Refactor `update_position`

The original implementation to determine the button opacity was clever, but not easy to understand. The new implementation is more verbose, but hopefully easier to get.

Refactor `update_position`
0eafe2c5 · Julian Hofer · 68642411 · 0eafe2c5
Commit 0eafe2c5 authored Oct 05, 2020 by Julian Hofer
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Showing with 12 additions and 6 deletions

paginator.rs src/widgets/paginator.rs +12 -6

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--- a/src/widgets/paginator.rs
+++ b/src/widgets/paginator.rs
@@ -64,16 +64,22 @@ impl PaginatorWidget {
    }

    fn update_position(&self) {
-        let n_pages = self.carousel.get_n_pages() as f64;
        let position = self.carousel.get_position();
        let page_nr = position.round() as u32;

-        let opacity_close = (position - n_pages + 2_f64).max(0_f64);
-        let opacity_previous = if position <= 1_f64 { position } else { 1_f64 };
-        let opacity_next = if position <= 1_f64 && position <= n_pages {
-            position % n_pages
+        let n_pages = self.carousel.get_n_pages() as f64;
+        let forelast_page = n_pages - 2.0;
+        let last_page = n_pages - 1.0;
+
+        let (opacity_close, opacity_previous, opacity_next) =
+            if (0.0 <= position) && (position < 1.0) {
+                (0.0, position, position)
+            } else if (1.0 <= position) && (position <= forelast_page) {
+                (0.0, 1.0, 1.0)
+            } else if (forelast_page < position) && (position <= last_page) {
+                (position - forelast_page, 1.0, 1.0)
            } else {
-            1_f64
+                panic!("Position of the carousel is outside the allowed range");
            };

        self.close_btn.set_opacity(opacity_close);