Implement Slider (#542)

CHANGELOG.md

@@ -1,5 +1,7 @@
 # Unreleased
 
+* Properties `size` and related now have a default value allowing conditional assign.
+* Add `zng::slider` with `Slider` widget.
 * Fix `force_size` returning the parent's constraint min size.
 * Fix hit-test in rounded rectangles with too large corner radius.
 * Fix headless rendering in Wayland. Property `needs_fallback_chrome` now is `false` for headless windows.

crates/README.md

@@ -115,6 +115,7 @@ or for custom properties that deeply integrate with a widget.
 - `zng-wgt-tooltip`
 - `zng-wgt-markdown`
 - `zng-wgt-progress`
+- `zng-wgt-slider`
 - `zng-wgt-material-icons`
 - `zng-wgt-webrender-debug`
 

crates/zng-wgt-size-offset/src/lib.rs

@@ -343,7 +343,7 @@ pub fn max_height(child: impl UiNode, max_height: impl IntoVar<Length>) -> impl
 /// [`height`]: fn@height
 /// [`force_size`]: fn@force_size
 /// [`align`]: fn@zng_wgt::align
-#[property(SIZE)]
+#[property(SIZE, default(Size::default()))]
 pub fn size(child: impl UiNode, size: impl IntoVar<Size>) -> impl UiNode {
     let size = size.into_var();
     match_node(child, move |child, op| match op {
@@ -399,7 +399,7 @@ pub fn size(child: impl UiNode, size: impl IntoVar<Size>) -> impl UiNode {
 /// [`min_width`]: fn@min_width
 /// [`max_width`]: fn@max_width
 /// [`force_width`]: fn@force_width
-#[property(SIZE)]
+#[property(SIZE, default(Length::Default))]
 pub fn width(child: impl UiNode, width: impl IntoVar<Length>) -> impl UiNode {
     let width = width.into_var();
     match_node(child, move |child, op| match op {
@@ -454,7 +454,7 @@ pub fn width(child: impl UiNode, width: impl IntoVar<Length>) -> impl UiNode {
 /// [`min_height`]: fn@min_height
 /// [`max_height`]: fn@max_height
 /// [`force_height`]: fn@force_height
-#[property(SIZE)]
+#[property(SIZE, default(Length::Default))]
 pub fn height(child: impl UiNode, height: impl IntoVar<Length>) -> impl UiNode {
     let height = height.into_var();
     match_node(child, move |child, op| match op {
@@ -507,7 +507,7 @@ pub fn height(child: impl UiNode, height: impl IntoVar<Length>) -> impl UiNode {
 ///
 /// [`force_width`]: fn@force_width
 /// [`force_height`]: fn@force_height
-#[property(SIZE)]
+#[property(SIZE, default(Size::default()))]
 pub fn force_size(child: impl UiNode, size: impl IntoVar<Size>) -> impl UiNode {
     let size = size.into_var();
     match_node(child, move |child, op| match op {
@@ -551,7 +551,7 @@ pub fn force_size(child: impl UiNode, size: impl IntoVar<Size>) -> impl UiNode {
 /// # `force_size`
 ///
 /// You can set both `force_width` and `force_height` at the same time using the [`force_size`](fn@force_size) property.
-#[property(SIZE)]
+#[property(SIZE, default(Length::Default))]
 pub fn force_width(child: impl UiNode, width: impl IntoVar<Length>) -> impl UiNode {
     let width = width.into_var();
     match_node(child, move |child, op| match op {
@@ -598,7 +598,7 @@ pub fn force_width(child: impl UiNode, width: impl IntoVar<Length>) -> impl UiNo
 /// # `force_size`
 ///
 /// You can set both `force_width` and `force_height` at the same time using the [`force_size`](fn@force_size) property.
-#[property(SIZE)]
+#[property(SIZE, default(Length::Default))]
 pub fn force_height(child: impl UiNode, height: impl IntoVar<Length>) -> impl UiNode {
     let height = height.into_var();
     match_node(child, move |child, op| match op {

crates/zng-wgt-slider/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "zng-wgt-slider"
+version = "0.1.0"
+authors = ["The Zng Project Developers"]
+edition = "2021"
+license = "Apache-2.0 OR MIT"
+readme = "README.md"
+description = "Part of the zng project."
+documentation = "https://zng-ui.github.io/doc/zng_wgt_slider"
+repository = "https://github.com/zng-ui/zng"
+categories = ["gui"]
+keywords = ["gui", "ui", "user-interface", "zng"]
+
+[dependencies]
+zng-var = { path = "../zng-var", version = "0.5.9" }
+zng-wgt = { path = "../zng-wgt", version = "0.5.5" }
+zng-wgt-style = { path = "../zng-wgt-style", version = "0.3.29" }
+zng-wgt-input = { path = "../zng-wgt-input", version = "0.2.41" }
+zng-ext-input = { path = "../zng-ext-input", version = "0.5.29" }
+zng-wgt-container = { path = "../zng-wgt-container", version = "0.4.1" }
+zng-wgt-size-offset = { path = "../zng-wgt-size-offset", version = "0.2.39" }
+zng-wgt-fill = { path = "../zng-wgt-fill", version = "0.2.39" }
+zng-wgt-transform = { path = "../zng-wgt-transform", version = "0.2.39" }
+
+parking_lot = "0.12"
+tracing = "0.1"

crates/zng-wgt-slider/README.md

@@ -0,0 +1,7 @@
+<!--do doc --readme header-->
+This crate is part of the [`zng`](https://github.com/zng-ui/zng?tab=readme-ov-file#crates) project.
+
+
+<!--do doc --readme features-->
+
+