Try moving subtitle adjustment for crop into the decoder.

3 files changed, 25 insertions, 39 deletions

diff --git a/src/lib/decoder.cc b/src/lib/decoder.cc
index e4b892ea4..c4759a872 100644
--- a/src/lib/decoder.cc
+++ b/src/lib/decoder.cc
@@ -48,6 +48,7 @@ extern "C" {
 #include "filter.h"
 #include "delay_line.h"
 #include "ffmpeg_compatibility.h"
+#include "subtitle.h"
 
 using namespace std;
 using namespace boost;
@@ -303,6 +304,14 @@ Decoder::process_video (AVFrame* frame, shared_ptr<Subtitle> sub)
 				image->make_black ();
 			}
 
+			if (sub && _opt->apply_crop) {
+				list<shared_ptr<SubtitleImage> > im = sub->images ();
+				for (list<shared_ptr<SubtitleImage> >::iterator i = im.begin(); i != im.end(); ++i) {
+					Position p = (*i)->position ();
+					(*i)->set_position (Position (p.x - _fs->crop.left, p.y - _fs->crop.top));
+				}
+			}
+
 			TIMING ("Decoder emits %1", _video_frame);
 			Video (image, _video_frame, sub);
 			++_video_frame;
diff --git a/src/lib/subtitle.cc b/src/lib/subtitle.cc
index 040a057fc..0ea5a72d5 100644
--- a/src/lib/subtitle.cc
+++ b/src/lib/subtitle.cc
@@ -70,46 +70,27 @@ SubtitleImage::SubtitleImage (AVSubtitleRect const * rect)
 	}
 }
 
-SubtitleTransform
-subtitle_transform (
-	int target_base_width, int target_base_height,
+Rectangle
+transformed_subtitle_area (
 	float target_x_scale, float target_y_scale,
-	Position sub_pos, int sub_width, int sub_height,
+	Rectangle sub_area,
 	shared_ptr<FilmState> fs
 	)
 {
-	SubtitleTransform tx;
+	Rectangle tx;
 
-	/* The area of the original subtitle, in the coordinate space of the source video frame */
-	Rectangle sub_area (sub_pos.x, sub_pos.y + fs->subtitle_offset, sub_width, sub_height);
-
-	/* The cropped area of the source video frame, in the same coordinate space */
-	Rectangle cropped_target_area (
-		fs->crop.left,
-		fs->crop.top,
-		target_base_width - (fs->crop.left + fs->crop.right),
-		target_base_height - (fs->crop.top + fs->crop.bottom)
-		);
-
-	/* Hence the area of the cropped subtitle, in the same coordinate space */
-	Rectangle cropped_sub_area = sub_area.intersection (cropped_target_area);
-
-	/* The crop that should be applied to the subtitle, in its coordinate space */
-	tx.crop.x = cropped_sub_area.x - sub_area.x;
-	tx.crop.y = cropped_sub_area.y - sub_area.y;
-	tx.crop.w = cropped_sub_area.w;
-	tx.crop.h = cropped_sub_area.h;
+	sub_area.y += fs->subtitle_offset;
 
 	/* We will scale the subtitle by the same amount as the video frame, and also by the additional
 	   subtitle_scale
 	*/
-	tx.transformed.w = cropped_sub_area.w * target_x_scale * fs->subtitle_scale;
-	tx.transformed.h = cropped_sub_area.h * target_y_scale * fs->subtitle_scale;
+	tx.w = sub_area.w * target_x_scale * fs->subtitle_scale;
+	tx.h = sub_area.h * target_y_scale * fs->subtitle_scale;
 
 	/* Then we need a corrective translation, consisting of two parts:
 	 *
 	 * 1.  that which is the result of the scaling of the subtitle by target_x_scale and target_y_scale; this will be
-	 *     (sub_area.x - fs->crop_left) * target_x_scale and (sub_area.y - fs->crop_top) * target_y_scale.
+	 *     sub_area.x * target_x_scale and sub_area.y * target_y_scale.
 	 *
 	 * 2.  that to shift the origin of the scale by fs->subtitle_scale to the centre of the subtitle; this will be
 	 *     (width_before_subtitle_scale * (1 - fs->subtitle_scale) / 2) and
@@ -118,8 +99,8 @@ subtitle_transform (
 	 * Combining these two translations gives these expressions.
 	 */
 	
-	tx.transformed.x = target_x_scale * ((sub_area.x - fs->crop.left) + (cropped_sub_area.w * (1 - fs->subtitle_scale) / 2));
-	tx.transformed.y = target_y_scale * ((sub_area.y - fs->crop.top) + (cropped_sub_area.h * (1 - fs->subtitle_scale) / 2));
+	tx.x = target_x_scale * (sub_area.x + (sub_area.w * (1 - fs->subtitle_scale) / 2));
+	tx.y = target_y_scale * (sub_area.y + (sub_area.h * (1 - fs->subtitle_scale) / 2));
 
 	return tx;
 }
diff --git a/src/lib/subtitle.h b/src/lib/subtitle.h
index fcb6bc70c..0b82320a1 100644
--- a/src/lib/subtitle.h
+++ b/src/lib/subtitle.h
@@ -45,17 +45,9 @@ private:
 	std::list<boost::shared_ptr<SubtitleImage> > _images;
 };
 
-struct SubtitleTransform
-{
-public:
-	Rectangle crop;
-	Rectangle transformed;
-};
-
-extern SubtitleTransform subtitle_transform (
-	int target_base_width, int target_base_height,
+extern Rectangle transformed_subtitle_area (
 	float target_x_scale, float target_y_scale,
-	Position sub_pos, int sub_width, int sub_height,
+	Rectangle sub_area,
 	boost::shared_ptr<FilmState> fs
 	);
 
@@ -64,6 +56,10 @@ class SubtitleImage
 public:
 	SubtitleImage (AVSubtitleRect const *);
 
+	void set_position (Position p) {
+		_position = p;
+	}
+
 	Position position () const {
 		return _position;
 	}