From c5301d109be97bf85ce343f7d9356a2262ce0ef6 Mon Sep 17 00:00:00 2001 From: Carl Hetherington Date: Thu, 23 Apr 2020 22:31:14 +0200 Subject: [PATCH] More extractions. --- src/lib/render_text.cc | 139 ++++++++++++++++++++++++----------------- 1 file changed, 82 insertions(+), 57 deletions(-) diff --git a/src/lib/render_text.cc b/src/lib/render_text.cc index d9c1d0d34..26396173e 100644 --- a/src/lib/render_text.cc +++ b/src/lib/render_text.cc @@ -200,6 +200,85 @@ setup_font (StringText const& subtitle, list > const& fonts) } +static float +calculate_fade_factor (StringText const& first, DCPTime time, int frame_rate) +{ + float fade_factor = 1; + + /* Round the fade start/end to the nearest frame start. Otherwise if a subtitle starts just after + the start of a frame it will be faded out. + */ + DCPTime const fade_in_start = DCPTime::from_seconds(first.in().as_seconds()).round(frame_rate); + DCPTime const fade_in_end = fade_in_start + DCPTime::from_seconds (first.fade_up_time().as_seconds ()); + DCPTime const fade_out_end = DCPTime::from_seconds (first.out().as_seconds()).round(frame_rate); + DCPTime const fade_out_start = fade_out_end - DCPTime::from_seconds (first.fade_down_time().as_seconds ()); + + if (fade_in_start <= time && time <= fade_in_end && fade_in_start != fade_in_end) { + fade_factor *= DCPTime(time - fade_in_start).seconds() / DCPTime(fade_in_end - fade_in_start).seconds(); + } + if (fade_out_start <= time && time <= fade_out_end && fade_out_start != fade_out_end) { + fade_factor *= 1 - DCPTime(time - fade_out_start).seconds() / DCPTime(fade_out_end - fade_out_start).seconds(); + } + if (time < fade_in_start || time > fade_out_end) { + fade_factor = 0; + } + + return fade_factor; +} + + +static int +x_position (StringText const& first, int target_width, int layout_width) +{ + int x = 0; + switch (first.h_align ()) { + case dcp::HALIGN_LEFT: + /* h_position is distance between left of frame and left of subtitle */ + x = first.h_position() * target_width; + break; + case dcp::HALIGN_CENTER: + /* h_position is distance between centre of frame and centre of subtitle */ + x = (0.5 + first.h_position()) * target_width - layout_width / 2; + break; + case dcp::HALIGN_RIGHT: + /* h_position is distance between right of frame and right of subtitle */ + x = (1.0 - first.h_position()) * target_width - layout_width; + break; + } + + return x; +} + + + +static int +y_position (StringText const& first, int target_height, int layout_height) +{ + int y = 0; + switch (first.v_align ()) { + case dcp::VALIGN_TOP: + /* SMPTE says that v_position is the distance between top + of frame and top of subtitle, but this doesn't always seem to be + the case in practice; Gunnar Ásgeirsson's Dolby server appears + to put VALIGN_TOP subs with v_position as the distance between top + of frame and bottom of subtitle. + */ + y = first.v_position() * target_height - layout_height; + break; + case dcp::VALIGN_CENTER: + /* v_position is distance between centre of frame and centre of subtitle */ + y = (0.5 + first.v_position()) * target_height - layout_height / 2; + break; + case dcp::VALIGN_BOTTOM: + /* v_position is distance between bottom of frame and bottom of subtitle */ + y = (1.0 - first.v_position()) * target_height - layout_height; + break; + } + + return y; +} + + /** @param subtitles A list of subtitles that are all on the same line, * at the same time and with the same fade in/out. */ @@ -254,26 +333,7 @@ render_line (list subtitles, list > fonts, dcp::Siz context->set_line_width (1); - /* Compute fade factor */ - float fade_factor = 1; - - /* Round the fade start/end to the nearest frame start. Otherwise if a subtitle starts just after - the start of a frame it will be faded out. - */ - DCPTime const fade_in_start = DCPTime::from_seconds(first.in().as_seconds()).round(frame_rate); - DCPTime const fade_in_end = fade_in_start + DCPTime::from_seconds (first.fade_up_time().as_seconds ()); - DCPTime const fade_out_end = DCPTime::from_seconds (first.out().as_seconds()).round(frame_rate); - DCPTime const fade_out_start = fade_out_end - DCPTime::from_seconds (first.fade_down_time().as_seconds ()); - - if (fade_in_start <= time && time <= fade_in_end && fade_in_start != fade_in_end) { - fade_factor *= DCPTime(time - fade_in_start).seconds() / DCPTime(fade_in_end - fade_in_start).seconds(); - } - if (fade_out_start <= time && time <= fade_out_end && fade_out_start != fade_out_end) { - fade_factor *= 1 - DCPTime(time - fade_out_start).seconds() / DCPTime(fade_out_end - fade_out_start).seconds(); - } - if (time < fade_in_start || time > fade_out_end) { - fade_factor = 0; - } + float const fade_factor = calculate_fade_factor (first, time, frame_rate); /* Render the subtitle at the top left-hand corner of image */ @@ -325,43 +385,8 @@ render_line (list subtitles, list > fonts, dcp::Siz layout_width *= xscale; layout_height *= yscale; - int x = 0; - switch (first.h_align ()) { - case dcp::HALIGN_LEFT: - /* h_position is distance between left of frame and left of subtitle */ - x = first.h_position() * target.width; - break; - case dcp::HALIGN_CENTER: - /* h_position is distance between centre of frame and centre of subtitle */ - x = (0.5 + first.h_position()) * target.width - layout_width / 2; - break; - case dcp::HALIGN_RIGHT: - /* h_position is distance between right of frame and right of subtitle */ - x = (1.0 - first.h_position()) * target.width - layout_width; - break; - } - - int y = 0; - switch (first.v_align ()) { - case dcp::VALIGN_TOP: - /* SMPTE says that v_position is the distance between top - of frame and top of subtitle, but this doesn't always seem to be - the case in practice; Gunnar Ásgeirsson's Dolby server appears - to put VALIGN_TOP subs with v_position as the distance between top - of frame and bottom of subtitle. - */ - y = first.v_position() * target.height - layout_height; - break; - case dcp::VALIGN_CENTER: - /* v_position is distance between centre of frame and centre of subtitle */ - y = (0.5 + first.v_position()) * target.height - layout_height / 2; - break; - case dcp::VALIGN_BOTTOM: - /* v_position is distance between bottom of frame and bottom of subtitle */ - y = (1.0 - first.v_position()) * target.height - layout_height; - break; - } - + int const x = x_position (first, target.width, layout_width); + int const y = y_position (first, target.height, layout_height); return PositionImage (image, Position (max (0, x), max (0, y))); } -- 2.30.2