epaint/
texture_handle.rs

1use std::sync::Arc;
2
3use crate::{
4    emath::NumExt, mutex::RwLock, textures::TextureOptions, ImageData, ImageDelta, TextureId,
5    TextureManager,
6};
7
8/// Used to paint images.
9///
10/// An _image_ is pixels stored in RAM, and represented using [`ImageData`].
11/// Before you can paint it however, you need to convert it to a _texture_.
12///
13/// If you are using egui, use `egui::Context::load_texture`.
14///
15/// The [`TextureHandle`] can be cloned cheaply.
16/// When the last [`TextureHandle`] for specific texture is dropped, the texture is freed.
17///
18/// See also [`TextureManager`].
19#[must_use]
20pub struct TextureHandle {
21    tex_mngr: Arc<RwLock<TextureManager>>,
22    id: TextureId,
23}
24
25impl Drop for TextureHandle {
26    fn drop(&mut self) {
27        self.tex_mngr.write().free(self.id);
28    }
29}
30
31impl Clone for TextureHandle {
32    fn clone(&self) -> Self {
33        self.tex_mngr.write().retain(self.id);
34        Self {
35            tex_mngr: self.tex_mngr.clone(),
36            id: self.id,
37        }
38    }
39}
40
41impl PartialEq for TextureHandle {
42    #[inline]
43    fn eq(&self, other: &Self) -> bool {
44        self.id == other.id
45    }
46}
47
48impl Eq for TextureHandle {}
49
50impl std::hash::Hash for TextureHandle {
51    #[inline]
52    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
53        self.id.hash(state);
54    }
55}
56
57impl TextureHandle {
58    /// If you are using egui, use `egui::Context::load_texture` instead.
59    pub fn new(tex_mngr: Arc<RwLock<TextureManager>>, id: TextureId) -> Self {
60        Self { tex_mngr, id }
61    }
62
63    #[inline]
64    pub fn id(&self) -> TextureId {
65        self.id
66    }
67
68    /// Assign a new image to an existing texture.
69    pub fn set(&mut self, image: impl Into<ImageData>, options: TextureOptions) {
70        self.tex_mngr
71            .write()
72            .set(self.id, ImageDelta::full(image.into(), options));
73    }
74
75    /// Assign a new image to a subregion of the whole texture.
76    pub fn set_partial(
77        &mut self,
78        pos: [usize; 2],
79        image: impl Into<ImageData>,
80        options: TextureOptions,
81    ) {
82        self.tex_mngr
83            .write()
84            .set(self.id, ImageDelta::partial(pos, image.into(), options));
85    }
86
87    /// width x height
88    pub fn size(&self) -> [usize; 2] {
89        self.tex_mngr
90            .read()
91            .meta(self.id)
92            .map_or([0, 0], |tex| tex.size)
93    }
94
95    /// width x height
96    pub fn size_vec2(&self) -> crate::Vec2 {
97        let [w, h] = self.size();
98        crate::Vec2::new(w as f32, h as f32)
99    }
100
101    /// `width x height x bytes_per_pixel`
102    pub fn byte_size(&self) -> usize {
103        self.tex_mngr
104            .read()
105            .meta(self.id)
106            .map_or(0, |tex| tex.bytes_used())
107    }
108
109    /// width / height
110    pub fn aspect_ratio(&self) -> f32 {
111        let [w, h] = self.size();
112        w as f32 / h.at_least(1) as f32
113    }
114
115    /// Debug-name.
116    pub fn name(&self) -> String {
117        self.tex_mngr
118            .read()
119            .meta(self.id)
120            .map_or_else(|| "<none>".to_owned(), |tex| tex.name.clone())
121    }
122}
123
124impl From<&TextureHandle> for TextureId {
125    #[inline(always)]
126    fn from(handle: &TextureHandle) -> Self {
127        handle.id()
128    }
129}
130
131impl From<&mut TextureHandle> for TextureId {
132    #[inline(always)]
133    fn from(handle: &mut TextureHandle) -> Self {
134        handle.id()
135    }
136}
epaint/texture_handle.rs

epaint/
texture_handle.rs
