reorg code

Cargo.toml

@@ -4,4 +4,4 @@ version = "0.1.0"
 authors = ["expectocode <expectocode@gmail.com>"]
 
 [dependencies]
-xcb = {version = "0.8.2", features = ["xkb"]}
+xcb = {version = "0.8.2", features = ["xkb", "shape"]}

src/main.rs

@@ -1,4 +1,58 @@
 extern crate xcb;
+use std::cmp::{max, min};
+use xcb::shape;
+
+const LINE_WIDTH: u16 = 3;
+
+fn set_shape(conn: &xcb::Connection, window: xcb::Window, rects: &[xcb::Rectangle]) {
+    shape::rectangles(
+        &conn,
+        shape::SO_SET as u8,
+        shape::SK_BOUNDING as u8,
+        0,
+        window,
+        0,
+        0,
+        &rects,
+    );
+}
+
+fn set_title(conn: &xcb::Connection, window: xcb::Window, title: &str) {
+    xcb::change_property(
+        &conn,
+        xcb::PROP_MODE_REPLACE as u8,
+        window,
+        xcb::ATOM_WM_NAME,
+        xcb::ATOM_STRING,
+        8,
+        title.as_bytes(),
+    );
+}
+
+fn grab_pointer_set_cursor(conn: &xcb::Connection, window: xcb::Window, screen: xcb::Screen) {
+    let font = conn.generate_id();
+    xcb::open_font(&conn, font, "cursor");
+
+    // TODO: create cursor with a Pixmap
+    // https://stackoverflow.com/questions/40578969/how-to-create-a-cursor-in-x11-from-raw-data-c
+    let cursor = conn.generate_id();
+    xcb::create_glyph_cursor(&conn, cursor, font, font, 0, 30, 0, 0, 0, 0, 0, 0);
+
+    xcb::grab_pointer(
+        &conn,
+        true,
+        screen.root(),
+        (xcb::EVENT_MASK_BUTTON_RELEASE
+            | xcb::EVENT_MASK_BUTTON_PRESS
+            | xcb::EVENT_MASK_BUTTON_MOTION) as u16,
+        xcb::GRAB_MODE_ASYNC as u8,
+        xcb::GRAB_MODE_ASYNC as u8,
+        xcb::NONE,
+        cursor,
+        xcb::CURRENT_TIME,
+    ).get_reply()
+    .unwrap();
+}
 
 fn main() {
     let (conn, screen_num) = xcb::Connection::connect(None).unwrap();
@@ -23,53 +77,23 @@ fn main() {
         xcb::COPY_FROM_PARENT as u8,
         window,
         screen.root(),
-        0, // x
+        0,                         // x
-        0, // y
+        0,                         // y
-        0, // width
+        screen.width_in_pixels(),  // width
-        0, // height
+        screen.height_in_pixels(), // height
         0,
         xcb::WINDOW_CLASS_INPUT_OUTPUT as u16,
         screen.root_visual(),
         &values,
     );
 
+    set_title(&conn, window, "hacksaw");
+    grab_pointer_set_cursor(&conn, window, screen);
+
+    set_shape(&conn, window, &[xcb::Rectangle::new(0, 0, 0, 0)]);
+
     xcb::map_window(&conn, window);
 
-    let title = "hacksaw";
-    // setting title
-    xcb::change_property(
-        &conn,
-        xcb::PROP_MODE_REPLACE as u8,
-        window,
-        xcb::ATOM_WM_NAME,
-        xcb::ATOM_STRING,
-        8,
-        title.as_bytes(),
-    );
-
-    let font = conn.generate_id();
-    xcb::open_font(&conn, font, "cursor");
-
-    // TODO: create cursor with a Pixmap
-    // https://stackoverflow.com/questions/40578969/how-to-create-a-cursor-in-x11-from-raw-data-c
-    let cursor = conn.generate_id();
-    xcb::create_glyph_cursor(&conn, cursor, font, font, 0, 30, 0, 0, 0, 0, 0, 0);
-
-    xcb::grab_pointer(
-        &conn,
-        true,
-        screen.root(),
-        (xcb::EVENT_MASK_BUTTON_RELEASE
-            | xcb::EVENT_MASK_BUTTON_PRESS
-            | xcb::EVENT_MASK_BUTTON_MOTION) as u16,
-        xcb::GRAB_MODE_ASYNC as u8,
-        xcb::GRAB_MODE_ASYNC as u8,
-        xcb::NONE,
-        cursor,
-        xcb::CURRENT_TIME,
-    ).get_reply()
-    .unwrap();
-
     conn.flush();
 
     // TODO formalise the fact that motion comes after press?
@@ -79,6 +103,9 @@ fn main() {
     let mut x = 0;
     let mut y = 0;
 
+    let mut width = 0;
+    let mut height = 0;
+
     loop {
         let ev = conn.wait_for_event().unwrap();
         match ev.response_type() {
@@ -105,7 +132,24 @@ fn main() {
                 let motion: &xcb::MotionNotifyEvent = unsafe { xcb::cast_event(&ev) };
                 x = motion.event_x();
                 y = motion.event_y();
-                // TODO draw rectangles (and guides)
+
+                // TODO investigate efficiency of let mut outside loop vs let inside
+                let top_x = min(x, start_x);
+                let top_y = min(y, start_y);
+                let bot_x = max(x, start_x);
+                let bot_y = max(y, start_y);
+
+                width = (x - start_x).abs() as u16;
+                height = (y - start_y).abs() as u16;
+
+                let rects = [
+                    xcb::Rectangle::new(top_x, top_y, LINE_WIDTH, height),
+                    xcb::Rectangle::new(top_x, top_y, width, LINE_WIDTH),
+                    xcb::Rectangle::new(bot_x, top_y, LINE_WIDTH, height),
+                    xcb::Rectangle::new(top_x, bot_y, width, LINE_WIDTH),
+                ];
+                set_shape(&conn, window, &rects);
+                conn.flush();
             }
             xcb::BUTTON_RELEASE => {
                 let motion: &xcb::ButtonReleaseEvent = unsafe { xcb::cast_event(&ev) };
@@ -115,15 +159,10 @@ fn main() {
                     _ => break,    // Move on after mouse released
                 }
             }
-            xcb::EXPOSE => {
-                println!("expose!");
-            }
             _ => continue,
         };
     }
 
     // Now we have taken coordinates, we use them
-    let width = (x - start_x).abs();
-    let height = (y - start_y).abs();
     println!("{}x{}+{}+{}", width, height, start_x, start_y);
 }