fix: make popup rendering deterministic

win.c

@@ -1,6 +1,7 @@
 #include <xcb/xcb.h>
 #include "dat.h"
 #include "fn.h"
+#include "popup_layout.h"
 
 enum {
 	Asciitofull = 0xFEE0,
@@ -12,9 +13,12 @@ static xcb_connection_t *conn;
 static xcb_screen_t *scr;
 static xcb_window_t win;
 static xcb_gcontext_t gc;
+static xcb_pixmap_t pix;
 static u32int *img;
 static int depth;
 
+extern int fontready(void);
+
 static xcb_screen_t*
 getscr(xcb_connection_t *c, int n)
 {
@@ -26,7 +30,70 @@ getscr(xcb_connection_t *c, int n)
 	return nil;
 }
 
+static xcb_visualtype_t*
+getvisual(xcb_screen_t *s)
+{
+	xcb_depth_iterator_t di;
+	xcb_visualtype_iterator_t vi;
+
+	for(di = xcb_screen_allowed_depths_iterator(s); di.rem;
+	    xcb_depth_next(&di)){
+		if(di.data->depth != s->root_depth)
+			continue;
+		for(vi = xcb_depth_visuals_iterator(di.data); vi.rem;
+		    xcb_visualtype_next(&vi))
+			if(vi.data->visual_id == s->root_visual)
+				return vi.data;
+	}
+	return nil;
+}
+
+static int
+validformat(xcb_connection_t *c, xcb_screen_t *s)
+{
+	const xcb_setup_t *setup;
+	xcb_format_iterator_t fi;
+	xcb_visualtype_t *v;
+	u32int one;
+	int lsb;
+
+	setup = xcb_get_setup(c);
+	v = getvisual(s);
+	if(setup == nil || v == nil || s->root_depth != 24 ||
+	   v->_class != XCB_VISUAL_CLASS_TRUE_COLOR ||
+	   v->bits_per_rgb_value != 8 ||
+	   v->red_mask != 0xff0000 || v->green_mask != 0x00ff00 ||
+	   v->blue_mask != 0x0000ff)
+		return 0;
+	one = 1;
+	lsb = *(uchar*)&one != 0;
+	if((lsb && setup->image_byte_order != XCB_IMAGE_ORDER_LSB_FIRST) ||
+	   (!lsb && setup->image_byte_order != XCB_IMAGE_ORDER_MSB_FIRST))
+		return 0;
+	for(fi = xcb_setup_pixmap_formats_iterator(setup); fi.rem;
+	    xcb_format_next(&fi))
+		if(fi.data->depth == 24 && fi.data->bits_per_pixel == 32 &&
+		   fi.data->scanline_pad == 32)
+			return 1;
+	return 0;
+}
+
 static void
+wincleanup(void)
+{
+	free(img);
+	img = nil;
+	if(conn != nil){
+		xcb_disconnect(conn);
+		conn = nil;
+	}
+	scr = nil;
+	win = 0;
+	gc = 0;
+	pix = 0;
+}
+
+static int
 wininit(void)
 {
 	int n;
@@ -35,11 +102,17 @@ wininit(void)
 	xcb_intern_atom_reply_t *r1, *r2;
 
 	conn = xcb_connect(nil, &n);
-	if(conn == nil || xcb_connection_has_error(conn))
-		die("xcb_connect");
+	if(conn == nil || xcb_connection_has_error(conn)){
+		fprint(2, "strans: popup disabled: cannot connect to X display\n");
+		wincleanup();
+		return 0;
+	}
 	scr = getscr(conn, n);
-	if(scr == nil)
-		die("no screen");
+	if(scr == nil || !validformat(conn, scr)){
+		fprint(2, "strans: popup disabled: unsupported X root format\n");
+		wincleanup();
+		return 0;
+	}
 	depth = scr->root_depth;
 	win = xcb_generate_id(conn);
 	mask = XCB_CW_BACK_PIXEL | XCB_CW_BORDER_PIXEL |
@@ -65,16 +138,29 @@ wininit(void)
 	free(r2);
 	gc = xcb_generate_id(conn);
 	xcb_create_gc(conn, gc, win, 0, nil);
+	pix = xcb_generate_id(conn);
+	xcb_create_pixmap(conn, depth, pix, win, Imgw, Imgh);
+	mask = XCB_CW_BACK_PIXMAP;
+	xcb_change_window_attributes(conn, win, mask, &pix);
 	img = emalloc(Imgw * Imgh * sizeof(img[0]));
 	fontinit(fontdir);
+	if(!fontready()){
+		fprint(2, "strans: popup disabled: no usable fonts\n");
+		wincleanup();
+		return 0;
+	}
+	return 1;
 }
 
 static void
 drawstr(u32int *buf, int x, int y, Rune *r, int n, int maxw, int maxh)
 {
 	while(n-- > 0){
-		putfont(buf, maxw, maxh, x, y, *r++);
-		x += Fontsz;
+		if(*r != 0xfe0e && *r != 0xfe0f){
+			putfont(buf, maxw, maxh, x, y, *r);
+			x += Fontsz;
+		}
+		r++;
 	}
 }
 
@@ -111,19 +197,20 @@ drawkouho(Drawcmd *dc, int first, int n, int w, int h)
 static void
 putimage(int w, int h)
 {
-	xcb_put_image(conn, XCB_IMAGE_FORMAT_Z_PIXMAP, win, gc,
+	xcb_put_image(conn, XCB_IMAGE_FORMAT_Z_PIXMAP, pix, gc,
 		w, h, 0, 0, 0, depth, w * h * 4, (u8int*)img);
-	xcb_flush(conn);
+	/* The retained background pixmap lets the server repaint exposures. */
+	xcb_clear_area(conn, 0, win, 0, 0, w, h);
 }
 
-static void
+static int
 winhide(void)
 {
 	xcb_unmap_window(conn, win);
-	xcb_flush(conn);
+	return xcb_flush(conn) > 0;
 }
 
-static void
+static int
 winshow(Drawcmd *dc)
 {
 	int npre, px, py, w, h, i, n, maxw;
@@ -134,23 +221,27 @@ winshow(Drawcmd *dc)
 	n = min(max(dc->nkouho, 0), Maxdisp);
 	npre = dc->pre.n != 0;
 	if(n == 0 && npre == 0){
-		winhide();
-		return;
+		return winhide();
 	}
-	cookie = xcb_query_pointer(conn, scr->root);
-	maxw = dc->pre.n;
+	maxw = popupcells(dc->pre.r, dc->pre.n);
 	for(i = 0; i < n; i++)
-		maxw = max(maxw, dc->kouho[i].n);
-	ptr = xcb_query_pointer_reply(conn, cookie, nil);
-	if(ptr == nil)
-		die("xcb_query_pointer");
-	px = ptr->root_x + 10;
-	py = ptr->root_y + 10;
-	free(ptr);
+		maxw = max(maxw, popupcells(dc->kouho[i].r, dc->kouho[i].n));
 	vals[3] = h = (n + npre) * Fontsz;
 	vals[2] = w = (maxw + 3) * Fontsz;
-	vals[1] = py = max(0, min(py, scr->height_in_pixels - h));
-	vals[0] = px = max(0, min(px, scr->width_in_pixels - w));
+	px = py = 0;
+	if(!dc->caret.valid){
+		cookie = xcb_query_pointer(conn, scr->root);
+		ptr = xcb_query_pointer_reply(conn, cookie, nil);
+		if(ptr == nil)
+			return 0;
+		px = ptr->root_x;
+		py = ptr->root_y;
+		free(ptr);
+	}
+	popupposition(&dc->caret, px, py, scr->width_in_pixels,
+		scr->height_in_pixels, w, h, &px, &py);
+	vals[1] = py;
+	vals[0] = px;
 	xcb_configure_window(conn, win,
 		XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y |
 		XCB_CONFIG_WINDOW_WIDTH | XCB_CONFIG_WINDOW_HEIGHT,
@@ -158,6 +249,7 @@ winshow(Drawcmd *dc)
 	xcb_map_window(conn, win);
 	drawkouho(dc, 0, n, w, h);
 	putimage(w, h);
+	return xcb_flush(conn) > 0;
 }
 
 void
@@ -166,13 +258,16 @@ drawthread(void*)
 	Drawcmd dc;
 
 	threadsetname("draw");
-	wininit();
+	if(!wininit())
+		return;
 	while(chanrecv(drawc, &dc) > 0){
 		while(channbrecv(drawc, &dc) > 0)
 			;
-		if(dc.nkouho == 0 && dc.pre.n == 0)
-			winhide();
-		else
-			winshow(&dc);
+		if(dc.nkouho == 0 && dc.pre.n == 0){
+			if(!winhide())
+				break;
+		}else if(!winshow(&dc))
+			break;
 	}
+	wincleanup();
 }