cleanup

modules/ScrollManager.lua

@@ -1,10 +1,3 @@
---- ScrollManager.lua
---- Handles scrolling, overflow detection, and scrollbar rendering/interaction for Elements
---- Extracted from Element.lua as part of element-refactor-modularization task 05
----
---- Dependencies (must be injected via deps parameter):
----   - Color: Color module for creating color instances
-
 ---@class ScrollManager
 ---@field overflow string -- "visible"|"hidden"|"auto"|"scroll"
 ---@field overflowX string? -- X-axis specific overflow (overrides overflow)
@@ -41,15 +34,15 @@ ScrollManager.__index = ScrollManager
 function ScrollManager.new(config, deps)
   local Color = deps.Color
   local self = setmetatable({}, ScrollManager)
-  
+
   -- Store dependency for instance methods
   self._Color = Color
-  
+
   -- Configuration
   self.overflow = config.overflow or "hidden"
   self.overflowX = config.overflowX
   self.overflowY = config.overflowY
-  
+
   -- Scrollbar appearance
   self.scrollbarWidth = config.scrollbarWidth or 12
   self.scrollbarColor = config.scrollbarColor or Color.new(0.5, 0.5, 0.5, 0.8)
@@ -57,7 +50,7 @@ function ScrollManager.new(config, deps)
   self.scrollbarRadius = config.scrollbarRadius or 6
   self.scrollbarPadding = config.scrollbarPadding or 2
   self.scrollSpeed = config.scrollSpeed or 20
-  
+
   -- hideScrollbars can be boolean or table {vertical: boolean, horizontal: boolean}
   if config.hideScrollbars ~= nil then
     if type(config.hideScrollbars) == "boolean" then
@@ -73,19 +66,19 @@ function ScrollManager.new(config, deps)
   else
     self.hideScrollbars = { vertical = false, horizontal = false }
   end
-  
+
   -- Internal overflow state
   self._overflowX = false
   self._overflowY = false
   self._contentWidth = 0
   self._contentHeight = 0
-  
+
   -- Scroll state (can be restored from config in immediate mode)
   self._scrollX = config._scrollX or 0
   self._scrollY = config._scrollY or 0
   self._maxScrollX = 0
   self._maxScrollY = 0
-  
+
   -- Scrollbar interaction state
   self._scrollbarHoveredVertical = false
   self._scrollbarHoveredHorizontal = false
@@ -93,10 +86,10 @@ function ScrollManager.new(config, deps)
   self._hoveredScrollbar = nil -- "vertical" or "horizontal"
   self._scrollbarDragOffset = 0
   self._scrollbarPressHandled = false
-  
+
   -- Element reference (set via initialize)
   self._element = nil
-  
+
   return self
 end
 
@@ -111,34 +104,34 @@ function ScrollManager:detectOverflow()
   if not self._element then
     error("ScrollManager:detectOverflow() called before initialize()")
   end
-  
+
   local element = self._element
-  
+
   -- Reset overflow state
   self._overflowX = false
   self._overflowY = false
   self._contentWidth = element.width
   self._contentHeight = element.height
-  
+
   -- Skip detection if overflow is visible (no clipping needed)
   local overflowX = self.overflowX or self.overflow
   local overflowY = self.overflowY or self.overflow
   if overflowX == "visible" and overflowY == "visible" then
     return
   end
-  
+
   -- Calculate content bounds based on children
   if #element.children == 0 then
     return -- No children, no overflow
   end
-  
+
   local minX, minY = 0, 0
   local maxX, maxY = 0, 0
-  
+
   -- Content area starts after padding
   local contentX = element.x + element.padding.left
   local contentY = element.y + element.padding.top
-  
+
   for _, child in ipairs(element.children) do
     -- Skip absolutely positioned children (they don't contribute to overflow)
     if not child._explicitlyAbsolute then
@@ -147,27 +140,27 @@ function ScrollManager:detectOverflow()
       local childTop = child.y - contentY
       local childRight = childLeft + child:getBorderBoxWidth() + child.margin.right
       local childBottom = childTop + child:getBorderBoxHeight() + child.margin.bottom
-      
+
       maxX = math.max(maxX, childRight)
       maxY = math.max(maxY, childBottom)
     end
   end
-  
+
   -- Calculate content dimensions
   self._contentWidth = maxX
   self._contentHeight = maxY
-  
+
   -- Detect overflow
   local containerWidth = element.width
   local containerHeight = element.height
-  
+
   self._overflowX = self._contentWidth > containerWidth
   self._overflowY = self._contentHeight > containerHeight
-  
+
   -- Calculate maximum scroll bounds
   self._maxScrollX = math.max(0, self._contentWidth - containerWidth)
   self._maxScrollY = math.max(0, self._contentHeight - containerHeight)
-  
+
   -- Clamp current scroll position to new bounds
   self._scrollX = math.max(0, math.min(self._scrollX, self._maxScrollX))
   self._scrollY = math.max(0, math.min(self._scrollY, self._maxScrollY))
@@ -235,28 +228,28 @@ function ScrollManager:calculateScrollbarDimensions()
   if not self._element then
     error("ScrollManager:calculateScrollbarDimensions() called before initialize()")
   end
-  
+
   local element = self._element
   local result = {
     vertical = { visible = false, trackHeight = 0, thumbHeight = 0, thumbY = 0 },
     horizontal = { visible = false, trackWidth = 0, thumbWidth = 0, thumbX = 0 },
   }
-  
+
   local overflowX = self.overflowX or self.overflow
   local overflowY = self.overflowY or self.overflow
-  
+
   -- Vertical scrollbar
   -- Note: overflow="scroll" always shows scrollbar; overflow="auto" only when content overflows
   if overflowY == "scroll" then
     -- Always show scrollbar for "scroll" mode
     result.vertical.visible = true
     result.vertical.trackHeight = element.height - (self.scrollbarPadding * 2)
-    
+
     if self._overflowY then
       -- Content overflows, calculate proper thumb size
       local contentRatio = element.height / math.max(self._contentHeight, element.height)
       result.vertical.thumbHeight = math.max(20, result.vertical.trackHeight * contentRatio)
-      
+
       -- Calculate thumb position based on scroll ratio
       local scrollRatio = self._maxScrollY > 0 and (self._scrollY / self._maxScrollY) or 0
       local maxThumbY = result.vertical.trackHeight - result.vertical.thumbHeight
@@ -270,29 +263,29 @@ function ScrollManager:calculateScrollbarDimensions()
     -- Only show scrollbar when content actually overflows
     result.vertical.visible = true
     result.vertical.trackHeight = element.height - (self.scrollbarPadding * 2)
-    
+
     -- Calculate thumb height based on content ratio
     local contentRatio = element.height / math.max(self._contentHeight, element.height)
     result.vertical.thumbHeight = math.max(20, result.vertical.trackHeight * contentRatio)
-    
+
     -- Calculate thumb position based on scroll ratio
     local scrollRatio = self._maxScrollY > 0 and (self._scrollY / self._maxScrollY) or 0
     local maxThumbY = result.vertical.trackHeight - result.vertical.thumbHeight
     result.vertical.thumbY = maxThumbY * scrollRatio
   end
-  
+
   -- Horizontal scrollbar
   -- Note: overflow="scroll" always shows scrollbar; overflow="auto" only when content overflows
   if overflowX == "scroll" then
     -- Always show scrollbar for "scroll" mode
     result.horizontal.visible = true
     result.horizontal.trackWidth = element.width - (self.scrollbarPadding * 2)
-    
+
     if self._overflowX then
       -- Content overflows, calculate proper thumb size
       local contentRatio = element.width / math.max(self._contentWidth, element.width)
       result.horizontal.thumbWidth = math.max(20, result.horizontal.trackWidth * contentRatio)
-      
+
       -- Calculate thumb position based on scroll ratio
       local scrollRatio = self._maxScrollX > 0 and (self._scrollX / self._maxScrollX) or 0
       local maxThumbX = result.horizontal.trackWidth - result.horizontal.thumbWidth
@@ -306,17 +299,17 @@ function ScrollManager:calculateScrollbarDimensions()
     -- Only show scrollbar when content actually overflows
     result.horizontal.visible = true
     result.horizontal.trackWidth = element.width - (self.scrollbarPadding * 2)
-    
+
     -- Calculate thumb width based on content ratio
     local contentRatio = element.width / math.max(self._contentWidth, element.width)
     result.horizontal.thumbWidth = math.max(20, result.horizontal.trackWidth * contentRatio)
-    
+
     -- Calculate thumb position based on scroll ratio
     local scrollRatio = self._maxScrollX > 0 and (self._scrollX / self._maxScrollX) or 0
     local maxThumbX = result.horizontal.trackWidth - result.horizontal.thumbWidth
     result.horizontal.thumbX = maxThumbX * scrollRatio
   end
-  
+
   return result
 end
 
@@ -328,19 +321,19 @@ function ScrollManager:getScrollbarAtPosition(mouseX, mouseY)
   if not self._element then
     error("ScrollManager:getScrollbarAtPosition() called before initialize()")
   end
-  
+
   local element = self._element
   local overflowX = self.overflowX or self.overflow
   local overflowY = self.overflowY or self.overflow
-  
+
   if not (overflowX == "scroll" or overflowX == "auto" or overflowY == "scroll" or overflowY == "auto") then
     return nil
   end
-  
+
   local dims = self:calculateScrollbarDimensions()
   local x, y = element.x, element.y
   local w, h = element.width, element.height
-  
+
   -- Check vertical scrollbar (only if not hidden)
   if dims.vertical.visible and not self.hideScrollbars.vertical then
     -- Position scrollbar within content area (x, y is border-box origin)
@@ -350,7 +343,7 @@ function ScrollManager:getScrollbarAtPosition(mouseX, mouseY)
     local trackY = contentY + self.scrollbarPadding
     local trackW = self.scrollbarWidth
     local trackH = dims.vertical.trackHeight
-    
+
     if mouseX >= trackX and mouseX <= trackX + trackW and mouseY >= trackY and mouseY <= trackY + trackH then
       -- Check if over thumb
       local thumbY = trackY + dims.vertical.thumbY
@@ -362,7 +355,7 @@ function ScrollManager:getScrollbarAtPosition(mouseX, mouseY)
       end
     end
   end
-  
+
   -- Check horizontal scrollbar (only if not hidden)
   if dims.horizontal.visible and not self.hideScrollbars.horizontal then
     -- Position scrollbar within content area (x, y is border-box origin)
@@ -372,7 +365,7 @@ function ScrollManager:getScrollbarAtPosition(mouseX, mouseY)
     local trackY = contentY + h - self.scrollbarWidth - self.scrollbarPadding
     local trackW = dims.horizontal.trackWidth
     local trackH = self.scrollbarWidth
-    
+
     if mouseX >= trackX and mouseX <= trackX + trackW and mouseY >= trackY and mouseY <= trackY + trackH then
       -- Check if over thumb
       local thumbX = trackX + dims.horizontal.thumbX
@@ -384,7 +377,7 @@ function ScrollManager:getScrollbarAtPosition(mouseX, mouseY)
       end
     end
   end
-  
+
   return nil
 end
 
@@ -397,23 +390,23 @@ function ScrollManager:handleMousePress(mouseX, mouseY, button)
   if not self._element then
     error("ScrollManager:handleMousePress() called before initialize()")
   end
-  
+
   if button ~= 1 then
     return false
   end -- Only left click
-  
+
   local scrollbar = self:getScrollbarAtPosition(mouseX, mouseY)
   if not scrollbar then
     return false
   end
-  
+
   if scrollbar.region == "thumb" then
     -- Start dragging thumb
     self._scrollbarDragging = true
     self._hoveredScrollbar = scrollbar.component
     local dims = self:calculateScrollbarDimensions()
     local element = self._element
-    
+
     if scrollbar.component == "vertical" then
       local contentY = element.y + element.padding.top
       local trackY = contentY + self.scrollbarPadding
@@ -425,14 +418,14 @@ function ScrollManager:handleMousePress(mouseX, mouseY, button)
       local thumbX = trackX + dims.horizontal.thumbX
       self._scrollbarDragOffset = mouseX - thumbX
     end
-    
+
     return true -- Event consumed
   elseif scrollbar.region == "track" then
     -- Click on track - jump to position
     self:_scrollToTrackPosition(mouseX, mouseY, scrollbar.component)
     return true
   end
-  
+
   return false
 end
 
@@ -444,28 +437,28 @@ function ScrollManager:handleMouseMove(mouseX, mouseY)
   if not self._element then
     return false
   end
-  
+
   if not self._scrollbarDragging then
     return false
   end
-  
+
   local dims = self:calculateScrollbarDimensions()
   local element = self._element
-  
+
   if self._hoveredScrollbar == "vertical" then
     local contentY = element.y + element.padding.top
     local trackY = contentY + self.scrollbarPadding
     local trackH = dims.vertical.trackHeight
     local thumbH = dims.vertical.thumbHeight
-    
+
     -- Calculate new thumb position
     local newThumbY = mouseY - self._scrollbarDragOffset - trackY
     newThumbY = math.max(0, math.min(newThumbY, trackH - thumbH))
-    
+
     -- Convert thumb position to scroll position
     local scrollRatio = (trackH - thumbH) > 0 and (newThumbY / (trackH - thumbH)) or 0
     local newScrollY = scrollRatio * self._maxScrollY
-    
+
     self:setScroll(nil, newScrollY)
     return true
   elseif self._hoveredScrollbar == "horizontal" then
@@ -473,19 +466,19 @@ function ScrollManager:handleMouseMove(mouseX, mouseY)
     local trackX = contentX + self.scrollbarPadding
     local trackW = dims.horizontal.trackWidth
     local thumbW = dims.horizontal.thumbWidth
-    
+
     -- Calculate new thumb position
     local newThumbX = mouseX - self._scrollbarDragOffset - trackX
     newThumbX = math.max(0, math.min(newThumbX, trackW - thumbW))
-    
+
     -- Convert thumb position to scroll position
     local scrollRatio = (trackW - thumbW) > 0 and (newThumbX / (trackW - thumbW)) or 0
     local newScrollX = scrollRatio * self._maxScrollX
-    
+
     self:setScroll(newScrollX, nil)
     return true
   end
-  
+
   return false
 end
 
@@ -496,12 +489,12 @@ function ScrollManager:handleMouseRelease(button)
   if button ~= 1 then
     return false
   end
-  
+
   if self._scrollbarDragging then
     self._scrollbarDragging = false
     return true
   end
-  
+
   return false
 end
 
@@ -513,39 +506,39 @@ function ScrollManager:_scrollToTrackPosition(mouseX, mouseY, component)
   if not self._element then
     return
   end
-  
+
   local dims = self:calculateScrollbarDimensions()
   local element = self._element
-  
+
   if component == "vertical" then
     local contentY = element.y + element.padding.top
     local trackY = contentY + self.scrollbarPadding
     local trackH = dims.vertical.trackHeight
     local thumbH = dims.vertical.thumbHeight
-    
+
     -- Calculate target thumb position (centered on click)
     local targetThumbY = mouseY - trackY - (thumbH / 2)
     targetThumbY = math.max(0, math.min(targetThumbY, trackH - thumbH))
-    
+
     -- Convert to scroll position
     local scrollRatio = (trackH - thumbH) > 0 and (targetThumbY / (trackH - thumbH)) or 0
     local newScrollY = scrollRatio * self._maxScrollY
-    
+
     self:setScroll(nil, newScrollY)
   elseif component == "horizontal" then
     local contentX = element.x + element.padding.left
     local trackX = contentX + self.scrollbarPadding
     local trackW = dims.horizontal.trackWidth
     local thumbW = dims.horizontal.thumbWidth
-    
+
     -- Calculate target thumb position (centered on click)
     local targetThumbX = mouseX - trackX - (thumbW / 2)
     targetThumbX = math.max(0, math.min(targetThumbX, trackW - thumbW))
-    
+
     -- Convert to scroll position
     local scrollRatio = (trackW - thumbW) > 0 and (targetThumbX / (trackW - thumbW)) or 0
     local newScrollX = scrollRatio * self._maxScrollX
-    
+
     self:setScroll(newScrollX, nil)
   end
 end
@@ -557,16 +550,16 @@ end
 function ScrollManager:handleWheel(x, y)
   local overflowX = self.overflowX or self.overflow
   local overflowY = self.overflowY or self.overflow
-  
+
   if not (overflowX == "scroll" or overflowX == "auto" or overflowY == "scroll" or overflowY == "auto") then
     return false
   end
-  
+
   local hasVerticalOverflow = self._overflowY and self._maxScrollY > 0
   local hasHorizontalOverflow = self._overflowX and self._maxScrollX > 0
-  
+
   local scrolled = false
-  
+
   -- Vertical scrolling
   if y ~= 0 and hasVerticalOverflow then
     local delta = -y * self.scrollSpeed -- Negative because wheel up = scroll up
@@ -574,7 +567,7 @@ function ScrollManager:handleWheel(x, y)
     self:setScroll(nil, newScrollY)
     scrolled = true
   end
-  
+
   -- Horizontal scrolling
   if x ~= 0 and hasHorizontalOverflow then
     local delta = -x * self.scrollSpeed
@@ -582,7 +575,7 @@ function ScrollManager:handleWheel(x, y)
     self:setScroll(newScrollX, nil)
     scrolled = true
   end
-  
+
   return scrolled
 end
 
@@ -591,7 +584,7 @@ end
 ---@param mouseY number
 function ScrollManager:updateHoverState(mouseX, mouseY)
   local scrollbar = self:getScrollbarAtPosition(mouseX, mouseY)
-  
+
   if scrollbar then
     if scrollbar.component == "vertical" then
       self._scrollbarHoveredVertical = true
@@ -640,7 +633,7 @@ function ScrollManager:setState(state)
   if not state then
     return
   end
-  
+
   if state.scrollX then
     self._scrollX = state.scrollX
   end