Crate ferrux_viewport

Ferrux Viewport is an abstraction layer over the Pixels crate. It manages the pixel buffer exposing simple operations to draw pixels, lines and figures of one color in the screen. In its current state it only works with Winit.

It is a new iteration and twist over my previous library Ferrux Canvas. This one works with coordinates on a [-1.0, 1.0] 3D space which makes the drawing easier as it can work with normalized vectors and allows the use of layers based on the depth without previous check from the user.

Building a new viewport

The Viewport requires a Window of winit, which will need itself an EventLoop reference.

let event_loop = winit::event_loop::EventLoop::new();
let window = winit::window::Window::new(&event_loop)?;
let viewport = ferrux_viewport::viewport::ViewportFactory::winit(&window, 100)?;

Running the viewport

The main flow to use the viewport is:

• Use the drawing functions like draw_line and draw_triangle.
• Call the render method to print it on screen.
• Use reset to clear the current buffer and draw a new frame.

The following example takes the Viewport we built and draws a red morphing triangle.

let mut i = 0.0;
let step = 0.05;
let mut incrementing = true;
 
event_loop.run(move |event, _, control_flow| {
  match event {
    Event::MainEventsCleared => {
        i += if incrementing { step } else { -step };
        if i >= 1.0 { incrementing = false } else if i <= 0.0 { incrementing = true }
        window.request_redraw();
    }
    Event::RedrawRequested(_) => {
      viewport.fill_triangle((0.0, 0.0, -0.1), (0.0 + i, -0.5 * i/2.0, -0.2), (0.0 + i, -0.3 * i/2.0, -0.2), 
        &[255, 0, 0, 255]);
      viewport.render().expect("render failed");
      viewport.reset_buffer();
    }
    _ => (),
  }
});

Coloring

All the library drawing operations request a color in the form of a &[u8; 4] (RGBA). This allows the library to be compatible with the different color crates (in the examples we use the rgb crate).

The array dimmension is not enforced at compilation time but a panic will be thrown if the provided value is not of length four. But this can probably change in the future, allowing to provide just RGB or single channels.

Even if we request the alpha, the crate currently DOES NOT have transparency as you expect it. You can use the alpha to play with the colors but they will always be mixed with the black background, not with whatever color could be behind.

Modules

error

Package with the errors that can occur using the library

render

Contains the logic the operate with the different library options

viewport

Package containing the viewport logic

Traits

PixelSize

Trait to englobe unsigned integers to use as PixelSize in the Viewport construcion