lines, barebones drawing window

addition of lines means ipc slightly changed, though can be ignored. also, minor malvim fix

wm/src/framebuffer.rs

@@ -108,6 +108,7 @@ impl FramebufferWriter {
       .copy_from_slice(&color[..]);
   }
 
+  //straight horizontal line
   fn _draw_line(&mut self, start_pos: usize, bytes: &[u8]) {
     self.buffer[start_pos..(start_pos + bytes.len())]
       .copy_from_slice(bytes);
@@ -244,6 +245,34 @@ impl FramebufferWriter {
     }
   }
 
+  //line
+
+  pub fn draw_line(&mut self, start: Point, end: Point, width: usize, color: RGBColor) {
+    //leftmost point
+    let lm;
+    let rm;
+    if start[0] < end[0] || (start[0] == end[0] && end[1] > start[1]) {
+      lm = start;
+      rm = end;
+    } else {
+      lm = end;
+      rm = start;
+    };
+    let dx = (rm[0] - lm[0]) as f64; //will not be negative
+    let dy = rm[1] as f64 - lm[1] as f64; //surely no point will be big enough to lose data here?
+    let use_x = dy.abs() < dx;
+    //slope
+    let m = if use_x { dy / dx } else { dx / dy };
+    for ci in 0..if use_x { dx as usize } else { dy.abs() as usize } {
+      let i = if !use_x && dy < 0.0 { -(ci as f64) } else { ci as f64 };
+      let ix = if use_x { i } else { (m * i).round() };
+      let iy = if use_x { (m * i).round() } else { i };
+      for j in 0..width {
+        self.draw_pixel([(lm[0] as f64 + ix) as usize + j, (lm[1] as f64 + iy) as usize], color);
+      }
+    }
+  }
+
   //bmps
 
   //reverse is workaround for when my bmp lib returns rgba instead of bgra

wm/src/window_manager.rs

@@ -648,6 +648,13 @@ impl WindowManager {
     [top_left[0], top_left[1] + if is_window { WINDOW_TOP_HEIGHT } else { 0 }]
   }
 
+  fn prevent_overflow_dimensions(dimensions: Dimensions, window_dimensions: Dimensions, top_left: Point) -> Dimensions {
+    [
+      min(dimensions[0], window_dimensions[0] - top_left[0]),
+      min(dimensions[1], window_dimensions[1] - top_left[1]),
+    ]
+  }
+
   //another issue with a huge vector of draw instructions; it takes up heap memory
   pub fn draw(&mut self, maybe_redraw_ids: Option<Vec<usize>>, use_saved_buffer: bool) {
     let theme_info = get_theme_info(&self.theme).unwrap();
@@ -694,6 +701,7 @@ impl WindowManager {
             DrawInstructions::Text(top_left, fonts, text, color, bg_color, horiz_spacing, mono_width) => DrawInstructions::Text(WindowManager::get_true_top_left(top_left, is_window), fonts.clone(), text.clone(), *color, *bg_color, *horiz_spacing, *mono_width),
             DrawInstructions::Bmp(top_left, path, reverse) => DrawInstructions::Bmp(WindowManager::get_true_top_left(top_left, is_window), path.to_string(), *reverse),
             DrawInstructions::Gradient(top_left, dimensions, start_color, end_color, steps) => DrawInstructions::Gradient(WindowManager::get_true_top_left(top_left, is_window), *dimensions, *start_color, *end_color, *steps),
+            DrawInstructions::Line(start, end, width, color) => DrawInstructions::Line(WindowManager::get_true_top_left(start, is_window), WindowManager::get_true_top_left(end, is_window), *width, *color),
           }
         }).collect();
         //draw window background
@@ -729,10 +737,7 @@ impl WindowManager {
         match instruction {
           DrawInstructions::Rect(top_left, dimensions, color) => {
             //try and prevent overflows out of the window
-            let true_dimensions = [
-              min(dimensions[0], window_dimensions[0] - top_left[0]),
-              min(dimensions[1], window_dimensions[1] - top_left[1]),
-            ];
+            let true_dimensions = WindowManager::prevent_overflow_dimensions(dimensions, window_dimensions, top_left);
             window_writer.draw_rect(top_left, true_dimensions, color);
           },
           DrawInstructions::Circle(centre, radius, color) => {
@@ -746,7 +751,11 @@ impl WindowManager {
             window_writer.draw_bmp(top_left, path, reverse);
           },
           DrawInstructions::Gradient(top_left, dimensions, start_color, end_color, steps) => {
-            window_writer.draw_gradient(top_left, dimensions, start_color, end_color, steps);
+            let true_dimensions = WindowManager::prevent_overflow_dimensions(dimensions, window_dimensions, top_left);
+            window_writer.draw_gradient(top_left, true_dimensions, start_color, end_color, steps);
+          },
+          DrawInstructions::Line(start, end, width, color) => {
+            window_writer.draw_line(start, end, width, color);
           },
         }
       }