From 88f591f389ba4ac13dd5aebfffa7863805758bcb Mon Sep 17 00:00:00 2001
From: Po Lu <luangruo@yahoo.com>
Date: Sat, 19 Feb 2022 20:05:18 +0800
Subject: [PATCH] Improve portability of alpha channel visual detection
* src/xfns.c (select_visual): Look for PictVisuals with an alpha
channel instead of blindly assuming that 32 bit visuals have an
alpha channel.
(Fx_show_tip): Fix crash on some displays where child is None.
* src/xterm.c (x_term_init): Initialize Xrender before
calling select_visual.
---
src/xfns.c | 52 +++++++++++++++++++++++++++++++++++-----------------
src/xterm.c | 31 ++++++++++++++++++-------------
2 files changed, 53 insertions(+), 30 deletions(-)
diff --git a/src/xfns.c b/src/xfns.c
index 0a8d18d9187..b0e7af9d8fa 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -6574,28 +6574,45 @@ select_visual (struct x_display_info *dpyinfo)
vinfo_template.screen = XScreenNumberOfScreen (screen);
-#if !defined USE_X_TOOLKIT && !(defined USE_GTK && !defined HAVE_GTK3)
- /* First attempt to use 32-bit visual if available */
-
- vinfo_template.depth = 32;
- vinfo_template.class = TrueColor;
+#if !defined USE_X_TOOLKIT && !(defined USE_GTK && !defined HAVE_GTK3) \
+ && defined HAVE_XRENDER
+ int i;
+ XRenderPictFormat *format;
- vinfo = XGetVisualInfo (dpy, (VisualScreenMask
- | VisualDepthMask
- | VisualClassMask),
- &vinfo_template, &n_visuals);
+ /* First attempt to find a visual with an alpha mask if
+ available. That information is only available when the
+ render extension is present, and we cannot do much with such
+ a visual if it isn't. */
- if (n_visuals > 0 && vinfo)
+ if (dpyinfo->xrender_supported_p)
{
- dpyinfo->n_planes = vinfo->depth;
- dpyinfo->visual = vinfo->visual;
- XFree (vinfo);
- return;
- }
+ vinfo = XGetVisualInfo (dpy, VisualScreenMask,
+ &vinfo_template, &n_visuals);
+
+ for (i = 0; i < n_visuals; ++i)
+ {
+ format = XRenderFindVisualFormat (dpy, vinfo[i].visual);
+
+ if (format && format->type == PictTypeDirect
+ && format->direct.alphaMask)
+ {
+ dpyinfo->n_planes = vinfo[i].depth;
+ dpyinfo->visual = vinfo[i].visual;
+ dpyinfo->pict_format = format;
+
+ XFree (vinfo);
+ return;
+ }
+ }
+
+ if (vinfo)
+ XFree (vinfo);
+ }
#endif /* !USE_X_TOOLKIT */
- /* 32-bit visual not available, fallback to default visual */
+ /* Visual with alpha channel (or the Render extension) not
+ available, fallback to default visual. */
dpyinfo->visual = DefaultVisualOfScreen (screen);
vinfo_template.visualid = XVisualIDFromVisual (dpyinfo->visual);
vinfo = XGetVisualInfo (dpy, VisualIDMask | VisualScreenMask,
@@ -8091,7 +8108,8 @@ Text larger than the specified size is clipped. */)
FRAME_DISPLAY_INFO (f)->root_window,
FRAME_DISPLAY_INFO (f)->root_window,
root_x, root_y, &dest_x_return,
- &dest_y_return, &child))
+ &dest_y_return, &child)
+ && child != None)
{
/* But only if the child is not override-redirect, which can
happen if the pointer is above a menu. */
diff --git a/src/xterm.c b/src/xterm.c
index 2dc420a8dee..e2ad0b48f58 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -15989,6 +15989,18 @@ x_term_init (Lisp_Object display_name, char *xrm_option, char *resource_name)
#else
dpyinfo->display->db = xrdb;
#endif
+
+#ifdef HAVE_XRENDER
+ int event_base, error_base;
+ dpyinfo->xrender_supported_p
+ = XRenderQueryExtension (dpyinfo->display, &event_base, &error_base);
+
+ if (dpyinfo->xrender_supported_p)
+ dpyinfo->xrender_supported_p
+ = XRenderQueryVersion (dpyinfo->display, &dpyinfo->xrender_major,
+ &dpyinfo->xrender_minor);
+#endif
+
/* Put the rdb where we can find it in a way that works on
all versions. */
dpyinfo->rdb = xrdb;
@@ -16004,19 +16016,12 @@ x_term_init (Lisp_Object display_name, char *xrm_option, char *resource_name)
reset_mouse_highlight (&dpyinfo->mouse_highlight);
#ifdef HAVE_XRENDER
- int event_base, error_base;
- dpyinfo->xrender_supported_p
- = XRenderQueryExtension (dpyinfo->display, &event_base, &error_base);
-
- if (dpyinfo->xrender_supported_p)
- {
- if (!XRenderQueryVersion (dpyinfo->display, &dpyinfo->xrender_major,
- &dpyinfo->xrender_minor))
- dpyinfo->xrender_supported_p = false;
- else
- dpyinfo->pict_format = XRenderFindVisualFormat (dpyinfo->display,
- dpyinfo->visual);
- }
+ if (dpyinfo->xrender_supported_p
+ /* This could already have been initialized by
+ `select_visual'. */
+ && !dpyinfo->pict_format)
+ dpyinfo->pict_format = XRenderFindVisualFormat (dpyinfo->display,
+ dpyinfo->visual);
#endif
#ifdef HAVE_XSYNC
--
2.39.5