Basic text input support

emigui/src/widgets/text_edit.rs

@@ -0,0 +1,113 @@
+use crate::*;
+
+#[derive(Debug)]
+pub struct TextEdit<'t> {
+    text: &'t mut String,
+    id: Option<Id>,
+    text_style: TextStyle, // TODO: Option<TextStyle>, where None means "use the default for the region"
+    text_color: Option<Color>,
+}
+
+impl<'t> TextEdit<'t> {
+    pub fn new(text: &'t mut String) -> Self {
+        TextEdit {
+            text,
+            id: None,
+            text_style: TextStyle::Body,
+            text_color: Default::default(),
+        }
+    }
+
+    pub fn id(mut self, id_source: impl std::hash::Hash) -> Self {
+        self.id = Some(Id::new(id_source));
+        self
+    }
+
+    pub fn text_style(mut self, text_style: TextStyle) -> Self {
+        self.text_style = text_style;
+        self
+    }
+
+    pub fn text_color(mut self, text_color: Color) -> Self {
+        self.text_color = Some(text_color);
+        self
+    }
+}
+
+impl<'t> Widget for TextEdit<'t> {
+    fn add_to(self, region: &mut Region) -> GuiResponse {
+        let id = region.make_child_id(self.id);
+
+        let font = &region.fonts()[self.text_style];
+        let line_spacing = font.line_spacing();
+        let (text, text_size) = font.layout_multiline(self.text.as_str(), region.available_width());
+        let desired_size = text_size.max(vec2(region.available_width(), line_spacing));
+        let interact = region.reserve_space(desired_size, Some(id));
+
+        if interact.clicked {
+            region.request_kb_focus(id);
+        }
+        if interact.hovered {
+            region.output().cursor_icon = CursorIcon::Text;
+        }
+        let has_kb_focus = region.has_kb_focus(id);
+
+        if has_kb_focus {
+            for event in &region.input().events {
+                match event {
+                    Event::Copy | Event::Cut => {
+                        // TODO: cut
+                        region.ctx().output.lock().copied_text = self.text.clone();
+                    }
+                    Event::Text(text) => {
+                        if text == "\u{7f}" {
+                            // backspace
+                        } else {
+                            *self.text += text;
+                        }
+                    }
+                    Event::Key { key, pressed: true } => {
+                        match key {
+                            Key::Backspace => {
+                                self.text.pop(); // TODO: unicode aware
+                            }
+                            _ => {}
+                        }
+                    }
+                    _ => {}
+                }
+            }
+        }
+
+        region.add_paint_cmd(PaintCmd::Rect {
+            rect: interact.rect,
+            corner_radius: 0.0,
+            // fill_color: Some(color::BLACK),
+            fill_color: region.style().interact_fill_color(&interact),
+            // fill_color: Some(region.style().background_fill_color()),
+            outline: None, //Some(Outline::new(1.0, color::WHITE)),
+        });
+
+        if has_kb_focus {
+            let cursor_blink_hz = region.style().cursor_blink_hz;
+            let show_cursor =
+                (region.input().time * cursor_blink_hz as f64 * 3.0).floor() as i64 % 3 != 0;
+            if show_cursor {
+                let cursor_pos = if let Some(last) = text.last() {
+                    interact.rect.min + vec2(last.max_x(), last.y_offset)
+                } else {
+                    interact.rect.min
+                };
+                region.add_paint_cmd(PaintCmd::line_segment(
+                    (cursor_pos, cursor_pos + vec2(0.0, line_spacing)),
+                    color::WHITE,
+                    region.style().text_cursor_width,
+                ));
+            }
+        }
+
+        region.add_text(interact.rect.min, self.text_style, text, self.text_color);
+
+        region.response(interact)
+    }
+}