Add pango-cairo example

examples/Cargo.toml

@@ -21,6 +21,9 @@ futures-preview = { version = "0.2", optional = true }
 byte-slice-cast = "0.2"
 failure = "0.1"
 failure_derive = "0.1"
+cairo-rs = { git = "https://github.com/gtk-rs/cairo", features=["use_glib"], optional = true }
+pango = { git = "https://github.com/gtk-rs/pango", optional = true }
+pangocairo = { git = "https://github.com/gtk-rs/pangocairo", optional = true }
 
 [features]
 gst-player = ["gstreamer-player"]
@@ -34,6 +37,7 @@ gst-rtsp-server = ["gstreamer-rtsp-server"]
 gst-rtsp-server-record = ["gstreamer-rtsp-server", "gstreamer-rtsp", "gio"]
 default-features = []
 v1_10 = ["gstreamer/v1_10"]
+pango-cairo = ["pango", "pangocairo", "cairo-rs"]
 
 [badges]
 travis-ci = { repository = "sdroege/gstreamer-rs", branch = "master" }
@@ -110,3 +114,7 @@ required-features = ["gst-rtsp-server-record"]
 
 [[bin]]
 name = "discoverer"
+
+[[bin]]
+name = "pango-cairo"
+required-features = ["pango-cairo"]

examples/src/bin/pango-cairo.rs

+extern crate glib;
+
+extern crate gstreamer as gst;
+use gst::prelude::*;
+
+extern crate cairo;
+extern crate gstreamer_video as gst_video;
+extern crate pango;
+use pango::prelude::*;
+extern crate pangocairo;
+
+use std::error::Error as StdError;
+use std::ops;
+use std::sync::{Arc, Mutex};
+
+extern crate failure;
+use failure::Error;
+
+#[macro_use]
+extern crate failure_derive;
+
+#[path = "../examples-common.rs"]
+mod examples_common;
+
+#[derive(Debug, Fail)]
+#[fail(display = "Missing element {}", _0)]
+struct MissingElement(&'static str);
+
+#[derive(Debug, Fail)]
+#[fail(
+    display = "Received error from {}: {} (debug: {:?})",
+    src,
+    error,
+    debug
+)]
+struct ErrorMessage {
+    src: String,
+    error: String,
+    debug: Option<String>,
+    #[cause]
+    cause: glib::Error,
+}
+
+struct DrawingContext {
+    layout: glib::SendUniqueCell<LayoutWrapper>,
+    info: Option<gst_video::VideoInfo>,
+}
+
+#[derive(Debug)]
+struct LayoutWrapper(pango::Layout);
+
+impl ops::Deref for LayoutWrapper {
+    type Target = pango::Layout;
+
+    fn deref(&self) -> &pango::Layout {
+        &self.0
+    }
+}
+
+unsafe impl glib::SendUnique for LayoutWrapper {
+    fn is_unique(&self) -> bool {
+        self.0.ref_count() == 1
+    }
+}
+
+fn create_pipeline() -> Result<gst::Pipeline, Error> {
+    gst::init()?;
+
+    let pipeline = gst::Pipeline::new(None);
+    let src =
+        gst::ElementFactory::make("videotestsrc", None).ok_or(MissingElement("videotestsrc"))?;
+    let overlay =
+        gst::ElementFactory::make("cairooverlay", None).ok_or(MissingElement("cairooverlay"))?;
+    let capsfilter =
+        gst::ElementFactory::make("capsfilter", None).ok_or(MissingElement("capsfilter"))?;
+    let videoconvert =
+        gst::ElementFactory::make("videoconvert", None).ok_or(MissingElement("videoconvert"))?;
+    let sink =
+        gst::ElementFactory::make("autovideosink", None).ok_or(MissingElement("autovideosink"))?;
+
+    pipeline.add_many(&[&src, &overlay, &capsfilter, &videoconvert, &sink])?;
+    gst::Element::link_many(&[&src, &overlay, &capsfilter, &videoconvert, &sink])?;
+
+    let caps = gst::Caps::builder("video/x-raw")
+        .field("width", &800i32)
+        .field("height", &800i32)
+        .build();
+    capsfilter.set_property("caps", &caps).unwrap();
+
+    src.set_property_from_str("pattern", "ball");
+
+    let fontmap = pangocairo::FontMap::new().unwrap();
+    let context = fontmap.create_context().unwrap();
+    let layout = LayoutWrapper(pango::Layout::new(&context));
+
+    let font_desc = pango::FontDescription::from_string("Sans Bold 26");
+    layout.set_font_description(&font_desc);
+    layout.set_text("GStreamer");
+
+    let drawer = Arc::new(Mutex::new(DrawingContext {
+        layout: glib::SendUniqueCell::new(layout).unwrap(),
+        info: None,
+    }));
+
+    let drawer_clone = drawer.clone();
+    overlay
+        .connect("draw", false, move |args| {
+            use std::f64::consts::PI;
+
+            let drawer = &drawer_clone;
+            let drawer = drawer.lock().unwrap();
+
+            let _overlay = args[0].get::<gst::Element>().unwrap();
+            let cr = args[1].get::<cairo::Context>().unwrap();
+            let timestamp = args[2].get::<gst::ClockTime>().unwrap();
+            let _duration = args[3].get::<gst::ClockTime>().unwrap();
+
+            let info = drawer.info.as_ref().unwrap();
+            let layout = drawer.layout.borrow();
+
+            let angle = 2.0
+                * PI
+                * ((timestamp % (10 * gst::SECOND)).unwrap() as f64
+                    / (10.0 * gst::SECOND_VAL as f64));
+
+            cr.translate(info.width() as f64 / 2.0, info.height() as f64 / 2.0);
+            cr.rotate(angle);
+
+            for i in 0..10 {
+                cr.save();
+
+                let angle = (360. * i as f64) / 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);
+
+                pangocairo::functions::update_layout(&cr, &layout);
+                let (width, _height) = layout.get_size();
+                cr.move_to(
+                    -(width as f64 / pango::SCALE as f64) / 2.0,
+                    -(info.height() as f64) / 2.0,
+                );
+                pangocairo::functions::show_layout(&cr, &layout);
+
+                cr.restore();
+            }
+
+            None
+        }).unwrap();
+
+    let drawer_clone = drawer.clone();
+    overlay
+        .connect("caps-changed", false, move |args| {
+            let _overlay = args[0].get::<gst::Element>().unwrap();
+            let caps = args[1].get::<gst::Caps>().unwrap();
+
+            let drawer = &drawer_clone;
+            let mut drawer = drawer.lock().unwrap();
+            drawer.info = Some(gst_video::VideoInfo::from_caps(&caps).unwrap());
+
+            None
+        }).unwrap();
+
+    Ok(pipeline)
+}
+
+fn main_loop(pipeline: gst::Pipeline) -> Result<(), Error> {
+    pipeline.set_state(gst::State::Playing).into_result()?;
+
+    let bus = pipeline
+        .get_bus()
+        .expect("Pipeline without bus. Shouldn't happen!");
+
+    while let Some(msg) = bus.timed_pop(gst::CLOCK_TIME_NONE) {
+        use gst::MessageView;
+
+        match msg.view() {
+            MessageView::Eos(..) => break,
+            MessageView::Error(err) => {
+                pipeline.set_state(gst::State::Null).into_result()?;
+                Err(ErrorMessage {
+                    src: err
+                        .get_src()
+                        .map(|s| s.get_path_string())
+                        .unwrap_or_else(|| String::from("None")),
+                    error: err.get_error().description().into(),
+                    debug: err.get_debug(),
+                    cause: err.get_error(),
+                })?;
+            }
+            _ => (),
+        }
+    }
+
+    pipeline.set_state(gst::State::Null).into_result()?;
+
+    Ok(())
+}
+
+fn example_main() {
+    match create_pipeline().and_then(main_loop) {
+        Ok(r) => r,
+        Err(e) => eprintln!("Error! {}", e),
+    }
+}
+
+fn main() {
+    // tutorials_common::run is only required to set up the application environent on macOS
+    // (but not necessary in normal Cocoa applications where this is set up autmatically)
+    examples_common::run(example_main);
+}