improve windows code

input-capture/src/windows/display_util.rs

@@ -0,0 +1,99 @@
+use windows::Win32::Foundation::RECT;
+
+use crate::Position;
+
+fn is_within_dp_region(point: (i32, i32), display: &RECT) -> bool {
+    [
+        Position::Left,
+        Position::Right,
+        Position::Top,
+        Position::Bottom,
+    ]
+    .iter()
+    .all(|&pos| is_within_dp_boundary(point, display, pos))
+}
+
+fn is_within_dp_boundary(point: (i32, i32), display: &RECT, pos: Position) -> bool {
+    let (x, y) = point;
+    match pos {
+        Position::Left => display.left <= x,
+        Position::Right => display.right > x,
+        Position::Top => display.top <= y,
+        Position::Bottom => display.bottom > y,
+    }
+}
+
+/// returns whether the given position is within the display bounds with respect to the given
+/// barrier position
+///
+/// # Arguments
+///
+/// * `x`:
+/// * `y`:
+/// * `displays`:
+/// * `pos`:
+///
+/// returns: bool
+///
+fn in_bounds(point: (i32, i32), displays: &[RECT], pos: Position) -> bool {
+    displays
+        .iter()
+        .any(|d| is_within_dp_boundary(point, d, pos))
+}
+
+fn in_display_region(point: (i32, i32), displays: &[RECT]) -> bool {
+    displays.iter().any(|d| is_within_dp_region(point, d))
+}
+
+fn moved_across_boundary(
+    prev_pos: (i32, i32),
+    curr_pos: (i32, i32),
+    displays: &[RECT],
+    pos: Position,
+) -> bool {
+    /* was within bounds, but is not anymore */
+    in_display_region(prev_pos, displays) && !in_bounds(curr_pos, displays, pos)
+}
+
+pub(crate) fn entered_barrier(
+    prev_pos: (i32, i32),
+    curr_pos: (i32, i32),
+    displays: &[RECT],
+) -> Option<Position> {
+    [
+        Position::Left,
+        Position::Right,
+        Position::Top,
+        Position::Bottom,
+    ]
+    .into_iter()
+    .find(|&pos| moved_across_boundary(prev_pos, curr_pos, displays, pos))
+}
+
+///
+/// clamp point to display bounds
+///
+/// # Arguments
+///
+/// * `prev_point`: coordinates, the cursor was before entering, within bounds of a display
+/// * `entry_point`: point to clamp
+///
+/// returns: (i32, i32), the corrected entry point
+///
+pub(crate) fn clamp_to_display_bounds(
+    display_regions: &[RECT],
+    prev_point: (i32, i32),
+    point: (i32, i32),
+) -> (i32, i32) {
+    /* find display where movement came from */
+    let display = display_regions
+        .iter()
+        .find(|&d| is_within_dp_region(prev_point, d))
+        .unwrap();
+
+    /* clamp to bounds (inclusive) */
+    let (x, y) = point;
+    let (min_x, max_x) = (display.left, display.right - 1);
+    let (min_y, max_y) = (display.top, display.bottom - 1);
+    (x.clamp(min_x, max_x), y.clamp(min_y, max_y))
+}