1 ==================================================================
2 Notes regarding fonts, code pages, and East Asian character widths
3 ==================================================================
9 * There are console registry settings in `HKCU\Console`. That key has many
10 default settings (e.g. the default font settings) and also per-app subkeys
11 for app-specific overrides.
13 * It is possible to override the code page with an app-specific setting.
15 * There are registry settings in
16 `HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Console`. In particular,
17 the `TrueTypeFont` subkey has a list of suitable font names associated with
18 various CJK code pages, as well as default font names.
20 * There are two values in `HKLM\SYSTEM\CurrentControlSet\Control\Nls\CodePage`
21 that specify the current code pages -- `OEMCP` and `ACP`. Setting the
22 system locale via the Control Panel's "Region" or "Language" dialogs seems
23 to change these code page values.
29 * The `FontFamily` field of `CONSOLE_FONT_INFOEX` has two parts:
30 - The high four bits can be exactly one of the `FF_xxxx` font families:
37 - The low four bits are a bitmask:
38 TMPF_FIXED_PITCH(1) -- actually means variable pitch
43 * Each console has its own independent console font table. The current font
44 is identified with an index into this table. The size of the table is
45 returned by the undocumented `GetNumberOfConsoleFonts` API. It is apparently
46 possible to get the table size without this API, by instead calling
47 `GetConsoleFontSize` on each nonnegative index starting with 0 until the API
48 fails by returning (0, 0).
50 * The font table grows dynamically. Each time the console is configured with
51 a previously-unused (FaceName, Size) combination, two entries are added to
52 the font table -- one with normal weight and one with bold weight. Fonts
53 added this way are always TrueType fonts.
55 * Initially, the font table appears to contain only raster fonts. For
56 example, on an English Windows 8 installation, here is the initial font
64 font 6: 8x12 -- the current font
68 `GetNumberOfConsoleFonts` returns 10, and this table matches the raster font
69 sizes according to the console properties dialog.
71 * With a Japanese or Chinese locale, the initial font table appears to contain
72 the sizes applicable to both the East Asian raster font, as well as the
73 sizes for the CP437/CP1252 raster font.
75 * The index passed to `SetCurrentConsoleFontEx` apparently has no effect.
76 The undocumented `SetConsoleFont` API, however, accepts *only* a font index,
77 and on Windows 8 English, it switches between all 10 fonts, even font index
80 * If the index passed to `SetConsoleFont` identifies a Raster Font
81 incompatible with the current code page, then another Raster Font is
84 * Passing "Terminal" to `SetCurrentConsoleFontEx` seems to have no effect.
85 Perhaps relatedly, `SetCurrentConsoleFontEx` does not fail if it is given a
86 bogus `FaceName`. Some font is still chosen and activated. Passing a face
87 name and height seems to work reliably, modulo the CP936 issue described
91 Console fonts and code pages
92 ============================
94 * On an English Windows installation, the default code page is 437, and it
95 cannot be set to 932 (Shift-JIS). (The API call fails.) Changing the
96 system locale to "Japanese (Japan)" using the Region/Language dialog
97 changes the default CP to 932 and permits changing the console CP between
100 * A console has both an input code page and an output code page
101 (`{Get,Set}ConsoleCP` and `{Get,Set}ConsoleOutputCP`). I'm not going to
102 distinguish between the two for this document; presumably only the output
103 CP matters. The code page can change while the console is open, e.g.
104 by running `mode con: cp select={932,437,1252}` or by calling
105 `SetConsoleOutputCP`.
107 * The current code page restricts which TrueType fonts and which Raster Font
108 sizes are available in the console properties dialog. This can change
109 while the console is open.
111 * Changing the code page almost(?) always changes the current console font.
112 So far, I don't know how the new font is chosen.
114 * With a CP of 932, the only TrueType font available in the console properties
115 dialog is "MS Gothic", displayed as "MS ゴシック". It is still possible to
116 use the English-default TrueType console fonts, Lucida Console and Consolas,
117 via `SetCurrentConsoleFontEx`.
119 * When using a Raster Font and CP437 or CP1252, writing a UTF-16 codepoint not
120 representable in the code page instead writes a question mark ('?') to the
121 console. This conversion does not apply with a TrueType font, nor with the
122 Raster Font for CP932 or CP936.
125 ReadConsoleOutput and double-width characters
126 ==============================================
128 * With a Raster Font active, when `ReadConsoleOutputW` reads two cells of a
129 double-width character, it fills only a single `CHAR_INFO` structure. The
130 unused trailing `CHAR_INFO` structures are zero-filled. With a TrueType
131 font active, `ReadConsoleOutputW` instead fills two `CHAR_INFO` structures,
132 the first marked with `COMMON_LVB_LEADING_BYTE` and the second marked with
133 `COMMON_LVB_TRAILING_BYTE`. The flag is a misnomer--there aren't two
134 *bytes*, but two cells, and they have equal `CHAR_INFO.Char.UnicodeChar`
137 * `ReadConsoleOutputA`, on the other hand, reads two `CHAR_INFO` cells, and
138 if the UTF-16 value can be represented as two bytes in the ANSI/OEM CP, then
139 the two bytes are placed in the two `CHAR_INFO.Char.AsciiChar` values, and
140 the `COMMON_LVB_{LEADING,TRAILING}_BYTE` values are also used. If the
141 codepoint isn't representable, I don't remember what happens -- I think the
142 `AsciiChar` values take on an invalid marker.
144 * Reading only one cell of a double-width character reads a space (U+0020)
145 instead. Raster-vs-TrueType and wide-vs-ANSI do not matter.
146 - XXX: what about attributes? Can a double-width character have mismatched
148 - XXX: what happens when writing to just one cell of a double-width
152 Default Windows fonts for East Asian languages
153 ==============================================
154 CP932 / Japanese: "MS ゴシック" (MS Gothic)
155 CP936 / Chinese Simplified: "新宋体" (SimSun)
158 Unreliable character width (half-width vs full-width)
159 =====================================================
161 The half-width vs full-width status of a codepoint depends on at least these variables:
162 * OS version (Win10 legacy and new modes are different versions)
163 * system locale (English vs Japanese vs Chinese Simplified vs Chinese Traditional, etc)
164 * code page (437 vs 932 vs 936, etc)
165 * raster vs TrueType (Terminal vs MS Gothic vs SimSun, etc)
167 * rendered-vs-model (rendered width can be larger or smaller than model width)
169 Example 1: U+2014 (EM DASH): East_Asian_Width: Ambiguous
170 --------------------------------------------------------
172 CP932: Win7/8 Raster Fonts half half
173 CP932: Win7/8 Gothic 14/15px half full
174 CP932: Win7/8 Consolas 14/15px half full
175 CP932: Win7/8 Lucida Console 14px half full
176 CP932: Win7/8 Lucida Console 15px half half
177 CP932: Win10New Raster Fonts half half
178 CP932: Win10New Gothic 14/15px half half
179 CP932: Win10New Consolas 14/15px half half
180 CP932: Win10New Lucida Console 14/15px half half
182 CP936: Win7/8 Raster Fonts full full
183 CP936: Win7/8 SimSun 14px full full
184 CP936: Win7/8 SimSun 15px full half
185 CP936: Win7/8 Consolas 14/15px half full
186 CP936: Win10New Raster Fonts full full
187 CP936: Win10New SimSum 14/15px full full
188 CP936: Win10New Consolas 14/15px half half
190 Example 2: U+3044 (HIRAGANA LETTER I): East_Asian_Width: Wide
191 -------------------------------------------------------------
193 CP932: Win7/8/10N Raster Fonts full full
194 CP932: Win7/8/10N Gothic 14/15px full full
195 CP932: Win7/8/10N Consolas 14/15px half(*2) full
196 CP932: Win7/8/10N Lucida Console 14/15px half(*3) full
198 CP936: Win7/8/10N Raster Fonts full full
199 CP936: Win7/8/10N SimSun 14/15px full full
200 CP936: Win7/8/10N Consolas 14/15px full full
202 Example 3: U+30FC (KATAKANA-HIRAGANA PROLONGED SOUND MARK): East_Asian_Width: Wide
203 ----------------------------------------------------------------------------------
205 CP932: Win7 Raster Fonts full full
206 CP932: Win7 Gothic 14/15px full full
207 CP932: Win7 Consolas 14/15px half(*2) full
208 CP932: Win7 Lucida Console 14px half(*3) full
209 CP932: Win7 Lucida Console 15px half(*3) half
210 CP932: Win8 Raster Fonts full full
211 CP932: Win8 Gothic 14px full half
212 CP932: Win8 Gothic 15px full full
213 CP932: Win8 Consolas 14/15px half(*2) full
214 CP932: Win8 Lucida Console 14px half(*3) full
215 CP932: Win8 Lucida Console 15px half(*3) half
216 CP932: Win10New Raster Fonts full full
217 CP932: Win10New Gothic 14/15px full full
218 CP932: Win10New Consolas 14/15px half(*2) half
219 CP932: Win10New Lucida Console 14/15px half(*2) half
221 CP936: Win7/8 Raster Fonts full full
222 CP936: Win7/8 SimSun 14px full full
223 CP936: Win7/8 SimSun 15px full half
224 CP936: Win7/8 Consolas 14px full full
225 CP936: Win7/8 Consolas 15px full half
226 CP936: Win10New Raster Fonts full full
227 CP936: Win10New SimSum 14/15px full full
228 CP936: Win10New Consolas 14/15px full full
230 Example 4: U+4000 (CJK UNIFIED IDEOGRAPH-4000): East_Asian_Width: Wide
231 ----------------------------------------------------------------------
233 CP932: Win7 Raster Fonts half(*1) half
234 CP932: Win7 Gothic 14/15px full full
235 CP932: Win7 Consolas 14/15px half(*2) full
236 CP932: Win7 Lucida Console 14px half(*3) full
237 CP932: Win7 Lucida Console 15px half(*3) half
238 CP932: Win8 Raster Fonts half(*1) half
239 CP932: Win8 Gothic 14px full half
240 CP932: Win8 Gothic 15px full full
241 CP932: Win8 Consolas 14/15px half(*2) full
242 CP932: Win8 Lucida Console 14px half(*3) full
243 CP932: Win8 Lucida Console 15px half(*3) half
244 CP932: Win10New Raster Fonts half(*1) half
245 CP932: Win10New Gothic 14/15px full full
246 CP932: Win10New Consolas 14/15px half(*2) half
247 CP932: Win10New Lucida Console 14/15px half(*2) half
249 CP936: Win7/8 Raster Fonts full full
250 CP936: Win7/8 SimSun 14px full full
251 CP936: Win7/8 SimSun 15px full half
252 CP936: Win7/8 Consolas 14px full full
253 CP936: Win7/8 Consolas 15px full half
254 CP936: Win10New Raster Fonts full full
255 CP936: Win10New SimSum 14/15px full full
256 CP936: Win10New Consolas 14/15px full full
258 (*1) Rendered as a half-width filled white box
259 (*2) Rendered as a half-width box with a question mark inside
260 (*3) Rendered as a half-width empty box
261 (!!) One of the only places in Win10New where rendered and modeled width disagree
264 Windows quirk: unreliable font heights with CP936 / Chinese Simplified
265 ======================================================================
267 When I set the font to 新宋体 17px, using either the properties dialog or
268 `SetCurrentConsoleFontEx`, the height reported by `GetCurrentConsoleFontEx` is
269 not 17, but is instead 19. The same problem does not affect Raster Fonts,
270 nor have I seen the problem in the English or Japanese locales. I observed
271 this with Windows 7 and Windows 10 new mode.
273 If I set the font using the facename, width, *and* height, then the
274 `SetCurrentConsoleFontEx` and `GetCurrentConsoleFontEx` values agree. If I
275 set the font using *only* the facename and height, then the two values
279 Windows bug: GetCurrentConsoleFontEx is initially invalid
280 =========================================================
282 - Assume there is no configured console font name in the registry. In this
283 case, the console defaults to a raster font.
284 - Open a new console and call the `GetCurrentConsoleFontEx` API.
285 - The `FaceName` field of the returned `CONSOLE_FONT_INFOEX` data
286 structure is incorrect. On Windows 7, 8, and 10, I observed that the
287 field was blank. On Windows 8, occasionally, it instead contained:
289 The other fields of the structure all appeared correct:
290 nFont=6 dwFontSize=(8,12) FontFamily=0x30 FontWeight=400
291 - The `FaceName` field becomes initialized easily:
292 - Open the console properties dialog and click OK. (Cancel is not
294 - Call the undocumented `SetConsoleFont` with the current font table
295 index, which is 6 in the example above.
296 - It seems that the console uncritically accepts whatever string is
297 stored in the registry, including a blank string, and passes it on the
298 the `GetCurrentConsoleFontEx` caller. It is possible to get the console
299 to *write* a blank setting into the registry -- simply open the console
300 (default or app-specific) properties and click OK.