static void AnalyzeLayout()
{
// Clear key buffer
VkToUnicode(VK.SPACE);
VkToUnicode(VK.SPACE);
// Compute an input locale identifier suitable for ToUnicodeEx(). This is
// necessary because some IMEs interfer with ToUnicodeEx, e.g. Japanese,
// so instead we pretend we use an English US keyboard.
// I could check that Korean (Microsoft IME) and Chinese Simplified
// (Microsoft Pinyin) are not affected.
// High bytes are the device ID, low bytes are the language ID
var current_device_id = (ulong)m_current_layout >> 16;
var japanese_lang_id = NativeMethods.MAKELANG(LANG.JAPANESE, SUBLANG.JAPANESE_JAPAN);
if (current_device_id == japanese_lang_id)
{
var english_lang_id = NativeMethods.MAKELANG(LANG.ENGLISH, SUBLANG.DEFAULT);
m_transformed_hkl = (IntPtr)((english_lang_id << 16) | english_lang_id);
}
// Check that the transformed HKL actually works; otherwise, revert.
if (VkToUnicode(VK.SPACE) != " ")
{
m_transformed_hkl = m_current_layout;
}
// Try every keyboard key followed by space to see which ones are
// dead keys. This way, when later we want to know if a dead key is
// currently buffered, we just call VkToUnicode(VK.SPACE) and match
// the result with what we found here. This code also precomputes
// characters obtained with AltGr.
m_possible_dead_keys = new Dictionary <string, int>();
m_possible_altgr_keys = new Dictionary <string, string>();
string[] no_altgr = new string[0x200];
byte[] state = new byte[256];
for (int i = 0; i < 0x400; ++i)
{
VK vk = (VK)(i & 0xff);
bool has_shift = (i & 0x100) != 0;
bool has_altgr = (i & 0x200) != 0;
state[(int)VK.SHIFT] = (byte)(has_shift ? 0x80 : 0x00);
state[(int)VK.CONTROL] = (byte)(has_altgr ? 0x80 : 0x00);
state[(int)VK.MENU] = (byte)(has_altgr ? 0x80 : 0x00);
// First the key we’re interested in, then the space key
string str_if_normal = VkToUnicode(vk, (SC)0, state, (LLKHF)0);
string str_if_dead = VkToUnicode(VK.SPACE);
VkToUnicode(VK.SPACE); // Additional safety to clear buffer
bool has_dead = str_if_dead != "" && str_if_dead != " ";
// If the AltGr gives us a result and it’s different from without
// AltGr, we need to remember it.
string str = has_dead ? str_if_dead : str_if_normal;
if (has_altgr)
{
if (no_altgr[i - 0x200] != "" && str != "" && no_altgr[i - 0x200] != str)
{
Log.Debug("VK {0} is “{1}” but “{2}” with AltGr",
vk.ToString(), no_altgr[i - 0x200], str);
m_possible_altgr_keys[no_altgr[i - 0x200]] = str;
}
}
else
{
no_altgr[i] = str;
}
// If the resulting string is not the space character, it means
// that it was a dead key. Good!
if (has_dead)
{
Log.Debug("VK {0} is dead key “{1}”",
vk.ToString(), str_if_dead);
m_possible_dead_keys[str_if_dead] = i;
}
}
}