================================================================== Notes regarding fonts, code pages, and East Asian character widths ================================================================== Registry settings ================= * There are console registry settings in `HKCU\Console`. That key has many default settings (e.g. the default font settings) and also per-app subkeys for app-specific overrides. * It is possible to override the code page with an app-specific setting. * There are registry settings in `HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Console`. In particular, the `TrueTypeFont` subkey has a list of suitable font names associated with various CJK code pages, as well as default font names. * There are two values in `HKLM\SYSTEM\CurrentControlSet\Control\Nls\CodePage` that specify the current code pages -- `OEMCP` and `ACP`. Setting the system locale via the Control Panel's "Region" or "Language" dialogs seems to change these code page values. Console fonts ============= * The `FontFamily` field of `CONSOLE_FONT_INFOEX` has two parts: - The high four bits can be exactly one of the `FF_xxxx` font families: FF_DONTCARE(0x00) FF_ROMAN(0x10) FF_SWISS(0x20) FF_MODERN(0x30) FF_SCRIPT(0x40) FF_DECORATIVE(0x50) - The low four bits are a bitmask: TMPF_FIXED_PITCH(1) -- actually means variable pitch TMPF_VECTOR(2) TMPF_TRUETYPE(4) TMPF_DEVICE(8) * Each console has its own independent console font table. The current font is identified with an index into this table. The size of the table is returned by the undocumented `GetNumberOfConsoleFonts` API. It is apparently possible to get the table size without this API, by instead calling `GetConsoleFontSize` on each nonnegative index starting with 0 until the API fails by returning (0, 0). * The font table grows dynamically. Each time the console is configured with a previously-unused (FaceName, Size) combination, two entries are added to the font table -- one with normal weight and one with bold weight. Fonts added this way are always TrueType fonts. * Initially, the font table appears to contain only raster fonts. For example, on an English Windows 8 installation, here is the initial font table: font 0: 4x6 font 1: 6x8 font 2: 8x8 font 3: 16x8 font 4: 5x12 font 5: 7x12 font 6: 8x12 -- the current font font 7: 16x12 font 8: 12x16 font 9: 10x18 `GetNumberOfConsoleFonts` returns 10, and this table matches the raster font sizes according to the console properties dialog. * With a Japanese or Chinese locale, the initial font table appears to contain the sizes applicable to both the East Asian raster font, as well as the sizes for the CP437/CP1252 raster font. * The index passed to `SetCurrentConsoleFontEx` apparently has no effect. The undocumented `SetConsoleFont` API, however, accepts *only* a font index, and on Windows 8 English, it switches between all 10 fonts, even font index #0. * If the index passed to `SetConsoleFont` identifies a Raster Font incompatible with the current code page, then another Raster Font is activated. * Passing "Terminal" to `SetCurrentConsoleFontEx` seems to have no effect. Perhaps relatedly, `SetCurrentConsoleFontEx` does not fail if it is given a bogus `FaceName`. Some font is still chosen and activated. Passing a face name and height seems to work reliably, modulo the CP936 issue described below. Console fonts and code pages ============================ * On an English Windows installation, the default code page is 437, and it cannot be set to 932 (Shift-JIS). (The API call fails.) Changing the system locale to "Japanese (Japan)" using the Region/Language dialog changes the default CP to 932 and permits changing the console CP between 437 and 932. * A console has both an input code page and an output code page (`{Get,Set}ConsoleCP` and `{Get,Set}ConsoleOutputCP`). I'm not going to distinguish between the two for this document; presumably only the output CP matters. The code page can change while the console is open, e.g. by running `mode con: cp select={932,437,1252}` or by calling `SetConsoleOutputCP`. * The current code page restricts which TrueType fonts and which Raster Font sizes are available in the console properties dialog. This can change while the console is open. * Changing the code page almost(?) always changes the current console font. So far, I don't know how the new font is chosen. * With a CP of 932, the only TrueType font available in the console properties dialog is "MS Gothic", displayed as "ＭＳ ゴシック". It is still possible to use the English-default TrueType console fonts, Lucida Console and Consolas, via `SetCurrentConsoleFontEx`. * When using a Raster Font and CP437 or CP1252, writing a UTF-16 codepoint not representable in the code page instead writes a question mark ('?') to the console. This conversion does not apply with a TrueType font, nor with the Raster Font for CP932 or CP936. ReadConsoleOutput and double-width characters ============================================== * With a Raster Font active, when `ReadConsoleOutputW` reads two cells of a double-width character, it fills only a single `CHAR_INFO` structure. The unused trailing `CHAR_INFO` structures are zero-filled. With a TrueType font active, `ReadConsoleOutputW` instead fills two `CHAR_INFO` structures, the first marked with `COMMON_LVB_LEADING_BYTE` and the second marked with `COMMON_LVB_TRAILING_BYTE`. The flag is a misnomer--there aren't two *bytes*, but two cells, and they have equal `CHAR_INFO.Char.UnicodeChar` values. * `ReadConsoleOutputA`, on the other hand, reads two `CHAR_INFO` cells, and if the UTF-16 value can be represented as two bytes in the ANSI/OEM CP, then the two bytes are placed in the two `CHAR_INFO.Char.AsciiChar` values, and the `COMMON_LVB_{LEADING,TRAILING}_BYTE` values are also used. If the codepoint isn't representable, I don't remember what happens -- I think the `AsciiChar` values take on an invalid marker. * Reading only one cell of a double-width character reads a space (U+0020) instead. Raster-vs-TrueType and wide-vs-ANSI do not matter. - XXX: what about attributes? Can a double-width character have mismatched color attributes? - XXX: what happens when writing to just one cell of a double-width character? Default Windows fonts for East Asian languages ============================================== CP932 / Japanese: "ＭＳ ゴシック" (MS Gothic) CP936 / Chinese Simplified: "新宋体" (SimSun) Unreliable character width (half-width vs full-width) ===================================================== The half-width vs full-width status of a codepoint depends on at least these variables: * OS version (Win10 legacy and new modes are different versions) * system locale (English vs Japanese vs Chinese Simplified vs Chinese Traditional, etc) * code page (437 vs 932 vs 936, etc) * raster vs TrueType (Terminal vs MS Gothic vs SimSun, etc) * font size * rendered-vs-model (rendered width can be larger or smaller than model width) Example 1: U+2014 (EM DASH): East_Asian_Width: Ambiguous -------------------------------------------------------- rendered modeled CP932: Win7/8 Raster Fonts half half CP932: Win7/8 Gothic 14/15px half full CP932: Win7/8 Consolas 14/15px half full CP932: Win7/8 Lucida Console 14px half full CP932: Win7/8 Lucida Console 15px half half CP932: Win10New Raster Fonts half half CP932: Win10New Gothic 14/15px half half CP932: Win10New Consolas 14/15px half half CP932: Win10New Lucida Console 14/15px half half CP936: Win7/8 Raster Fonts full full CP936: Win7/8 SimSun 14px full full CP936: Win7/8 SimSun 15px full half CP936: Win7/8 Consolas 14/15px half full CP936: Win10New Raster Fonts full full CP936: Win10New SimSum 14/15px full full CP936: Win10New Consolas 14/15px half half Example 2: U+3044 (HIRAGANA LETTER I): East_Asian_Width: Wide ------------------------------------------------------------- rendered modeled CP932: Win7/8/10N Raster Fonts full full CP932: Win7/8/10N Gothic 14/15px full full CP932: Win7/8/10N Consolas 14/15px half(*2) full CP932: Win7/8/10N Lucida Console 14/15px half(*3) full CP936: Win7/8/10N Raster Fonts full full CP936: Win7/8/10N SimSun 14/15px full full CP936: Win7/8/10N Consolas 14/15px full full Example 3: U+30FC (KATAKANA-HIRAGANA PROLONGED SOUND MARK): East_Asian_Width: Wide ---------------------------------------------------------------------------------- rendered modeled CP932: Win7 Raster Fonts full full CP932: Win7 Gothic 14/15px full full CP932: Win7 Consolas 14/15px half(*2) full CP932: Win7 Lucida Console 14px half(*3) full CP932: Win7 Lucida Console 15px half(*3) half CP932: Win8 Raster Fonts full full CP932: Win8 Gothic 14px full half CP932: Win8 Gothic 15px full full CP932: Win8 Consolas 14/15px half(*2) full CP932: Win8 Lucida Console 14px half(*3) full CP932: Win8 Lucida Console 15px half(*3) half CP932: Win10New Raster Fonts full full CP932: Win10New Gothic 14/15px full full CP932: Win10New Consolas 14/15px half(*2) half CP932: Win10New Lucida Console 14/15px half(*2) half CP936: Win7/8 Raster Fonts full full CP936: Win7/8 SimSun 14px full full CP936: Win7/8 SimSun 15px full half CP936: Win7/8 Consolas 14px full full CP936: Win7/8 Consolas 15px full half CP936: Win10New Raster Fonts full full CP936: Win10New SimSum 14/15px full full CP936: Win10New Consolas 14/15px full full Example 4: U+4000 (CJK UNIFIED IDEOGRAPH-4000): East_Asian_Width: Wide ---------------------------------------------------------------------- rendered modeled CP932: Win7 Raster Fonts half(*1) half CP932: Win7 Gothic 14/15px full full CP932: Win7 Consolas 14/15px half(*2) full CP932: Win7 Lucida Console 14px half(*3) full CP932: Win7 Lucida Console 15px half(*3) half CP932: Win8 Raster Fonts half(*1) half CP932: Win8 Gothic 14px full half CP932: Win8 Gothic 15px full full CP932: Win8 Consolas 14/15px half(*2) full CP932: Win8 Lucida Console 14px half(*3) full CP932: Win8 Lucida Console 15px half(*3) half CP932: Win10New Raster Fonts half(*1) half CP932: Win10New Gothic 14/15px full full CP932: Win10New Consolas 14/15px half(*2) half CP932: Win10New Lucida Console 14/15px half(*2) half CP936: Win7/8 Raster Fonts full full CP936: Win7/8 SimSun 14px full full CP936: Win7/8 SimSun 15px full half CP936: Win7/8 Consolas 14px full full CP936: Win7/8 Consolas 15px full half CP936: Win10New Raster Fonts full full CP936: Win10New SimSum 14/15px full full CP936: Win10New Consolas 14/15px full full (*1) Rendered as a half-width filled white box (*2) Rendered as a half-width box with a question mark inside (*3) Rendered as a half-width empty box (!!) One of the only places in Win10New where rendered and modeled width disagree Windows quirk: unreliable font heights with CP936 / Chinese Simplified ====================================================================== When I set the font to 新宋体 17px, using either the properties dialog or `SetCurrentConsoleFontEx`, the height reported by `GetCurrentConsoleFontEx` is not 17, but is instead 19. The same problem does not affect Raster Fonts, nor have I seen the problem in the English or Japanese locales. I observed this with Windows 7 and Windows 10 new mode. If I set the font using the facename, width, *and* height, then the `SetCurrentConsoleFontEx` and `GetCurrentConsoleFontEx` values agree. If I set the font using *only* the facename and height, then the two values disagree. Windows bug: GetCurrentConsoleFontEx is initially invalid ========================================================= - Assume there is no configured console font name in the registry. In this case, the console defaults to a raster font. - Open a new console and call the `GetCurrentConsoleFontEx` API. - The `FaceName` field of the returned `CONSOLE_FONT_INFOEX` data structure is incorrect. On Windows 7, 8, and 10, I observed that the field was blank. On Windows 8, occasionally, it instead contained: U+AE72 U+75BE U+0001 The other fields of the structure all appeared correct: nFont=6 dwFontSize=(8,12) FontFamily=0x30 FontWeight=400 - The `FaceName` field becomes initialized easily: - Open the console properties dialog and click OK. (Cancel is not sufficient.) - Call the undocumented `SetConsoleFont` with the current font table index, which is 6 in the example above. - It seems that the console uncritically accepts whatever string is stored in the registry, including a blank string, and passes it on the the `GetCurrentConsoleFontEx` caller. It is possible to get the console to *write* a blank setting into the registry -- simply open the console (default or app-specific) properties and click OK.