I have found a hack patch to deal with this problem: it is created by cjacker in 2012,
After this patch can not apply, I created cnfonts as a Chinese new emacser.
--- emacs-23.4/src/xftfont.c 2012-01-15 10:53:31.000000000 +0800
+++ emacs-23.4n/src/xftfont.c 2012-04-18 08:59:40.218009268 +0800
@@ -61,6 +61,8 @@
Display *display;
int screen;
XftFont *xftfont;
+ FRAME_PTR frame; /* hold frame ptr, cjk double width fix need it */
+ int is_cjk; /* Flag to tell if it is CJK font or not. */
};
/* Structure pointed by (struct face *)->extra */
@@ -141,6 +143,86 @@
}
}
+static int xftfont_is_cjk_font(struct xftfont_info *);
+static int xftfont_get_cjk_padding(int, int, int*);
+static int xftfont_get_default_width(struct xftfont_info *);
+
+/* Check whether the font contains CJK Ideograph 'number one', 0x4E00,
+ It should be ok for Chinese/Japanese font.
+ Or font contains Korean script syllable 'Ka',0xAC00,
+ because Korean fonts may not have any Chinese characters at all.
+ codes from xterm.*/
+static int
+xftfont_is_cjk_font(struct xftfont_info *xftfont_info)
+{
+ if(XftCharExists(xftfont_info->display, xftfont_info->xftfont, 0x4E00) ||
+ XftCharExists(xftfont_info->display, xftfont_info->xftfont, 0xAC00))
+ return 1;
+ return 0;
+}
+
+/* Get the padding according to default monospace font width */
+static int
+xftfont_get_cjk_padding(int default_width, int char_width, int *half_width_cjk)
+{
+ int padding = 0;
+ if(half_width_cjk)
+ *half_width_cjk = 0;
+
+ if( default_width == 0 || /* something wrong */
+ default_width == -1 || /* default font is not monospace */
+ char_width == default_width) /* already good */
+ return 0;
+ if( char_width < default_width) {
+ /* almost impossible, but we can handle it */
+ padding = default_width - char_width;
+ if(half_width_cjk)
+ *half_width_cjk = 1;
+ } else /* get the padding, all cjk symbols is DOUBLE width */
+ padding = default_width * 2 - char_width;
+ /* 1, Some old CJK pcf fonts may bigger than 2*default_width.
+ 2, User may set a very big font size for script HAN manually.
+ Keep it unchanged, NOT adjust default font width. */
+ return (padding > 0 && padding < default_width) ? padding : 0;
+}
+
+/* Get the font width of monospace font.
+ Something wrong: return 0;
+ Default is not monospace: return -1;
+ Otherwise: return monospace font width; */
+static int
+xftfont_get_default_width(struct xftfont_info *xftfont_info)
+{
+ Lisp_Object font_object;
+ double request_pixel_size;
+ FRAME_PTR frame = xftfont_info->frame;
+ FcPattern * pattern = xftfont_info->xftfont->pattern;
+ int id = lookup_basic_face (frame, DEFAULT_FACE_ID);
+ struct face *face = FACE_FROM_ID (frame, id);
+ if(!face && !face->font)
+ return 0;
+ XSETFONT (font_object, face->font);
+ /* default font is not monospace */
+ if (XINT(AREF (font_object, FONT_SPACING_INDEX)) != FONT_SPACING_MONO)
+ return -1;
+ if(FcPatternGetDouble(pattern, FC_PIXEL_SIZE, 0, &request_pixel_size) != FcResultMatch)
+ return 0;
+ /* the font of minibuf/modeline never changed when rescaling.
+ it's a little bit difficult to determine where the xftfont draw to.
+ for example, when use mule/leim to input some CJK text.
+ it will draw on the selected frame and minibuf(candidate string).
+ by the way, the 'int' conversion should be ok. */
+ if(FRAME_FONT(frame)->pixel_size == (int)request_pixel_size)
+ return FRAME_SPACE_WIDTH(frame);
+ /* User may set a fixed font size for script han manually,
+ the font will not rescale when issue rescaling,
+ should not ajust the width offset and avoid to make it too wide.
+ its alignment will be wrong, but let's respect user settings.*/
+ if(face->font->pixel_size != (int)request_pixel_size)
+ return FRAME_SPACE_WIDTH(frame);
+ /* otherwise return the current font width */
+ return face->font->space_width;
+}
static Lisp_Object xftfont_list P_ ((Lisp_Object, Lisp_Object));
static Lisp_Object xftfont_match P_ ((Lisp_Object, Lisp_Object));
@@ -450,6 +532,14 @@
XftTextExtents8 (display, xftfont, ascii_printable + 1, 94, &extents);
font->average_width = (font->space_width + extents.xOff) / 95;
}
+
+ /* to fix CJK double width alignment issue.
+ pass FRAME_PTR to every xftfont_info structure,
+ we can not get it in "xftfont_text_extents". */
+ xftfont_info->frame = f;
+ /* mark it is CJK font or not when font opened,
+ avoid calling "xftfont_is_cjk_font" many times. */
+ xftfont_info->is_cjk = xftfont_is_cjk_font(xftfont_info);
UNBLOCK_INPUT;
font->ascent = xftfont->ascent;
@@ -625,20 +715,27 @@
{
struct xftfont_info *xftfont_info = (struct xftfont_info *) font;
XGlyphInfo extents;
-
+ int cjk_padding = 0;
+ int l_padding = 0;
+ int r_padding = 0;
BLOCK_INPUT;
XftGlyphExtents (xftfont_info->display, xftfont_info->xftfont, code, nglyphs,
&extents);
+ if(xftfont_info->is_cjk)
+ cjk_padding = xftfont_get_cjk_padding(xftfont_get_default_width(xftfont_info), extents.xOff, NULL);
+ /* cjk_padding may equals to 0, then all is zero, still ok */
+ l_padding = cjk_padding >> 1; /* get half */
+ r_padding = cjk_padding - l_padding; /* may not divided by 2 exactly */
UNBLOCK_INPUT;
if (metrics)
{
- metrics->lbearing = - extents.x;
- metrics->rbearing = - extents.x + extents.width;
- metrics->width = extents.xOff;
+ metrics->lbearing = - extents.x - l_padding;
+ metrics->rbearing = - extents.x + extents.width + r_padding;
+ metrics->width = extents.xOff + cjk_padding;
metrics->ascent = extents.y;
metrics->descent = extents.height - extents.y;
}
- return extents.xOff;
+ return extents.xOff + cjk_padding;
}
static XftDraw *
@@ -699,9 +796,27 @@
for (i = 0; i < len; i++)
XftDrawGlyphs (xft_draw, &fg, xftfont_info->xftfont,
x + i, y, code + i, 1);
- else
- XftDrawGlyphs (xft_draw, &fg, xftfont_info->xftfont,
- x, y, code, len);
+ else {
+ int default_width = xftfont_get_default_width(xftfont_info);
+ if(!xftfont_info->is_cjk || default_width == -1) /* not cjk or default not monospace */
+ XftDrawGlyphs (xft_draw, &fg, xftfont_info->xftfont, x, y, code, len);
+ else /* draw CJK glyphs one by one and adjust the offset */
+ for (i = 0; i < len; i++) {
+ int cjk_padding = 0;
+ int offset = 0;
+ int half_width_cjk = 0;
+ XGlyphInfo extents;
+ XftGlyphExtents (xftfont_info->display, xftfont_info->xftfont, code+i, 1,
+ &extents);
+ cjk_padding = xftfont_get_cjk_padding(default_width,extents.xOff, &half_width_cjk);
+ if(cjk_padding)
+ offset = default_width * i * (half_width_cjk ? 1 : 2) + (cjk_padding>>1);
+ else
+ offset = extents.xOff * i;
+ XftDrawGlyphs (xft_draw, &fg, xftfont_info->xftfont,
+ x+offset, y, code+i, 1);
+ }
+ }
UNBLOCK_INPUT;
return len;
At 2021-11-13 22:49:15, "tumashu" <tumashu@163.com> wrote:
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>At 2021-11-13 22:36:11, "tumashu" <tumashu@163.com> wrote:
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>>Hello everyone:
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>> (1) How to let A Chinese char width = 2 * Ascii char width is an eternal topic for Chinese new emacser.
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>>it let all Chinese new users and many old users puzzle a lot, that is the reason my cnfonts package (a Chinese fonts setup utils) get >600 github star.
>>recent day, we talk about Emacs fonts, so I want to know, is it possible provide a feature in emacs core to solve this problem?
>>The way cnfonts provide just a hack way I think. https://github.com/tumashu/cnfonts
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>>The two question is that: How to force set min line-width to a value? Chinese emaser use will use two fonts generally, a Ascii fonts and A Chinese fonts.
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>Sorry, is min line-height, not min line-width.
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>>Two fonts will use different height to let 1 Chinese Char width = 2 * Ascii char width, but this set will get other problem:
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>> (2) Chinese char Height > Ascii char height,
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>>The results is that head-line, mode-line and minibuffer's height will shark (change frequently depend Chinese char exist or not).
>>it looks very very ugly.
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>>These two questions make Chinese Emacs new users feel that Emacs is particularly low ！！！
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>>Thanks！
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