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boxdraw.c (6237B)

          1 /*
          2  * Copyright 2018 Avi Halachmi (:avih) avihpit@yahoo.com https://github.com/avih
          3  * MIT/X Consortium License
          4  */
          5
          6 #include <X11/Xft/Xft.h>
          7 #include "st.h"
          8 #include "boxdraw_data.h"
          9
         10 /* Rounded non-negative integers division of n / d  */
         11 #define DIV(n, d) (((n) + (d) / 2) / (d))
         12
         13 static Display *xdpy;
         14 static Colormap xcmap;
         15 static XftDraw *xd;
         16 static Visual *xvis;
         17
         18 static void drawbox(int, int, int, int, XftColor *, XftColor *, ushort);
         19 static void drawboxlines(int, int, int, int, XftColor *, ushort);
         20
         21 /* public API */
         22
         23 void
         24 boxdraw_xinit(Display *dpy, Colormap cmap, XftDraw *draw, Visual *vis)
         25 {
         26 	xdpy = dpy; xcmap = cmap; xd = draw, xvis = vis;
         27 }
         28
         29 int
         30 isboxdraw(Rune u)
         31 {
         32 	Rune block = u & ~0xff;
         33 	return (boxdraw && block == 0x2500 && boxdata[(uint8_t)u]) ||
         34 	       (boxdraw_braille && block == 0x2800);
         35 }
         36
         37 /* the "index" is actually the entire shape data encoded as ushort */
         38 ushort
         39 boxdrawindex(const Glyph *g)
         40 {
         41 	if (boxdraw_braille && (g->u & ~0xff) == 0x2800)
         42 		return BRL | (uint8_t)g->u;
         43 	if (boxdraw_bold && (g->mode & ATTR_BOLD))
         44 		return BDB | boxdata[(uint8_t)g->u];
         45 	return boxdata[(uint8_t)g->u];
         46 }
         47
         48 void
         49 drawboxes(int x, int y, int cw, int ch, XftColor *fg, XftColor *bg,
         50           const XftGlyphFontSpec *specs, int len)
         51 {
         52 	for ( ; len-- > 0; x += cw, specs++)
         53 		drawbox(x, y, cw, ch, fg, bg, (ushort)specs->glyph);
         54 }
         55
         56 /* implementation */
         57
         58 void
         59 drawbox(int x, int y, int w, int h, XftColor *fg, XftColor *bg, ushort bd)
         60 {
         61 	ushort cat = bd & ~(BDB | 0xff);  /* mask out bold and data */
         62 	if (bd & (BDL | BDA)) {
         63 		/* lines (light/double/heavy/arcs) */
         64 		drawboxlines(x, y, w, h, fg, bd);
         65
         66 	} else if (cat == BBD) {
         67 		/* lower (8-X)/8 block */
         68 		int d = DIV((uint8_t)bd * h, 8);
         69 		XftDrawRect(xd, fg, x, y + d, w, h - d);
         70
         71 	} else if (cat == BBU) {
         72 		/* upper X/8 block */
         73 		XftDrawRect(xd, fg, x, y, w, DIV((uint8_t)bd * h, 8));
         74
         75 	} else if (cat == BBL) {
         76 		/* left X/8 block */
         77 		XftDrawRect(xd, fg, x, y, DIV((uint8_t)bd * w, 8), h);
         78
         79 	} else if (cat == BBR) {
         80 		/* right (8-X)/8 block */
         81 		int d = DIV((uint8_t)bd * w, 8);
         82 		XftDrawRect(xd, fg, x + d, y, w - d, h);
         83
         84 	} else if (cat == BBQ) {
         85 		/* Quadrants */
         86 		int w2 = DIV(w, 2), h2 = DIV(h, 2);
         87 		if (bd & TL)
         88 			XftDrawRect(xd, fg, x, y, w2, h2);
         89 		if (bd & TR)
         90 			XftDrawRect(xd, fg, x + w2, y, w - w2, h2);
         91 		if (bd & BL)
         92 			XftDrawRect(xd, fg, x, y + h2, w2, h - h2);
         93 		if (bd & BR)
         94 			XftDrawRect(xd, fg, x + w2, y + h2, w - w2, h - h2);
         95
         96 	} else if (bd & BBS) {
         97 		/* Shades - data is 1/2/3 for 25%/50%/75% alpha, respectively */
         98 		int d = (uint8_t)bd;
         99 		XftColor xfc;
        100 		XRenderColor xrc = { .alpha = 0xffff };
        101
        102 		xrc.red = DIV(fg->color.red * d + bg->color.red * (4 - d), 4);
        103 		xrc.green = DIV(fg->color.green * d + bg->color.green * (4 - d), 4);
        104 		xrc.blue = DIV(fg->color.blue * d + bg->color.blue * (4 - d), 4);
        105
        106 		XftColorAllocValue(xdpy, xvis, xcmap, &xrc, &xfc);
        107 		XftDrawRect(xd, &xfc, x, y, w, h);
        108 		XftColorFree(xdpy, xvis, xcmap, &xfc);
        109
        110 	} else if (cat == BRL) {
        111 		/* braille, each data bit corresponds to one dot at 2x4 grid */
        112 		int w1 = DIV(w, 2);
        113 		int h1 = DIV(h, 4), h2 = DIV(h, 2), h3 = DIV(3 * h, 4);
        114
        115 		if (bd & 1)   XftDrawRect(xd, fg, x, y, w1, h1);
        116 		if (bd & 2)   XftDrawRect(xd, fg, x, y + h1, w1, h2 - h1);
        117 		if (bd & 4)   XftDrawRect(xd, fg, x, y + h2, w1, h3 - h2);
        118 		if (bd & 8)   XftDrawRect(xd, fg, x + w1, y, w - w1, h1);
        119 		if (bd & 16)  XftDrawRect(xd, fg, x + w1, y + h1, w - w1, h2 - h1);
        120 		if (bd & 32)  XftDrawRect(xd, fg, x + w1, y + h2, w - w1, h3 - h2);
        121 		if (bd & 64)  XftDrawRect(xd, fg, x, y + h3, w1, h - h3);
        122 		if (bd & 128) XftDrawRect(xd, fg, x + w1, y + h3, w - w1, h - h3);
        123
        124 	}
        125 }
        126
        127 void
        128 drawboxlines(int x, int y, int w, int h, XftColor *fg, ushort bd)
        129 {
        130 	/* s: stem thickness. width/8 roughly matches underscore thickness. */
        131 	/* We draw bold as 1.5 * normal-stem and at least 1px thicker.      */
        132 	/* doubles draw at least 3px, even when w or h < 3. bold needs 6px. */
        133 	int mwh = MIN(w, h);
        134 	int base_s = MAX(1, DIV(mwh, 8));
        135 	int bold = (bd & BDB) && mwh >= 6;  /* possibly ignore boldness */
        136 	int s = bold ? MAX(base_s + 1, DIV(3 * base_s, 2)) : base_s;
        137 	int w2 = DIV(w - s, 2), h2 = DIV(h - s, 2);
        138 	/* the s-by-s square (x + w2, y + h2, s, s) is the center texel.    */
        139 	/* The base length (per direction till edge) includes this square.  */
        140
        141 	int light = bd & (LL | LU | LR | LD);
        142 	int double_ = bd & (DL | DU | DR | DD);
        143
        144 	if (light) {
        145 		/* d: additional (negative) length to not-draw the center   */
        146 		/* texel - at arcs and avoid drawing inside (some) doubles  */
        147 		int arc = bd & BDA;
        148 		int multi_light = light & (light - 1);
        149 		int multi_double = double_ & (double_ - 1);
        150 		/* light crosses double only at DH+LV, DV+LH (ref. shapes)  */
        151 		int d = arc || (multi_double && !multi_light) ? -s : 0;
        152
        153 		if (bd & LL)
        154 			XftDrawRect(xd, fg, x, y + h2, w2 + s + d, s);
        155 		if (bd & LU)
        156 			XftDrawRect(xd, fg, x + w2, y, s, h2 + s + d);
        157 		if (bd & LR)
        158 			XftDrawRect(xd, fg, x + w2 - d, y + h2, w - w2 + d, s);
        159 		if (bd & LD)
        160 			XftDrawRect(xd, fg, x + w2, y + h2 - d, s, h - h2 + d);
        161 	}
        162
        163 	/* double lines - also align with light to form heavy when combined */
        164 	if (double_) {
        165 		/*
        166 		* going clockwise, for each double-ray: p is additional length
        167 		* to the single-ray nearer to the previous direction, and n to
        168 		* the next. p and n adjust from the base length to lengths
        169 		* which consider other doubles - shorter to avoid intersections
        170 		* (p, n), or longer to draw the far-corner texel (n).
        171 		*/
        172 		int dl = bd & DL, du = bd & DU, dr = bd & DR, dd = bd & DD;
        173 		if (dl) {
        174 			int p = dd ? -s : 0, n = du ? -s : dd ? s : 0;
        175 			XftDrawRect(xd, fg, x, y + h2 + s, w2 + s + p, s);
        176 			XftDrawRect(xd, fg, x, y + h2 - s, w2 + s + n, s);
        177 		}
        178 		if (du) {
        179 			int p = dl ? -s : 0, n = dr ? -s : dl ? s : 0;
        180 			XftDrawRect(xd, fg, x + w2 - s, y, s, h2 + s + p);
        181 			XftDrawRect(xd, fg, x + w2 + s, y, s, h2 + s + n);
        182 		}
        183 		if (dr) {
        184 			int p = du ? -s : 0, n = dd ? -s : du ? s : 0;
        185 			XftDrawRect(xd, fg, x + w2 - p, y + h2 - s, w - w2 + p, s);
        186 			XftDrawRect(xd, fg, x + w2 - n, y + h2 + s, w - w2 + n, s);
        187 		}
        188 		if (dd) {
        189 			int p = dr ? -s : 0, n = dl ? -s : dr ? s : 0;
        190 			XftDrawRect(xd, fg, x + w2 + s, y + h2 - p, s, h - h2 + p);
        191 			XftDrawRect(xd, fg, x + w2 - s, y + h2 - n, s, h - h2 + n);
        192 		}
        193 	}
        194 }