Add default support for scrolling with the mouse wheel.

Also changes the scrollback() function so that the amount to scroll
can be configured as a fraction of the screen height.

This fixes martanne#103.

Makefile

@@ -10,7 +10,7 @@ DEBUG_CFLAGS = ${CFLAGS} -UNDEBUG -O0 -g -ggdb -Wall -Wextra -Wno-unused-paramet
 
 all: dvtm dvtm-editor
 
-config.h:
+config.h: config.def.h
 	cp config.def.h config.h
 
 dvtm: config.h config.mk *.c *.h

config.def.h

@@ -120,12 +120,12 @@ static KeyBinding bindings[] = {
 	{ { MOD, 'E',          }, { copymode,       { "dvtm-pager" }            } },
 	{ { MOD, '/',          }, { copymode,       { "dvtm-pager", "/" }       } },
 	{ { MOD, 'p',          }, { paste,          { NULL }                    } },
-	{ { MOD, KEY_PPAGE,    }, { scrollback,     { "-1" }                    } },
-	{ { MOD, KEY_NPAGE,    }, { scrollback,     { "1"  }                    } },
+	{ { MOD, KEY_PPAGE,    }, { scrollback,     { "-2" }                    } },
+	{ { MOD, KEY_NPAGE,    }, { scrollback,     { "2"  }                    } },
 	{ { MOD, '?',          }, { create,         { "man dvtm", "dvtm help" } } },
 	{ { MOD, MOD,          }, { send,           { (const char []){MOD, 0} } } },
-	{ { KEY_SPREVIOUS,     }, { scrollback,     { "-1" }                    } },
-	{ { KEY_SNEXT,         }, { scrollback,     { "1"  }                    } },
+	{ { KEY_SPREVIOUS,     }, { scrollback,     { "-2" }                    } },
+	{ { KEY_SNEXT,         }, { scrollback,     { "2"  }                    } },
 	{ { MOD, '0',          }, { view,           { NULL }                    } },
 	{ { MOD, KEY_F(1),     }, { view,           { tags[0] }                 } },
 	{ { MOD, KEY_F(2),     }, { view,           { tags[1] }                 } },
@@ -177,6 +177,8 @@ static const ColorRule colorrules[] = {
 
 #ifdef NCURSES_MOUSE_VERSION
 # define CONFIG_MOUSE /* compile in mouse support if we build against ncurses */
+#else
+# warning "Compiling without mouse support"
 #endif
 
 #define ENABLE_MOUSE true /* whether to enable mouse events by default */
@@ -187,6 +189,12 @@ static Button buttons[] = {
 	{ BUTTON1_DOUBLE_CLICKED, { mouse_fullscreen, { "[ ]" } } },
 	{ BUTTON2_CLICKED,        { mouse_zoom,       { NULL  } } },
 	{ BUTTON3_CLICKED,        { mouse_minimize,   { NULL  } } },
+# if NCURSES_MOUSE_VERSION > 1
+	{ BUTTON4_PRESSED,        { scrollback,       { "-4" } } },
+	{ BUTTON5_PRESSED,        { scrollback,       { "4"  } } },
+# else
+#  warning "Compiling without mouse wheel support"
+# endif
 };
 #endif /* CONFIG_MOUSE */
 

dvtm.1

@@ -243,6 +243,10 @@ Zoom/cycle current window to/from master area.
 .
 .It Ic Button3 click
 Toggle minimization of current window.
+.
+.It Ic Button4/Button5 (mouse wheel)
+Scroll using the mouse wheel. This is only available if dvtm was compiled
+with ncurses version 6 or higher.
 .El
 .
 .

dvtm.c

@@ -1328,13 +1328,19 @@ redraw(const char *args[]) {
 
 static void
 scrollback(const char *args[]) {
+	int div = 0;
 	if (!is_content_visible(sel))
 		return;
 
-	if (!args[0] || atoi(args[0]) < 0)
-		vt_scroll(sel->term, -sel->h/2);
+	if (args[0])
+		div = atoi(args[0]);
+	if (!div)
+		div = -2;
+
+	if (div > sel->h)
+		vt_scroll(sel->term,  abs(div)/div);
 	else
-		vt_scroll(sel->term,  sel->h/2);
+		vt_scroll(sel->term,  sel->h/div);
 
 	draw(sel);
 	curs_set(vt_cursor_visible(sel->term));
@@ -1644,6 +1650,7 @@ handle_mouse(void) {
 #ifdef CONFIG_MOUSE
 	MEVENT event;
 	unsigned int i;
+	debug("mouse\n");
 	if (getmouse(&event) != OK)
 		return;
 	msel = get_client_by_coord(event.x, event.y);