migrations/egui
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Introduce egui_extras with RetainedImage for loading svg,png,jpeg,… (#1282)

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This commit is contained in:
Emil Ernerfeldt
2022-02-21 15:26:26 +01:00
committed by GitHub
parent 713917e481
commit c3fc8997d6
18 changed files with 453 additions and 176 deletions
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34
eframe/examples/download_image.rs
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@@ -1,6 +1,7 @@
#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")] // hide console window on Windows in release
use eframe::{egui, epi};
use egui_extras::RetainedImage;
use poll_promise::Promise;
fn main() {
@@ -11,7 +12,7 @@ fn main() {
#[derive(Default)]
struct MyApp {
/// `None` when download hasn't started yet.
promise: Option<Promise<ehttp::Result<egui::TextureHandle>>>,
promise: Option<Promise<ehttp::Result<RetainedImage>>>,
}
impl epi::App for MyApp {
@@ -24,14 +25,13 @@ impl epi::App for MyApp {
// Begin download.
// We download the image using `ehttp`, a library that works both in WASM and on native.
// We use the `poll-promise` library to communicate with the UI thread.
let ctx = ctx.clone();
let frame = frame.clone();
let (sender, promise) = Promise::new();
let request = ehttp::Request::get("https://picsum.photos/seed/1.759706314/1024");
ehttp::fetch(request, move |response| {
let image = response.and_then(parse_response);
sender.send(image); // send the results back to the UI thread.
frame.request_repaint(); // wake up UI thread
let texture = response.and_then(|response| parse_response(&ctx, response));
sender.send(texture); // send the results back to the UI thread.
});
promise
});
@@ -43,24 +43,17 @@ impl epi::App for MyApp {
Some(Err(err)) => {
ui.colored_label(egui::Color32::RED, err); // something went wrong
}
Some(Ok(texture)) => {
let mut size = texture.size_vec2();
size *= (ui.available_width() / size.x).min(1.0);
size *= (ui.available_height() / size.y).min(1.0);
ui.image(texture, size);
Some(Ok(image)) => {
image.show_max_size(ui, ui.available_size());
}
});
}
}
fn parse_response(
ctx: &egui::Context,
response: ehttp::Response,
) -> Result<egui::TextureHandle, String> {
fn parse_response(response: ehttp::Response) -> Result<RetainedImage, String> {
let content_type = response.content_type().unwrap_or_default();
if content_type.starts_with("image/") {
let image = load_image(&response.bytes).map_err(|err| err.to_string())?;
Ok(ctx.load_texture("my-image", image))
RetainedImage::from_image_bytes(&response.url, &response.bytes)
} else {
Err(format!(
"Expected image, found content-type {:?}",
@@ -68,14 +61,3 @@ fn parse_response(
))
}
}
fn load_image(image_data: &[u8]) -> Result<egui::ColorImage, image::ImageError> {
let image = image::load_from_memory(image_data)?;
let size = [image.width() as _, image.height() as _];
let image_buffer = image.to_rgba8();
let pixels = image_buffer.as_flat_samples();
Ok(egui::ColorImage::from_rgba_unmultiplied(
size,
pixels.as_slice(),
))
}