From 49464d233e230992e1e2ee8c40dbdd00a6646ad6 Mon Sep 17 00:00:00 2001
From: Manuel Stoeckl <code@mstoeckl.com>
Date: Fri, 8 Nov 2024 21:45:51 -0500
Subject: [PATCH] swaynag: coalesce surface redraw operations

This avoids exhausting the buffer pool when multiple events that would
trigger redraws occur rapidly (for example: scrolling, resizing output).
---
 include/swaynag/swaynag.h |  1 +
 swaynag/render.c          |  1 +
 swaynag/swaynag.c         | 22 ++++++++++++----------
 3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/include/swaynag/swaynag.h b/include/swaynag/swaynag.h
index fb9e9c21..8e80b570 100644
--- a/include/swaynag/swaynag.h
+++ b/include/swaynag/swaynag.h
@@ -90,6 +90,7 @@ struct swaynag {
 	struct wp_cursor_shape_manager_v1 *cursor_shape_manager;
 	struct wl_surface *surface;
 
+	bool needs_redraw;
 	uint32_t width;
 	uint32_t height;
 	int32_t scale;
diff --git a/swaynag/render.c b/swaynag/render.c
index bfa4b0c1..dcc0d06a 100644
--- a/swaynag/render.c
+++ b/swaynag/render.c
@@ -250,6 +250,7 @@ void render_frame(struct swaynag *swaynag) {
 	if (!swaynag->run_display) {
 		return;
 	}
+	swaynag->needs_redraw = false;
 
 	cairo_surface_t *recorder = cairo_recording_surface_create(
 			CAIRO_CONTENT_COLOR_ALPHA, NULL);
diff --git a/swaynag/swaynag.c b/swaynag/swaynag.c
index da32eeb7..ac48cdff 100644
--- a/swaynag/swaynag.c
+++ b/swaynag/swaynag.c
@@ -47,7 +47,7 @@ static void swaynag_button_execute(struct swaynag *swaynag,
 		swaynag->run_display = false;
 	} else if (button->type == SWAYNAG_ACTION_EXPAND) {
 		swaynag->details.visible = !swaynag->details.visible;
-		render_frame(swaynag);
+		swaynag->needs_redraw = true;
 	} else {
 		pid_t pid = fork();
 		if (pid < 0) {
@@ -98,7 +98,7 @@ static void layer_surface_configure(void *data,
 	swaynag->width = width;
 	swaynag->height = height;
 	zwlr_layer_surface_v1_ack_configure(surface, serial);
-	render_frame(swaynag);
+	swaynag->needs_redraw = true;
 }
 
 static void layer_surface_closed(void *data,
@@ -122,7 +122,7 @@ static void surface_enter(void *data, struct wl_surface *surface,
 					swaynag_output->name);
 			swaynag->output = swaynag_output;
 			swaynag->scale = swaynag->output->scale;
-			render_frame(swaynag);
+			swaynag->needs_redraw = true;
 			break;
 		}
 	};
@@ -244,7 +244,7 @@ static void wl_pointer_button(void *data, struct wl_pointer *wl_pointer,
 				&& y < button_up.y + button_up.height
 				&& swaynag->details.offset > 0) {
 			swaynag->details.offset--;
-			render_frame(swaynag);
+			swaynag->needs_redraw = true;
 			return;
 		}
 
@@ -257,7 +257,7 @@ static void wl_pointer_button(void *data, struct wl_pointer *wl_pointer,
 				&& y < button_down.y + button_down.height
 				&& swaynag->details.offset < bot) {
 			swaynag->details.offset++;
-			render_frame(swaynag);
+			swaynag->needs_redraw = true;
 			return;
 		}
 	}
@@ -284,7 +284,7 @@ static void wl_pointer_axis(void *data, struct wl_pointer *wl_pointer,
 		swaynag->details.offset++;
 	}
 
-	render_frame(swaynag);
+	swaynag->needs_redraw = true;
 }
 
 static const struct wl_pointer_listener pointer_listener = {
@@ -327,7 +327,7 @@ static void output_scale(void *data, struct wl_output *output,
 		if (!swaynag_output->swaynag->cursor_shape_manager) {
 			update_all_cursors(swaynag_output->swaynag);
 		}
-		render_frame(swaynag_output->swaynag);
+		swaynag_output->swaynag->needs_redraw = true;
 	}
 }
 
@@ -503,9 +503,11 @@ void swaynag_setup(struct swaynag *swaynag) {
 void swaynag_run(struct swaynag *swaynag) {
 	swaynag->run_display = true;
 	render_frame(swaynag);
-	while (swaynag->run_display
-			&& wl_display_dispatch(swaynag->display) != -1) {
-		// This is intentionally left blank
+	while (wl_display_dispatch(swaynag->display) != -1
+			&& swaynag->run_display) {
+		if (swaynag->needs_redraw) {
+			render_frame(swaynag);
+		}
 	}
 }