egui/egui/src/widgets/image.rs

120 lines
3.3 KiB
Rust

use crate::*;
/// An widget to show an image of a given size.
///
/// In order to display an image you must first acquire a [`TextureHandle`]
/// using [`Context::load_texture`].
///
/// ```
/// struct MyImage {
/// texture: Option<egui::TextureHandle>,
/// }
///
/// impl MyImage {
/// fn ui(&mut self, ui: &mut egui::Ui) {
/// let texture: &egui::TextureHandle = self.texture.get_or_insert_with(|| {
/// // Load the texture only once.
/// ui.ctx().load_texture("my-image", egui::ColorImage::example())
/// });
///
/// // Show the image:
/// ui.add(egui::Image::new(texture, texture.size_vec2()));
///
/// // Shorter version:
/// ui.image(texture, texture.size_vec2());
/// }
/// }
/// ```
///
/// Se also [`crate::Ui::image`] and [`crate::ImageButton`].
#[must_use = "You should put this widget in an ui with `ui.add(widget);`"]
#[derive(Clone, Copy, Debug)]
pub struct Image {
texture_id: TextureId,
uv: Rect,
size: Vec2,
bg_fill: Color32,
tint: Color32,
sense: Sense,
}
impl Image {
pub fn new(texture_id: impl Into<TextureId>, size: impl Into<Vec2>) -> Self {
Self {
texture_id: texture_id.into(),
uv: Rect::from_min_max(pos2(0.0, 0.0), pos2(1.0, 1.0)),
size: size.into(),
bg_fill: Default::default(),
tint: Color32::WHITE,
sense: Sense::hover(),
}
}
/// Select UV range. Default is (0,0) in top-left, (1,1) bottom right.
pub fn uv(mut self, uv: impl Into<Rect>) -> Self {
self.uv = uv.into();
self
}
/// A solid color to put behind the image. Useful for transparent images.
pub fn bg_fill(mut self, bg_fill: impl Into<Color32>) -> Self {
self.bg_fill = bg_fill.into();
self
}
/// Multiply image color with this. Default is WHITE (no tint).
pub fn tint(mut self, tint: impl Into<Color32>) -> Self {
self.tint = tint.into();
self
}
/// Make the image respond to clicks and/or drags.
///
/// Consider using [`ImageButton`] instead, for an on-hover effect.
pub fn sense(mut self, sense: Sense) -> Self {
self.sense = sense;
self
}
}
impl Image {
pub fn size(&self) -> Vec2 {
self.size
}
pub fn paint_at(&self, ui: &mut Ui, rect: Rect) {
if ui.is_rect_visible(rect) {
use epaint::*;
let Self {
texture_id,
uv,
size: _,
bg_fill,
tint,
sense: _,
} = self;
if *bg_fill != Default::default() {
let mut mesh = Mesh::default();
mesh.add_colored_rect(rect, *bg_fill);
ui.painter().add(Shape::mesh(mesh));
}
{
// TODO: builder pattern for Mesh
let mut mesh = Mesh::with_texture(*texture_id);
mesh.add_rect_with_uv(rect, *uv, *tint);
ui.painter().add(Shape::mesh(mesh));
}
}
}
}
impl Widget for Image {
fn ui(self, ui: &mut Ui) -> Response {
let (rect, response) = ui.allocate_exact_size(self.size, self.sense);
self.paint_at(ui, rect);
response
}
}