From d37572486b12bd28babba40b299cb2594a3635fa Mon Sep 17 00:00:00 2001
From: Alexander Orzechowski <alex@ozal.ski>
Date: Sat, 19 Nov 2022 22:38:50 -0500
Subject: [PATCH] backend/wayland: handle scale

---
 backend/wayland/output.c  | 43 +++++++++++++++++++++++++++------------
 backend/wayland/pointer.c |  5 +++--
 backend/wayland/seat.c    |  5 +++--
 3 files changed, 36 insertions(+), 17 deletions(-)

diff --git a/backend/wayland/output.c b/backend/wayland/output.c
index 88dca06be..db14a1d41 100644
--- a/backend/wayland/output.c
+++ b/backend/wayland/output.c
@@ -293,6 +293,12 @@ static bool output_commit(struct wlr_output *wlr_output,
 		return false;
 	}
 
+	bool needs_commit = false;
+	if (state->committed & WLR_OUTPUT_STATE_SCALE) {
+		wl_surface_set_buffer_scale(output->surface, ceil(state->scale));
+		needs_commit = true;
+	}
+
 	if (state->committed & WLR_OUTPUT_STATE_BUFFER) {
 		if (output->requested.needs_ack) {
 			output->requested.needs_ack = false;
@@ -340,7 +346,7 @@ static bool output_commit(struct wlr_output *wlr_output,
 			}
 		}
 
-		wl_surface_commit(output->surface);
+		needs_commit = true;
 
 		if (wp_feedback != NULL) {
 			struct wlr_wl_presentation_feedback *feedback =
@@ -365,6 +371,10 @@ static bool output_commit(struct wlr_output *wlr_output,
 		}
 	}
 
+	if (needs_commit) {
+		wl_surface_commit(output->surface);
+	}
+
 	wl_display_flush(output->backend->remote_display);
 
 	if (state->committed & WLR_OUTPUT_STATE_MODE) {
@@ -463,22 +473,17 @@ void update_wl_output_cursor(struct wlr_wl_output *output) {
 		return;
 	}
 
-	struct wlr_wl_buffer *buffer =
-		get_or_create_wl_buffer(output->backend, output->cursor.buffer);
-	if (!buffer) {
-		return;
-	}
-
-	wl_surface_attach(surface, buffer->wl_buffer, 0, 0);
+	int scale = ceil(output->wlr_output.scale);
 	wl_surface_damage_buffer(surface, 0, 0, INT32_MAX, INT32_MAX);
+	wl_surface_set_buffer_scale(surface, scale);
 	wl_surface_commit(surface);
 
 	wl_display_flush(backend->remote_display);
 
 	struct wlr_wl_seat *seat = pointer->seat;
 	wl_pointer_set_cursor(seat->wl_pointer, output->enter_serial,
-		output->cursor.surface, output->cursor.hotspot_x,
-		output->cursor.hotspot_y);
+		output->cursor.surface, output->cursor.hotspot_x / scale,
+		output->cursor.hotspot_y / scale);
 }
 
 static bool output_move_cursor(struct wlr_output *_output, int x, int y) {
@@ -505,16 +510,28 @@ void surface_update(struct wlr_wl_output *output) {
 		return;
 	}
 
+	uint32_t scale = 1;
+
+	struct wlr_wl_active_remote_output *active;
+	wl_list_for_each(active, &output->active_remote_outputs, link) {
+		struct wlr_wl_remote_output *output = active->remote_output;
+		if (scale < output->scale) {
+			scale = output->scale;
+		}
+	}
+
 	struct wlr_output_state state = {
-		.committed = WLR_OUTPUT_STATE_MODE,
+		.committed = WLR_OUTPUT_STATE_MODE | WLR_OUTPUT_STATE_SCALE,
 		.mode_type = WLR_OUTPUT_STATE_MODE_CUSTOM,
+		.scale = scale,
 		.custom_mode = {
-			.width = output->requested.width,
-			.height = output->requested.height
+			.width = output->requested.width * scale,
+			.height = output->requested.height * scale
 		},
 	};
 
 	wlr_output_send_request_state(&output->wlr_output, &state);
+	update_wl_output_cursor(output);
 }
 
 static void xdg_surface_handle_configure(void *data,
diff --git a/backend/wayland/pointer.c b/backend/wayland/pointer.c
index 4ce233e52..f50f6600f 100644
--- a/backend/wayland/pointer.c
+++ b/backend/wayland/pointer.c
@@ -87,11 +87,12 @@ static void pointer_handle_motion(void *data, struct wl_pointer *wl_pointer,
 	}
 
 	struct wlr_output *wlr_output = &pointer->output->wlr_output;
+	int scale = ceil(wlr_output->scale);
 	struct wlr_pointer_motion_absolute_event event = {
 		.pointer = &pointer->wlr_pointer,
 		.time_msec = time,
-		.x = wl_fixed_to_double(sx) / wlr_output->width,
-		.y = wl_fixed_to_double(sy) / wlr_output->height,
+		.x = wl_fixed_to_double(sx) * scale / wlr_output->width,
+		.y = wl_fixed_to_double(sy) * scale / wlr_output->height,
 	};
 	wl_signal_emit_mutable(&pointer->wlr_pointer.events.motion_absolute, &event);
 }
diff --git a/backend/wayland/seat.c b/backend/wayland/seat.c
index a64795a8c..ff28c2f61 100644
--- a/backend/wayland/seat.c
+++ b/backend/wayland/seat.c
@@ -127,8 +127,9 @@ static void touch_coordinates_to_absolute(struct wlr_wl_seat *seat,
 	 */
 	struct wlr_wl_output *output, *tmp;
 	wl_list_for_each_safe(output, tmp, &seat->backend->outputs, link) {
-		*sx = wl_fixed_to_double(x) / output->wlr_output.width;
-		*sy = wl_fixed_to_double(y) / output->wlr_output.height;
+		int scale = ceil(output->wlr_output.scale);
+		*sx = wl_fixed_to_double(x) * scale / output->wlr_output.width;
+		*sy = wl_fixed_to_double(y) * scale / output->wlr_output.height;
 		return; // Choose the first output in the list
 	}