Render the grid of the goban

otg/gtk/src/components/goban.rs

@@ -44,6 +44,7 @@ use gtk::{
     subclass::prelude::*,
 };
 use image::io::Reader as ImageReader;
+use otg_core::Color;
 use std::{cell::RefCell, io::Cursor, rc::Rc};
 
 const WIDTH: i32 = 800;
@@ -140,5 +141,112 @@ impl Goban {
 
         ctx.set_source_rgb(0.7, 0.7, 0.7);
         let _ = ctx.paint();
+
+        let board = self.imp().board_state.borrow();
+
+        ctx.set_source_rgb(0.1, 0.1, 0.1);
+        ctx.set_line_width(2.);
+        let hspace_between = ((width - 40) as f64) / ((board.size.width - 1) as f64);
+        let vspace_between = ((height - 40) as f64) / ((board.size.height - 1) as f64);
+
+        let pen = Pen {
+            x_offset: MARGIN as f64,
+            y_offset: MARGIN as f64,
+            hspace_between,
+            vspace_between,
+        };
+
+        (0..board.size.width).for_each(|col| {
+            ctx.move_to(
+                (MARGIN as f64) + (col as f64) * hspace_between,
+                MARGIN as f64,
+            );
+            ctx.line_to(
+                (MARGIN as f64) + (col as f64) * hspace_between,
+                (height as f64) - (MARGIN as f64),
+            );
+            let _ = ctx.stroke();
+        });
+        (0..board.size.height).for_each(|row| {
+            ctx.move_to(
+                MARGIN as f64,
+                (MARGIN as f64) + (row as f64) * vspace_between,
+            );
+            ctx.line_to(
+                (width - MARGIN) as f64,
+                (MARGIN as f64) + (row as f64) * vspace_between,
+            );
+            let _ = ctx.stroke();
+        });
+        vec![3, 9, 15].into_iter().for_each(|col| {
+            vec![3, 9, 15].into_iter().for_each(|row| {
+                pen.star_point(ctx, col, row);
+            });
+        });
+    }
+}
+
+struct Pen {
+    x_offset: f64,
+    y_offset: f64,
+    hspace_between: f64,
+    vspace_between: f64,
+}
+
+impl Pen {
+    fn star_point(&self, context: &cairo::Context, row: u8, col: u8) {
+        context.arc(
+            self.x_offset + (col as f64) * self.hspace_between,
+            self.y_offset + (row as f64) * self.vspace_between,
+            5.,
+            0.,
+            2. * std::f64::consts::PI,
+        );
+        let _ = context.fill();
+    }
+
+    fn stone(
+        &self,
+        context: &cairo::Context,
+        row: u8,
+        col: u8,
+        color: Color,
+        liberties: Option<u8>,
+    ) {
+        match color {
+            Color::White => context.set_source_rgb(0.9, 0.9, 0.9),
+            Color::Black => context.set_source_rgb(0.0, 0.0, 0.0),
+        };
+        self.draw_stone(context, row, col);
+
+        if let Some(liberties) = liberties {
+            let stone_location = self.stone_location(row, col);
+            context.set_source_rgb(1., 0., 1.);
+            context.set_font_size(32.);
+            context.move_to(stone_location.0 - 10., stone_location.1 + 10.);
+            let _ = context.show_text(&format!("{}", liberties));
+        }
+    }
+
+    fn ghost_stone(&self, context: &cairo::Context, row: u8, col: u8, color: Color) {
+        match color {
+            Color::White => context.set_source_rgba(0.9, 0.9, 0.9, 0.5),
+            Color::Black => context.set_source_rgba(0.0, 0.0, 0.0, 0.5),
+        };
+        self.draw_stone(context, row, col);
+    }
+
+    fn draw_stone(&self, context: &cairo::Context, row: u8, col: u8) {
+        let radius = self.hspace_between / 2. - 2.;
+        let (x_loc, y_loc) = self.stone_location(row, col);
+        context.arc(x_loc, y_loc, radius, 0.0, 2.0 * std::f64::consts::PI);
+        let _ = context.fill();
+    }
+
+    fn stone_location(&self, row: u8, col: u8) -> (f64, f64) {
+        (
+            self.x_offset + (col as f64) * self.hspace_between,
+            self.y_offset + (row as f64) * self.vspace_between,
+        )
     }
 }