add libttf

1 files changed, 274 insertions, 0 deletions

diff --git a/sys/src/libttf/render.c b/sys/src/libttf/render.c
new file mode 100644
index 000000000..bea21f61f
--- /dev/null
+++ b/sys/src/libttf/render.c
@@ -0,0 +1,274 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+#include <ttf.h>
+#include "impl.h"
+
+static int
+ttfparsekern(TTFontU *f)
+{
+	u16int ver, len, cov, ntab;
+	int i;
+
+	if(ttfgototable(f, "kern") < 0)
+		return -1;
+	ttfunpack(f, "ww", &ver, &ntab);
+	if(ver != 0)
+		return -1;
+	if(ntab == 0)
+		return -1;
+	for(i = 0; i < ntab; i++){
+		ttfunpack(f, "www", &ver, &len, &cov);
+		if((cov & 1) != 0) break;
+		Bseek(f->bin, len - 6, 1);
+	}
+	ttfunpack(f, "w6", &len);
+	f->nkern = len;
+	f->kern = mallocz(sizeof(TTKern) * len, 1);
+	for(i = 0; i < len; i++)
+		ttfunpack(f, "lS", &f->kern[i].idx, &f->kern[i].val);
+	return 0;
+}
+
+static int
+ttfkern(TTFont *f, int l, int r)
+{
+	u32int idx;
+	int a, b, c;
+	TTFontU *u;
+	
+	u = f->u;
+	if(u->nkern == 0)
+		return 0;
+	idx = l << 16 | r;
+	a = 0;
+	b = u->nkern - 1;
+	if(u->kern[a].idx > idx || u->kern[b].idx < idx)
+		return 0;
+	while(a <= b){
+		c = (a + b) / 2;
+		if(u->kern[c].idx < idx){
+			a = c + 1;
+		}else if(u->kern[c].idx > idx){
+			b = c - 1;
+		}else
+			return ttfrounddiv(u->kern[c].val * f->ppem, u->emsize);
+	}
+	return 0;
+}
+
+typedef struct {
+	TTBitmap *b;
+	TTFont *font;
+	TTGlyph **glyph;
+	int *gwidth;
+	char **cpos;
+	char *pp;
+	int nglyph, aglyph;
+	int linew;
+	int adj;
+	int nspc;
+	int oy, lh;
+	int spcidx;
+	int flags;
+	int spcw;
+	int spcminus;
+} Render;
+
+static int
+addglyph(Render *r, char *p, TTGlyph *g)
+{
+	void *v;
+	int k;
+
+	if(r->nglyph >= r->aglyph){
+		r->aglyph += 32;
+		v = realloc(r->glyph, sizeof(TTGlyph *) * r->aglyph);
+		if(v == nil) return -1;
+		r->glyph = v;
+		v = realloc(r->gwidth, sizeof(int) * r->aglyph);
+		if(v == nil) return -1;
+		r->gwidth = v;
+		v = realloc(r->cpos, sizeof(char *) * r->aglyph);
+		if(v == nil) return -1;
+		r->cpos = v;
+	}
+	r->glyph[r->nglyph] = g;
+	r->cpos[r->nglyph] = p;
+	r->gwidth[r->nglyph] = g->advanceWidthpx;
+	if(r->nglyph > 0){
+		k = ttfkern(r->font, r->glyph[r->nglyph-1]->idx, g->idx);
+		r->gwidth[r->nglyph-1] += k;
+		r->linew += k;
+	}
+	r->nglyph++;
+	r->linew += r->gwidth[r->nglyph-1];
+	if(g->idx == r->spcidx)
+		r->nspc++;
+	return 0;
+}
+
+static void
+flushglyphs(Render *r, int justify)
+{
+	int i, n, k, x, y;
+	int llen;
+	int adj, spcw, nspc, c;
+	TTFont *f;
+
+	f = r->font;
+	if((r->flags & TTFMODE) == TTFLALIGN && !justify)
+		while(r->nglyph > 0 && r->glyph[r->nglyph - 1]->idx == r->spcidx){
+			r->linew -= r->gwidth[--r->nglyph];
+			r->nspc--;
+		}
+	llen = r->linew;
+	k = n = r->nglyph;
+	nspc = r->nspc;
+	adj = (nspc * r->spcminus + 63) / 64;
+	if(r->linew - adj > r->b->width){
+		n = r->nglyph;
+		while(n > 0 && r->glyph[n - 1]->idx != r->spcidx)
+			llen -= r->gwidth[--n];
+		k = n;
+		while(n > 0 && r->glyph[n - 1]->idx == r->spcidx){
+			llen -= r->gwidth[--n];
+			nspc--;
+		}
+		if(n == 0){
+			while(n < r->nglyph && llen + r->gwidth[n] < r->b->width)
+				llen += r->gwidth[n++];
+			k = n;
+		}
+	}
+	if(justify){
+		if(nspc == 0)
+			spcw = 0;
+		else
+			spcw = (r->b->width - llen + nspc * r->spcw) * 64 / nspc;
+	}else
+		spcw = r->spcw * 64;
+	switch(r->flags & TTFMODE | justify * TTFJUSTIFY){
+	case TTFRALIGN:
+		x = r->b->width - llen;
+		break;
+	case TTFCENTER:
+		x = (r->b->width - llen)/2;
+		break;
+	default:
+		x = 0;
+	}
+	y = r->oy + f->ascentpx;
+	c = 0;
+	for(i = 0; i < k; i++){
+		if(r->glyph[i]->idx == r->spcidx){
+			c += spcw;
+			x += c >> 6;
+			c &= 63;
+			r->nspc--;
+		}else{
+			ttfblit(r->b, x + r->glyph[i]->xminpx, y - r->glyph[i]->ymaxpx, r->glyph[i], 0, 0, r->glyph[i]->width, r->glyph[i]->height);
+			x += r->gwidth[i];
+		}
+		r->linew -= r->gwidth[i];
+		ttfputglyph(r->glyph[i]);
+	}
+	if(n > 0)
+		r->pp = r->cpos[n-1];
+	r->oy += r->lh;
+	memmove(r->glyph, r->glyph + k, (r->nglyph - k) * sizeof(TTGlyph *));
+	memmove(r->cpos, r->cpos + k, (r->nglyph - k) * sizeof(char *));
+	memmove(r->gwidth, r->gwidth + k, (r->nglyph - k) * sizeof(int));
+	r->nglyph -= k;
+}
+
+TTBitmap *
+_ttfrender(TTFont *f, int (*getrune)(Rune *, char *), char *p, char *end, int w, int h, int flags, char **rp)
+{
+	Render r;
+	Rune ch;
+	int i, adj;
+	TTGlyph *g;
+	
+	if(rp != nil) *rp = p;
+	if(f->u->nkern < 0 && ttfparsekern(f->u) < 0)
+		f->u->nkern = 0;
+	memset(&r, 0, sizeof(Render));
+	r.flags = flags;
+	r.font = f;
+	r.b = ttfnewbitmap(w, h);
+	if(r.b == nil) goto error;
+	r.oy = 0;
+	r.lh = f->ascentpx + f->descentpx;
+	r.pp = p;
+	
+	g = ttfgetglyph(f, ttffindchar(f, ' '), 1);
+	r.spcidx = g->idx;
+	r.spcw = g->advanceWidthpx;
+	if((flags & TTFJUSTIFY) != 0)
+		r.spcminus = r.spcw * 21;
+	else
+		r.spcminus = 0;
+		
+	while(p < end && r.oy + r.lh < h){
+		p += getrune(&ch, p);
+		if(ch == '\n'){
+			flushglyphs(&r, 0);
+			continue;
+		}
+		g = ttfgetglyph(f, ttffindchar(f, ch), 1);
+		if(g == nil){
+			g = ttfgetglyph(f, 0, 1);
+			if(g == nil)
+				continue;
+		}
+		if(addglyph(&r, p, g) < 0)
+			goto error;
+		adj = (r.nspc * r.spcminus + 63) / 64;
+		if(r.linew - adj > r.b->width){
+			flushglyphs(&r, (flags & TTFJUSTIFY) != 0);
+		}
+	}
+	if(r.oy + r.lh < h)
+		flushglyphs(&r, 0);
+	for(i = 0; i < r.nglyph; i++)
+		ttfputglyph(r.glyph[i]);
+	free(r.glyph);
+	free(r.gwidth);
+	free(r.cpos);
+	if(rp != nil)
+		*rp = r.pp;
+	return r.b;
+error:
+	ttffreebitmap(r.b);
+	free(r.glyph);
+	free(r.gwidth);
+	return nil;
+}
+
+TTBitmap *
+ttfrender(TTFont *f, char *str, char *end, int w, int h, int flags, char **rstr)
+{
+	if(str == nil)
+		end = nil;
+	else if(end == nil)
+		end = str + strlen(str);
+	return _ttfrender(f, chartorune, str, end, w, h, flags, rstr);
+}
+
+static int
+incrune(Rune *r, char *s)
+{
+	*r = *(Rune*)s;
+	return sizeof(Rune);
+}
+
+TTBitmap *
+ttfrunerender(TTFont *f, Rune *str, Rune *end, int w, int h, int flags, Rune **rstr)
+{
+	if(str == nil)
+		end = nil;
+	else if(end == nil)
+		end = str + runestrlen(str);
+	return _ttfrender(f, incrune, (char *) str, (char *) end, w, h, flags, (char **) rstr);
+}