path: root/wgpu/src/renderer/widget/text_input.rs

use crate::{Primitive, Renderer};

use iced_native::{
    text::HorizontalAlignment, text::VerticalAlignment, text_input, Background,
    Color, MouseCursor, Point, Rectangle, TextInput, Vector,
};
use std::f32;

impl text_input::Renderer for Renderer {
    fn default_size(&self) -> u16 {
        // TODO: Make this configurable
        20
    }

    fn draw<Message>(
        &mut self,
        text_input: &TextInput<Message>,
        bounds: Rectangle,
        text_bounds: Rectangle,
        cursor_position: Point,
    ) -> Self::Output {
        let is_mouse_over = bounds.contains(cursor_position);

        let border = Primitive::Quad {
            bounds,
            background: Background::Color(
                if is_mouse_over || text_input.state.is_focused {
                    Color {
                        r: 0.5,
                        g: 0.5,
                        b: 0.5,
                        a: 1.0,
                    }
                } else {
                    Color {
                        r: 0.7,
                        g: 0.7,
                        b: 0.7,
                        a: 1.0,
                    }
                },
            ),
            border_radius: 5,
        };

        let input = Primitive::Quad {
            bounds: Rectangle {
                x: bounds.x + 1.0,
                y: bounds.y + 1.0,
                width: bounds.width - 2.0,
                height: bounds.height - 2.0,
            },
            background: Background::Color(Color::WHITE),
            border_radius: 5,
        };

        let size = f32::from(text_input.size.unwrap_or(self.default_size()));
        let text = text_input.value.to_string();

        let value = Primitive::Text {
            content: if text.is_empty() {
                text_input.placeholder.clone()
            } else {
                text.clone()
            },
            color: if text.is_empty() {
                Color {
                    r: 0.7,
                    g: 0.7,
                    b: 0.7,
                    a: 1.0,
                }
            } else {
                Color {
                    r: 0.3,
                    g: 0.3,
                    b: 0.3,
                    a: 1.0,
                }
            },
            bounds: Rectangle {
                width: f32::INFINITY,
                ..text_bounds
            },
            size,
            horizontal_alignment: HorizontalAlignment::Left,
            vertical_alignment: VerticalAlignment::Center,
        };

        let (contents_primitive, offset) = if text_input.state.is_focused {
            use wgpu_glyph::{GlyphCruncher, Scale, Section};

            let text_before_cursor = &text_input
                .value
                .until(text_input.state.cursor_position(&text_input.value))
                .to_string();

            let mut text_value_width = self
                .glyph_brush
                .borrow_mut()
                .glyph_bounds(Section {
                    text: text_before_cursor,
                    bounds: (f32::INFINITY, text_bounds.height),
                    scale: Scale { x: size, y: size },
                    ..Default::default()
                })
                .map(|bounds| bounds.width().round())
                .unwrap_or(0.0);

            let spaces_at_the_end =
                text_before_cursor.len() - text_before_cursor.trim_end().len();

            if spaces_at_the_end > 0 {
                let space_width = {
                    let glyph_brush = self.glyph_brush.borrow();

                    // TODO: Select appropriate font
                    let font = &glyph_brush.fonts()[0];

                    font.glyph(' ')
                        .scaled(Scale { x: size, y: size })
                        .h_metrics()
                        .advance_width
                };

                text_value_width += spaces_at_the_end as f32 * space_width;
            }

            let cursor = Primitive::Quad {
                bounds: Rectangle {
                    x: text_bounds.x + text_value_width,
                    y: text_bounds.y,
                    width: 1.0,
                    height: text_bounds.height,
                },
                background: Background::Color(Color::BLACK),
                border_radius: 0,
            };

            (
                Primitive::Group {
                    primitives: vec![value, cursor],
                },
                Vector::new(
                    ((text_value_width + 5.0) - text_bounds.width).max(0.0)
                        as u32,
                    0,
                ),
            )
        } else {
            (value, Vector::new(0, 0))
        };

        let contents = Primitive::Clip {
            bounds: text_bounds,
            offset,
            content: Box::new(contents_primitive),
        };

        (
            Primitive::Group {
                primitives: vec![border, input, contents],
            },
            if is_mouse_over {
                MouseCursor::Text
            } else {
                MouseCursor::OutOfBounds
            },
        )
    }
}