Implement slider

src/app.rs

@@ -3,6 +3,7 @@ use crate::gui::Gui;
 #[derive(Default)]
 pub struct App {
     count: i32,
+    slider_value: f32,
 }
 
 impl App {
@@ -10,14 +11,10 @@ impl App {
         if gui.button("Click me").clicked {
             self.count += 1;
         }
-        if gui.button("Or click me instead!").clicked {
-            self.count += 1;
-        }
 
-        gui.label(format!(
-            "The buttons have been clicked {} times",
-            self.count
-        ));
+        gui.label(format!("The button have been clicked {} times", self.count));
+
+        gui.slider_f32("Slider", &mut self.slider_value, 0.0, 10.0);
 
         let commands_json = format!("{:#?}", gui.gui_commands());
         gui.label(format!("All gui commands: {}", commands_json));

src/gui.rs

@@ -1,4 +1,4 @@
-use crate::types::*;
+use crate::{math::*, types::*};
 
 // TODO: implement Gui on this so we can add children to a widget
 // pub struct Widget {}
@@ -37,18 +37,7 @@ impl Gui {
             size: Vec2 { x: 200.0, y: 32.0 }, // TODO: get from some settings
         };
 
-        let hovered = rect.contains(self.input.mouse_pos);
-        let clicked = hovered && self.input.mouse_clicked;
-        if clicked {
-            self.state.active_id = Some(id);
-        }
-        let active = self.state.active_id == Some(id);
-
-        let interact = InteractInfo {
-            hovered,
-            clicked,
-            active,
-        };
+        let interact = self.interactive_rect(id, &rect);
 
         self.commands.push(GuiCmd::Rect {
             interact,
@@ -78,8 +67,58 @@ impl Gui {
         self.cursor.y += 16.0; // Padding
     }
 
+    pub fn slider_f32<S: Into<String>>(
+        &mut self,
+        label: S,
+        value: &mut f32,
+        min: f32,
+        max: f32,
+    ) -> InteractInfo {
+        let label: String = label.into();
+        let id = self.get_id(&label);
+        let rect = Rect {
+            pos: self.cursor,
+            size: Vec2 { x: 200.0, y: 24.0 }, // TODO: get from some settings
+        };
+        let interact = self.interactive_rect(id, &rect);
+
+        debug_assert!(min <= max);
+
+        if interact.active {
+            *value = remap_clamp(self.input.mouse_pos.x, rect.min().x, rect.max().x, min, max);
+        }
+
+        self.commands.push(GuiCmd::Slider {
+            interact,
+            label,
+            max,
+            min,
+            rect,
+            value: *value,
+        });
+
+        self.cursor.y += rect.size.y + 16.0;
+
+        interact
+    }
+
     // ------------------------------------------------------------------------
 
+    fn interactive_rect(&mut self, id: Id, rect: &Rect) -> InteractInfo {
+        let hovered = rect.contains(self.input.mouse_pos);
+        let clicked = hovered && self.input.mouse_clicked;
+        if clicked {
+            self.state.active_id = Some(id);
+        }
+        let active = self.state.active_id == Some(id);
+
+        InteractInfo {
+            hovered,
+            clicked,
+            active,
+        }
+    }
+
     fn get_id(&self, id_str: &str) -> Id {
         use std::hash::Hasher;
         let mut hasher = std::collections::hash_map::DefaultHasher::new();

src/lib.rs

@@ -1,20 +1,23 @@
+#![deny(warnings)]
+
 extern crate lazy_static;
 extern crate serde;
 extern crate serde_json;
 extern crate wasm_bindgen;
 extern crate web_sys;
 
-#[macro_use]
+#[macro_use] // TODO: get rid of this
 extern crate serde_derive;
 
 use std::sync::Mutex;
 
 use wasm_bindgen::prelude::*;
 
-use crate::types::*;
+use crate::{math::Vec2, types::*};
 
 pub mod app;
 pub mod gui;
+pub mod math;
 pub mod style;
 pub mod types;
 

src/math.rs

@@ -0,0 +1,90 @@
+#[derive(Clone, Copy, Debug, Default, Deserialize, Serialize)]
+pub struct Vec2 {
+    pub x: f32,
+    pub y: f32,
+}
+
+impl std::ops::Add for Vec2 {
+    type Output = Vec2;
+    fn add(self, rhs: Vec2) -> Vec2 {
+        Vec2 {
+            x: self.x + rhs.x,
+            y: self.y + rhs.y,
+        }
+    }
+}
+
+impl std::ops::Sub for Vec2 {
+    type Output = Vec2;
+    fn sub(self, rhs: Vec2) -> Vec2 {
+        Vec2 {
+            x: self.x - rhs.x,
+            y: self.y - rhs.y,
+        }
+    }
+}
+
+impl std::ops::Mul<f32> for Vec2 {
+    type Output = Vec2;
+    fn mul(self, factor: f32) -> Vec2 {
+        Vec2 {
+            x: self.x * factor,
+            y: self.y * factor,
+        }
+    }
+}
+
+pub fn vec2(x: f32, y: f32) -> Vec2 {
+    Vec2 { x, y }
+}
+
+#[derive(Clone, Copy, Debug, Default, Deserialize, Serialize)]
+pub struct Rect {
+    pub pos: Vec2,
+    pub size: Vec2,
+}
+
+impl Rect {
+    pub fn from_center_size(center: Vec2, size: Vec2) -> Self {
+        Rect {
+            pos: center - size * 0.5,
+            size,
+        }
+    }
+
+    pub fn contains(&self, p: Vec2) -> bool {
+        self.pos.x <= p.x
+            && p.x <= self.pos.x + self.size.x
+            && self.pos.y <= p.y
+            && p.y <= self.pos.y + self.size.y
+    }
+
+    pub fn center(&self) -> Vec2 {
+        Vec2 {
+            x: self.pos.x + self.size.x / 2.0,
+            y: self.pos.y + self.size.y / 2.0,
+        }
+    }
+
+    pub fn min(&self) -> Vec2 {
+        self.pos
+    }
+    pub fn max(&self) -> Vec2 {
+        self.pos + self.size
+    }
+}
+
+pub fn lerp(t: f32, min: f32, max: f32) -> f32 {
+    (1.0 - t) * min + t * max
+}
+
+pub fn remap_clamp(from: f32, from_min: f32, from_max: f32, to_min: f32, to_max: f32) -> f32 {
+    let t = if from <= from_min {
+        0.0
+    } else if from >= from_max {
+        1.0
+    } else {
+        (from - from_min) / (from_max - from_min)
+    };
+    lerp(t, to_min, to_max)
+}

src/style.rs

@@ -1,7 +1,7 @@
-use crate::types::*;
+use crate::{math::*, types::*};
 
 /// TODO: a Style struct which defines colors etc
-fn translate_cmd(cmd: GuiCmd) -> PaintCmd {
+fn translate_cmd(out_commands: &mut Vec<PaintCmd>, cmd: GuiCmd) {
     match cmd {
         GuiCmd::Rect {
             rect,
@@ -16,12 +16,12 @@ fn translate_cmd(cmd: GuiCmd) -> PaintCmd {
                 } else {
                     "#222222ff".to_string()
                 };
-                PaintCmd::RoundedRect {
+                out_commands.push(PaintCmd::RoundedRect {
                     corner_radius: 5.0,
                     fill_style,
                     pos: rect.pos,
                     size: rect.size,
-                }
+                });
             }
         },
         GuiCmd::Text {
@@ -34,17 +34,66 @@ fn translate_cmd(cmd: GuiCmd) -> PaintCmd {
                 TextStyle::Button => "#ffffffbb".to_string(),
                 TextStyle::Label => "#ffffffbb".to_string(),
             };
-            PaintCmd::Text {
+            out_commands.push(PaintCmd::Text {
                 fill_style,
                 font: "14px Palatino".to_string(),
                 pos,
                 text,
                 text_align,
-            }
+            });
+        }
+        GuiCmd::Slider {
+            interact,
+            label,
+            max,
+            min,
+            rect,
+            value,
+        } => {
+            let thin_rect = Rect::from_center_size(rect.center(), vec2(rect.size.x, 8.0));
+
+            let marker_center_x = remap_clamp(value, min, max, rect.min().x, rect.max().x);
+
+            let marker_rect =
+                Rect::from_center_size(vec2(marker_center_x, rect.center().y), vec2(16.0, 16.0));
+
+            let marker_fill_style = if interact.active {
+                "#888888ff".to_string()
+            } else if interact.hovered {
+                "#444444ff".to_string()
+            } else {
+                "#222222ff".to_string()
+            };
+
+            out_commands.push(PaintCmd::RoundedRect {
+                corner_radius: 2.0,
+                fill_style: "#111111ff".to_string(),
+                pos: thin_rect.pos,
+                size: thin_rect.size,
+            });
+
+            out_commands.push(PaintCmd::RoundedRect {
+                corner_radius: 3.0,
+                fill_style: marker_fill_style,
+                pos: marker_rect.pos,
+                size: marker_rect.size,
+            });
+
+            out_commands.push(PaintCmd::Text {
+                fill_style: "#ffffffbb".to_string(),
+                font: "14px Palatino".to_string(),
+                pos: rect.center(),
+                text: format!("{}: {:.3}", label, value),
+                text_align: TextAlign::Center,
+            });
         }
     }
 }
 
 pub fn into_paint_commands(gui_commands: &[GuiCmd]) -> Vec<PaintCmd> {
-    gui_commands.iter().cloned().map(translate_cmd).collect()
+    let mut paint_commands = vec![];
+    for gui_cmd in gui_commands {
+        translate_cmd(&mut paint_commands, gui_cmd.clone())
+    }
+    paint_commands
 }

src/types.rs

@@ -1,30 +1,4 @@
-#[derive(Clone, Copy, Debug, Default, Deserialize, Serialize)]
-pub struct Vec2 {
-    pub x: f32,
-    pub y: f32,
-}
-
-#[derive(Clone, Copy, Debug, Default, Deserialize, Serialize)]
-pub struct Rect {
-    pub pos: Vec2,
-    pub size: Vec2,
-}
-
-impl Rect {
-    pub fn contains(&self, p: Vec2) -> bool {
-        self.pos.x <= p.x
-            && p.x <= self.pos.x + self.size.x
-            && self.pos.y <= p.y
-            && p.y <= self.pos.y + self.size.y
-    }
-
-    pub fn center(&self) -> Vec2 {
-        Vec2 {
-            x: self.pos.x + self.size.x / 2.0,
-            y: self.pos.y + self.size.y / 2.0,
-        }
-    }
-}
+use crate::math::{Rect, Vec2};
 
 // ----------------------------------------------------------------------------
 
@@ -141,6 +115,14 @@ pub enum GuiCmd {
         text_align: TextAlign,
         style: TextStyle,
     },
+    Slider {
+        interact: InteractInfo,
+        label: String,
+        max: f32,
+        min: f32,
+        rect: Rect,
+        value: f32,
+    },
 }
 
 // ----------------------------------------------------------------------------