image example

[aeosynth]

can we have an example showing how to display an image (say, the rust logo) with this library?

[tversteeg]

I've created a library to do just that.

[emoon]

Yeah including such example would be easy. @tversteeg library seems handy as well but it might be a good idea to just include a very basic one that opens an image and displays it.

[tversteeg]

Here is a trait for drawing a RgbImage from the image library (got this from my library):

use image::*;

pub trait DrawExt {
    fn draw_to_buffer(&self, dst: &mut [u32], dst_width: usize, offset: (i32, i32));
}

impl DrawExt for RgbImage {
    fn draw_to_buffer(&self, dst: &mut [u32], dst_width: usize, offset: (i32, i32)) {
        let dst_size = (dst_width as i32, (dst.len() / dst_width) as i32);

        let (width, height) = self.dimensions();

        // Make sure only the pixels get rendered that are inside the dst
        let min_x = cmp::max(-offset.0, 0);
        let min_y = cmp::max(-offset.1, 0);

        let max_x = cmp::min(dst_size.0 - offset.0, width as i32);
        let max_y = cmp::min(dst_size.1 - offset.1, height as i32);

        for y in min_y..max_y {
            for x in min_x..max_x {
                let pixel = self.get_pixel(x as u32, y as u32).data;

                // Convert pixel to Color
                let raw = 0xFF000000 | ((pixel[0] as u32) << 16) | ((pixel[1] as u32) << 8) | (pixel[2] as u32);

                // Apply the offsets
                let dst_x = (x + offset.0) as usize;
                let dst_y = (y + offset.1) as usize;

                // Calculate the index
                let index = dst_x + dst_y * dst_size.0 as usize;
                dst[index] = raw.u32();
            }
        }
    }
}

const WIDTH: usize = 250;
const HEIGHT: usize = 250;

fn main() {
    let mut buffer: Vec<u32> = vec![0x00FFFFFF; WIDTH * HEIGHT];

    let img = image::open("img.png").unwrap();
    let rgb = img.as_rgb8().unwrap();

    rgb.draw_to_buffer(&mut buffer, WIDTH, (0, 0));
}

[emoon]

Cool. Thanks!

[aeosynth]

thanks, this is what I came up with combining @tversteeg's example and the minifb example:

extern crate image;
extern crate minifb;

use std::cmp;
use image::*;
use minifb::{Key, WindowOptions, Window};

pub trait DrawExt {
    fn draw_to_buffer(&self, dst: &mut [u32], dst_width: usize, offset: (i32, i32));
}

impl DrawExt for RgbImage {
    fn draw_to_buffer(&self, dst: &mut [u32], dst_width: usize, offset: (i32, i32)) {
        let dst_size = (dst_width as i32, (dst.len() / dst_width) as i32);

        let (width, height) = self.dimensions();

        // Make sure only the pixels get rendered that are inside the dst
        let min_x = cmp::max(-offset.0, 0);
        let min_y = cmp::max(-offset.1, 0);

        let max_x = cmp::min(dst_size.0 - offset.0, width as i32);
        let max_y = cmp::min(dst_size.1 - offset.1, height as i32);

        for y in min_y..max_y {
            for x in min_x..max_x {
                let pixel = self.get_pixel(x as u32, y as u32).data;

                // Convert pixel to Color
                let raw = 0xFF000000 | ((pixel[0] as u32) << 16) | ((pixel[1] as u32) << 8) | (pixel[2] as u32);

                // Apply the offsets
                let dst_x = (x + offset.0) as usize;
                let dst_y = (y + offset.1) as usize;

                // Calculate the index
                let index = dst_x + dst_y * dst_size.0 as usize;
                dst[index] = raw;
            }
        }
    }
}

const WIDTH: usize = 1024;
const HEIGHT: usize = 768;

fn main() {
    let mut buffer: Vec<u32> = vec![0x00FFFFFF; WIDTH * HEIGHT];

    let img = image::open("image.jpg").unwrap();
    let rgb = img.as_rgb8().unwrap();

    rgb.draw_to_buffer(&mut buffer, WIDTH, (0, 0));

    let mut window = Window::new("Test - ESC to exit",
                                 WIDTH,
                                 HEIGHT,
                                 WindowOptions::default()).unwrap_or_else(|e| {
        panic!("{}", e);
    });

    while window.is_open() && !window.is_key_down(Key::Escape) {
        // We unwrap here as we want this code to exit if it fails. Real applications may want to handle this in a different way
        window.update_with_buffer(&buffer).unwrap();
    }
}