renderer: use direct FreeType with explicit font files

font.c

@@ -1,29 +1,18 @@
-#define STB_TRUETYPE_IMPLEMENTATION
-#include "stb_truetype.h"
 #include "dat.h"
+#include <ft2build.h>
+#include FT_FREETYPE_H
 #include "fn.h"
 
-typedef struct Glyph Glyph;
 typedef struct Font Font;
-struct Glyph
-{
-	uchar *bmp;
-	int w, h, ox, oy, base;
-};
-
 struct Font
 {
-	stbtt_fontinfo info;
-	uchar *data;
-	float scale;
+	FT_Face face;
 	int base;
 };
 
-enum { Maxfonts = 4 };
-
+static FT_Library lib;
 static Font fonts[Maxfonts];
 static int nfonts;
-static Glyph cache[Nglyphs];
 static u32int blendtab[2][256];
 
 static u32int
@@ -41,117 +30,139 @@ blend(u32int bg, u32int fg, int a)
 static int
 loadfont(char *path)
 {
+	FT_Face face;
 	Font *f;
-	int ascent, descent, gap, fd;
-	long sz, n;
+	vlong height, pixels;
 
-	fd = open(path, OREAD);
-	if(fd < 0){
-		fprint(2, "strans: popup: can't open font: %s\n", path);
+	if(nfonts >= nelem(fonts))
+		return 0;
+	if(FT_New_Face(lib, path, 0, &face) != 0){
+		fprint(2, "strans: popup: can't load font: %s\n", path);
 		return 0;
 	}
-	sz = seek(fd, 0, 2);
-	seek(fd, 0, 0);
-	if(sz <= 0){
-		fprint(2, "strans: popup: empty font: %s\n", path);
-		close(fd);
+	height = (vlong)face->ascender - face->descender;
+	if(height <= 0 || face->units_per_EM == 0){
+		fprint(2, "strans: popup: invalid font metrics: %s\n", path);
+		FT_Done_Face(face);
+		return 0;
+	}
+	pixels = (vlong)Fontsz * face->units_per_EM / height;
+	if(pixels < 1)
+		pixels = 1;
+	if(FT_Set_Pixel_Sizes(face, 0, pixels) != 0){
+		fprint(2, "strans: popup: can't size font: %s\n", path);
+		FT_Done_Face(face);
 		return 0;
 	}
 	f = &fonts[nfonts];
-	f->data = emalloc(sz);
-	n = readn(fd, f->data, sz);
-	close(fd);
-	if(n != sz){
-		fprint(2, "strans: popup: can't read font: %s\n", path);
-		free(f->data);
-		f->data = nil;
-		return 0;
-	}
-	if(!stbtt_InitFont(&f->info, f->data,
-	   stbtt_GetFontOffsetForIndex(f->data, 0))){
-		fprint(2, "strans: popup: can't init font: %s\n", path);
-		free(f->data);
-		f->data = nil;
-		return 0;
-	}
-	f->scale = stbtt_ScaleForPixelHeight(&f->info, Fontsz);
-	stbtt_GetFontVMetrics(&f->info, &ascent, &descent, &gap);
-	(void)descent;
-	(void)gap;
-	f->base = (int)(ascent * f->scale);
+	f->face = face;
+	f->base = (vlong)Fontsz * face->ascender / height;
 	nfonts++;
 	return 1;
 }
 
-int
-fontinit(char *dir)
+static void
+clearfonts(void)
 {
-	static char *names[] = {
-		"NotoSans-Regular.ttf",
-		"NotoSansMonoCJKjp-Regular.otf",
-		"NotoEmoji-Regular.ttf",
-	};
-	int i, a;
-	char path[256];
+	int i;
 
+	for(i = 0; i < nfonts; i++){
+		FT_Done_Face(fonts[i].face);
+		fonts[i].face = nil;
+	}
 	nfonts = 0;
-	memset(cache, 0, sizeof cache);
-	for(i = 0; i < nelem(names); i++){
-		if(strlen(dir) + 1 + strlen(names[i]) + 1 > sizeof path){
-			fprint(2, "strans: popup: font path is too long\n");
-			continue;
+}
+
+int
+fontinit(char **path, int npath)
+{
+	int i, a;
+
+	if(path == nil || npath < 1 || npath > nelem(fonts)){
+		fprint(2, "strans: popup: need 1-%d font files\n", nelem(fonts));
+		clearfonts();
+		return 0;
+	}
+	if(lib == nil && FT_Init_FreeType(&lib) != 0){
+		fprint(2, "strans: popup: can't initialize FreeType\n");
+		return 0;
+	}
+	clearfonts();
+	for(i = 0; i < npath; i++){
+		if(path[i] == nil || !loadfont(path[i])){
+			clearfonts();
+			return 0;
 		}
-		snprint(path, sizeof path, "%s/%s", dir, names[i]);
-		loadfont(path);
 	}
 	for(a = 0; a < 256; a++){
 		blendtab[0][a] = blend(Colbg, Colfg, a);
 		blendtab[1][a] = blend(Colsel, Colfg, a);
 	}
-	return nfonts != 0;
+	return 1;
+}
+
+static int
+drawglyph(Font *f, u32int *buf, int w, int h, int px, int py)
+{
+	FT_Bitmap *b;
+	FT_GlyphSlot g;
+	uchar *row;
+	vlong pitch, x0, x1, y0, y1;
+	int a, sel, x, xa, xb, y, ya, yb;
+	u32int *p;
+
+	g = f->face->glyph;
+	b = &g->bitmap;
+	if(b->pixel_mode != FT_PIXEL_MODE_GRAY || b->num_grays != 256)
+		return 0;
+	if(b->width == 0 || b->rows == 0)
+		return 1;
+	pitch = b->pitch;
+	if(pitch < 0)
+		pitch = -pitch;
+	if(b->buffer == nil || pitch < b->width)
+		return 0;
+	x0 = (vlong)px + g->bitmap_left;
+	y0 = (vlong)py + f->base - g->bitmap_top;
+	x1 = x0 + b->width;
+	y1 = y0 + b->rows;
+	if(x1 <= 0 || y1 <= 0 || x0 >= w || y0 >= h)
+		return 1;
+	xa = x0 < 0 ? 0 : x0;
+	xb = x1 > w ? w : x1;
+	ya = y0 < 0 ? 0 : y0;
+	yb = y1 > h ? h : y1;
+	for(y = ya; y < yb; y++){
+		if(b->pitch < 0)
+			row = b->buffer + ((vlong)b->rows - 1 - (y - y0)) * pitch;
+		else
+			row = b->buffer + ((vlong)y - y0) * pitch;
+		for(x = xa; x < xb; x++){
+			a = row[(vlong)x - x0];
+			if(a != 0){
+				p = &buf[y * w + x];
+				sel = *p == Colsel;
+				*p = blendtab[sel][a];
+			}
+		}
+	}
+	return 1;
 }
 
 void
 putfont(u32int *buf, int w, int h, int px, int py, Rune r)
 {
-	Glyph *g;
-	int i, j, a, sel, f;
-	int y0, j0, j1, x0, i0, i1;
-	u32int *p;
+	FT_UInt g;
+	int f;
 
-	if(r >= Nglyphs)
+	if(buf == nil || w <= 0 || h <= 0)
 		return;
-	g = &cache[r];
-	if(g->bmp == nil){
-		for(f = 0; f < nfonts; f++){
-			if(stbtt_FindGlyphIndex(&fonts[f].info, r) == 0)
-				continue;
-			g->bmp = stbtt_GetCodepointBitmap(&fonts[f].info,
-				fonts[f].scale, fonts[f].scale, r,
-				&g->w, &g->h, &g->ox, &g->oy);
-			if(g->bmp != nil){
-				g->base = fonts[f].base;
-				break;
-			}
-		}
-		if(g->bmp == nil)
+	for(f = 0; f < nfonts; f++){
+		g = FT_Get_Char_Index(fonts[f].face, r);
+		if(g == 0 || FT_Load_Glyph(fonts[f].face, g, FT_LOAD_DEFAULT) != 0 ||
+		   FT_Render_Glyph(fonts[f].face->glyph, FT_RENDER_MODE_NORMAL) != 0)
+			continue;
+		if(drawglyph(&fonts[f], buf, w, h, px, py))
 			return;
 	}
-
-	y0 = py + g->base + g->oy;
-	j0 = y0 < 0 ? -y0 : 0;
-	j1 = y0 + g->h > h ? h - y0 : g->h;
-	x0 = px + g->ox;
-	i0 = x0 < 0 ? -x0 : 0;
-	i1 = x0 + g->w > w ? w - x0 : g->w;
-	for(j = j0; j < j1; j++){
-		for(i = i0; i < i1; i++){
-			a = g->bmp[j * g->w + i];
-			if(a > 0){
-				p = &buf[(y0 + j) * w + x0 + i];
-				sel = (*p == Colsel) ? 1 : 0;
-				*p = blendtab[sel][a];
-			}
-		}
-	}
 }