Xilem example for http cats API, requiring workers and image comp…

…onent (#571)

This example is inspired by:
https://troz.net/post/2024/swiftui-mac-2024/

Current status:
- Lists status code
- Can select status code
- Downloads image from status code
- Shows image from status code

This adds two new features to Xilem:
- The worker view, which is the obvious extension to `task` for multiple
operations
- The `image` view, which just uses Masonry `Image`.

It also fixes a the Masonry Image view's layout to use the already
extant but unused method.

README.md

@@ -157,8 +157,10 @@ cargo update -p package_name --precise 0.1.1
 Licensed under the Apache License, Version 2.0
 ([LICENSE](LICENSE) or <http://www.apache.org/licenses/LICENSE-2.0>)
 
-The font file (`RobotoFlex-Subset.ttf`) in `xilem/resources/fonts/roboto_flex/` is licensed solely as documented in that folder,
-(and is not licensed under the Apache License, Version 2.0).
+Some files used for examples are under different licenses:
+
+- The font file (`RobotoFlex-Subset.ttf`) in `xilem/resources/fonts/roboto_flex/` is licensed solely as documented in that folder (and is not licensed under the Apache License, Version 2.0).
+- The data file (`status.csv`) in `xilem/resources/data/http_cats_status/` is licensed solely as documented in that folder (and is not licensed under the Apache License, Version 2.0).
 
 ## Contribution
 

masonry/src/widget/image.rs

@@ -22,6 +22,10 @@ use crate::{
 /// A widget that renders a bitmap Image.
 ///
 /// The underlying image uses `Arc` for buffer data, making it cheap to clone.
+///
+/// This currently uses bilinear interpolation, which falls down when the image is
+/// larger than its layout size (e.g. it is in a [sized box](super::SizedBox) smaller
+/// than the image size).
 pub struct Image {
     image_data: ImageBuf,
     fill: FillStrat,
@@ -32,7 +36,6 @@ impl Image {
     /// Create an image drawing widget from an image buffer.
     ///
     /// By default, the Image will scale to fit its box constraints ([`FillStrat::Fill`]).
-
     #[inline]
     pub fn new(image_data: ImageBuf) -> Self {
         Image {
@@ -82,17 +85,16 @@ impl Widget for Image {
         // If either the width or height is constrained calculate a value so that the image fits
         // in the size exactly. If it is unconstrained by both width and height take the size of
         // the image.
-        let max = bc.max();
         let image_size = Size::new(self.image_data.width as f64, self.image_data.height as f64);
-        let size = if bc.is_width_bounded() && !bc.is_height_bounded() {
-            let ratio = max.width / image_size.width;
-            Size::new(max.width, ratio * image_size.height)
-        } else if bc.is_height_bounded() && !bc.is_width_bounded() {
-            let ratio = max.height / image_size.height;
-            Size::new(ratio * image_size.width, max.height)
-        } else {
-            bc.constrain(image_size)
-        };
+        if image_size.is_empty() {
+            let size = bc.min();
+            trace!("Computed size: {}", size);
+            return size;
+        }
+        // This size logic has NOT been carefully considered, in particular with regards to self.fill.
+        // TODO: Carefully consider it
+        let size =
+            bc.constrain_aspect_ratio(image_size.height / image_size.width, image_size.width);
         trace!("Computed size: {}", size);
         size
     }

xilem/Cargo.toml

@@ -9,7 +9,7 @@ license.workspace = true
 repository.workspace = true
 homepage.workspace = true
 rust-version.workspace = true
-exclude = ["/resources/fonts/roboto_flex/"]
+exclude = ["/resources/fonts/roboto_flex/", "/resources/data/http_cats_status/"]
 
 [package.metadata.docs.rs]
 all-features = true
@@ -36,6 +36,16 @@ path = "examples/calc.rs"
 # cdylib is required for cargo-apk
 crate-type = ["cdylib"]
 
+[[example]]
+name = "http_cats"
+
+[[example]]
+name = "http_cats_android"
+path = "examples/http_cats.rs"
+# cdylib is required for cargo-apk
+crate-type = ["cdylib"]
+
+
 [[example]]
 name = "stopwatch"
 
@@ -65,14 +75,28 @@ tracing.workspace = true
 vello.workspace = true
 smallvec.workspace = true
 accesskit.workspace = true
-tokio = { version = "1.39.1", features = ["rt", "rt-multi-thread", "time"] }
+tokio = { version = "1.39.1", features = [
+    "rt",
+    "rt-multi-thread",
+    "time",
+    "sync",
+] }
 
 [dev-dependencies]
 # Used for `variable_clock`
 time = { workspace = true, features = ["local-offset"] }
 
+# Used for http_cats
+reqwest = { version = "0.12.7", default-features = false, features = [
+    # We use rustls as Android doesn't ship with openssl
+    # and this is likely to be easiest to get working.
+    "rustls-tls",
+] }
+image = { workspace = true, features = ["jpeg"] }
+
 # Make wgpu use tracing for its spans.
 profiling = { version = "1.0.15", features = ["profile-with-tracing"] }
+anyhow = "1.0.86"
 
 [target.'cfg(target_os = "android")'.dev-dependencies]
 winit = { features = ["android-native-activity"], workspace = true }
@@ -81,3 +105,7 @@ winit = { features = ["android-native-activity"], workspace = true }
 # Do not use when releasing a production app.
 [package.metadata.android.application]
 debuggable = true
+
+[[package.metadata.android.uses_permission]]
+# Needed for http_cats
+name = "android.permission.INTERNET"

xilem/README.md

@@ -64,9 +64,12 @@ Unless you explicitly state otherwise, any contribution intentionally submitted
 
 Licensed under the Apache License, Version 2.0 ([LICENSE](LICENSE) or <http://www.apache.org/licenses/LICENSE-2.0>)
 
-The font file (`RobotoFlex-Subset.ttf`) in `resources/fonts/roboto_flex/` is licensed solely as documented in that folder,
-(and is not licensed under the Apache License, Version 2.0).
-Note that this file is *not* distributed with the.
+Some files used for examples are under different licenses:
+
+* The font file (`RobotoFlex-Subset.ttf`) in `resources/fonts/roboto_flex/` is licensed solely as documented in that folder (and is not licensed under the Apache License, Version 2.0).
+* The data file (`status.csv`) in `resources/data/http_cats_status/` is licensed solely as documented in that folder (and is not licensed under the Apache License, Version 2.0).
+
+Note that these files are *not* distributed with the released crate.
 
 [Masonry]: https://crates.io/crates/masonry
 [Druid]: https://crates.io/crates/druid