Fix drawing getting stuck in empty terminal

Fix drawing getting stuck in loops when terminal is too small by
checking for it.

melib/src/text_processing/grapheme_clusters.rs

@@ -71,10 +71,16 @@ pub trait TextProcessing: UnicodeSegmentation + CodePointsIter {
 
 impl TextProcessing for str {
     fn split_lines(&self, width: usize) -> Vec<String> {
+        if width == 0 {
+            return vec![];
+        }
         super::line_break::linear(self, width)
     }
 
     fn split_lines_reflow(&self, reflow: Reflow, width: Option<usize>) -> Vec<String> {
+        if width == Some(0) {
+            return vec![];
+        }
         super::line_break::split_lines_reflow(self, reflow, width)
     }
 }

melib/src/text_processing/line_break.rs

@@ -1023,6 +1023,9 @@ pub fn split_lines_reflow(text: &str, reflow: Reflow, width: Option<usize>) -> V
                                 ret.push(format!("⤷{}", &line[prev_line_offset..end_offset]));
                             }
                         }
+                        if prev_line_offset == end_offset && prev == new_off {
+                            break;
+                        }
                         prev_line_offset = end_offset;
                         prev = new_off;
                     }

src/components/mail/listing/compact.rs

@@ -294,6 +294,9 @@ impl ListingTrait for CompactListing {
             return;
         }
         let rows = get_y(bottom_right) - get_y(upper_left) + 1;
+        if rows == 0 {
+            return;
+        }
 
         if let Some(mvm) = self.movement.take() {
             match mvm {

src/components/mail/listing/conversations.rs

@@ -295,6 +295,9 @@ impl ListingTrait for ConversationsListing {
             return;
         }
         let rows = (get_y(bottom_right) - get_y(upper_left) + 1) / 3;
+        if rows == 0 {
+            return;
+        }
         let pad = (get_y(bottom_right) - get_y(upper_left) + 1) % 3;
 
         if let Some(mvm) = self.movement.take() {

src/components/mail/listing/plain.rs

@@ -300,6 +300,9 @@ impl ListingTrait for PlainListing {
             return;
         }
         let rows = get_y(bottom_right) - get_y(upper_left) + 1;
+        if rows == 0 {
+            return;
+        }
 
         if let Some(mvm) = self.movement.take() {
             match mvm {

src/components/mail/listing/thread.rs

@@ -225,6 +225,9 @@ impl ListingTrait for ThreadListing {
             return;
         }
         let rows = get_y(bottom_right) - get_y(upper_left) + 1;
+        if rows == 0 {
+            return;
+        }
         if let Some(mvm) = self.movement.take() {
             match mvm {
                 PageMovement::Up(amount) => {

src/terminal/position.rs

@@ -57,12 +57,8 @@ pub fn pos_dec(p: Pos, dec: (usize, usize)) -> Pos {
 /// An `Area` consists of two points: the upper left and bottom right corners.
 ///
 /// Example:
-/// ```
+/// ```no_run
-/// # #[macro_use] extern crate ui; fn main() {
-/// use ui::*;
-///
 /// let new_area = ((0, 0), (1, 1));
-/// # }
 /// ```
 pub type Area = (Pos, Pos);
 
@@ -70,12 +66,8 @@ pub type Area = (Pos, Pos);
 ///
 /// Example:
 /// ```
-/// # #[macro_use] extern crate ui; fn main() {
-/// use ui::*;
-///
 /// let new_area = ((0, 0), (1, 1));
 /// assert_eq!(height!(new_area), 1);
-/// # }
 /// ```
 #[macro_export]
 macro_rules! height {
@@ -88,12 +80,8 @@ macro_rules! height {
 ///
 /// Example:
 /// ```
-/// # #[macro_use] extern crate ui; fn main() {
-/// use ui::*;
-///
 /// let new_area = ((0, 0), (1, 1));
 /// assert_eq!(width!(new_area), 1);
-/// # }
 /// ```
 #[macro_export]
 macro_rules! width {
@@ -106,12 +94,8 @@ macro_rules! width {
 ///
 /// Example:
 /// ```
-/// # #[macro_use] extern crate ui; fn main() {
-/// use ui::*;
-///
 /// let new_area = ((0, 0), (1, 1));
 /// assert_eq!(upper_left!(new_area), (0, 0));
-/// # }
 /// ```
 #[macro_export]
 macro_rules! upper_left {
@@ -124,12 +108,8 @@ macro_rules! upper_left {
 ///
 /// Example:
 /// ```
-/// # #[macro_use] extern crate ui; fn main() {
-/// use ui::*;
-///
 /// let new_area = ((0, 0), (1, 1));
 /// assert_eq!(bottom_right!(new_area), (1, 1));
-/// # }
 /// ```
 #[macro_export]
 macro_rules! bottom_right {
@@ -142,15 +122,12 @@ macro_rules! bottom_right {
 ///
 /// Example:
 /// ```
-/// # #[macro_use] extern crate ui; fn main() {
-/// use ui::*;
-///
 /// let valid_area = ((0, 0), (1, 1));
 /// assert!(is_valid_area!(valid_area));
 ///
 /// let invalid_area = ((2, 2), (1, 1));
 /// assert!(!is_valid_area!(invalid_area));
-/// # }
+/// ```
 ///
 #[macro_export]
 macro_rules! is_valid_area {