Rework line overlapping algorithm and improve arrow styles

src/consts.rs

@@ -10,18 +10,12 @@ pub const CHAR_HOR_UP_L: char = '┴';
 pub const CHAR_HOR_DOWN_L: char = '┬';
 pub const CHAR_VER_RIGHT_L: char = '├';
 pub const CHAR_VER_LEFT_L: char = '┤';
+pub const CHAR_CROSS: char = '┼';
 
-pub const CHAR_ARROW_DOWN: char = '🭯';
-pub const CHAR_ARROW_UP: char = '🭭';
-pub const CHAR_ARROW_RIGHT: char = '►';
-pub const CHAR_ARROW_LEFT: char = '◄';
-
-pub fn is_arrowhead(c: char) -> bool {
-    c.eq(&CHAR_ARROW_LEFT)
-        || c.eq(&CHAR_ARROW_RIGHT)
-        || c.eq(&CHAR_ARROW_UP)
-        || c.eq(&CHAR_ARROW_DOWN)
-}
+pub const CHAR_ARROW_UP: char = '🭯';
+pub const CHAR_ARROW_DOWN: char = '🭭';
+pub const CHAR_ARROW_RIGHT: char = '▶';
+pub const CHAR_ARROW_LEFT: char = '◀';
 
 pub const CHAR_SPACE: char = ' ';
 pub const CHAR_NEWLINE: char = '\n';

src/data/grid_cell.rs

@@ -1,11 +1,14 @@
-use crate::consts::{CHAR_NEWLINE, CHAR_SPACE};
+use crate::consts::CHAR_SPACE;
+use crate::data::overlap;
+use crate::shapes::line::LineDirection;
 
 #[derive(Clone, Copy)]
 pub struct GridCell {
     pub highlight_index: usize,
     pub content: char,
     pub preview: Option<char>,
     pub highlighted: bool,
+    pub line_direction: Option<LineDirection>,
 }
 
 impl GridCell {
@@ -15,22 +18,22 @@ impl GridCell {
             content,
             preview: None,
             highlighted: false,
+            line_direction: None,
         }
     }
 
-    pub fn empty() -> Self {
-        GridCell::new(CHAR_SPACE)
+    pub fn set_line_direction(&mut self, direction: LineDirection) {
+        self.line_direction = Some(direction);
     }
 
-    pub fn newline() -> Self {
-        GridCell::new(CHAR_NEWLINE)
+    pub fn empty() -> Self {
+        GridCell::new(CHAR_SPACE)
     }
 
-    pub fn read(&self) -> char {
-        if let Some(content) = self.preview {
-            return content;
-        }
-        self.content
+    pub fn read(&self) -> (char, char) {
+        let content = self.content;
+        let preview = self.preview.unwrap_or(' ');
+        (content, preview)
     }
 
     pub fn read_content(&self) -> char {
@@ -53,13 +56,19 @@ impl GridCell {
 
     pub fn commit(&mut self) {
         if let Some(preview) = self.preview {
-            self.content = preview;
+            // TODO: Implement line overlap processing here
+            // Each cell should carry an information about the starting point and the drawing
+            // direction, so the overlap algorithm could use
+            self.content =
+                overlap::calculate_cell_content(self.line_direction, self.content, preview);
             self.preview = None;
+            self.line_direction = None;
         }
     }
 
     pub fn discard(&mut self) {
         self.preview = None;
+        self.line_direction = None;
     }
 
     pub fn highlight(&mut self, highlight_index: usize) {

src/data/grid_list.rs

@@ -73,7 +73,7 @@ impl GridList {
                 }
             }
             last_i = Some(cell.highlight_index);
-            line.push(cell.read());
+            line.push(cell.read().0);
         }
         if !line.is_empty() {
             result.push(line);

src/data/mod.rs

@@ -7,6 +7,8 @@ pub mod grid_list;
 pub mod selection;
 pub mod shape_list;
 
+mod overlap;
+
 #[derive(Clone, PartialEq, Data)]
 pub struct ApplicationState {
     pub mode: DrawingTools,