From eef23108ceb07b56cde9f0393aeaca5b429444e6 Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Fri, 20 Jan 2023 23:53:45 +0100
Subject: [PATCH] Add bounding_box().

---
 src/lib/render_text.cc | 30 ++++++++++++++++++++++++++++++
 src/lib/render_text.h  |  4 +++-
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/lib/render_text.cc b/src/lib/render_text.cc
index 0b6a30e80..0e2b024d6 100644
--- a/src/lib/render_text.cc
+++ b/src/lib/render_text.cc
@@ -427,6 +427,36 @@ render_text (list<StringText> subtitles, dcp::Size target, DCPTime time, int fra
 }
 
 
+list<dcpomatic::Rect<int>>
+bounding_box(list<StringText> subtitles, dcp::Size target)
+{
+	list<StringText> pending;
+	list<dcpomatic::Rect<int>> rects;
+
+	auto use_pending = [&pending, &rects, target]() {
+		/* We can provide dummy values for time and frame rate here as they are only used to calculate fades */
+		auto layout = setup_layout(pending, target, DCPTime(), 24);
+		int const x = x_position(pending.front(), target.width, layout.size.width);
+		int const y = y_position(pending.front(), target.height, layout.position.y, layout.size.height);
+		rects.push_back({Position<int>(x, y), layout.size.width, layout.size.height});
+	};
+
+	for (auto const& i: subtitles) {
+		if (!pending.empty() && (i.v_align() != pending.back().v_align() || fabs(i.v_position() - pending.back().v_position()) > 1e-4)) {
+			use_pending();
+			pending.clear();
+		}
+		pending.push_back(i);
+	}
+
+	if (!pending.empty()) {
+		use_pending();
+	}
+
+	return rects;
+}
+
+
 float
 FontMetrics::height(StringText const& subtitle)
 {
diff --git a/src/lib/render_text.h b/src/lib/render_text.h
index 762d79446..bceee964e 100644
--- a/src/lib/render_text.h
+++ b/src/lib/render_text.h
@@ -19,8 +19,9 @@
 */
 
 
-#include "position_image.h"
 #include "dcpomatic_time.h"
+#include "position_image.h"
+#include "rect.h"
 #include "string_text.h"
 #include <dcp/util.h>
 #include <memory>
@@ -33,6 +34,7 @@ namespace dcpomatic {
 
 std::string marked_up (std::list<StringText> subtitles, int target_height, float fade_factor, std::string font_name);
 std::list<PositionImage> render_text (std::list<StringText>, dcp::Size, dcpomatic::DCPTime, int);
+std::list<dcpomatic::Rect<int>> bounding_box(std::list<StringText> subtitles, dcp::Size target);
 
 
 class FontMetrics
-- 
2.30.2