viewporter: new protocol implementation

Closes: https://github.com/swaywm/wlroots/issues/633

4 files changed, 260 insertions, 0 deletions

diff --git a/include/wlr/types/wlr_viewporter.h b/include/wlr/types/wlr_viewporter.h
new file mode 100644
index 00000000..b695420d
--- /dev/null
+++ b/include/wlr/types/wlr_viewporter.h
@@ -0,0 +1,34 @@
+/*
+ * This an unstable interface of wlroots. No guarantees are made regarding the
+ * future consistency of this API.
+ */
+#ifndef WLR_USE_UNSTABLE
+#error "Add -DWLR_USE_UNSTABLE to enable unstable wlroots features"
+#endif
+
+#ifndef WLR_TYPES_WLR_VIEWPORTER_H
+#define WLR_TYPES_WLR_VIEWPORTER_H
+
+#include <wayland-server-core.h>
+
+struct wlr_viewporter {
+	struct wl_global *global;
+
+	struct {
+		struct wl_signal destroy;
+	} events;
+
+	struct wl_listener display_destroy;
+};
+
+struct wlr_viewport {
+	struct wl_resource *resource;
+	struct wlr_surface *surface;
+
+	struct wl_listener surface_destroy;
+	struct wl_listener surface_commit;
+};
+
+struct wlr_viewporter *wlr_viewporter_create(struct wl_display *display);
+
+#endif
diff --git a/protocol/meson.build b/protocol/meson.build
index 1b90b4f0..2369b70e 100644
--- a/protocol/meson.build
+++ b/protocol/meson.build
@@ -14,6 +14,7 @@ protocols = {
 	# Stable upstream protocols
 	'xdg-shell': wl_protocol_dir / 'stable/xdg-shell/xdg-shell.xml',
 	'presentation-time': wl_protocol_dir / 'stable/presentation-time/presentation-time.xml',
+	'viewporter': wl_protocol_dir / 'stable/viewporter/viewporter.xml',
 	# Unstable upstream protocols
 	'fullscreen-shell-unstable-v1': wl_protocol_dir / 'unstable/fullscreen-shell/fullscreen-shell-unstable-v1.xml',
 	'idle-inhibit-unstable-v1': wl_protocol_dir / 'unstable/idle-inhibit/idle-inhibit-unstable-v1.xml',
diff --git a/types/meson.build b/types/meson.build
index face4bdf..998e6b45 100644
--- a/types/meson.build
+++ b/types/meson.build
@@ -64,6 +64,7 @@ wlr_files += files(
 	'wlr_tablet_tool.c',
 	'wlr_text_input_v3.c',
 	'wlr_touch.c',
+	'wlr_viewporter.c',
 	'wlr_virtual_keyboard_v1.c',
 	'wlr_virtual_pointer_v1.c',
 	'wlr_xcursor_manager.c',
diff --git a/types/wlr_viewporter.c b/types/wlr_viewporter.c
new file mode 100644
index 00000000..9b7e1099
--- /dev/null
+++ b/types/wlr_viewporter.c
@@ -0,0 +1,224 @@
+#include <assert.h>
+#include <stdlib.h>
+#include <wlr/types/wlr_surface.h>
+#include <wlr/types/wlr_viewporter.h>
+#include <wlr/util/log.h>
+#include "util/signal.h"
+#include "viewporter-protocol.h"
+
+#define VIEWPORTER_VERSION 1
+
+static const struct wp_viewport_interface viewport_impl;
+
+// Returns NULL if the viewport is inert
+static struct wlr_viewport *viewport_from_resource(
+		struct wl_resource *resource) {
+	assert(wl_resource_instance_of(resource, &wp_viewport_interface,
+		&viewport_impl));
+	return wl_resource_get_user_data(resource);
+}
+
+static void viewport_handle_destroy(struct wl_client *client,
+		struct wl_resource *resource) {
+	wl_resource_destroy(resource);
+}
+
+static void viewport_handle_set_source(struct wl_client *client,
+		struct wl_resource *resource, wl_fixed_t x_fixed, wl_fixed_t y_fixed,
+		wl_fixed_t width_fixed, wl_fixed_t height_fixed) {
+	struct wlr_viewport *viewport = viewport_from_resource(resource);
+	if (viewport == NULL) {
+		wl_resource_post_error(resource, WP_VIEWPORT_ERROR_NO_SURFACE,
+			"wp_viewport.set_source sent after wl_surface has been destroyed");
+		return;
+	}
+
+	struct wlr_surface_state *pending = &viewport->surface->pending;
+
+	double x = wl_fixed_to_double(x_fixed);
+	double y = wl_fixed_to_double(y_fixed);
+	double width = wl_fixed_to_double(width_fixed);
+	double height = wl_fixed_to_double(height_fixed);
+
+	if (x == -1.0 && y == -1.0 && width == -1.0 && height == -1.0) {
+		pending->viewport.has_src = false;
+	} else if (x < 0 || y < 0 || width <= 0 || height <= 0) {
+		wl_resource_post_error(resource, WP_VIEWPORT_ERROR_BAD_VALUE,
+			"wl_viewport.set_source sent with invalid values");
+		return;
+	} else {
+		pending->viewport.has_src = true;
+	}
+
+	pending->viewport.src.x = x;
+	pending->viewport.src.y = y;
+	pending->viewport.src.width = width;
+	pending->viewport.src.height = height;
+
+	pending->committed |= WLR_SURFACE_STATE_VIEWPORT;
+}
+
+static void viewport_handle_set_destination(struct wl_client *client,
+		struct wl_resource *resource, int32_t width, int32_t height) {
+	struct wlr_viewport *viewport = viewport_from_resource(resource);
+	if (viewport == NULL) {
+		wl_resource_post_error(resource, WP_VIEWPORT_ERROR_NO_SURFACE,
+			"wp_viewport.set_destination sent after wl_surface has been destroyed");
+		return;
+	}
+
+	struct wlr_surface_state *pending = &viewport->surface->pending;
+
+	if (width == -1 && height == -1) {
+		pending->viewport.has_dst = false;
+	} else if (width <= 0 || height <= 0) {
+		wl_resource_post_error(resource, WP_VIEWPORT_ERROR_BAD_VALUE,
+			"wl_viewport.set_destination sent with invalid values");
+		return;
+	} else {
+		pending->viewport.has_dst = true;
+	}
+
+	pending->viewport.dst_width = width;
+	pending->viewport.dst_height = height;
+
+	pending->committed |= WLR_SURFACE_STATE_VIEWPORT;
+}
+
+static const struct wp_viewport_interface viewport_impl = {
+	.destroy = viewport_handle_destroy,
+	.set_source = viewport_handle_set_source,
+	.set_destination = viewport_handle_set_destination,
+};
+
+static void viewport_destroy(struct wlr_viewport *viewport) {
+	if (viewport == NULL) {
+		return;
+	}
+	wl_resource_set_user_data(viewport->resource, NULL);
+	wl_list_remove(&viewport->surface_destroy.link);
+	wl_list_remove(&viewport->surface_commit.link);
+	free(viewport);
+}
+
+static void viewport_handle_resource_destroy(struct wl_resource *resource) {
+	struct wlr_viewport *viewport = viewport_from_resource(resource);
+	viewport_destroy(viewport);
+}
+
+static void viewport_handle_surface_destroy(struct wl_listener *listener,
+		void *data) {
+	struct wlr_viewport *viewport =
+		wl_container_of(listener, viewport, surface_destroy);
+	viewport_destroy(viewport);
+}
+
+static void viewport_handle_surface_commit(struct wl_listener *listener,
+		void *data) {
+	struct wlr_viewport *viewport =
+		wl_container_of(listener, viewport, surface_commit);
+
+	struct wlr_surface_state *current = &viewport->surface->pending;
+
+	if (!current->viewport.has_dst &&
+			(floor(current->viewport.src.width) != current->viewport.src.width ||
+			floor(current->viewport.src.height) != current->viewport.src.height)) {
+		wl_resource_post_error(viewport->resource, WP_VIEWPORT_ERROR_BAD_SIZE,
+			"wl_viewport.set_source width and height must be integers "
+			"when the destination rectangle is unset");
+		return;
+	}
+
+	if (current->viewport.has_src && current->buffer_resource != NULL &&
+			(current->viewport.src.x + current->viewport.src.width >
+				current->buffer_width ||
+			current->viewport.src.y + current->viewport.src.height >
+				current->buffer_height)) {
+		wl_resource_post_error(viewport->resource, WP_VIEWPORT_ERROR_OUT_OF_BUFFER,
+			"source rectangle out of buffer bounds");
+		return;
+	}
+}
+
+static void viewporter_handle_destroy(struct wl_client *client,
+		struct wl_resource *resource) {
+	wl_resource_destroy(resource);
+}
+
+static void viewporter_handle_get_viewport(struct wl_client *client,
+		struct wl_resource *resource, uint32_t id,
+		struct wl_resource *surface_resource) {
+	struct wlr_surface *surface = wlr_surface_from_resource(surface_resource);
+
+	struct wlr_viewport *viewport = calloc(1, sizeof(*viewport));
+	if (viewport == NULL) {
+		wl_client_post_no_memory(client);
+		return;
+	}
+
+	uint32_t version = wl_resource_get_version(resource);
+	viewport->resource = wl_resource_create(client, &wp_viewport_interface,
+		version, id);
+	if (viewport->resource == NULL) {
+		wl_client_post_no_memory(client);
+		free(viewport);
+		return;
+	}
+	wl_resource_set_implementation(viewport->resource, &viewport_impl,
+		viewport, viewport_handle_resource_destroy);
+
+	viewport->surface = surface;
+
+	viewport->surface_destroy.notify = viewport_handle_surface_destroy;
+	wl_signal_add(&surface->events.destroy, &viewport->surface_destroy);
+
+	viewport->surface_commit.notify = viewport_handle_surface_commit;
+	wl_signal_add(&surface->events.commit, &viewport->surface_commit);
+}
+
+static const struct wp_viewporter_interface viewporter_impl = {
+	.destroy = viewporter_handle_destroy,
+	.get_viewport = viewporter_handle_get_viewport,
+};
+
+static void viewporter_bind(struct wl_client *client, void *data,
+		uint32_t version, uint32_t id) {
+	struct wlr_viewporter *viewporter = data;
+
+	struct wl_resource *resource = wl_resource_create(client,
+		&wp_viewporter_interface, version, id);
+	if (resource == NULL) {
+		wl_client_post_no_memory(client);
+		return;
+	}
+	wl_resource_set_implementation(resource, &viewporter_impl, viewporter, NULL);
+}
+
+static void handle_display_destroy(struct wl_listener *listener, void *data) {
+	struct wlr_viewporter *viewporter =
+		wl_container_of(listener, viewporter, display_destroy);
+	wlr_signal_emit_safe(&viewporter->events.destroy, NULL);
+	wl_global_destroy(viewporter->global);
+	free(viewporter);
+}
+
+struct wlr_viewporter *wlr_viewporter_create(struct wl_display *display) {
+	struct wlr_viewporter *viewporter = calloc(1, sizeof(*viewporter));
+	if (viewporter == NULL) {
+		return NULL;
+	}
+
+	viewporter->global = wl_global_create(display, &wp_viewporter_interface,
+		VIEWPORTER_VERSION, viewporter, viewporter_bind);
+	if (viewporter->global == NULL) {
+		free(viewporter);
+		return NULL;
+	}
+
+	wl_signal_init(&viewporter->events.destroy);
+
+	viewporter->display_destroy.notify = handle_display_destroy;
+	wl_display_add_destroy_listener(display, &viewporter->display_destroy);
+
+	return viewporter;
+}