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-rw-r--r--boxdraw.c194
1 files changed, 194 insertions, 0 deletions
diff --git a/boxdraw.c b/boxdraw.c
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+++ b/boxdraw.c
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+/*
+ * 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);
+ }
+ }
+}