Reduce Increase-/DecreaseFontSize step to 0.5

Until now the Increase-/DecreaseFontSize keybinds hand a step size of 1.0. Since the font size however is multiplied by two to allow more granular font size control, this lead to the bindings skipping one font size (incrementing/decrementing by +-2).

To fix this the step size of the Increase-/DecreaseFontSize bindings has been reduced to the minimum step size that exists with the current font configuration (0.5). This should allow users to increment and decrement the font size by a single point instead of two.

This also adds a few tests to make sure the methods for increasing/decreasing/resetting font size work properly.

1 files changed, 74 insertions, 4 deletions

diff --git a/src/term/mod.rs b/src/term/mod.rs
index 4f56e7fc..27cc9312 100644
--- a/src/term/mod.rs
+++ b/src/term/mod.rs
@@ -30,6 +30,7 @@ use selection::{self, Span, Selection};
 use config::{Config, VisualBellAnimation};
 use {MouseCursor, Rgb};
 use copypasta::{Clipboard, Load, Store};
+use input::FONT_SIZE_STEP;
 
 pub mod cell;
 pub mod color;
@@ -841,10 +842,10 @@ impl Term {
         }
     }
 
-    pub fn change_font_size(&mut self, delta: i8) {
-        // Saturating addition with minimum font size 1
-        let new_size = self.font_size + Size::new(f32::from(delta));
-        self.font_size = max(new_size, Size::new(1.));
+    pub fn change_font_size(&mut self, delta: f32) {
+        // Saturating addition with minimum font size FONT_SIZE_STEP
+        let new_size = self.font_size + Size::new(delta);
+        self.font_size = max(new_size, Size::new(FONT_SIZE_STEP));
         self.dirty = true;
     }
 
@@ -1947,6 +1948,9 @@ mod tests {
     use ansi::{Handler, CharsetIndex, StandardCharset};
     use selection::Selection;
     use std::mem;
+    use input::FONT_SIZE_STEP;
+    use font::Size;
+    use config::Config;
 
     #[test]
     fn semantic_selection_works() {
@@ -2052,6 +2056,72 @@ mod tests {
 
         assert_eq!(term.grid()[&cursor].c, '▒');
     }
+
+    fn change_font_size_works(font_size: f32) {
+        let size = SizeInfo {
+            width: 21.0,
+            height: 51.0,
+            cell_width: 3.0,
+            cell_height: 3.0,
+            padding_x: 0.0,
+            padding_y: 0.0,
+        };
+        let config: Config = Default::default();
+        let mut term: Term = Term::new(&config, size);
+        term.change_font_size(font_size);
+
+        let expected_font_size: Size = config.font().size() + Size::new(font_size);
+        assert_eq!(term.font_size, expected_font_size);
+    }
+
+    #[test]
+    fn increase_font_size_works() {
+        change_font_size_works(10.0);
+    }
+
+    #[test]
+    fn decrease_font_size_works() {
+        change_font_size_works(-10.0);
+    }
+
+    #[test]
+    fn prevent_font_below_threshold_works() {
+        let size = SizeInfo {
+            width: 21.0,
+            height: 51.0,
+            cell_width: 3.0,
+            cell_height: 3.0,
+            padding_x: 0.0,
+            padding_y: 0.0,
+        };
+        let config: Config = Default::default();
+        let mut term: Term = Term::new(&config, size);
+
+        term.change_font_size(-100.0);
+
+        let expected_font_size: Size = Size::new(FONT_SIZE_STEP);
+        assert_eq!(term.font_size, expected_font_size);
+    }
+
+    #[test]
+    fn reset_font_size_works() {
+        let size = SizeInfo {
+            width: 21.0,
+            height: 51.0,
+            cell_width: 3.0,
+            cell_height: 3.0,
+            padding_x: 0.0,
+            padding_y: 0.0,
+        };
+        let config: Config = Default::default();
+        let mut term: Term = Term::new(&config, size);
+
+        term.change_font_size(10.0);
+        term.reset_font_size();
+
+        let expected_font_size: Size = config.font().size();
+        assert_eq!(term.font_size, expected_font_size);
+    }
 }
 
 #[cfg(all(test, feature = "bench"))]