3 files changed, 160 insertions, 66 deletions

diff --git a/src/app.rs b/src/app.rs
index c0d3018..3c57f27 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -103,61 +103,30 @@ impl<'ctx> AppState<'ctx> {
         center: P,
         val: bool,
     ) -> Result<Vec<ModifyRecord>, ()> {
-        let radius = self.brush_size;
-        if radius == 1 {
-            let center_point: Point = center.into();
-            return Ok(if let Some(pt) = self.idx_at_coord(center_point) {
-                let old_val = self.pixmap.set(pt, val);
-                Ok(ModifyRecord::new(pt, old_val, val))
-            } else {
-                Err(())
-            }
-            .map(|x| vec![x])?);
-        } else {
-            if let Some(center_on_grid) = self.idx_at_coord(center) {
-                // center_on_grid is now a coordinate on the drawing grid
-                let (x0, y0) = (center_on_grid.0 as i64, center_on_grid.1 as i64);
-                let (mut dx, mut dy, mut err) = (radius as i64, 0i64, 1 - radius as i64);
-                let mut circle = vec![];
-                let mut old_vals = vec![];
-                while dx >= dy {
-                    circle.push((x0 + dx, y0 + dy));
-                    circle.push((x0 - dx, y0 + dy));
-                    circle.push((x0 + dx, y0 - dy));
-                    circle.push((x0 - dx, y0 - dy));
-                    circle.push((x0 + dy, y0 + dx));
-                    circle.push((x0 - dy, y0 + dx));
-                    circle.push((x0 + dy, y0 - dx));
-                    circle.push((x0 - dy, y0 - dx));
-                    dy = dy + 1;
-                    if err < 0 {
-                        err = err + 2 * dy + 1;
-                    } else {
-                        dx -= 1;
-                        err += 2 * (dy - dx) + 1;
-                    }
-                }
-                // circle's insides
-                for x in 0..radius as i64 {
-                    for y in 0..radius as i64 {
-                        if x.pow(2) + y.pow(2) < (radius as i64).pow(2) {
-                            circle.push((x0 + x, y0 + y));
-                            circle.push((x0 - x, y0 + y));
-                            circle.push((x0 + x, y0 - y));
-                            circle.push((x0 - x, y0 - y));
-                        }
-                    }
-                }
-                for circumference_pt in circle {
-                    if let Ok(mp) = MapPoint::try_from(circumference_pt) {
-                        let old_val = self.pixmap.set(mp, val);
-                        old_vals.push(ModifyRecord::new((mp.x, mp.y), old_val, val));
-                    }
-                }
-                return Ok(old_vals);
+        let radius = self.brush_size as u32;
+        let center = self.idx_at_coord(center).ok_or(())?;
+        let mut circle_modify_record = vec![];
+        for point in self.pixmap.get_circle(center, radius) {
+            let old_val = self.pixmap.set(point, val);
+            circle_modify_record.push(ModifyRecord::new(point, old_val, val));
+        }
+        Ok(circle_modify_record)
+    }
+
+    fn paint_line<P: Into<Point>>(&mut self, start: P, end: P) -> Result<Vec<ModifyRecord>, ()> {
+        let start = self.idx_at_coord(start).ok_or(())?;
+        let end = self.idx_at_coord(end).ok_or(())?;
+        let line_coords = self.pixmap.get_line(start, end);
+        let mut line_modify_record = vec![];
+        let val = self.active_color;
+        for point in line_coords {
+            let circle_around_point = self.pixmap.get_circle(point, self.brush_size as u32);
+            for c in circle_around_point {
+                let old_val = self.pixmap.set(c, val);
+                line_modify_record.push(ModifyRecord::new(c, old_val, val));
             }
         }
-        return Err(());
+        Ok(line_modify_record)
     }
 
     fn apply_operation(&mut self, op: Operation, op_kind: OpKind) {
@@ -176,6 +145,17 @@ impl<'ctx> AppState<'ctx> {
         }
     }
 
+    fn commit_operation(&mut self) {
+        if !self.current_operation.is_empty() {
+            let op = self
+                .current_operation
+                .drain(..)
+                .filter(|v| !v.old_val == v.val)
+                .collect::<Vec<_>>();
+            self.undo_stack.push(op);
+        }
+    }
+
     fn zoom_in(&mut self, p: (i32, i32)) {
         // attempt to center around cursor
         if let Some(p) = self.idx_at_coord(p) {
@@ -192,8 +172,8 @@ impl<'ctx> AppState<'ctx> {
         self.brush_size += 1;
     }
 
-    fn descrease_brush_size(&mut self) {
-        if self.brush_size > 1 {
+    fn decrease_brush_size(&mut self) {
+        if self.brush_size > 0 {
             self.brush_size -= 1;
         }
     }
@@ -296,7 +276,7 @@ impl<'ctx> AppState<'ctx> {
         Self {
             start: Point::new(60, 60),
             zoom: 5,
-            brush_size: 1,
+            brush_size: 0,
             pixmap,
             grid: Grid::new(),
             canvas,
@@ -339,12 +319,25 @@ impl<'ctx> AppState<'ctx> {
                                 self.modify(|e| e.zoom_out(cursor));
                             }
                             // brush ops
-                            Keycode::Q => self.modify(|e| e.descrease_brush_size()),
-                            Keycode::E => self.modify(|e| e.increase_brush_size()),
+                            Keycode::Q => self.decrease_brush_size(),
+                            Keycode::E => self.increase_brush_size(),
                             // flip color
                             Keycode::X => self.modify(|e| e.change_active_color()),
                             // toggle grid
                             Keycode::Tab => self.modify(|e| e.toggle_grid()),
+                            // line drawing
+                            Keycode::F => self.modify(|e| {
+                                let end = (mouse.x(), mouse.y()).into();
+                                if let Some(start) = e.last_point {
+                                    if let Ok(o) = e.paint_line(start, end) {
+                                        e.commit_operation();
+                                        e.current_operation =
+                                            o.into_iter().filter(|v| !v.old_val == v.val).collect();
+                                        e.commit_operation();
+                                        e.last_point = Some(end);
+                                    }
+                                }
+                            }),
                             // exit
                             Keycode::Escape => break 'running,
                             // undo & redo
@@ -381,9 +374,7 @@ impl<'ctx> AppState<'ctx> {
                     Event::MouseMotion {
                         x, y, mousestate, ..
                     } => {
-                        let is_left = mousestate.is_mouse_button_pressed(MouseButton::Left);
-                        let is_right = mousestate.is_mouse_button_pressed(MouseButton::Right);
-                        if is_left {
+                        if mousestate.is_mouse_button_pressed(MouseButton::Left) {
                             self.modify(|e| {
                                 let pt = (x, y);
                                 let val = e.active_color;
@@ -391,7 +382,7 @@ impl<'ctx> AppState<'ctx> {
                                     e.current_operation.extend(o);
                                 }
                             });
-                        } else if is_right {
+                        } else if mousestate.is_mouse_button_pressed(MouseButton::Right) {
                             self.modify(|e| {
                                 let pt = (x, y);
                                 let val = !e.active_color;
diff --git a/src/bitmap.rs b/src/bitmap.rs
index 01a39d9..8ff311b 100644
--- a/src/bitmap.rs
+++ b/src/bitmap.rs
@@ -1,4 +1,7 @@
-use std::convert::{From, Into, TryFrom};
+use std::{
+    convert::{From, Into, TryFrom},
+    ops::Sub,
+};
 
 #[derive(Debug)]
 pub struct Pixmap<T> {
@@ -59,6 +62,7 @@ where
             data,
         }
     }
+
     pub fn new_with(width: u32, height: u32, start: T) -> Self {
         let data = vec![start; (width * height) as usize];
         Pixmap {
@@ -67,18 +71,22 @@ where
             data,
         }
     }
+
     pub fn is_inside<P: Into<MapPoint>>(&self, pt: P) -> bool {
         let MapPoint { x, y } = pt.into();
         x < self.width && y < self.height
     }
+
     pub fn idx<P: Into<MapPoint>>(&self, pt: P) -> usize {
         let MapPoint { x, y } = pt.into();
         (y * self.width + x) as usize
     }
+
     pub fn get<P: Into<MapPoint>>(&self, pt: P) -> T {
         let idx = self.idx(pt);
         self.data[idx]
     }
+
     pub fn set<P: Into<MapPoint>>(&mut self, pt: P, new_val: T) -> T {
         let pt = pt.into();
         let old_val = self.get(pt);
@@ -86,4 +94,97 @@ where
         self.data[idx] = new_val;
         old_val
     }
+
+    pub fn get_circle<P: Into<MapPoint>>(&self, center: P, radius: u32) -> Vec<MapPoint> {
+        let mut circle: Vec<(i64, i64)> = vec![];
+        let MapPoint { x, y } = center.into();
+        let x = x as i64;
+        let y = y as i64;
+        let (mut dx, mut dy, mut err) = (radius as i64, 0i64, 1 - radius as i64);
+        while dx >= dy {
+            circle.push((x + dx, y + dy));
+            circle.push((x - dx, y + dy));
+            circle.push((x + dx, y - dy));
+            circle.push((x - dx, y - dy));
+            circle.push((x + dy, y + dx));
+            circle.push((x - dy, y + dx));
+            circle.push((x + dy, y - dx));
+            circle.push((x - dy, y - dx));
+            dy = dy + 1;
+            if err < 0 {
+                err = err + 2 * dy + 1;
+            } else {
+                dx -= 1;
+                err += 2 * (dy - dx) + 1;
+            }
+        }
+        for xi in 0..radius as i64 {
+            for yi in 0..radius as i64 {
+                if xi.pow(2) + yi.pow(2) < (radius as i64).pow(2) {
+                    circle.push((x + xi, y + yi));
+                    circle.push((x - xi, y + yi));
+                    circle.push((x + xi, y - yi));
+                    circle.push((x - xi, y - yi));
+                }
+            }
+        }
+        circle
+            .into_iter()
+            .flat_map(|pt| MapPoint::try_from(pt))
+            .filter(|&pt| self.is_inside(pt))
+            .collect()
+    }
+
+    pub fn get_line<P: Into<MapPoint>>(&self, start: P, end: P) -> Vec<MapPoint> {
+        let MapPoint { x: x1, y: y1 } = start.into();
+        let MapPoint { x: x2, y: y2 } = end.into();
+        let mut coordinates = vec![];
+        let dx = abs_difference(x1, x2) as i64;
+        let dy = abs_difference(y1, y2) as i64;
+        let sx = {
+            if x1 < x2 {
+                1
+            } else {
+                -1
+            }
+        };
+        let sy = {
+            if y1 < y2 {
+                1
+            } else {
+                -1
+            }
+        };
+        let mut err: i64 = dx - dy;
+        let mut current_x = x1 as i64;
+        let mut current_y = y1 as i64;
+        loop {
+            coordinates.push((current_x, current_y));
+            if current_x == x2 as i64 && current_y == y2 as i64 {
+                break;
+            }
+            let e2 = 2 * err;
+            if e2 > -dy {
+                err -= dy;
+                current_x += sx;
+            }
+            if e2 < dx {
+                err += dx;
+                current_y += sy;
+            }
+        }
+        coordinates
+            .into_iter()
+            .flat_map(|pt| MapPoint::try_from(pt))
+            .filter(|&pt| self.is_inside(pt))
+            .collect()
+    }
+}
+
+fn abs_difference<T: Sub<Output = T> + Ord>(x: T, y: T) -> T {
+    if x < y {
+        y - x
+    } else {
+        x - y
+    }
 }
diff --git a/src/undo.rs b/src/undo.rs
index b590312..ae96a66 100644
--- a/src/undo.rs
+++ b/src/undo.rs
@@ -1,14 +1,16 @@
+use crate::bitmap::MapPoint;
+
 #[derive(Copy, Clone, Debug)]
 pub struct ModifyRecord {
-    pub point: (u32, u32),
+    pub point: MapPoint,
     pub old_val: bool,
     pub val: bool,
 }
 
 impl ModifyRecord {
-    pub fn new(point: (u32, u32), old_val: bool, val: bool) -> Self {
+    pub fn new<P: Into<MapPoint>>(point: P, old_val: bool, val: bool) -> Self {
         ModifyRecord {
-            point,
+            point: point.into(),
             old_val,
             val,
         }