From 42583595f2cea83f54a1fed55004f271d712f715 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= Date: Mon, 24 Jan 2022 14:29:04 +0200 Subject: [PATCH] examples: Make use of `glib::closure!` for the overlay-composition example --- examples/src/bin/overlay-composition.rs | 229 ++++++++++++------------ 1 file changed, 114 insertions(+), 115 deletions(-) diff --git a/examples/src/bin/overlay-composition.rs b/examples/src/bin/overlay-composition.rs index 523901a7a..770578435 100644 --- a/examples/src/bin/overlay-composition.rs +++ b/examples/src/bin/overlay-composition.rs @@ -116,7 +116,6 @@ fn create_pipeline() -> Result { info: None, })); - let drawer_clone = drawer.clone(); // Connect to the overlaycomposition element's "draw" signal, which is emitted for // each videoframe piped through the element. The signal handler needs to // return a gst_video::VideoOverlayComposition to be drawn on the frame @@ -128,126 +127,124 @@ fn create_pipeline() -> Result { // // In this case, the signal passes the gst::Element and a gst::Sample with // the current buffer - overlay.connect("draw", false, move |args| { - use std::f64::consts::PI; + overlay.connect_closure( + "draw", + false, + glib::closure!(@strong drawer => move |_overlay: &gst::Element, + sample: &gst::Sample| { + use std::f64::consts::PI; - let drawer = &drawer_clone; - let drawer = drawer.lock().unwrap(); + let drawer = drawer.lock().unwrap(); - // Get the signal's arguments - let _overlay = args[0].get::().unwrap(); - let sample = args[1].get::().unwrap(); - let buffer = sample.buffer().unwrap(); - let timestamp = buffer.pts().unwrap(); + let buffer = sample.buffer().unwrap(); + let timestamp = buffer.pts().unwrap(); - let info = drawer.info.as_ref().unwrap(); - let layout = drawer.layout.borrow(); + let info = drawer.info.as_ref().unwrap(); + let layout = drawer.layout.borrow(); - let angle = 2.0 * PI * (timestamp % (10 * gst::ClockTime::SECOND)).nseconds() as f64 - / (10.0 * gst::ClockTime::SECOND.nseconds() as f64); + let angle = 2.0 * PI * (timestamp % (10 * gst::ClockTime::SECOND)).nseconds() as f64 + / (10.0 * gst::ClockTime::SECOND.nseconds() as f64); - /* Create a Cairo image surface to draw into and the context around it. */ - let surface = cairo::ImageSurface::create( - cairo::Format::ARgb32, - info.width() as i32, - info.height() as i32, - ) - .unwrap(); - let cr = cairo::Context::new(&surface).expect("Failed to create cairo context"); + /* Create a Cairo image surface to draw into and the context around it. */ + let surface = cairo::ImageSurface::create( + cairo::Format::ARgb32, + info.width() as i32, + info.height() as i32, + ) + .unwrap(); + let cr = cairo::Context::new(&surface).expect("Failed to create cairo context"); - cr.save().expect("Failed to save state"); - cr.set_operator(cairo::Operator::Clear); - cr.paint().expect("Failed to clear background"); - cr.restore().expect("Failed to restore state"); - - // The image we draw (the text) will be static, but we will change the - // transformation on the drawing context, which rotates and shifts everything - // that we draw afterwards. Like this, we have no complicated calulations - // in the actual drawing below. - // Calling multiple transformation methods after each other will apply the - // new transformation on top. If you repeat the cr.rotate(angle) line below - // this a second time, everything in the canvas will rotate twice as fast. - cr.translate( - f64::from(info.width()) / 2.0, - f64::from(info.height()) / 2.0, - ); - cr.rotate(angle); - - // This loop will render 10 times the string "GStreamer" in a circle - for i in 0..10 { - // Cairo, like most rendering frameworks, is using a stack for transformations - // with this, we push our current transformation onto this stack - allowing us - // to make temporary changes / render something / and then returning to the - // previous transformations. cr.save().expect("Failed to save state"); - - let angle = (360. * f64::from(i)) / 10.0; - let red = (1.0 + f64::cos((angle - 60.0) * PI / 180.0)) / 2.0; - cr.set_source_rgb(red, 0.0, 1.0 - red); - cr.rotate(angle * PI / 180.0); - - // Update the text layout. This function is only updating pango's internal state. - // So e.g. that after a 90 degree rotation it knows that what was previously going - // to end up as a 200x100 rectangle would now be 100x200. - pangocairo::functions::update_layout(&cr, &**layout); - let (width, _height) = layout.size(); - // Using width and height of the text, we can properly possition it within - // our canvas. - cr.move_to( - -(f64::from(width) / f64::from(pango::SCALE)) / 2.0, - -(f64::from(info.height())) / 2.0, - ); - // After telling the layout object where to draw itself, we actually tell - // it to draw itself into our cairo context. - pangocairo::functions::show_layout(&cr, &**layout); - - // Here we go one step up in our stack of transformations, removing any - // changes we did to them since the last call to cr.save(); + cr.set_operator(cairo::Operator::Clear); + cr.paint().expect("Failed to clear background"); cr.restore().expect("Failed to restore state"); - } - /* Drop the Cairo context to release the additional reference to the data and - * then take ownership of the data. This only works if we have the one and only - * reference to the image surface */ - drop(cr); - let stride = surface.stride(); - let data = surface.take_data().unwrap(); + // The image we draw (the text) will be static, but we will change the + // transformation on the drawing context, which rotates and shifts everything + // that we draw afterwards. Like this, we have no complicated calulations + // in the actual drawing below. + // Calling multiple transformation methods after each other will apply the + // new transformation on top. If you repeat the cr.rotate(angle) line below + // this a second time, everything in the canvas will rotate twice as fast. + cr.translate( + f64::from(info.width()) / 2.0, + f64::from(info.height()) / 2.0, + ); + cr.rotate(angle); - /* Create an RGBA buffer, and add a video meta that the videooverlaycomposition expects */ - let mut buffer = gst::Buffer::from_mut_slice(data); + // This loop will render 10 times the string "GStreamer" in a circle + for i in 0..10 { + // Cairo, like most rendering frameworks, is using a stack for transformations + // with this, we push our current transformation onto this stack - allowing us + // to make temporary changes / render something / and then returning to the + // previous transformations. + cr.save().expect("Failed to save state"); - gst_video::VideoMeta::add_full( - buffer.get_mut().unwrap(), - gst_video::VideoFrameFlags::empty(), - gst_video::VideoFormat::Bgra, - info.width(), - info.height(), - &[0], - &[stride], - ) - .unwrap(); + let angle = (360. * f64::from(i)) / 10.0; + let red = (1.0 + f64::cos((angle - 60.0) * PI / 180.0)) / 2.0; + cr.set_source_rgb(red, 0.0, 1.0 - red); + cr.rotate(angle * PI / 180.0); - /* Turn the buffer into a VideoOverlayRectangle, then place - * that into a VideoOverlayComposition and return it. - * - * A VideoOverlayComposition can take a Vec of such rectangles - * spaced around the video frame, but we're just outputting 1 - * here */ - let rect = gst_video::VideoOverlayRectangle::new_raw( - &buffer, - 0, - 0, - info.width(), - info.height(), - gst_video::VideoOverlayFormatFlags::PREMULTIPLIED_ALPHA, - ); + // Update the text layout. This function is only updating pango's internal state. + // So e.g. that after a 90 degree rotation it knows that what was previously going + // to end up as a 200x100 rectangle would now be 100x200. + pangocairo::functions::update_layout(&cr, &**layout); + let (width, _height) = layout.size(); + // Using width and height of the text, we can properly possition it within + // our canvas. + cr.move_to( + -(f64::from(width) / f64::from(pango::SCALE)) / 2.0, + -(f64::from(info.height())) / 2.0, + ); + // After telling the layout object where to draw itself, we actually tell + // it to draw itself into our cairo context. + pangocairo::functions::show_layout(&cr, &**layout); + + // Here we go one step up in our stack of transformations, removing any + // changes we did to them since the last call to cr.save(); + cr.restore().expect("Failed to restore state"); + } + + /* Drop the Cairo context to release the additional reference to the data and + * then take ownership of the data. This only works if we have the one and only + * reference to the image surface */ + drop(cr); + let stride = surface.stride(); + let data = surface.take_data().unwrap(); + + /* Create an RGBA buffer, and add a video meta that the videooverlaycomposition expects */ + let mut buffer = gst::Buffer::from_mut_slice(data); + + gst_video::VideoMeta::add_full( + buffer.get_mut().unwrap(), + gst_video::VideoFrameFlags::empty(), + gst_video::VideoFormat::Bgra, + info.width(), + info.height(), + &[0], + &[stride], + ) + .unwrap(); + + /* Turn the buffer into a VideoOverlayRectangle, then place + * that into a VideoOverlayComposition and return it. + * + * A VideoOverlayComposition can take a Vec of such rectangles + * spaced around the video frame, but we're just outputting 1 + * here */ + let rect = gst_video::VideoOverlayRectangle::new_raw( + &buffer, + 0, + 0, + info.width(), + info.height(), + gst_video::VideoOverlayFormatFlags::PREMULTIPLIED_ALPHA, + ); - Some( gst_video::VideoOverlayComposition::new(Some(&rect)) .unwrap() - .to_value(), - ) - }); + }), + ); // Add a signal handler to the overlay's "caps-changed" signal. This could e.g. // be called when the sink that we render to does not support resizing the image @@ -256,15 +253,17 @@ fn create_pipeline() -> Result { // resize our canvas's size. // Another possibility for when this might happen is, when our video is a network // stream that dynamically changes resolution when enough bandwith is available. - overlay.connect("caps-changed", false, move |args| { - let _overlay = args[0].get::().unwrap(); - let caps = args[1].get::().unwrap(); - - let mut drawer = drawer.lock().unwrap(); - drawer.info = Some(gst_video::VideoInfo::from_caps(&caps).unwrap()); - - None - }); + overlay.connect_closure( + "caps-changed", + false, + glib::closure!(move |_overlay: &gst::Element, + caps: &gst::Caps, + _width: u32, + _height: u32| { + let mut drawer = drawer.lock().unwrap(); + drawer.info = Some(gst_video::VideoInfo::from_caps(caps).unwrap()); + }), + ); Ok(pipeline) }