include!("icon_pixels.rs");

pub fn compile_windows_icon() {

if std::env::var("CARGO_CFG_TARGET_OS").as_deref() != Ok("windows") {

return;

}

let output_dir = std::path::PathBuf::from(std::env::var_os("OUT_DIR").unwrap());

let icon_path = output_dir.join("escom.ico");

std::fs::write(&icon_path, encode_ico(&escom_icon_rgba())).expect("write generated icon");

let mut resource = winresource::WindowsResource::new();

resource.set_icon(icon_path.to_str().expect("UTF-8 output path"));

resource.compile().expect("compile Windows resources");

}

fn encode_ico(rgba: &[u8]) -> Vec<u8> {

let width = ICON_SIZE;

let height = ICON_SIZE;

let xor_size = width * height * 4;

let mask_stride = width.div_ceil(32) * 4;

let mask_size = mask_stride * height;

let bitmap_size = 40 + xor_size + mask_size;

let mut output = Vec::with_capacity((22 + bitmap_size) as usize);

output.extend_from_slice(&0_u16.to_le_bytes());

output.extend_from_slice(&1_u16.to_le_bytes());

output.extend_from_slice(&1_u16.to_le_bytes());

output.push(width as u8);

output.push(height as u8);

output.push(0);

output.push(0);

output.extend_from_slice(&1_u16.to_le_bytes());

output.extend_from_slice(&32_u16.to_le_bytes());

output.extend_from_slice(&bitmap_size.to_le_bytes());

output.extend_from_slice(&22_u32.to_le_bytes());

output.extend_from_slice(&40_u32.to_le_bytes());

output.extend_from_slice(&(width as i32).to_le_bytes());

output.extend_from_slice(&((height * 2) as i32).to_le_bytes());

output.extend_from_slice(&1_u16.to_le_bytes());

output.extend_from_slice(&32_u16.to_le_bytes());

output.extend_from_slice(&0_u32.to_le_bytes());

output.extend_from_slice(&xor_size.to_le_bytes());

output.extend_from_slice(&0_i32.to_le_bytes());

output.extend_from_slice(&0_i32.to_le_bytes());

output.extend_from_slice(&0_u32.to_le_bytes());

output.extend_from_slice(&0_u32.to_le_bytes());

for y in (0..height).rev() {

for x in 0..width {

let index = ((y * width + x) * 4) as usize;

output.extend_from_slice(&[

rgba[index + 2],

rgba[index + 1],

rgba[index],

rgba[index + 3],

]);

}

}

output.resize(output.len() + mask_size as usize, 0);

output

}

#[cfg(test)]

mod tests {

use super::*;

#[test]

fn generated_ico_has_expected_header_and_size() {

let icon = encode_ico(&escom_icon_rgba());

assert_eq!(&icon[..6], &[0, 0, 1, 0, 1, 0]);

assert!(icon.len() > (ICON_SIZE * ICON_SIZE * 4) as usize);

}

}