page: tidy horizontal scrolling

bebop/page.py

@@ -40,7 +40,7 @@ class Page:
         content_position = self.current_line, self.current_column
         self.pad.refresh(*content_position, 0, 0, x, y)
 
-    def scroll_v(self, num_lines: int, window_height: int =None):
+    def scroll_v(self, num_lines: int, window_height: int =0):
         """Make the content pad scroll up and down by num_lines.
 
         Arguments:
@@ -63,14 +63,18 @@ class Page:
                 return True
         return False
 
-    def scroll_left(self):
-        if self.current_column > 0:
-            self.current_column -= 1
-            return True
-        return False
-
-    def scroll_right(self, window_width):
-        if self.current_column < Page.MAX_COLS - window_width:
-            self.current_column += 1
-            return True
+    def scroll_h(self, num_columns: int, window_width: int =0):
+        if num_columns < 0:
+            num_columns = -num_columns
+            min_column = 0
+            if self.current_column > min_column:
+                new_column = self.current_column - num_columns
+                self.current_column = max(new_column, min_column)
+                return True
+        else:
+            max_column = self.dim[1] - window_width
+            if self.current_column < max_column:
+                new_column = self.current_column + num_columns
+                self.current_column = min(new_column, max_column)
+                return True
         return False

bebop/screen.py

@@ -76,17 +76,17 @@ class Screen:
             elif char == ord("s"):
                 self.set_status(f"h {self.h} w {self.w}")
             elif char == ord("h"):
-                if self.page.scroll_left():
-                    self.refresh_page()
+                self.scroll_page_horizontally(-1)
             elif char == ord("j"):
-                if self.page.scroll_v(1, self.h - 2):
-                    self.refresh_page()
+                self.scroll_page_vertically(1)
             elif char == ord("k"):
-                if self.page.scroll_v(-1, self.h - 2):
-                    self.refresh_page()
+                self.scroll_page_vertically(-1)
             elif char == ord("l"):
-                if self.page.scroll_right(self.w):
-                    self.refresh_page()
+                self.scroll_page_horizontally(1)
+            elif char == ord("f"):
+                self.scroll_page_vertically(self.page_pad_size[0])
+            elif char == ord("b"):
+                self.scroll_page_vertically(-self.page_pad_size[0])
             elif char == ord("H"):
                 self.go_back()
             elif curses.ascii.isdigit(char):
@@ -324,11 +324,9 @@ class Screen:
         Right now, only vertical scrolling is handled.
         """
         if bstate & ButtonState.SCROLL_UP:
-            if self.page.scroll_v(-3):
-                self.refresh_page()
+            self.scroll_page_vertically(-3)
         elif bstate & ButtonState.SCROLL_DOWN:
-            if self.page.scroll_v(3, self.h - 2):
-                self.refresh_page()
+            self.scroll_page_vertically(3)
 
     def handle_resize(self):
         """Try to not make everything collapse on resizes."""
@@ -356,6 +354,14 @@ class Screen:
             self.screen.refresh()
         self.refresh_windows()
 
+    def scroll_page_vertically(self, by_lines: int):
+        if self.page.scroll_v(by_lines, self.h - 2):
+            self.refresh_page()
+
+    def scroll_page_horizontally(self, by_columns: int):
+        if self.page.scroll_h(by_columns, self.w):
+            self.refresh_page()
+
     def go_back(self):
         """Go back in history if possible."""
         if self.history: