Struct pixel_game_lib::canvas::Canvas

pub struct Canvas<'a> { /* private fields */ }

Simple wrapper around a pixel buffer that can be passed around to rendering calls.

Implementations

impl<'a> Canvas<'a>

pub fn set_pixel(&mut self, position: Vec2<f64>, color: u32)

Set a pixel on the buffer at the coordinate passed.

If the coordinate is out of bounds nothing will be done.

This is quite a slow operation because it needs to calculate the index of the coordinate, if setting multiple pixels it might be more efficient to create a sprite from them.

Examples found in repository

examples/draw.rs (line 68)

fn main() {
    // Window configuration with huge pixels
    let window_config = WindowConfig {
        buffer_size: Extent2::new(64, 64),
        scaling: 8,
        ..Default::default()
    };

    // Open the window and start the game-loop
    pixel_game_lib::window(
        // Keep track of the mouse as our "game state"
        Vec2::zero(),
        window_config.clone(),
        // Update loop exposing input events we can handle, this is where you would handle the game logic
        |state, input, mouse, _dt| {
            // Set the mouse position as the game state
            if let Some(mouse) = mouse {
                *state = mouse;
            }

            // Exit when escape is pressed
            input.key_pressed(KeyCode::Escape)
        },
        // Render loop exposing the pixel buffer we can mutate
        move |mouse, canvas, _dt| {
            // Reset the canvas with a white color
            canvas.fill(0xFFFFFFFF);

            // Draw a gray circle with the radius being the distance of the center to the mouse
            let circle_center = Vec2::new(50.0, 50.0);
            let dist_from_mouse = mouse.as_().distance(circle_center);
            canvas.draw_circle(Disk::new(circle_center, dist_from_mouse), 0xFF999999);
            // Draw a darker gray circle outline on top of the circle
            canvas.draw_circle_outline(Disk::new(circle_center, dist_from_mouse), 0xFF333333);

            // Draw a light green blue triangle with one corner being snapped to the mouse
            canvas.draw_triangle(
                [Vec2::new(45.0, 5.0), Vec2::new(60.0, 8.0), mouse.as_()],
                0xFF99FF99,
            );

            // Draw a light blue quadrilateral with one corner being snapped to the mouse
            canvas.draw_quad(
                [
                    Vec2::new(5.0, 5.0),
                    Vec2::new(20.0, 8.0),
                    Vec2::new(8.0, 30.0),
                    mouse.as_(),
                ],
                0xFF9999FF,
            );

            // Draw a black line from the center of the canvas to our mouse
            canvas.draw_line(
                (window_config.buffer_size.as_() / 2.0).into(),
                mouse.as_(),
                0xFF000000,
            );

            // Draw a red pixel under the mouse
            canvas.set_pixel(mouse.as_(), 0xFFFF0000);
        },
    )
    .expect("Error opening window");
}

pub fn draw_line(&mut self, start: Vec2<f64>, end: Vec2<f64>, color: u32)

Draw a line using Bresenham’s line algorithm.

Examples found in repository

examples/draw.rs (lines 61-65)

fn main() {
    // Window configuration with huge pixels
    let window_config = WindowConfig {
        buffer_size: Extent2::new(64, 64),
        scaling: 8,
        ..Default::default()
    };

    // Open the window and start the game-loop
    pixel_game_lib::window(
        // Keep track of the mouse as our "game state"
        Vec2::zero(),
        window_config.clone(),
        // Update loop exposing input events we can handle, this is where you would handle the game logic
        |state, input, mouse, _dt| {
            // Set the mouse position as the game state
            if let Some(mouse) = mouse {
                *state = mouse;
            }

            // Exit when escape is pressed
            input.key_pressed(KeyCode::Escape)
        },
        // Render loop exposing the pixel buffer we can mutate
        move |mouse, canvas, _dt| {
            // Reset the canvas with a white color
            canvas.fill(0xFFFFFFFF);

            // Draw a gray circle with the radius being the distance of the center to the mouse
            let circle_center = Vec2::new(50.0, 50.0);
            let dist_from_mouse = mouse.as_().distance(circle_center);
            canvas.draw_circle(Disk::new(circle_center, dist_from_mouse), 0xFF999999);
            // Draw a darker gray circle outline on top of the circle
            canvas.draw_circle_outline(Disk::new(circle_center, dist_from_mouse), 0xFF333333);

            // Draw a light green blue triangle with one corner being snapped to the mouse
            canvas.draw_triangle(
                [Vec2::new(45.0, 5.0), Vec2::new(60.0, 8.0), mouse.as_()],
                0xFF99FF99,
            );

            // Draw a light blue quadrilateral with one corner being snapped to the mouse
            canvas.draw_quad(
                [
                    Vec2::new(5.0, 5.0),
                    Vec2::new(20.0, 8.0),
                    Vec2::new(8.0, 30.0),
                    mouse.as_(),
                ],
                0xFF9999FF,
            );

            // Draw a black line from the center of the canvas to our mouse
            canvas.draw_line(
                (window_config.buffer_size.as_() / 2.0).into(),
                mouse.as_(),
                0xFF000000,
            );

            // Draw a red pixel under the mouse
            canvas.set_pixel(mouse.as_(), 0xFFFF0000);
        },
    )
    .expect("Error opening window");
}

pub fn draw_scanline(&mut self, y: usize, x: Range<usize>, color: u32)

Fill a horizontal line, very cheap operation.

pub fn draw_circle_outline(&mut self, circle: Disk<f64, f64>, color: u32)

Draw a circle using Bresenham’s circle algorithm.

Examples found in repository

examples/draw.rs (line 41)

fn main() {
    // Window configuration with huge pixels
    let window_config = WindowConfig {
        buffer_size: Extent2::new(64, 64),
        scaling: 8,
        ..Default::default()
    };

    // Open the window and start the game-loop
    pixel_game_lib::window(
        // Keep track of the mouse as our "game state"
        Vec2::zero(),
        window_config.clone(),
        // Update loop exposing input events we can handle, this is where you would handle the game logic
        |state, input, mouse, _dt| {
            // Set the mouse position as the game state
            if let Some(mouse) = mouse {
                *state = mouse;
            }

            // Exit when escape is pressed
            input.key_pressed(KeyCode::Escape)
        },
        // Render loop exposing the pixel buffer we can mutate
        move |mouse, canvas, _dt| {
            // Reset the canvas with a white color
            canvas.fill(0xFFFFFFFF);

            // Draw a gray circle with the radius being the distance of the center to the mouse
            let circle_center = Vec2::new(50.0, 50.0);
            let dist_from_mouse = mouse.as_().distance(circle_center);
            canvas.draw_circle(Disk::new(circle_center, dist_from_mouse), 0xFF999999);
            // Draw a darker gray circle outline on top of the circle
            canvas.draw_circle_outline(Disk::new(circle_center, dist_from_mouse), 0xFF333333);

            // Draw a light green blue triangle with one corner being snapped to the mouse
            canvas.draw_triangle(
                [Vec2::new(45.0, 5.0), Vec2::new(60.0, 8.0), mouse.as_()],
                0xFF99FF99,
            );

            // Draw a light blue quadrilateral with one corner being snapped to the mouse
            canvas.draw_quad(
                [
                    Vec2::new(5.0, 5.0),
                    Vec2::new(20.0, 8.0),
                    Vec2::new(8.0, 30.0),
                    mouse.as_(),
                ],
                0xFF9999FF,
            );

            // Draw a black line from the center of the canvas to our mouse
            canvas.draw_line(
                (window_config.buffer_size.as_() / 2.0).into(),
                mouse.as_(),
                0xFF000000,
            );

            // Draw a red pixel under the mouse
            canvas.set_pixel(mouse.as_(), 0xFFFF0000);
        },
    )
    .expect("Error opening window");
}

pub fn draw_circle(&mut self, circle: Disk<f64, f64>, color: u32)

Fill a circle using Bresenham’s circle algorithm.

Based on: https://funloop.org/post/2021-03-15-bresenham-circle-drawing-algorithm.html

Examples found in repository

examples/draw.rs (line 39)

fn main() {
    // Window configuration with huge pixels
    let window_config = WindowConfig {
        buffer_size: Extent2::new(64, 64),
        scaling: 8,
        ..Default::default()
    };

    // Open the window and start the game-loop
    pixel_game_lib::window(
        // Keep track of the mouse as our "game state"
        Vec2::zero(),
        window_config.clone(),
        // Update loop exposing input events we can handle, this is where you would handle the game logic
        |state, input, mouse, _dt| {
            // Set the mouse position as the game state
            if let Some(mouse) = mouse {
                *state = mouse;
            }

            // Exit when escape is pressed
            input.key_pressed(KeyCode::Escape)
        },
        // Render loop exposing the pixel buffer we can mutate
        move |mouse, canvas, _dt| {
            // Reset the canvas with a white color
            canvas.fill(0xFFFFFFFF);

            // Draw a gray circle with the radius being the distance of the center to the mouse
            let circle_center = Vec2::new(50.0, 50.0);
            let dist_from_mouse = mouse.as_().distance(circle_center);
            canvas.draw_circle(Disk::new(circle_center, dist_from_mouse), 0xFF999999);
            // Draw a darker gray circle outline on top of the circle
            canvas.draw_circle_outline(Disk::new(circle_center, dist_from_mouse), 0xFF333333);

            // Draw a light green blue triangle with one corner being snapped to the mouse
            canvas.draw_triangle(
                [Vec2::new(45.0, 5.0), Vec2::new(60.0, 8.0), mouse.as_()],
                0xFF99FF99,
            );

            // Draw a light blue quadrilateral with one corner being snapped to the mouse
            canvas.draw_quad(
                [
                    Vec2::new(5.0, 5.0),
                    Vec2::new(20.0, 8.0),
                    Vec2::new(8.0, 30.0),
                    mouse.as_(),
                ],
                0xFF9999FF,
            );

            // Draw a black line from the center of the canvas to our mouse
            canvas.draw_line(
                (window_config.buffer_size.as_() / 2.0).into(),
                mouse.as_(),
                0xFF000000,
            );

            // Draw a red pixel under the mouse
            canvas.set_pixel(mouse.as_(), 0xFFFF0000);
        },
    )
    .expect("Error opening window");
}

pub fn draw_triangle(&mut self, corners: [Vec2<f64>; 3], color: u32)

Fill a triangle.

Based on: https://joshbeam.com/articles/triangle_rasterization/

Examples found in repository

examples/draw.rs (lines 44-47)

fn main() {
    // Window configuration with huge pixels
    let window_config = WindowConfig {
        buffer_size: Extent2::new(64, 64),
        scaling: 8,
        ..Default::default()
    };

    // Open the window and start the game-loop
    pixel_game_lib::window(
        // Keep track of the mouse as our "game state"
        Vec2::zero(),
        window_config.clone(),
        // Update loop exposing input events we can handle, this is where you would handle the game logic
        |state, input, mouse, _dt| {
            // Set the mouse position as the game state
            if let Some(mouse) = mouse {
                *state = mouse;
            }

            // Exit when escape is pressed
            input.key_pressed(KeyCode::Escape)
        },
        // Render loop exposing the pixel buffer we can mutate
        move |mouse, canvas, _dt| {
            // Reset the canvas with a white color
            canvas.fill(0xFFFFFFFF);

            // Draw a gray circle with the radius being the distance of the center to the mouse
            let circle_center = Vec2::new(50.0, 50.0);
            let dist_from_mouse = mouse.as_().distance(circle_center);
            canvas.draw_circle(Disk::new(circle_center, dist_from_mouse), 0xFF999999);
            // Draw a darker gray circle outline on top of the circle
            canvas.draw_circle_outline(Disk::new(circle_center, dist_from_mouse), 0xFF333333);

            // Draw a light green blue triangle with one corner being snapped to the mouse
            canvas.draw_triangle(
                [Vec2::new(45.0, 5.0), Vec2::new(60.0, 8.0), mouse.as_()],
                0xFF99FF99,
            );

            // Draw a light blue quadrilateral with one corner being snapped to the mouse
            canvas.draw_quad(
                [
                    Vec2::new(5.0, 5.0),
                    Vec2::new(20.0, 8.0),
                    Vec2::new(8.0, 30.0),
                    mouse.as_(),
                ],
                0xFF9999FF,
            );

            // Draw a black line from the center of the canvas to our mouse
            canvas.draw_line(
                (window_config.buffer_size.as_() / 2.0).into(),
                mouse.as_(),
                0xFF000000,
            );

            // Draw a red pixel under the mouse
            canvas.set_pixel(mouse.as_(), 0xFFFF0000);
        },
    )
    .expect("Error opening window");
}

pub fn draw_quad(&mut self, corners: [Vec2<f64>; 4], color: u32)

Fill a polygon with 4 corners.

If any of the 4 points falls inside the triangle of the other three only a single triangle will be drawn.

Based on: https://stackoverflow.com/a/2122620

Examples found in repository

examples/draw.rs (lines 50-58)

fn main() {
    // Window configuration with huge pixels
    let window_config = WindowConfig {
        buffer_size: Extent2::new(64, 64),
        scaling: 8,
        ..Default::default()
    };

    // Open the window and start the game-loop
    pixel_game_lib::window(
        // Keep track of the mouse as our "game state"
        Vec2::zero(),
        window_config.clone(),
        // Update loop exposing input events we can handle, this is where you would handle the game logic
        |state, input, mouse, _dt| {
            // Set the mouse position as the game state
            if let Some(mouse) = mouse {
                *state = mouse;
            }

            // Exit when escape is pressed
            input.key_pressed(KeyCode::Escape)
        },
        // Render loop exposing the pixel buffer we can mutate
        move |mouse, canvas, _dt| {
            // Reset the canvas with a white color
            canvas.fill(0xFFFFFFFF);

            // Draw a gray circle with the radius being the distance of the center to the mouse
            let circle_center = Vec2::new(50.0, 50.0);
            let dist_from_mouse = mouse.as_().distance(circle_center);
            canvas.draw_circle(Disk::new(circle_center, dist_from_mouse), 0xFF999999);
            // Draw a darker gray circle outline on top of the circle
            canvas.draw_circle_outline(Disk::new(circle_center, dist_from_mouse), 0xFF333333);

            // Draw a light green blue triangle with one corner being snapped to the mouse
            canvas.draw_triangle(
                [Vec2::new(45.0, 5.0), Vec2::new(60.0, 8.0), mouse.as_()],
                0xFF99FF99,
            );

            // Draw a light blue quadrilateral with one corner being snapped to the mouse
            canvas.draw_quad(
                [
                    Vec2::new(5.0, 5.0),
                    Vec2::new(20.0, 8.0),
                    Vec2::new(8.0, 30.0),
                    mouse.as_(),
                ],
                0xFF9999FF,
            );

            // Draw a black line from the center of the canvas to our mouse
            canvas.draw_line(
                (window_config.buffer_size.as_() / 2.0).into(),
                mouse.as_(),
                0xFF000000,
            );

            // Draw a red pixel under the mouse
            canvas.set_pixel(mouse.as_(), 0xFFFF0000);
        },
    )
    .expect("Error opening window");
}

pub fn fill(&mut self, color: u32)

Fill the canvas with a single color.

Examples found in repository

examples/window.rs (line 32)

    fn render(&mut self, canvas: &mut Canvas<'_>) {
        // Fill the window with a background color, if we don't fill it the pixels of the last frame will be drawn again
        canvas.fill(0xFFFFFFFF);

        // Ensure that we don't draw pixels outside of the canvas
        let max_pixels_to_draw = canvas.size().product();
        let pixels_to_draw = self.pixels_to_draw.min(max_pixels_to_draw);

        // Draw a red color for each pixel
        canvas.raw_buffer()[0..pixels_to_draw].fill(0xFFFF0000);
    }

examples/draw.rs (line 34)

fn main() {
    // Window configuration with huge pixels
    let window_config = WindowConfig {
        buffer_size: Extent2::new(64, 64),
        scaling: 8,
        ..Default::default()
    };

    // Open the window and start the game-loop
    pixel_game_lib::window(
        // Keep track of the mouse as our "game state"
        Vec2::zero(),
        window_config.clone(),
        // Update loop exposing input events we can handle, this is where you would handle the game logic
        |state, input, mouse, _dt| {
            // Set the mouse position as the game state
            if let Some(mouse) = mouse {
                *state = mouse;
            }

            // Exit when escape is pressed
            input.key_pressed(KeyCode::Escape)
        },
        // Render loop exposing the pixel buffer we can mutate
        move |mouse, canvas, _dt| {
            // Reset the canvas with a white color
            canvas.fill(0xFFFFFFFF);

            // Draw a gray circle with the radius being the distance of the center to the mouse
            let circle_center = Vec2::new(50.0, 50.0);
            let dist_from_mouse = mouse.as_().distance(circle_center);
            canvas.draw_circle(Disk::new(circle_center, dist_from_mouse), 0xFF999999);
            // Draw a darker gray circle outline on top of the circle
            canvas.draw_circle_outline(Disk::new(circle_center, dist_from_mouse), 0xFF333333);

            // Draw a light green blue triangle with one corner being snapped to the mouse
            canvas.draw_triangle(
                [Vec2::new(45.0, 5.0), Vec2::new(60.0, 8.0), mouse.as_()],
                0xFF99FF99,
            );

            // Draw a light blue quadrilateral with one corner being snapped to the mouse
            canvas.draw_quad(
                [
                    Vec2::new(5.0, 5.0),
                    Vec2::new(20.0, 8.0),
                    Vec2::new(8.0, 30.0),
                    mouse.as_(),
                ],
                0xFF9999FF,
            );

            // Draw a black line from the center of the canvas to our mouse
            canvas.draw_line(
                (window_config.buffer_size.as_() / 2.0).into(),
                mouse.as_(),
                0xFF000000,
            );

            // Draw a red pixel under the mouse
            canvas.set_pixel(mouse.as_(), 0xFFFF0000);
        },
    )
    .expect("Error opening window");
}

pub fn raw_buffer(&mut self) -> &mut [u32]

Get the raw buffer of pixels.

Examples found in repository

examples/window.rs (line 39)

    fn render(&mut self, canvas: &mut Canvas<'_>) {
        // Fill the window with a background color, if we don't fill it the pixels of the last frame will be drawn again
        canvas.fill(0xFFFFFFFF);

        // Ensure that we don't draw pixels outside of the canvas
        let max_pixels_to_draw = canvas.size().product();
        let pixels_to_draw = self.pixels_to_draw.min(max_pixels_to_draw);

        // Draw a red color for each pixel
        canvas.raw_buffer()[0..pixels_to_draw].fill(0xFFFF0000);
    }

pub fn width(&self) -> usize

Width in pixels.

pub fn height(&self) -> usize

Height in pixels.

pub fn size(&self) -> Extent2<usize>

Size in pixels.

Examples found in repository

examples/window.rs (line 35)

    fn render(&mut self, canvas: &mut Canvas<'_>) {
        // Fill the window with a background color, if we don't fill it the pixels of the last frame will be drawn again
        canvas.fill(0xFFFFFFFF);

        // Ensure that we don't draw pixels outside of the canvas
        let max_pixels_to_draw = canvas.size().product();
        let pixels_to_draw = self.pixels_to_draw.min(max_pixels_to_draw);

        // Draw a red color for each pixel
        canvas.raw_buffer()[0..pixels_to_draw].fill(0xFFFF0000);
    }