From f0253633d3cdde994b48c25692707e1df2f1e1e7 Mon Sep 17 00:00:00 2001
From: Alexander Orzechowski <alex@ozal.ski>
Date: Sat, 4 Jan 2025 22:26:00 -0500
Subject: [PATCH 1/3] render: Expose render_overlay

This function updates the overlay that foot uses. It will be used to
update the overlay when the flash effect ends.
---
 pgo/pgo.c | 2 ++
 render.c  | 2 +-
 render.h  | 2 ++
 3 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/pgo/pgo.c b/pgo/pgo.c
index aab18847..24154277 100644
--- a/pgo/pgo.c
+++ b/pgo/pgo.c
@@ -72,6 +72,8 @@ void render_refresh_title(struct terminal *term) {}
 void render_refresh_app_id(struct terminal *term) {}
 void render_refresh_icon(struct terminal *term) {}
 
+void render_overlay(struct terminal *term) {}
+
 bool
 render_xcursor_is_valid(const struct seat *seat, const char *cursor)
 {
diff --git a/render.c b/render.c
index 5a924743..020dee79 100644
--- a/render.c
+++ b/render.c
@@ -1862,7 +1862,7 @@ render_overlay_single_pixel(struct terminal *term, enum overlay_style style,
     }
 }
 
-static void
+void
 render_overlay(struct terminal *term)
 {
     struct wayl_sub_surface *overlay = &term->window->overlay;
diff --git a/render.h b/render.h
index 1898351c..81d2a905 100644
--- a/render.h
+++ b/render.h
@@ -31,6 +31,8 @@ bool render_xcursor_set(
     struct seat *seat, struct terminal *term, enum cursor_shape shape);
 bool render_xcursor_is_valid(const struct seat *seat, const char *cursor);
 
+void render_overlay(struct terminal *term);
+
 struct render_worker_context {
     int my_id;
     struct terminal *term;

From c2add346ad5c1673ba0334264300e86eb50b2293 Mon Sep 17 00:00:00 2001
From: Alexander Orzechowski <alex@ozal.ski>
Date: Sat, 4 Jan 2025 21:59:19 -0500
Subject: [PATCH 2/3] terminal: Refresh only overlay when flash expires

If we call render_refresh, that will wait for a callback to the main
surface. In the case of a flash, the main surface might not get callbacks
if the compositor implements fancy culling optimizations like wlroots
wlr_scene compositors such as sway version >=1.10.
---
 terminal.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/terminal.c b/terminal.c
index 5a74631a..7b5a4d2d 100644
--- a/terminal.c
+++ b/terminal.c
@@ -419,7 +419,12 @@ fdm_flash(struct fdm *fdm, int fd, int events, void *data)
             (unsigned long long)expiration_count);
 
     term->flash.active = false;
-    render_refresh(term);
+    render_overlay(term);
+
+    // since the overlay surface is synced with the main window surface, we have
+    // to commit the main surface for the compositor to acknowledge the new
+    // overlay state.
+    wl_surface_commit(term->window->surface.surf);
     return true;
 }
 

From 301101e7d9d9675b48b874128a36ecf3005b727e Mon Sep 17 00:00:00 2001
From: Alexander Orzechowski <alex@ozal.ski>
Date: Sat, 4 Jan 2025 21:36:33 -0500
Subject: [PATCH 3/3] Revert "config: don't allow colors.flash-alpha to be 1.0"

This reverts commit 56d2c3e990509d18de31e6009e0d0c6254f99b67.
---
 CHANGELOG.md |  3 ---
 config.c     |  4 ++--
 render.c     | 21 ---------------------
 3 files changed, 2 insertions(+), 26 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index bc1d3bc3..508174b2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -80,9 +80,6 @@
 
 * Runtime changes to the app-id (OSC-176) now limits the app-id string
   to 2048 characters ([#1897][1897]).
-* `colors.flash-alpha` can no longer be set to 1.0 (i.e. fully
-  opaque). This fixes an issue where the window would be stuck in the
-  flash state.
 
 [1897]: https://codeberg.org/dnkl/foot/issues/1897
 
diff --git a/config.c b/config.c
index 3b8ce7e8..7f1ce055 100644
--- a/config.c
+++ b/config.c
@@ -1445,8 +1445,8 @@ parse_section_colors(struct context *ctx)
         if (!value_to_float(ctx, &alpha))
             return false;
 
-        if (alpha < 0. || alpha >= 1.) {
-            LOG_CONTEXTUAL_ERR("not in range 0.0-0.999");
+        if (alpha < 0. || alpha > 1.) {
+            LOG_CONTEXTUAL_ERR("not in range 0.0-1.0");
             return false;
         }
 
diff --git a/render.c b/render.c
index 020dee79..b1791a90 100644
--- a/render.c
+++ b/render.c
@@ -1898,27 +1898,6 @@ render_overlay(struct terminal *term)
         break;
 
     case OVERLAY_FLASH:
-        /*
-         * A compositor will not send a frame callback for our main
-         * window if it is fully occluded (for example, by a fully
-         * opaque overlay...). This causes the overlay to stuck.
-         *
-         * For regular buffers, it _should_ be enough to *not* hint
-         * the compositor it's opaque. But at least some compositor
-         * special cases single-pixel buffers, and actually look at
-         * their pixel value.
-         *
-         * Thus, we have two options: implement frame callback
-         * handling for the overlay sub-surface, or ensure we don't
-         * use a fully opaque surface. Since no overlays are fully
-         * opaque by default, and the flash surface is the only one
-         * that can be configured to be opaque (colors.flash-alpha),
-         * and since adding frame callback handling adds a lot of
-         * boilerplate code... let's go with the simpler solution of
-         * not allowing colors.flash-alpha to be 1.0.
-         */
-        xassert(term->conf->colors.flash_alpha != 0xffff);
-
         color = color_hex_to_pixman_with_alpha(
                 term->conf->colors.flash,
                 term->conf->colors.flash_alpha);