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https://gitlab.freedesktop.org/gstreamer/gstreamer-rs.git
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examples: Add Direct2D/DirectWrite text rendering example
Similar to overlay-composition example but for Direct2D/DirectWrite Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/merge_requests/1206>
This commit is contained in:
Seungha Yang
Sebastian Dröge
parent
85e427345e
commit
6cb19c1f18
2 changed files with 364 additions and 1 deletions
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@ -47,7 +47,7 @@ windows = { version = "0.48", features=["Win32_Graphics_Direct3D11",
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"Win32_Foundation", "Win32_Graphics_Direct3D", "Win32_Graphics_Dxgi",
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"Win32_Graphics_Dxgi_Common", "Win32_Graphics_Direct2D",
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"Win32_Graphics_Direct2D_Common", "Win32_Graphics_DirectWrite",
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"Foundation_Numerics"], optional = true }
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"Win32_Graphics_Imaging", "Win32_System_Com", "Foundation_Numerics"], optional = true }
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[target.'cfg(target_os = "macos")'.dependencies]
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cocoa = "0.24"
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@ -173,6 +173,10 @@ required-features = ["pango-cairo"]
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name = "overlay-composition"
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required-features = ["overlay-composition"]
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[[bin]]
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name = "overlay-composition-d2d"
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required-features = ["windows"]
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[[bin]]
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name = "ges"
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required-features = ["ges"]
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359
examples/src/bin/overlay-composition-d2d.rs
Normal file
359
examples/src/bin/overlay-composition-d2d.rs
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@ -0,0 +1,359 @@
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// This example demonstrates how to draw an overlay on a video stream using
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// Direct2D/DirectWrite/WIC and the overlay composition element.
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// {videotestsrc} - {overlaycomposition} - {capsfilter} - {videoconvert} - {autovideosink}
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// The capsfilter element allows us to dictate the video resolution we want for the
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// videotestsrc and the overlaycomposition element.
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use std::sync::{Arc, Mutex};
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use byte_slice_cast::*;
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use anyhow::Error;
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use derive_more::{Display, Error};
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use gst::prelude::*;
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use windows::{
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Foundation::Numerics::*,
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Win32::{
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Graphics::{
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Direct2D::{Common::*, *},
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DirectWrite::*,
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Dxgi::Common::*,
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Imaging::*,
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},
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System::Com::*,
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},
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};
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#[derive(Debug, Display, Error)]
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#[display(fmt = "Received error from {}: {} (debug: {:?})", src, error, debug)]
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struct ErrorMessage {
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src: glib::GString,
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error: glib::Error,
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debug: Option<glib::GString>,
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}
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struct DrawingContext {
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// Factory for creating render target
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d2d_factory: ID2D1Factory,
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// Used to create WIC bitmap surface
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wic_factory: IWICImagingFactory,
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// text layout holding text information (string, font, size, etc)
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text_layout: IDWriteTextLayout,
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// Holding rendred image
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bitmap: Option<IWICBitmap>,
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// Bound to bitmap and used to actual Direct2D rendering
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render_target: Option<ID2D1RenderTarget>,
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info: Option<gst_video::VideoInfo>,
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}
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// Required for IWICBitmap
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unsafe impl Send for DrawingContext {}
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fn create_pipeline() -> Result<gst::Pipeline, Error> {
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gst::init()?;
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let pipeline = gst::Pipeline::default();
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// The videotestsrc supports multiple test patterns. In this example, we will use the
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// pattern with a white ball moving around the video's center point.
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let src = gst::ElementFactory::make("videotestsrc")
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.property_from_str("pattern", "ball")
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.build()?;
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let overlay = gst::ElementFactory::make("overlaycomposition").build()?;
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let caps = gst_video::VideoCapsBuilder::new()
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.width(800)
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.height(800)
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.framerate((30, 1).into())
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.build();
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let capsfilter = gst::ElementFactory::make("capsfilter")
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.property("caps", &caps)
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.build()?;
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let videoconvert = gst::ElementFactory::make("videoconvert").build()?;
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let sink = gst::ElementFactory::make("autovideosink").build()?;
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pipeline.add_many(&[&src, &overlay, &capsfilter, &videoconvert, &sink])?;
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gst::Element::link_many(&[&src, &overlay, &capsfilter, &videoconvert, &sink])?;
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// Most Direct2D/DirectWrite APIs (including factory methods) are marked as
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// "unsafe", but they shouldn't fail in practice
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let drawer = unsafe {
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let d2d_factory =
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D2D1CreateFactory::<ID2D1Factory>(D2D1_FACTORY_TYPE_MULTI_THREADED, None).unwrap();
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let dwrite_factory =
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DWriteCreateFactory::<IDWriteFactory>(DWRITE_FACTORY_TYPE_SHARED).unwrap();
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let text_format = dwrite_factory
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.CreateTextFormat(
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windows::w!("Arial"),
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None,
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DWRITE_FONT_WEIGHT_BOLD,
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DWRITE_FONT_STYLE_NORMAL,
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DWRITE_FONT_STRETCH_NORMAL,
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32f32,
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windows::w!("en-us"),
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)
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.unwrap();
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let text_layout = dwrite_factory
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.CreateTextLayout(
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windows::w!("GStreamer").as_wide(),
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&text_format,
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// Size will be updated later on "caps-changed" signal
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800f32,
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800f32,
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)
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.unwrap();
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// Top (default) and center alignment
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text_layout
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.SetTextAlignment(DWRITE_TEXT_ALIGNMENT_CENTER)
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.unwrap();
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let wic_factory: IWICImagingFactory =
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CoCreateInstance(&CLSID_WICImagingFactory, None, CLSCTX_ALL).unwrap();
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Arc::new(Mutex::new(DrawingContext {
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d2d_factory,
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wic_factory,
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text_layout,
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bitmap: None,
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render_target: None,
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info: None,
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}))
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};
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overlay.connect_closure(
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"draw",
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false,
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glib::closure!(@strong drawer => move |_overlay: &gst::Element,
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sample: &gst::Sample| {
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use std::f64::consts::PI;
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let drawer = drawer.lock().unwrap();
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let buffer = sample.buffer().unwrap();
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let timestamp = buffer.pts().unwrap();
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let info = drawer.info.as_ref().unwrap();
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let text_layout = &drawer.text_layout;
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let bitmap = drawer.bitmap.as_ref().unwrap();
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let render_target = drawer.render_target.as_ref().unwrap();
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let global_angle = 360. * (timestamp % (10 * gst::ClockTime::SECOND)).nseconds() as f64
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/ (10.0 * gst::ClockTime::SECOND.nseconds() as f64);
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let center_x = (info.width() / 2) as f32;
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let center_y = (info.height() / 2) as f32;
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let top_margin = (info.height() / 20) as f32;
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unsafe {
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// Begin drawing
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render_target.BeginDraw();
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// Clear background
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render_target.Clear(Some(&D2D1_COLOR_F {
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r: 0f32,
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g: 0f32,
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b: 0f32,
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a: 0f32,
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}));
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// This loop will render 10 times the string "GStreamer" in a circle
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for i in 0..10 {
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let angle = (360. * f64::from(i)) / 10.0;
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let red = ((1.0 + f64::cos((angle - 60.0) * PI / 180.0)) / 2.0) as f32;
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let text_brush = render_target
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.CreateSolidColorBrush(
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&D2D1_COLOR_F {
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r: red,
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g: 0f32,
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b: 1f32 - red,
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a: 1f32,
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},
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None,
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)
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.unwrap();
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let angle = (angle + global_angle) as f32;
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let matrix = Matrix3x2::rotation(angle, center_x, center_y);
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render_target.SetTransform(&matrix);
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render_target.DrawTextLayout(
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D2D_POINT_2F { x: 0f32, y: top_margin },
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text_layout,
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&text_brush,
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D2D1_DRAW_TEXT_OPTIONS_NONE,
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);
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}
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// EndDraw may not be successful for some reasons.
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// Ignores any error in this example
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let _ = render_target.EndDraw(None, None);
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// Make sure all operations is completed before copying
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// bitmap to buffer
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let _ = render_target.Flush(None::<*mut u64>, None::<*mut u64>);
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}
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let mut buffer = gst::Buffer::with_size((info.width() * info.height() * 4) as usize).unwrap();
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{
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let buffer_mut = buffer.get_mut().unwrap();
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let mut map = buffer_mut.map_writable().unwrap();
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let dst = map.as_mut_slice_of::<u8>().unwrap();
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unsafe {
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// Bitmap size is equal to the background image size.
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// Copy entire memory
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bitmap.CopyPixels(std::ptr::null(), info.width() * 4, dst).unwrap();
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}
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}
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gst_video::VideoMeta::add_full(
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buffer.get_mut().unwrap(),
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gst_video::VideoFrameFlags::empty(),
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gst_video::VideoFormat::Bgra,
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info.width(),
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info.height(),
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&[0],
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&[(info.width() * 4) as i32],
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)
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.unwrap();
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// Turn the buffer into a VideoOverlayRectangle, then place
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// that into a VideoOverlayComposition and return it.
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//
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// A VideoOverlayComposition can take a Vec of such rectangles
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// spaced around the video frame, but we're just outputting 1
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// here
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let rect = gst_video::VideoOverlayRectangle::new_raw(
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&buffer,
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0,
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0,
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info.width(),
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info.height(),
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gst_video::VideoOverlayFormatFlags::PREMULTIPLIED_ALPHA,
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);
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gst_video::VideoOverlayComposition::new(Some(&rect))
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.unwrap()
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}),
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);
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// Add a signal handler to the overlay's "caps-changed" signal. This could e.g.
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// be called when the sink that we render to does not support resizing the image
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// itself - but the user just changed the window-size. The element after the overlay
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// will then change its caps and we use the notification about this change to
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// resize our canvas's size.
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// Another possibility for when this might happen is, when our video is a network
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// stream that dynamically changes resolution when enough bandwith is available.
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overlay.connect_closure(
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"caps-changed",
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false,
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glib::closure!(move |_overlay: &gst::Element,
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caps: &gst::Caps,
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_width: u32,
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_height: u32| {
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let mut drawer = drawer.lock().unwrap();
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let info = gst_video::VideoInfo::from_caps(caps).unwrap();
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unsafe {
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// Update text layout to be identical to new video resolution
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drawer.text_layout.SetMaxWidth(info.width() as f32).unwrap();
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drawer
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.text_layout
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.SetMaxHeight(info.height() as f32)
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.unwrap();
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// Create new WIC bitmap with PBGRA format (pre-multiplied BGRA)
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let bitmap = drawer
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.wic_factory
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.CreateBitmap(
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info.width(),
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info.height(),
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&GUID_WICPixelFormat32bppPBGRA,
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WICBitmapCacheOnDemand,
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)
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.unwrap();
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let render_target = drawer
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.d2d_factory
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.CreateWicBitmapRenderTarget(
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&bitmap,
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&D2D1_RENDER_TARGET_PROPERTIES {
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r#type: D2D1_RENDER_TARGET_TYPE_DEFAULT,
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pixelFormat: D2D1_PIXEL_FORMAT {
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format: DXGI_FORMAT_B8G8R8A8_UNORM,
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alphaMode: D2D1_ALPHA_MODE_PREMULTIPLIED,
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},
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// zero means default DPI
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dpiX: 0f32,
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dpiY: 0f32,
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usage: D2D1_RENDER_TARGET_USAGE_NONE,
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minLevel: D2D1_FEATURE_LEVEL_DEFAULT,
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},
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)
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.unwrap();
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drawer.render_target = Some(render_target);
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drawer.bitmap = Some(bitmap);
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}
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drawer.info = Some(info);
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}),
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);
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Ok(pipeline)
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}
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fn main_loop(pipeline: gst::Pipeline) -> Result<(), Error> {
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pipeline.set_state(gst::State::Playing)?;
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let bus = pipeline
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.bus()
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.expect("Pipeline without bus. Shouldn't happen!");
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for msg in bus.iter_timed(gst::ClockTime::NONE) {
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use gst::MessageView;
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match msg.view() {
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MessageView::Eos(..) => break,
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MessageView::Error(err) => {
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pipeline.set_state(gst::State::Null)?;
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return Err(ErrorMessage {
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src: msg
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.src()
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.map(|s| s.path_string())
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.unwrap_or_else(|| glib::GString::from("UNKNOWN")),
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error: err.error(),
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debug: err.debug(),
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}
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.into());
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}
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_ => (),
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}
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}
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pipeline.set_state(gst::State::Null)?;
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Ok(())
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}
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fn main() {
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// WIC requires COM initialization
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unsafe {
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CoInitializeEx(None, COINIT_MULTITHREADED).unwrap();
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}
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match create_pipeline().and_then(main_loop) {
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Ok(r) => r,
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Err(e) => eprintln!("Error! {}", e),
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}
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unsafe {
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CoUninitialize();
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}
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}
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