feat(widget): Add SpinButtonModel

Enables convenient handling of spin messages, and specifying steppings, minimum, and maximum values

src/widget/spin_button/model.rs

@@ -0,0 +1,150 @@
+// Copyright 2022 System76 <info@system76.com>
+// SPDX-License-Identifier: MPL-2.0
+
+use super::{SpinButton, SpinMessage};
+use crate::Element;
+use derive_setters::Setters;
+use std::hash::Hash;
+use std::ops::{Add, Sub};
+
+#[derive(Setters)]
+pub struct SpinButtonModel<T> {
+    /// The current value of the spin button.
+    pub value: T,
+    /// The amount to increment the value.
+    pub step: T,
+    /// The minimum value permitted.
+    pub min: T,
+    /// The maximum value permitted.
+    pub max: T,
+}
+
+impl<T: 'static> SpinButtonModel<T>
+where
+    T: Copy + Hash + ToString + Sub<Output = T> + Add<Output = T> + Ord,
+{
+    pub fn view(&self) -> Element<'static, SpinMessage> {
+        SpinButton::new(self.value).into_element()
+    }
+
+    pub fn update(&mut self, message: SpinMessage) {
+        self.value = match message {
+            SpinMessage::Increment => {
+                std::cmp::min(std::cmp::max(self.value + self.step, self.min), self.max)
+            }
+            SpinMessage::Decrement => {
+                std::cmp::max(std::cmp::min(self.value - self.step, self.max), self.min)
+            }
+        }
+    }
+}
+
+impl Default for SpinButtonModel<i8> {
+    fn default() -> Self {
+        Self {
+            value: 0,
+            step: 1,
+            min: i8::MIN,
+            max: i8::MAX,
+        }
+    }
+}
+
+impl Default for SpinButtonModel<i16> {
+    fn default() -> Self {
+        Self {
+            value: 0,
+            step: 1,
+            min: i16::MIN,
+            max: i16::MAX,
+        }
+    }
+}
+
+impl Default for SpinButtonModel<i32> {
+    fn default() -> Self {
+        Self {
+            value: 0,
+            step: 1,
+            min: i32::MIN,
+            max: i32::MAX,
+        }
+    }
+}
+
+impl Default for SpinButtonModel<isize> {
+    fn default() -> Self {
+        Self {
+            value: 0,
+            step: 1,
+            min: isize::MIN,
+            max: isize::MAX,
+        }
+    }
+}
+
+impl Default for SpinButtonModel<u8> {
+    fn default() -> Self {
+        Self {
+            value: 0,
+            step: 1,
+            min: u8::MIN,
+            max: u8::MAX,
+        }
+    }
+}
+
+impl Default for SpinButtonModel<u16> {
+    fn default() -> Self {
+        Self {
+            value: 0,
+            step: 1,
+            min: u16::MIN,
+            max: u16::MAX,
+        }
+    }
+}
+
+impl Default for SpinButtonModel<u32> {
+    fn default() -> Self {
+        Self {
+            value: 0,
+            step: 1,
+            min: u32::MIN,
+            max: u32::MAX,
+        }
+    }
+}
+
+impl Default for SpinButtonModel<usize> {
+    fn default() -> Self {
+        Self {
+            value: 0,
+            step: 1,
+            min: usize::MIN,
+            max: usize::MAX,
+        }
+    }
+}
+
+impl Default for SpinButtonModel<f32> {
+    fn default() -> Self {
+        Self {
+            value: 0.0,
+            step: 1.0,
+            min: f32::MIN,
+            max: f32::MAX,
+        }
+    }
+}
+
+impl Default for SpinButtonModel<f64> {
+    fn default() -> Self {
+        Self {
+            value: 0.0,
+            step: 1.0,
+            min: f64::MIN,
+            max: f64::MAX,
+        }
+    }
+}