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boxdraw_v2: custom render lines/blocks/braille for perfect alignment

It seems impossible to ensure that blocks and line drawing glyphs
align without visible gaps for all combinations of arbitrary font,
size and width/height scale factor.

This commit adds options to render most of the lines/blocks and
braille codepoints without using the font such that they align
perfectly regardless of font, size or other configuration values.

Supported codepoints are U+2500 - U+259F except dashes/diagonals,
and U28XX.

The lines/blocks data is stored as 16-bit values at boxdraw_data.h

boxdraw/braille are independent, disabled by default at config[.def].h
master
Avi Halachmi (:avih) 3 years ago committed by Amolith
parent
commit
a20fe9919d
Signed by: Amolith
GPG Key ID: 5548AD9930655715
  1. 3
      Makefile
  2. 194
      boxdraw.c
  3. 214
      boxdraw_data.h
  4. 12
      config.def.h
  5. 3
      st.c
  6. 10
      st.h
  7. 21
      x.c

3
Makefile

@ -4,7 +4,7 @@
include config.mk
SRC = st.c x.c
SRC = st.c x.c boxdraw.c
OBJ = $(SRC:.c=.o)
all: options st
@ -23,6 +23,7 @@ config.h:
st.o: config.h st.h win.h
x.o: arg.h config.h st.h win.h
boxdraw.o: config.h st.h boxdraw_data.h
$(OBJ): config.h config.mk

194
boxdraw.c

@ -0,0 +1,194 @@
/*
* Copyright 2018 Avi Halachmi (:avih) avihpit@yahoo.com https://github.com/avih
* MIT/X Consortium License
*/
#include <X11/Xft/Xft.h>
#include "st.h"
#include "boxdraw_data.h"
/* Rounded non-negative integers division of n / d */
#define DIV(n, d) (((n) + (d) / 2) / (d))
static Display *xdpy;
static Colormap xcmap;
static XftDraw *xd;
static Visual *xvis;
static void drawbox(int, int, int, int, XftColor *, XftColor *, ushort);
static void drawboxlines(int, int, int, int, XftColor *, ushort);
/* public API */
void
boxdraw_xinit(Display *dpy, Colormap cmap, XftDraw *draw, Visual *vis)
{
xdpy = dpy; xcmap = cmap; xd = draw, xvis = vis;
}
int
isboxdraw(Rune u)
{
Rune block = u & ~0xff;
return (boxdraw && block == 0x2500 && boxdata[(uint8_t)u]) ||
(boxdraw_braille && block == 0x2800);
}
/* the "index" is actually the entire shape data encoded as ushort */
ushort
boxdrawindex(const Glyph *g)
{
if (boxdraw_braille && (g->u & ~0xff) == 0x2800)
return BRL | (uint8_t)g->u;
if (boxdraw_bold && (g->mode & ATTR_BOLD))
return BDB | boxdata[(uint8_t)g->u];
return boxdata[(uint8_t)g->u];
}
void
drawboxes(int x, int y, int cw, int ch, XftColor *fg, XftColor *bg,
const XftGlyphFontSpec *specs, int len)
{
for ( ; len-- > 0; x += cw, specs++)
drawbox(x, y, cw, ch, fg, bg, (ushort)specs->glyph);
}
/* implementation */
void
drawbox(int x, int y, int w, int h, XftColor *fg, XftColor *bg, ushort bd)
{
ushort cat = bd & ~(BDB | 0xff); /* mask out bold and data */
if (bd & (BDL | BDA)) {
/* lines (light/double/heavy/arcs) */
drawboxlines(x, y, w, h, fg, bd);
} else if (cat == BBD) {
/* lower (8-X)/8 block */
int d = DIV((uint8_t)bd * h, 8);
XftDrawRect(xd, fg, x, y + d, w, h - d);
} else if (cat == BBU) {
/* upper X/8 block */
XftDrawRect(xd, fg, x, y, w, DIV((uint8_t)bd * h, 8));
} else if (cat == BBL) {
/* left X/8 block */
XftDrawRect(xd, fg, x, y, DIV((uint8_t)bd * w, 8), h);
} else if (cat == BBR) {
/* right (8-X)/8 block */
int d = DIV((uint8_t)bd * w, 8);
XftDrawRect(xd, fg, x + d, y, w - d, h);
} else if (cat == BBQ) {
/* Quadrants */
int w2 = DIV(w, 2), h2 = DIV(h, 2);
if (bd & TL)
XftDrawRect(xd, fg, x, y, w2, h2);
if (bd & TR)
XftDrawRect(xd, fg, x + w2, y, w - w2, h2);
if (bd & BL)
XftDrawRect(xd, fg, x, y + h2, w2, h - h2);
if (bd & BR)
XftDrawRect(xd, fg, x + w2, y + h2, w - w2, h - h2);
} else if (bd & BBS) {
/* Shades - data is 1/2/3 for 25%/50%/75% alpha, respectively */
int d = (uint8_t)bd;
XftColor xfc;
XRenderColor xrc = { .alpha = 0xffff };
xrc.red = DIV(fg->color.red * d + bg->color.red * (4 - d), 4);
xrc.green = DIV(fg->color.green * d + bg->color.green * (4 - d), 4);
xrc.blue = DIV(fg->color.blue * d + bg->color.blue * (4 - d), 4);
XftColorAllocValue(xdpy, xvis, xcmap, &xrc, &xfc);
XftDrawRect(xd, &xfc, x, y, w, h);
XftColorFree(xdpy, xvis, xcmap, &xfc);
} else if (cat == BRL) {
/* braille, each data bit corresponds to one dot at 2x4 grid */
int w1 = DIV(w, 2);
int h1 = DIV(h, 4), h2 = DIV(h, 2), h3 = DIV(3 * h, 4);
if (bd & 1) XftDrawRect(xd, fg, x, y, w1, h1);
if (bd & 2) XftDrawRect(xd, fg, x, y + h1, w1, h2 - h1);
if (bd & 4) XftDrawRect(xd, fg, x, y + h2, w1, h3 - h2);
if (bd & 8) XftDrawRect(xd, fg, x + w1, y, w - w1, h1);
if (bd & 16) XftDrawRect(xd, fg, x + w1, y + h1, w - w1, h2 - h1);
if (bd & 32) XftDrawRect(xd, fg, x + w1, y + h2, w - w1, h3 - h2);
if (bd & 64) XftDrawRect(xd, fg, x, y + h3, w1, h - h3);
if (bd & 128) XftDrawRect(xd, fg, x + w1, y + h3, w - w1, h - h3);
}
}
void
drawboxlines(int x, int y, int w, int h, XftColor *fg, ushort bd)
{
/* s: stem thickness. width/8 roughly matches underscore thickness. */
/* We draw bold as 1.5 * normal-stem and at least 1px thicker. */
/* doubles draw at least 3px, even when w or h < 3. bold needs 6px. */
int mwh = MIN(w, h);
int base_s = MAX(1, DIV(mwh, 8));
int bold = (bd & BDB) && mwh >= 6; /* possibly ignore boldness */
int s = bold ? MAX(base_s + 1, DIV(3 * base_s, 2)) : base_s;
int w2 = DIV(w - s, 2), h2 = DIV(h - s, 2);
/* the s-by-s square (x + w2, y + h2, s, s) is the center texel. */
/* The base length (per direction till edge) includes this square. */
int light = bd & (LL | LU | LR | LD);
int double_ = bd & (DL | DU | DR | DD);
if (light) {
/* d: additional (negative) length to not-draw the center */
/* texel - at arcs and avoid drawing inside (some) doubles */
int arc = bd & BDA;
int multi_light = light & (light - 1);
int multi_double = double_ & (double_ - 1);
/* light crosses double only at DH+LV, DV+LH (ref. shapes) */
int d = arc || (multi_double && !multi_light) ? -s : 0;
if (bd & LL)
XftDrawRect(xd, fg, x, y + h2, w2 + s + d, s);
if (bd & LU)
XftDrawRect(xd, fg, x + w2, y, s, h2 + s + d);
if (bd & LR)
XftDrawRect(xd, fg, x + w2 - d, y + h2, w - w2 + d, s);
if (bd & LD)
XftDrawRect(xd, fg, x + w2, y + h2 - d, s, h - h2 + d);
}
/* double lines - also align with light to form heavy when combined */
if (double_) {
/*
* going clockwise, for each double-ray: p is additional length
* to the single-ray nearer to the previous direction, and n to
* the next. p and n adjust from the base length to lengths
* which consider other doubles - shorter to avoid intersections
* (p, n), or longer to draw the far-corner texel (n).
*/
int dl = bd & DL, du = bd & DU, dr = bd & DR, dd = bd & DD;
if (dl) {
int p = dd ? -s : 0, n = du ? -s : dd ? s : 0;
XftDrawRect(xd, fg, x, y + h2 + s, w2 + s + p, s);
XftDrawRect(xd, fg, x, y + h2 - s, w2 + s + n, s);
}
if (du) {
int p = dl ? -s : 0, n = dr ? -s : dl ? s : 0;
XftDrawRect(xd, fg, x + w2 - s, y, s, h2 + s + p);
XftDrawRect(xd, fg, x + w2 + s, y, s, h2 + s + n);
}
if (dr) {
int p = du ? -s : 0, n = dd ? -s : du ? s : 0;
XftDrawRect(xd, fg, x + w2 - p, y + h2 - s, w - w2 + p, s);
XftDrawRect(xd, fg, x + w2 - n, y + h2 + s, w - w2 + n, s);
}
if (dd) {
int p = dr ? -s : 0, n = dl ? -s : dr ? s : 0;
XftDrawRect(xd, fg, x + w2 + s, y + h2 - p, s, h - h2 + p);
XftDrawRect(xd, fg, x + w2 - s, y + h2 - n, s, h - h2 + n);
}
}
}

214
boxdraw_data.h

@ -0,0 +1,214 @@
/*
* Copyright 2018 Avi Halachmi (:avih) avihpit@yahoo.com https://github.com/avih
* MIT/X Consortium License
*/
/*
* U+25XX codepoints data
*
* References:
* http://www.unicode.org/charts/PDF/U2500.pdf
* http://www.unicode.org/charts/PDF/U2580.pdf
*
* Test page:
* https://github.com/GNOME/vte/blob/master/doc/boxes.txt
*/
/* Each shape is encoded as 16-bits. Higher bits are category, lower are data */
/* Categories (mutually exclusive except BDB): */
/* For convenience, BDL/BDA/BBS/BDB are 1 bit each, the rest are enums */
#define BDL (1<<8) /* Box Draw Lines (light/double/heavy) */
#define BDA (1<<9) /* Box Draw Arc (light) */
#define BBD (1<<10) /* Box Block Down (lower) X/8 */
#define BBL (2<<10) /* Box Block Left X/8 */
#define BBU (3<<10) /* Box Block Upper X/8 */
#define BBR (4<<10) /* Box Block Right X/8 */
#define BBQ (5<<10) /* Box Block Quadrants */
#define BRL (6<<10) /* Box Braille (data is lower byte of U28XX) */
#define BBS (1<<14) /* Box Block Shades */
#define BDB (1<<15) /* Box Draw is Bold */
/* (BDL/BDA) Light/Double/Heavy x Left/Up/Right/Down/Horizontal/Vertical */
/* Heavy is light+double (literally drawing light+double align to form heavy) */
#define LL (1<<0)
#define LU (1<<1)
#define LR (1<<2)
#define LD (1<<3)
#define LH (LL+LR)
#define LV (LU+LD)
#define DL (1<<4)
#define DU (1<<5)
#define DR (1<<6)
#define DD (1<<7)
#define DH (DL+DR)
#define DV (DU+DD)
#define HL (LL+DL)
#define HU (LU+DU)
#define HR (LR+DR)
#define HD (LD+DD)
#define HH (HL+HR)
#define HV (HU+HD)
/* (BBQ) Quadrants Top/Bottom x Left/Right */
#define TL (1<<0)
#define TR (1<<1)
#define BL (1<<2)
#define BR (1<<3)
/* Data for U+2500 - U+259F except dashes/diagonals */
static const unsigned short boxdata[256] = {
/* light lines */
[0x00] = BDL + LH, /* light horizontal */
[0x02] = BDL + LV, /* light vertical */
[0x0c] = BDL + LD + LR, /* light down and right */
[0x10] = BDL + LD + LL, /* light down and left */
[0x14] = BDL + LU + LR, /* light up and right */
[0x18] = BDL + LU + LL, /* light up and left */
[0x1c] = BDL + LV + LR, /* light vertical and right */
[0x24] = BDL + LV + LL, /* light vertical and left */
[0x2c] = BDL + LH + LD, /* light horizontal and down */
[0x34] = BDL + LH + LU, /* light horizontal and up */
[0x3c] = BDL + LV + LH, /* light vertical and horizontal */
[0x74] = BDL + LL, /* light left */
[0x75] = BDL + LU, /* light up */
[0x76] = BDL + LR, /* light right */
[0x77] = BDL + LD, /* light down */
/* heavy [+light] lines */
[0x01] = BDL + HH,
[0x03] = BDL + HV,
[0x0d] = BDL + HR + LD,
[0x0e] = BDL + HD + LR,
[0x0f] = BDL + HD + HR,
[0x11] = BDL + HL + LD,
[0x12] = BDL + HD + LL,
[0x13] = BDL + HD + HL,
[0x15] = BDL + HR + LU,
[0x16] = BDL + HU + LR,
[0x17] = BDL + HU + HR,
[0x19] = BDL + HL + LU,
[0x1a] = BDL + HU + LL,
[0x1b] = BDL + HU + HL,
[0x1d] = BDL + HR + LV,
[0x1e] = BDL + HU + LD + LR,
[0x1f] = BDL + HD + LR + LU,
[0x20] = BDL + HV + LR,
[0x21] = BDL + HU + HR + LD,
[0x22] = BDL + HD + HR + LU,
[0x23] = BDL + HV + HR,
[0x25] = BDL + HL + LV,
[0x26] = BDL + HU + LD + LL,
[0x27] = BDL + HD + LU + LL,
[0x28] = BDL + HV + LL,
[0x29] = BDL + HU + HL + LD,
[0x2a] = BDL + HD + HL + LU,
[0x2b] = BDL + HV + HL,
[0x2d] = BDL + HL + LD + LR,
[0x2e] = BDL + HR + LL + LD,
[0x2f] = BDL + HH + LD,
[0x30] = BDL + HD + LH,
[0x31] = BDL + HD + HL + LR,
[0x32] = BDL + HR + HD + LL,
[0x33] = BDL + HH + HD,
[0x35] = BDL + HL + LU + LR,
[0x36] = BDL + HR + LU + LL,
[0x37] = BDL + HH + LU,
[0x38] = BDL + HU + LH,
[0x39] = BDL + HU + HL + LR,
[0x3a] = BDL + HU + HR + LL,
[0x3b] = BDL + HH + HU,
[0x3d] = BDL + HL + LV + LR,
[0x3e] = BDL + HR + LV + LL,
[0x3f] = BDL + HH + LV,
[0x40] = BDL + HU + LH + LD,
[0x41] = BDL + HD + LH + LU,
[0x42] = BDL + HV + LH,
[0x43] = BDL + HU + HL + LD + LR,
[0x44] = BDL + HU + HR + LD + LL,
[0x45] = BDL + HD + HL + LU + LR,
[0x46] = BDL + HD + HR + LU + LL,
[0x47] = BDL + HH + HU + LD,
[0x48] = BDL + HH + HD + LU,
[0x49] = BDL + HV + HL + LR,
[0x4a] = BDL + HV + HR + LL,
[0x4b] = BDL + HV + HH,
[0x78] = BDL + HL,
[0x79] = BDL + HU,
[0x7a] = BDL + HR,
[0x7b] = BDL + HD,
[0x7c] = BDL + HR + LL,
[0x7d] = BDL + HD + LU,
[0x7e] = BDL + HL + LR,
[0x7f] = BDL + HU + LD,
/* double [+light] lines */
[0x50] = BDL + DH,
[0x51] = BDL + DV,
[0x52] = BDL + DR + LD,
[0x53] = BDL + DD + LR,
[0x54] = BDL + DR + DD,
[0x55] = BDL + DL + LD,
[0x56] = BDL + DD + LL,
[0x57] = BDL + DL + DD,
[0x58] = BDL + DR + LU,
[0x59] = BDL + DU + LR,
[0x5a] = BDL + DU + DR,
[0x5b] = BDL + DL + LU,
[0x5c] = BDL + DU + LL,
[0x5d] = BDL + DL + DU,
[0x5e] = BDL + DR + LV,
[0x5f] = BDL + DV + LR,
[0x60] = BDL + DV + DR,
[0x61] = BDL + DL + LV,
[0x62] = BDL + DV + LL,
[0x63] = BDL + DV + DL,
[0x64] = BDL + DH + LD,
[0x65] = BDL + DD + LH,
[0x66] = BDL + DD + DH,
[0x67] = BDL + DH + LU,
[0x68] = BDL + DU + LH,
[0x69] = BDL + DH + DU,
[0x6a] = BDL + DH + LV,
[0x6b] = BDL + DV + LH,
[0x6c] = BDL + DH + DV,
/* (light) arcs */
[0x6d] = BDA + LD + LR,
[0x6e] = BDA + LD + LL,
[0x6f] = BDA + LU + LL,
[0x70] = BDA + LU + LR,
/* Lower (Down) X/8 block (data is 8 - X) */
[0x81] = BBD + 7, [0x82] = BBD + 6, [0x83] = BBD + 5, [0x84] = BBD + 4,
[0x85] = BBD + 3, [0x86] = BBD + 2, [0x87] = BBD + 1, [0x88] = BBD + 0,
/* Left X/8 block (data is X) */
[0x89] = BBL + 7, [0x8a] = BBL + 6, [0x8b] = BBL + 5, [0x8c] = BBL + 4,
[0x8d] = BBL + 3, [0x8e] = BBL + 2, [0x8f] = BBL + 1,
/* upper 1/2 (4/8), 1/8 block (X), right 1/2, 1/8 block (8-X) */
[0x80] = BBU + 4, [0x94] = BBU + 1,
[0x90] = BBR + 4, [0x95] = BBR + 7,
/* Quadrants */
[0x96] = BBQ + BL,
[0x97] = BBQ + BR,
[0x98] = BBQ + TL,
[0x99] = BBQ + TL + BL + BR,
[0x9a] = BBQ + TL + BR,
[0x9b] = BBQ + TL + TR + BL,
[0x9c] = BBQ + TL + TR + BR,
[0x9d] = BBQ + TR,
[0x9e] = BBQ + BL + TR,
[0x9f] = BBQ + BL + TR + BR,
/* Shades, data is an alpha value in 25% units (1/4, 1/2, 3/4) */
[0x91] = BBS + 1, [0x92] = BBS + 2, [0x93] = BBS + 3,
/* U+2504 - U+250B, U+254C - U+254F: unsupported (dashes) */
/* U+2571 - U+2573: unsupported (diagonals) */
};

12
config.def.h

@ -67,6 +67,18 @@ static unsigned int blinktimeout = 800;
*/
static unsigned int cursorthickness = 2;
/*
* 1: render most of the lines/blocks characters without using the font for
* perfect alignment between cells (U2500 - U259F except dashes/diagonals).
* Bold affects lines thickness if boxdraw_bold is not 0. Italic is ignored.
* 0: disable (render all U25XX glyphs normally from the font).
*/
const int boxdraw = 0;
const int boxdraw_bold = 0;
/* braille (U28XX): 1: render as adjacent "pixels", 0: use font */
const int boxdraw_braille = 0;
/*
* bell volume. It must be a value between -100 and 100. Use 0 for disabling
* it

3
st.c

@ -1219,6 +1219,9 @@ tsetchar(Rune u, Glyph *attr, int x, int y)
term.dirty[y] = 1;
term.line[y][x] = *attr;
term.line[y][x].u = u;
if (isboxdraw(u))
term.line[y][x].mode |= ATTR_BOXDRAW;
}
void

10
st.h

@ -33,6 +33,7 @@ enum glyph_attribute {
ATTR_WRAP = 1 << 8,
ATTR_WIDE = 1 << 9,
ATTR_WDUMMY = 1 << 10,
ATTR_BOXDRAW = 1 << 11,
ATTR_BOLD_FAINT = ATTR_BOLD | ATTR_FAINT,
};
@ -111,6 +112,14 @@ void *xmalloc(size_t);
void *xrealloc(void *, size_t);
char *xstrdup(char *);
int isboxdraw(Rune);
ushort boxdrawindex(const Glyph *);
#ifdef XFT_VERSION
/* only exposed to x.c, otherwise we'll need Xft.h for the types */
void boxdraw_xinit(Display *, Colormap, XftDraw *, Visual *);
void drawboxes(int, int, int, int, XftColor *, XftColor *, const XftGlyphFontSpec *, int);
#endif
/* config.h globals */
extern char *utmp;
extern char *scroll;
@ -123,3 +132,4 @@ extern char *termname;
extern unsigned int tabspaces;
extern unsigned int defaultfg;
extern unsigned int defaultbg;
extern const int boxdraw, boxdraw_bold, boxdraw_braille;

21
x.c

@ -1206,6 +1206,8 @@ xinit(int cols, int rows)
xsel.xtarget = XInternAtom(xw.dpy, "UTF8_STRING", 0);
if (xsel.xtarget == None)
xsel.xtarget = XA_STRING;
boxdraw_xinit(xw.dpy, xw.cmap, xw.draw, xw.vis);
}
int
@ -1252,8 +1254,13 @@ xmakeglyphfontspecs(XftGlyphFontSpec *specs, const Glyph *glyphs, int len, int x
yp = winy + font->ascent;
}
/* Lookup character index with default font. */
glyphidx = XftCharIndex(xw.dpy, font->match, rune);
if (mode & ATTR_BOXDRAW) {
/* minor shoehorning: boxdraw uses only this ushort */
glyphidx = boxdrawindex(&glyphs[i]);
} else {
/* Lookup character index with default font. */
glyphidx = XftCharIndex(xw.dpy, font->match, rune);
}
if (glyphidx) {
specs[numspecs].font = font->match;
specs[numspecs].glyph = glyphidx;
@ -1457,8 +1464,12 @@ xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, i
r.width = width;
XftDrawSetClipRectangles(xw.draw, winx, winy, &r, 1);
/* Render the glyphs. */
XftDrawGlyphFontSpec(xw.draw, fg, specs, len);
if (base.mode & ATTR_BOXDRAW) {
drawboxes(winx, winy, width / len, win.ch, fg, bg, specs, len);
} else {
/* Render the glyphs. */
XftDrawGlyphFontSpec(xw.draw, fg, specs, len);
}
/* Render underline and strikethrough. */
if (base.mode & ATTR_UNDERLINE) {
@ -1501,7 +1512,7 @@ xdrawcursor(int cx, int cy, Glyph g, int ox, int oy, Glyph og)
/*
* Select the right color for the right mode.
*/
g.mode &= ATTR_BOLD|ATTR_ITALIC|ATTR_UNDERLINE|ATTR_STRUCK|ATTR_WIDE;
g.mode &= ATTR_BOLD|ATTR_ITALIC|ATTR_UNDERLINE|ATTR_STRUCK|ATTR_WIDE|ATTR_BOXDRAW;
if (IS_SET(MODE_REVERSE)) {
g.mode |= ATTR_REVERSE;

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