Merge FilmState / Film.

[dcpomatic.git] / src / lib / subtitle.cc

diff --git a/src/lib/subtitle.cc b/src/lib/subtitle.cc
index 01e8cac1396ea62b386cb60e995fbee50a330cd4..282a2cde1a68b9e494af6fcc005d3f88b8f7b4d2 100644 (file)
--- a/src/lib/subtitle.cc
+++ b/src/lib/subtitle.cc
@@ -17,18 +17,28 @@
 
 */
 
+/** @file  src/subtitle.cc
+ *  @brief Representations of subtitles.
+ */
+
 #include "subtitle.h"
 #include "image.h"
 #include "exceptions.h"
-#include "film_state.h"
 
 using namespace std;
 using namespace boost;
 
-TimedSubtitle::TimedSubtitle (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);
@@ -73,20 +83,34 @@ 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
+
+/** 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;
 
@@ -114,8 +138,9 @@ subtitle_transformed_area (
        return tx;
 }
 
-Rectangle
+/** @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);
 }