hint gaming

src/core/text/build.rs

@@ -1,20 +1,15 @@
 use std::marker::{PhantomData, Sized};
-
 use crate::prelude::*;
 use cosmic_text::{Attrs, Family, Metrics};
 
-pub trait TextBuilderOutput: Sized {
+pub struct TextBuilder<O = TextOutput, H: WidgetOption = ()> {
-    type Output;
-    fn run(ui: &mut Ui, builder: TextBuilder<Self>) -> Self::Output;
-}
-
-pub struct TextBuilder<O = TextOutput> {
     pub content: String,
     pub attrs: TextAttrs,
+    pub hint: H,
     _pd: PhantomData<O>,
 }
 
-impl<O> TextBuilder<O> {
+impl<O, H: WidgetOption> TextBuilder<O, H> {
     pub fn size(mut self, size: impl UiNum) -> Self {
         self.attrs.font_size = size.to_f32();
         self.attrs.line_height = self.attrs.font_size * 1.1;
@@ -40,29 +35,47 @@ impl<O> TextBuilder<O> {
         self.attrs.wrap = wrap;
         self
     }
-    pub fn editable(self) -> TextBuilder<TextEditOutput> {
+    pub fn editable(self) -> TextBuilder<TextEditOutput, H> {
         TextBuilder {
             content: self.content,
             attrs: self.attrs,
+            hint: self.hint,
             _pd: PhantomData,
         }
     }
 }
 
+impl<O> TextBuilder<O> {
+    pub fn hint<W: WidgetLike<Tag>, Tag>(self, hint: W) -> TextBuilder<O, impl WidgetOption> {
+        TextBuilder {
+            content: self.content,
+            attrs: self.attrs,
+            hint: move |ui: &mut Ui| Some(hint.add(ui).any()),
+            _pd: PhantomData,
+        }
+    }
+}
+
+pub trait TextBuilderOutput: Sized {
+    type Output;
+    fn run<H: WidgetOption>(ui: &mut Ui, builder: TextBuilder<Self, H>) -> Self::Output;
+}
+
 pub struct TextOutput;
 impl TextBuilderOutput for TextOutput {
     type Output = Text;
 
-    fn run(ui: &mut Ui, builder: TextBuilder<Self>) -> Self::Output {
+    fn run<H: WidgetOption>(ui: &mut Ui, builder: TextBuilder<Self, H>) -> Self::Output {
         let mut buf = TextBuffer::new_empty(Metrics::new(
             builder.attrs.font_size,
             builder.attrs.line_height,
         ));
+        let hint = builder.hint.get(ui);
         let font_system = &mut ui.data.text.font_system;
         buf.set_text(font_system, &builder.content, &Attrs::new(), SHAPING, None);
         let mut text = Text {
             content: builder.content.into(),
-            view: TextView::new(buf, builder.attrs),
+            view: TextView::new(buf, builder.attrs, hint),
         };
         text.content.changed = false;
         builder.attrs.apply(font_system, &mut text.view.buf, None);
@@ -74,13 +87,13 @@ pub struct TextEditOutput;
 impl TextBuilderOutput for TextEditOutput {
     type Output = TextEdit;
 
-    fn run(ui: &mut Ui, builder: TextBuilder<Self>) -> Self::Output {
+    fn run<H: WidgetOption>(ui: &mut Ui, builder: TextBuilder<Self, H>) -> Self::Output {
         let buf = TextBuffer::new_empty(Metrics::new(
             builder.attrs.font_size,
             builder.attrs.line_height,
         ));
         let mut text = TextEdit {
-            view: TextView::new(buf, builder.attrs),
+            view: TextView::new(buf, builder.attrs, builder.hint.get(ui)),
             cursor: None,
         };
         let font_system = &mut ui.data.text.font_system;
@@ -91,7 +104,7 @@ impl TextBuilderOutput for TextEditOutput {
     }
 }
 
-impl<O: TextBuilderOutput> FnOnce<(&mut Ui,)> for TextBuilder<O> {
+impl<O: TextBuilderOutput, H: WidgetOption> FnOnce<(&mut Ui,)> for TextBuilder<O, H> {
     type Output = O::Output;
 
     extern "rust-call" fn call_once(self, args: (&mut Ui,)) -> Self::Output {
@@ -103,6 +116,7 @@ pub fn text(content: impl Into<String>) -> TextBuilder {
     TextBuilder {
         content: content.into(),
         attrs: TextAttrs::default(),
+        hint: (),
         _pd: PhantomData,
     }
 }

src/core/text/edit.rs

@@ -47,11 +47,11 @@ impl Widget for TextEdit {
     }
 
     fn desired_width(&mut self, ctx: &mut SizeCtx) -> Len {
-        Len::abs(self.view.render(ctx).size.x)
+        self.view.desired_width(ctx)
     }
 
     fn desired_height(&mut self, ctx: &mut SizeCtx) -> Len {
-        Len::abs(self.view.render(ctx).size.y)
+        self.view.desired_height(ctx)
     }
 }
 

src/core/text/mod.rs

@@ -21,18 +21,20 @@ pub struct TextView {
     // cache
     tex: Option<RenderedText>,
     width: Option<f32>,
+    pub hint: Option<WidgetId>,
 }
 
 impl TextView {
-    pub fn new(buf: TextBuffer, attrs: TextAttrs) -> Self {
+    pub fn new(buf: TextBuffer, attrs: TextAttrs, hint: Option<WidgetId>) -> Self {
         Self {
             attrs: attrs.into(),
             buf: buf.into(),
             tex: None,
             width: None,
+            hint,
         }
     }
-    pub fn render(&mut self, ctx: &mut SizeCtx) -> RenderedText {
+    fn render(&mut self, ctx: &mut SizeCtx) -> RenderedText {
         let width = if self.attrs.wrap {
             Some(ctx.px_size().x)
         } else {
@@ -71,6 +73,12 @@ impl TextView {
         let mut region = region.offset(tex.top_left_offset);
         region.x.end = region.x.start + UiScalar::abs(dims.x);
         region.y.end = region.y.start + UiScalar::abs(dims.y);
+        if let Some(hint) = &self.hint
+            && let [line] = &self.buf.lines[..]
+            && line.text().is_empty()
+        {
+            painter.widget(hint);
+        }
         painter.texture_within(&tex.handle, region);
         region
     }
@@ -82,7 +90,7 @@ impl Text {
         let buf = TextBuffer::new_empty(Metrics::new(attrs.font_size, attrs.line_height));
         Self {
             content: content.into().into(),
-            view: TextView::new(buf, attrs),
+            view: TextView::new(buf, attrs, None),
         }
     }
     fn update_buf(&mut self, ctx: &mut SizeCtx) {

src/layout/color.rs

@@ -13,6 +13,7 @@ pub struct Color<T: ColorNum> {
 impl<T: ColorNum> Color<T> {
     pub const BLACK: Self = Self::rgb(T::MIN, T::MIN, T::MIN);
     pub const WHITE: Self = Self::rgb(T::MAX, T::MAX, T::MAX);
+    pub const GRAY: Self = Self::rgb(T::MID, T::MID, T::MID);
 
     pub const RED: Self = Self::rgb(T::MAX, T::MIN, T::MIN);
     pub const ORANGE: Self = Self::rgb(T::MAX, T::MID, T::MIN);

src/layout/widget.rs

@@ -135,3 +135,19 @@ impl_widget_arr!(9;A B C D E F G H I);
 impl_widget_arr!(10;A B C D E F G H I J);
 impl_widget_arr!(11;A B C D E F G H I J K);
 impl_widget_arr!(12;A B C D E F G H I J K L);
+
+pub trait WidgetOption {
+    fn get(self, ui: &mut Ui) -> Option<WidgetId>;
+}
+
+impl WidgetOption for () {
+    fn get(self, _: &mut Ui) -> Option<WidgetId> {
+        None
+    }
+}
+
+impl<F: FnOnce(&mut Ui) -> Option<WidgetId>> WidgetOption for F {
+    fn get(self, ui: &mut Ui) -> Option<WidgetId> {
+        self(ui)
+    }
+}