X-Git-Url: https://git.carlh.net/gitweb/?a=blobdiff_plain;f=src%2Flib%2Fsubtitle.cc;h=37c372c20548f2f01508ead78346daf363494afc;hb=44b57d623dec97a3f9955082f0b8a7a8d27b7518;hp=0eb40b14e83229abab3c8dd8c3a0148c6bffda6f;hpb=13511ed2fcc23f4d5f9c507c775c3c5cfd82d155;p=dcpomatic.git

diff --git a/src/lib/subtitle.cc b/src/lib/subtitle.cc
index 0eb40b14e..37c372c20 100644
--- a/src/lib/subtitle.cc
+++ b/src/lib/subtitle.cc
@@ -17,6 +17,10 @@
 
 */
 
+/** @file  src/subtitle.cc
+ *  @brief Representations of subtitles.
+ */
+
 #include "subtitle.h"
 #include "image.h"
 #include "exceptions.h"
@@ -25,41 +29,40 @@
 using namespace std;
 using namespace boost;
 
-Subtitle::Subtitle (AVSubtitle const & sub)
+/** Construct a TimedSubtitle.  This is a subtitle image, position,
+ *  and a range of time over which it should be shown.
+ *  @param sub AVSubtitle to read.
+ *  @param c Fractional seconds that should be subtracted from the AVSubtitle's PTS.
+ */
+TimedSubtitle::TimedSubtitle (AVSubtitle const & sub, double c)
 {
+	assert (sub.rects > 0);
+	
 	/* subtitle PTS in seconds */
-	float const packet_time = (sub.pts / AV_TIME_BASE) + float (sub.pts % AV_TIME_BASE) / 1e6;
+	double const packet_time = ((sub.pts / AV_TIME_BASE) + float (sub.pts % AV_TIME_BASE) / 1e6) - c;
 	
 	/* hence start time for this sub */
 	_from = packet_time + (double (sub.start_display_time) / 1e3);
 	_to = packet_time + (double (sub.end_display_time) / 1e3);
 
-	for (unsigned int i = 0; i < sub.num_rects; ++i) {
-		_images.push_back (shared_ptr<SubtitleImage> (new SubtitleImage (sub.rects[i])));
+	if (sub.num_rects > 1) {
+		throw DecodeError ("multi-part subtitles not yet supported");
 	}
-}
 
-/** @param t Time in seconds from the start of the film */
-bool
-Subtitle::displayed_at (double t)
-{
-	return t >= _from && t <= _to;
-}
+	AVSubtitleRect const * rect = sub.rects[0];
 
-SubtitleImage::SubtitleImage (AVSubtitleRect const * rect)
-	: _position (rect->x, rect->y)
-	, _image (new AlignedImage (PIX_FMT_RGBA, Size (rect->w, rect->h)))
-{
 	if (rect->type != SUBTITLE_BITMAP) {
 		throw DecodeError ("non-bitmap subtitles not yet supported");
 	}
+	
+	shared_ptr<Image> image (new AlignedImage (PIX_FMT_RGBA, Size (rect->w, rect->h)));
 
 	/* Start of the first line in the subtitle */
 	uint8_t* sub_p = rect->pict.data[0];
 	/* sub_p looks up into a RGB palette which is here */
 	uint32_t const * palette = (uint32_t *) rect->pict.data[1];
 	/* Start of the output data */
-	uint32_t* out_p = (uint32_t *) _image->data()[0];
+	uint32_t* out_p = (uint32_t *) image->data()[0];
 	
 	for (int y = 0; y < rect->h; ++y) {
 		uint8_t* sub_line_p = sub_p;
@@ -68,25 +71,55 @@ SubtitleImage::SubtitleImage (AVSubtitleRect const * rect)
 			*out_line_p++ = palette[*sub_line_p++];
 		}
 		sub_p += rect->pict.linesize[0];
-		out_p += _image->stride()[0] / sizeof (uint32_t);
+		out_p += image->stride()[0] / sizeof (uint32_t);
 	}
+
+	_subtitle.reset (new Subtitle (Position (rect->x, rect->y), image));
+}	
+
+/** @param t Time in seconds from the start of the film */
+bool
+TimedSubtitle::displayed_at (double t) const
+{
+	return t >= _from && t <= _to;
+}
+
+/** Construct a subtitle, which is an image and a position.
+ *  @param p Position within the (uncropped) source frame.
+ *  @param i Image of the subtitle (should be RGBA).
+ */
+Subtitle::Subtitle (Position p, shared_ptr<Image> i)
+	: _position (p)
+	, _image (i)
+{
+
 }
 
-Rectangle
-transformed_subtitle_area (
+/** Given the area of a subtitle, work out the area it should
+ *  take up when its video frame is scaled up, and it is optionally
+ *  itself scaled and offset.
+ *  @param target_x_scale the x scaling of the video frame that the subtitle is in.
+ *  @param target_y_scale the y scaling of the video frame that the subtitle is in.
+ *  @param sub_area The area of the subtitle within the original source.
+ *  @param subtitle_offset y offset to apply to the subtitle position (+ve is down)
+ *  in the coordinate space of the source.
+ *  @param subtitle_scale scaling factor to apply to the subtitle image.
+ */
+Rect
+subtitle_transformed_area (
 	float target_x_scale, float target_y_scale,
-	Rectangle sub_area, int subtitle_offset, float subtitle_scale
+	Rect sub_area, int subtitle_offset, float subtitle_scale
 	)
 {
-	Rectangle tx;
+	Rect tx;
 
 	sub_area.y += subtitle_offset;
 
 	/* We will scale the subtitle by the same amount as the video frame, and also by the additional
 	   subtitle_scale
 	*/
-	tx.w = sub_area.w * target_x_scale * subtitle_scale;
-	tx.h = sub_area.h * target_y_scale * subtitle_scale;
+	tx.width = sub_area.width * target_x_scale * subtitle_scale;
+	tx.height = sub_area.height * target_y_scale * subtitle_scale;
 
 	/* Then we need a corrective translation, consisting of two parts:
 	 *
@@ -100,14 +133,15 @@ transformed_subtitle_area (
 	 * Combining these two translations gives these expressions.
 	 */
 	
-	tx.x = target_x_scale * (sub_area.x + (sub_area.w * (1 - subtitle_scale) / 2));
-	tx.y = target_y_scale * (sub_area.y + (sub_area.h * (1 - subtitle_scale) / 2));
+	tx.x = target_x_scale * (sub_area.x + (sub_area.width * (1 - subtitle_scale) / 2));
+	tx.y = target_y_scale * (sub_area.y + (sub_area.height * (1 - subtitle_scale) / 2));
 
 	return tx;
 }
 
-Rectangle
-SubtitleImage::area () const
+/** @return area that this subtitle take up, in the original uncropped source's coordinate space */
+Rect
+Subtitle::area () const
 {
-	return Rectangle (_position.x, _position.y, _image->size().width, _image->size().height);
+	return Rect (_position.x, _position.y, _image->size().width, _image->size().height);
 }