winit/
icon.rs

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1use crate::platform_impl::PlatformIcon;
2use std::error::Error;
3use std::{fmt, io, mem};
4
5#[repr(C)]
6#[derive(Debug)]
7pub(crate) struct Pixel {
8    pub(crate) r: u8,
9    pub(crate) g: u8,
10    pub(crate) b: u8,
11    pub(crate) a: u8,
12}
13
14pub(crate) const PIXEL_SIZE: usize = mem::size_of::<Pixel>();
15
16#[derive(Debug)]
17/// An error produced when using [`Icon::from_rgba`] with invalid arguments.
18pub enum BadIcon {
19    /// Produced when the length of the `rgba` argument isn't divisible by 4, thus `rgba` can't be
20    /// safely interpreted as 32bpp RGBA pixels.
21    ByteCountNotDivisibleBy4 { byte_count: usize },
22    /// Produced when the number of pixels (`rgba.len() / 4`) isn't equal to `width * height`.
23    /// At least one of your arguments is incorrect.
24    DimensionsVsPixelCount { width: u32, height: u32, width_x_height: usize, pixel_count: usize },
25    /// Produced when underlying OS functionality failed to create the icon
26    OsError(io::Error),
27}
28
29impl fmt::Display for BadIcon {
30    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
31        match self {
32            BadIcon::ByteCountNotDivisibleBy4 { byte_count } => write!(
33                f,
34                "The length of the `rgba` argument ({byte_count:?}) isn't divisible by 4, making \
35                 it impossible to interpret as 32bpp RGBA pixels.",
36            ),
37            BadIcon::DimensionsVsPixelCount { width, height, width_x_height, pixel_count } => {
38                write!(
39                    f,
40                    "The specified dimensions ({width:?}x{height:?}) don't match the number of \
41                     pixels supplied by the `rgba` argument ({pixel_count:?}). For those \
42                     dimensions, the expected pixel count is {width_x_height:?}.",
43                )
44            },
45            BadIcon::OsError(e) => write!(f, "OS error when instantiating the icon: {e:?}"),
46        }
47    }
48}
49
50impl Error for BadIcon {}
51
52#[derive(Debug, Clone, PartialEq, Eq)]
53pub(crate) struct RgbaIcon {
54    pub(crate) rgba: Vec<u8>,
55    pub(crate) width: u32,
56    pub(crate) height: u32,
57}
58
59/// For platforms which don't have window icons (e.g. web)
60#[derive(Debug, Clone, PartialEq, Eq)]
61pub(crate) struct NoIcon;
62
63#[allow(dead_code)] // These are not used on every platform
64mod constructors {
65    use super::*;
66
67    impl RgbaIcon {
68        pub fn from_rgba(rgba: Vec<u8>, width: u32, height: u32) -> Result<Self, BadIcon> {
69            if rgba.len() % PIXEL_SIZE != 0 {
70                return Err(BadIcon::ByteCountNotDivisibleBy4 { byte_count: rgba.len() });
71            }
72            let pixel_count = rgba.len() / PIXEL_SIZE;
73            if pixel_count != (width * height) as usize {
74                Err(BadIcon::DimensionsVsPixelCount {
75                    width,
76                    height,
77                    width_x_height: (width * height) as usize,
78                    pixel_count,
79                })
80            } else {
81                Ok(RgbaIcon { rgba, width, height })
82            }
83        }
84    }
85
86    impl NoIcon {
87        pub fn from_rgba(rgba: Vec<u8>, width: u32, height: u32) -> Result<Self, BadIcon> {
88            // Create the rgba icon anyway to validate the input
89            let _ = RgbaIcon::from_rgba(rgba, width, height)?;
90            Ok(NoIcon)
91        }
92    }
93}
94
95/// An icon used for the window titlebar, taskbar, etc.
96#[derive(Clone)]
97pub struct Icon {
98    pub(crate) inner: PlatformIcon,
99}
100
101impl fmt::Debug for Icon {
102    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
103        fmt::Debug::fmt(&self.inner, formatter)
104    }
105}
106
107impl Icon {
108    /// Creates an icon from 32bpp RGBA data.
109    ///
110    /// The length of `rgba` must be divisible by 4, and `width * height` must equal
111    /// `rgba.len() / 4`. Otherwise, this will return a `BadIcon` error.
112    pub fn from_rgba(rgba: Vec<u8>, width: u32, height: u32) -> Result<Self, BadIcon> {
113        let _span = tracing::debug_span!("winit::Icon::from_rgba", width, height).entered();
114
115        Ok(Icon { inner: PlatformIcon::from_rgba(rgba, width, height)? })
116    }
117}
winit/icon.rs

winit/
icon.rs
