X11+Windows: Guess initial DPI factor (#583)

* X11: Guess initial DPI factor

* Windows: Guess initial DPI factor

src/platform/linux/x11/util/geometry.rs

@@ -3,34 +3,34 @@ use std::cmp;
 use super::*;
 use {LogicalPosition, LogicalSize};
 
+// Friendly neighborhood axis-aligned rectangle
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub struct Rect {
-    left: i64,
-    right: i64,
-    top: i64,
-    bottom: i64,
+pub struct AaRect {
+    x: i64,
+    y: i64,
+    width: i64,
+    height: i64,
 }
 
-impl Rect {
+impl AaRect {
     pub fn new((x, y): (i32, i32), (width, height): (u32, u32)) -> Self {
         let (x, y) = (x as i64, y as i64);
         let (width, height) = (width as i64, height as i64);
-        Rect {
-            left: x,
-            right: x + width,
-            top: y,
-            bottom: y + height,
-        }
+        AaRect { x, y, width, height }
+    }
+
+    pub fn contains_point(&self, x: i64, y: i64) -> bool {
+        x >= self.x && x <= self.x + self.width && y >= self.y && y <= self.y + self.height
     }
 
     pub fn get_overlapping_area(&self, other: &Self) -> i64 {
         let x_overlap = cmp::max(
             0,
-            cmp::min(self.right, other.right) - cmp::max(self.left, other.left),
+            cmp::min(self.x + self.width, other.x + other.width) - cmp::max(self.x, other.x),
         );
         let y_overlap = cmp::max(
             0,
-            cmp::min(self.bottom, other.bottom) - cmp::max(self.top, other.top),
+            cmp::min(self.y + self.height, other.y + other.height) - cmp::max(self.y, other.y),
         );
         x_overlap * y_overlap
     }

src/platform/linux/x11/util/input.rs

@@ -3,6 +3,9 @@ use std::str;
 use super::*;
 use events::ModifiersState;
 
+pub const VIRTUAL_CORE_POINTER: c_int = 2;
+pub const VIRTUAL_CORE_KEYBOARD: c_int = 3;
+
 // A base buffer size of 1kB uses a negligible amount of RAM while preventing us from having to
 // re-allocate (and make another round-trip) in the *vast* majority of cases.
 // To test if `lookup_utf8` works correctly, set this to 1.
@@ -24,8 +27,8 @@ pub struct PointerState<'a> {
     xconn: &'a XConnection,
     root: ffi::Window,
     child: ffi::Window,
-    root_x: c_double,
-    root_y: c_double,
+    pub root_x: c_double,
+    pub root_y: c_double,
     win_x: c_double,
     win_y: c_double,
     buttons: ffi::XIButtonState,

src/platform/linux/x11/util/randr.rs

@@ -24,6 +24,7 @@ pub fn calc_dpi_factor(
 
     // See http://xpra.org/trac/ticket/728 for more information.
     if width_mm == 0 || width_mm == 0 {
+        warn!("XRandR reported that the display's 0mm in size, which is certifiably insane");
         return 1.0;
     }