st-fix-glyphs.diff

From e3b821dcb3511d60341dec35ee05a4a0abfef7f2 Mon Sep 17 00:00:00 2001
From: Dreomite <dreomite@protonmail.com>
Date: Sat, 13 Jun 2020 02:29:41 +0300
Subject: [PATCH] Fix wide glyphs truncation

---
 st.h |   6 +++
 x.c  | 123 ++++++++++++++++++++++++++++++++---------------------------
 2 files changed, 73 insertions(+), 56 deletions(-)

diff --git a/st.h b/st.h
index 33cc5d43..b85474b3 100644
--- a/st.h
+++ b/st.h
@@ -37,6 +37,12 @@ enum glyph_attribute {
 	ATTR_BOLD_FAINT = ATTR_BOLD | ATTR_FAINT,
 };
 
+enum drawing_mode {
+	DRAW_NONE = 0,
+	DRAW_BG   = 1 << 0,
+	DRAW_FG   = 1 << 1,
+};
+
 enum selection_mode {
 	SEL_IDLE = 0,
 	SEL_EMPTY = 1,
diff --git a/x.c b/x.c
index 5b5c4040..c1f050b2 100644
--- a/x.c
+++ b/x.c
@@ -152,7 +152,7 @@ typedef struct {
 
 static inline ushort sixd_to_16bit(int);
 static int xmakeglyphfontspecs(XftGlyphFontSpec *, const Glyph *, int, int, int);
-static void xdrawglyphfontspecs(const XftGlyphFontSpec *, Glyph, int, int, int);
+static void xdrawglyphfontspecs(const XftGlyphFontSpec *, Glyph, int, int, int, int);
 static void xdrawglyph(Glyph, int, int);
 static void xclear(int, int, int, int);
 static int xgeommasktogravity(int);
@@ -1445,7 +1445,7 @@ xmakeglyphfontspecs(XftGlyphFontSpec *specs, const Glyph *glyphs, int len, int x
 }
 
 void
-xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, int y)
+xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, int y, int dmode)
 {
 	int charlen = len * ((base.mode & ATTR_WIDE) ? 2 : 1);
 	int winx = win.hborderpx + x * win.cw, winy = win.vborderpx + y * win.ch,
@@ -1531,40 +1531,44 @@ xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, i
 	if (base.mode & ATTR_INVISIBLE)
 		fg = bg;
 
-	/* Intelligent cleaning up of the borders. */
-	if (x == 0) {
-		xclear(0, (y == 0)? 0 : winy, win.vborderpx,
-			winy + win.ch +
-			((winy + win.ch >= win.vborderpx + win.th)? win.h : 0));
-	}
-	if (winx + width >= win.hborderpx + win.tw) {
-		xclear(winx + width, (y == 0)? 0 : winy, win.w,
-			((winy + win.ch >= win.vborderpx + win.th)? win.h : (winy + win.ch)));
-	}
-	if (y == 0)
-		xclear(winx, 0, winx + width, win.hborderpx);
-	if (winy + win.ch >= win.vborderpx + win.th)
-		xclear(winx, winy + win.ch, winx + width, win.h);
-
-	/* Clean up the region we want to draw to. */
-	XftDrawRect(xw.draw, bg, winx, winy, width, win.ch);
+	if (dmode & DRAW_BG) {
+		/* Intelligent cleaning up of the borders. */
+		if (x == 0) {
+			xclear(0, (y == 0)? 0 : winy, win.vborderpx,
+					winy + win.ch +
+					((winy + win.ch >= win.vborderpx + win.th)? win.h : 0));
+		}
+		if (winx + width >= win.hborderpx + win.tw) {
+			xclear(winx + width, (y == 0)? 0 : winy, win.w,
+					((winy + win.ch >= win.vborderpx + win.th)? win.h : (winy + win.ch)));
+		}
+		if (y == 0)
+			xclear(winx, 0, winx + width, win.hborderpx);
+		if (winy + win.ch >= win.vborderpx + win.th)
+			xclear(winx, winy + win.ch, winx + width, win.h);
 
-	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);
+		/* Fill the background */
+		XftDrawRect(xw.draw, bg, winx, winy, width, win.ch);
 	}
 
-	/* Render underline and strikethrough. */
-	if (base.mode & ATTR_UNDERLINE) {
-		XftDrawRect(xw.draw, fg, winx, winy + win.cyo + dc.font.ascent + 1,
-				width, 1);
-	}
+	if (dmode & DRAW_FG) {
+		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);
+		}
 
-	if (base.mode & ATTR_STRUCK) {
-		XftDrawRect(xw.draw, fg, winx, winy + win.cyo + 2 * dc.font.ascent / 3,
-				width, 1);
+		/* Render underline and strikethrough. */
+		if (base.mode & ATTR_UNDERLINE) {
+			XftDrawRect(xw.draw, fg, winx, winy + win.cyo + dc.font.ascent + 1,
+					width, 1);
+		}
+
+		if (base.mode & ATTR_STRUCK) {
+			XftDrawRect(xw.draw, fg, winx, winy + win.cyo + 2 * dc.font.ascent / 3,
+					width, 1);
+		}
 	}
 }
 
@@ -1575,7 +1579,7 @@ xdrawglyph(Glyph g, int x, int y)
 	XftGlyphFontSpec spec;
 
 	numspecs = xmakeglyphfontspecs(&spec, &g, 1, x, y);
-	xdrawglyphfontspecs(&spec, g, numspecs, x, y);
+	xdrawglyphfontspecs(&spec, g, numspecs, x, y, DRAW_BG | DRAW_FG);
 }
 
 void
@@ -1694,32 +1698,39 @@ xstartdraw(void)
 void
 xdrawline(Line line, int x1, int y1, int x2)
 {
-	int i, x, ox, numspecs;
+	int i, x, ox, numspecs, numspecs_cached;
 	Glyph base, new;
-	XftGlyphFontSpec *specs = xw.specbuf;
-
-	numspecs = xmakeglyphfontspecs(specs, &line[x1], x2 - x1, x1, y1);
-	i = ox = 0;
-	for (x = x1; x < x2 && i < numspecs; x++) {
-		new = line[x];
-		if (new.mode == ATTR_WDUMMY)
-			continue;
-		if (selected(x, y1))
-			new.mode ^= ATTR_REVERSE;
-		if (i > 0 && ATTRCMP(base, new)) {
-			xdrawglyphfontspecs(specs, base, i, ox, y1);
-			specs += i;
-			numspecs -= i;
-			i = 0;
-		}
-		if (i == 0) {
-			ox = x;
-			base = new;
+	XftGlyphFontSpec *specs;
+
+	numspecs_cached = xmakeglyphfontspecs(xw.specbuf, &line[x1], x2 - x1, x1, y1);
+
+	/* Draw line in 2 passes: background and foreground. This way wide glyphs
+	   won't get truncated (#223) */
+	for (int dmode = DRAW_BG; dmode <= DRAW_FG; dmode <<= 1) {
+		specs = xw.specbuf;
+		numspecs = numspecs_cached;
+		i = ox = 0;
+		for (x = x1; x < x2 && i < numspecs; x++) {
+			new = line[x];
+			if (new.mode == ATTR_WDUMMY)
+				continue;
+			if (selected(x, y1))
+				new.mode ^= ATTR_REVERSE;
+			if (i > 0 && ATTRCMP(base, new)) {
+				xdrawglyphfontspecs(specs, base, i, ox, y1, dmode);
+				specs += i;
+				numspecs -= i;
+				i = 0;
+			}
+			if (i == 0) {
+				ox = x;
+				base = new;
+			}
+			i++;
 		}
-		i++;
+		if (i > 0)
+			xdrawglyphfontspecs(specs, base, i, ox, y1, dmode);
 	}
-	if (i > 0)
-		xdrawglyphfontspecs(specs, base, i, ox, y1);
 }
 
 void