add helper methods for intersection

examples/output-layout.c

@@ -46,24 +46,20 @@ static void handle_output_frame(struct output_state *output, struct timespec *ts
 	struct sample_state *sample = state->data;
 	struct wlr_output *wlr_output = output->output;
 
-	int32_t width, height;
-	wlr_output_effective_resolution(wlr_output, &width, &height);
-
 	wlr_output_make_current(wlr_output);
 	wlr_renderer_begin(sample->renderer, wlr_output);
 
+	if (wlr_output_layout_intersects(sample->layout, output->output,
+				sample->x_offs, sample->y_offs,
+				sample->x_offs + 128, sample->y_offs + 128)) {
 		float matrix[16];
 
 		// transform global coordinates to local coordinates
 		int local_x = sample->x_offs;
 		int local_y = sample->y_offs;
-
 		wlr_output_layout_output_coords(sample->layout, output->output, &local_x,
 				&local_y);
 
-	if (local_x < width && local_x + 128 > 0 && local_y < height &&
-			local_y + 128 > 0) {
-		// render the image if it intersects with the output
 		wlr_texture_get_matrix(sample->cat_texture, &matrix,
 			&wlr_output->transform_matrix, local_x, local_y);
 		wlr_render_with_matrix(sample->renderer,

include/wlr/types/wlr_output_layout.h

@@ -40,4 +40,10 @@ void wlr_output_layout_remove(struct wlr_output_layout *layout,
 void wlr_output_layout_output_coords(struct wlr_output_layout *layout,
     struct wlr_output *reference, int *x, int *y);
 
+bool wlr_output_layout_contains_point(struct wlr_output_layout *layout,
+	struct wlr_output *reference, int x, int y);
+
+bool wlr_output_layout_intersects(struct wlr_output_layout *layout,
+	struct wlr_output *reference, int x1, int y1, int x2, int y2);
+
 #endif

types/wlr_output_layout.c

@@ -47,6 +47,36 @@ struct wlr_output_layout_output *wlr_output_layout_get(
 
 }
 
+static bool output_contains_point( struct wlr_output_layout_output *l_output,
+		int x, int y, int width, int height) {
+	return x >= l_output->x && x <= l_output->x + width &&
+		y >= l_output->y && y <= l_output->y + height;
+}
+
+bool wlr_output_layout_contains_point(struct wlr_output_layout *layout,
+		struct wlr_output *reference, int x, int y) {
+	struct wlr_output_layout_output *layout_output = wlr_output_layout_get(layout, reference);
+	int width, height;
+	wlr_output_effective_resolution(layout_output->output, &width, &height);
+	return output_contains_point(layout_output, x, y, width, height);
+}
+
+bool wlr_output_layout_intersects(struct wlr_output_layout *layout,
+		struct wlr_output *reference, int x1, int y1, int x2, int y2) {
+	struct wlr_output_layout_output *l_output = wlr_output_layout_get(layout, reference);
+	if (!l_output) {
+		return false;
+	}
+	int width, height;
+	wlr_output_effective_resolution(l_output->output, &width, &height);
+
+	// the output must contain one of the points
+	return output_contains_point(l_output, x1, y1, width, height) ||
+		output_contains_point(l_output, x2, y2, width, height) ||
+		output_contains_point(l_output, x2, y1, width, height) ||
+		output_contains_point(l_output, y2, x1, width, height);
+}
+
 struct wlr_output *wlr_output_layout_output_at(struct wlr_output_layout *layout,
 		double x, double y) {
 	struct wlr_output *ret = NULL;