Vendor things

third-party/vendor/png/examples/show.rs

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+use glium::{
+    backend::glutin::Display,
+    glutin::{
+        self, dpi,
+        event::{ElementState, Event, KeyboardInput, VirtualKeyCode, WindowEvent},
+        event_loop::ControlFlow,
+    },
+    texture::{ClientFormat, RawImage2d},
+    BlitTarget, Rect, Surface,
+};
+use std::{borrow::Cow, env, fs::File, io, path};
+
+/// Load the image using `png`
+fn load_image(path: &path::PathBuf) -> io::Result<RawImage2d<'static, u8>> {
+    use png::ColorType::*;
+    let mut decoder = png::Decoder::new(File::open(path)?);
+    decoder.set_transformations(png::Transformations::normalize_to_color8());
+    let mut reader = decoder.read_info()?;
+    let mut img_data = vec![0; reader.output_buffer_size()];
+    let info = reader.next_frame(&mut img_data)?;
+
+    let (data, format) = match info.color_type {
+        Rgb => (img_data, ClientFormat::U8U8U8),
+        Rgba => (img_data, ClientFormat::U8U8U8U8),
+        Grayscale => (
+            {
+                let mut vec = Vec::with_capacity(img_data.len() * 3);
+                for g in img_data {
+                    vec.extend([g, g, g].iter().cloned())
+                }
+                vec
+            },
+            ClientFormat::U8U8U8,
+        ),
+        GrayscaleAlpha => (
+            {
+                let mut vec = Vec::with_capacity(img_data.len() * 3);
+                for ga in img_data.chunks(2) {
+                    let g = ga[0];
+                    let a = ga[1];
+                    vec.extend([g, g, g, a].iter().cloned())
+                }
+                vec
+            },
+            ClientFormat::U8U8U8U8,
+        ),
+        _ => unreachable!("uncovered color type"),
+    };
+
+    Ok(RawImage2d {
+        data: Cow::Owned(data),
+        width: info.width,
+        height: info.height,
+        format,
+    })
+}
+
+fn main_loop(files: Vec<path::PathBuf>) -> io::Result<()> {
+    let mut files = files.into_iter();
+    let image = load_image(&files.next().unwrap())?;
+
+    let event_loop = glutin::event_loop::EventLoop::new();
+    let window_builder = glutin::window::WindowBuilder::new().with_title("Show Example");
+    let context_builder = glutin::ContextBuilder::new().with_vsync(true);
+    let display = glium::Display::new(window_builder, context_builder, &event_loop)
+        .map_err(|err| io::Error::new(io::ErrorKind::Other, err))?;
+    resize_window(&display, &image);
+    let mut texture = glium::Texture2d::new(&display, image).unwrap();
+    draw(&display, &texture);
+
+    event_loop.run(move |event, _, control_flow| match event {
+        Event::WindowEvent {
+            event: WindowEvent::CloseRequested,
+            ..
+        } => exit(control_flow),
+        Event::WindowEvent {
+            event:
+                WindowEvent::KeyboardInput {
+                    input:
+                        KeyboardInput {
+                            state: ElementState::Pressed,
+                            virtual_keycode: code,
+                            ..
+                        },
+                    ..
+                },
+            ..
+        } => match code {
+            Some(VirtualKeyCode::Escape) => exit(control_flow),
+            Some(VirtualKeyCode::Right) => match &files.next() {
+                Some(path) => {
+                    match load_image(path) {
+                        Ok(image) => {
+                            resize_window(&display, &image);
+                            texture = glium::Texture2d::new(&display, image).unwrap();
+                            draw(&display, &texture);
+                        }
+                        Err(err) => {
+                            println!("Error: {}", err);
+                            exit(control_flow);
+                        }
+                    };
+                }
+                None => exit(control_flow),
+            },
+            _ => {}
+        },
+        Event::RedrawRequested(_) => draw(&display, &texture),
+        _ => {}
+    });
+}
+
+fn draw(display: &glium::Display, texture: &glium::Texture2d) {
+    let frame = display.draw();
+    fill_v_flipped(
+        &texture.as_surface(),
+        &frame,
+        glium::uniforms::MagnifySamplerFilter::Linear,
+    );
+    frame.finish().unwrap();
+}
+
+fn exit(control_flow: &mut ControlFlow) {
+    *control_flow = ControlFlow::Exit;
+}
+
+fn fill_v_flipped<S1, S2>(src: &S1, target: &S2, filter: glium::uniforms::MagnifySamplerFilter)
+where
+    S1: Surface,
+    S2: Surface,
+{
+    let src_dim = src.get_dimensions();
+    let src_rect = Rect {
+        left: 0,
+        bottom: 0,
+        width: src_dim.0,
+        height: src_dim.1,
+    };
+    let target_dim = target.get_dimensions();
+    let target_rect = BlitTarget {
+        left: 0,
+        bottom: target_dim.1,
+        width: target_dim.0 as i32,
+        height: -(target_dim.1 as i32),
+    };
+    src.blit_color(&src_rect, target, &target_rect, filter);
+}
+
+fn resize_window(display: &Display, image: &RawImage2d<'static, u8>) {
+    let mut width = image.width;
+    let mut height = image.height;
+    if width < 50 && height < 50 {
+        width *= 10;
+        height *= 10;
+    }
+    display
+        .gl_window()
+        .window()
+        .set_inner_size(dpi::LogicalSize::new(f64::from(width), f64::from(height)));
+}
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+    if args.len() < 2 {
+        println!("Usage: show files [...]");
+    } else {
+        let mut files = vec![];
+        for file in args.iter().skip(1) {
+            match if file.contains('*') {
+                (|| -> io::Result<_> {
+                    for entry in glob::glob(file)
+                        .map_err(|err| io::Error::new(io::ErrorKind::Other, err.msg))?
+                    {
+                        files.push(
+                            entry
+                                .map_err(|_| io::Error::new(io::ErrorKind::Other, "glob error"))?,
+                        )
+                    }
+                    Ok(())
+                })()
+            } else {
+                files.push(path::PathBuf::from(file));
+                Ok(())
+            } {
+                Ok(_) => (),
+                Err(err) => {
+                    println!("{}: {}", file, err);
+                    break;
+                }
+            }
+        }
+        // "tests/pngsuite/pngsuite.png"
+        match main_loop(files) {
+            Ok(_) => (),
+            Err(err) => println!("Error: {}", err),
+        }
+    }
+}