support clicking in scrollbar to move cursor/view

2 files changed, 73 insertions, 12 deletions

diff --git a/main.lua b/main.lua
index 9e8a888..1f93058 100644
--- a/main.lua
+++ b/main.lua
@@ -1044,18 +1044,24 @@ local function process_mouse_click(ev)
 		return
 	end
 
-	local line = osd:get_mouse_line(mouse_state.pos)
-	if line then
-		line = line - (osd.lines - osd:menu_lines(state))
+	local area
+	local val = osd:mouse_scrollbar_ratio(mouse_state.pos)
+	if val then
+		area = 'scrollbar'
+	else
+		local line = osd:mouse_menu_line(mouse_state.pos)
+		if line then
+			area = 'menu'
+			val = line - (osd.lines - osd:menu_lines(state))
+		end
 	end
 
-	local key, dbl = handle_mouse_click(ev, line)
-	return key, dbl, line
+	local key, dbl = handle_mouse_click(ev, area == 'menu' and val or nil)
+	return key, dbl, area, val
 end
 
-local function mouse_click_left(ev)
-	local key, dbl, line = process_mouse_click(ev)
-	if not key or not line or line == 0 then
+local function mouse_click_left_menu(dbl, line)
+	if line == 0 then
 		return
 	end
 
@@ -1091,9 +1097,32 @@ local function mouse_click_left(ev)
 	end
 end
 
-local function mouse_click_right(ev)
-	local key, dbl, line = process_mouse_click(ev)
-	if not key or not dbl or not line or line < 1 then
+local function mouse_click_left_scrollbar(dbl, ratio)
+	if not dbl then
+		return
+	end
+
+	-- set_cursor handles out-of-bounds moves (when ratio == 1)
+	set_cursor(
+		math.floor(ratio * #state:menu().options) + 1,
+		{centre = true})
+end
+
+local function mouse_click_left(ev)
+	local key, dbl, area, val = process_mouse_click(ev)
+	if not key then
+		return
+	end
+
+	if area == 'menu' then
+		return mouse_click_left_menu(dbl, val)
+	elseif area == 'scrollbar' then
+		return mouse_click_left_scrollbar(dbl, val)
+	end
+end
+
+local function mouse_click_right_menu(dbl, line)
+	if not dbl or line < 1 then
 		return
 	end
 
@@ -1106,6 +1135,17 @@ local function mouse_click_right(ev)
 	open_option_info(menu.options[pos])
 end
 
+local function mouse_click_right(ev)
+	local key, dbl, area, val = process_mouse_click(ev)
+	if not key then
+		return
+	end
+
+	if area == 'menu' then
+		return mouse_click_right_menu(dbl, val)
+	end
+end
+
 local function reload_data()
 	if state.depth > 1 then
 		osd:flash_error('Can only reload data from root menu')
diff --git a/osd.lua b/osd.lua
index 3be5e2d..35115a1 100644
--- a/osd.lua
+++ b/osd.lua
@@ -419,6 +419,7 @@ function mt:draw_scrollbar(state)
 	local opts = #menu.options
 	local lines = self:menu_lines(state)
 	if opts <= lines then
+		self.scrollbar_coords = nil
 		return
 	end
 
@@ -427,6 +428,12 @@ function mt:draw_scrollbar(state)
 	local w = self.padding - 4
 	local hh = math.max(config.font_size / 2, h * lines / opts)
 	local pos = (h - hh) * (menu.view_top - 1) / (opts - lines)
+	self.scrollbar_coords = {
+		x1 = 2,
+		y1 = top,
+		x2 = 2 + w,
+		y2 = top + h,
+	}
 
 	return (
 		-- bg
@@ -603,7 +610,7 @@ function mt:is_hidden()
 	return self.fg.hidden
 end
 
-function mt:get_mouse_line(mpos)
+function mt:mouse_menu_line(mpos)
 	local x = mpos.x / self.scale
 	local w = self.width / self.scale
 	if x < self.padding or x > w - self.padding then
@@ -618,6 +625,20 @@ function mt:get_mouse_line(mpos)
 	return line
 end
 
+function mt:mouse_scrollbar_ratio(mpos)
+	local x = mpos.x / self.scale
+	local y = mpos.y / self.scale
+	local coords = self.scrollbar_coords
+
+	if not coords or x < coords.x1 or x > coords.x2 or
+			y < coords.y1 or y > coords.y2 then
+		return
+	end
+
+	local ratio = (y - coords.y1) / (coords.y2 - coords.y1)
+	return math.max(0, math.min(1, ratio))
+end
+
 function mt:mouse_over_button_area(mpos)
 	if not mpos.hover then
 		return false