preload text by default

src/core/text.rs

@@ -81,6 +81,63 @@ impl Widget for Text {
     }
 }
 
-pub fn text(content: impl Into<String>) -> Text {
+pub fn text(content: impl Into<String>) -> TextBuilder {
-    Text::new(content)
+    TextBuilder {
+        content: content.into(),
+        align: Align::Center,
+        attrs: TextAttrs::default(),
+    }
+}
+
+pub struct TextBuilder {
+    pub content: String,
+    pub attrs: TextAttrs,
+    /// inner alignment of text region (within where its drawn)
+    pub align: Align,
+}
+
+impl TextBuilder {
+    pub fn font_size(mut self, size: impl UiNum) -> Self {
+        self.attrs.font_size = size.to_f32();
+        self.attrs.line_height = self.attrs.font_size * 1.1;
+        self
+    }
+    pub fn color(mut self, color: UiColor) -> Self {
+        self.attrs.color = color;
+        self
+    }
+    pub fn family(mut self, family: Family<'static>) -> Self {
+        self.attrs.family = family;
+        self
+    }
+    pub fn line_height(mut self, height: f32) -> Self {
+        self.attrs.line_height = height;
+        self
+    }
+}
+
+impl<Ctx> FnOnce<(&mut Ui<Ctx>,)> for TextBuilder {
+    type Output = Text;
+
+    extern "rust-call" fn call_once(self, args: (&mut Ui<Ctx>,)) -> Self::Output {
+        let mut buf =
+            TextBuffer::new_empty(Metrics::new(self.attrs.font_size, self.attrs.line_height));
+        buf.set_text(
+            &mut args.0.text.font_system,
+            &self.content,
+            &Attrs::new(),
+            Shaping::Advanced,
+        );
+        let mut text = Text {
+            content: self.content.into(),
+            buf,
+            attrs: self.attrs,
+            align: self.align,
+            size: Vec2::ZERO,
+        };
+        text.content.changed = false;
+        self.attrs
+            .apply(&mut args.0.text.font_system, &mut text.buf);
+        text
+    }
 }