Cocoa: fix #40081 #40853 by completely reimplementing TManualScrollView with Legacy/Overlay Style Scroller, Merge branch 'cocoa/scroll'

TCocoaManualScrollView is based on NSView without native Scroller.
it doesn't require the document to have the full size it claims, so it is usually suitable for components of unlimited size.
it corresponds to components such as TreeView, Grid, SynEdit.
Legacy and Overlay style Scroller were implemented, they have visual effects highly similar to native Scrollers.

on the contrary, TCocoaScrollView is based on NSScrollView with native Scroller.
it requires the document to have the full size it claims, so it is usually suitable for components of limited size.
it corresponds to components such as ListBox, ListView, ScrollBox, Form.

lcl/interfaces/cocoa/cocoaconfig.pas

@@ -8,7 +8,78 @@ interface
 uses
   CocoaAll, Cocoa_Extra, CocoaConst;
 
+type
+  NSColorFunction = Function(): NSColor;
+
+  function getCocoaScrollerDefaultKnobColor: NSColor;
+
 var
+  // the style of the TCocoaScrollBar managed by TCocoaManualScrollView,
+  // the default value is System Preferred.
+  // note: TCocoaScrollBar not managed by TCocoaManualScrollView is always
+  //       Legacy Style.
+  CocoaScrollerPreferredStyle : NSScrollerStyle = -1;
+
+  // Scroller Knob Fade in/out time interval, in Seconds
+  CocoaScrollerKnobFadeTimeInterval : Double = 0.02;
+
+  // Scroller Knob Radius, in Dots
+  CocoaScrollerKnobRadius : Double = 4;
+
+
+  // Legacy Style Scroller Knob Color
+  CocoaScrollerOverlayStyleKnobColor : NSColorFunction = @getCocoaScrollerDefaultKnobColor;
+
+  // Legacy Style Scroller Knob Alpha in Normal
+  CocoaScrollerLegacyStyleAlpha : Double = 0.25;
+
+  // Legacy Style Scroller Knob Alpha when mouse enters
+  CocoaScrollerLegacyStyleAlphaBlack : Double = 0.50;
+
+  // Legacy Style Scroller Knob Alpha Step when fading in/out
+  CocoaScrollerLegacyStyleFadeStep : Double = 0.05;
+
+  // Legacy Style Scroller Knob Position, in Dots
+  CocoaScrollerLegacyStyleKnobPos : Double = 3;
+
+  // Legacy Style Scroller Knob Shrunk Size, in Dots
+  CocoaScrollerLegacyStyleKnobShrunkSize : Double = 5;
+
+
+  // Overly Style Scroller Knob Color
+  CocoaScrollerLegacyStyleKnobColor : NSColorFunction = @getCocoaScrollerDefaultKnobColor;
+
+  // Overly Style Scroller Auto Hide Delay Time, in Seconds
+  CocoaScrollerOverlayStyleAutoHideDelayTime : Double = 0.9;
+
+  // Overlay Style Scroller Alpha in Normal
+  CocoaScrollerOverlayStyleAlpha : Double = 0.5;
+
+  // Overlay Style Scroller Alpha Step when fading out
+  CocoaScrollerOverlayStyleFadeStep : Double = -0.1;
+
+  // Overlay Style Scroller Alpha when fade out ends
+  CocoaScrollerOverlayStyleFadeTo : Double = 0;
+
+  // Overlay Style Scroller expands time interval, in Seconds
+  CocoaScrollerOverlayStyleExpandTimeInterval : Double = 0.03;
+
+  // Overlay Style Scroller expands when the mouse enters, in Dots
+  CocoaScrollerOverlayStyleExpandSize : Double = 4;
+
+  // Overlay Style Scroller Knob Position, in Dots
+  CocoaScrollerOverlayStyleKnobPos : Double = 5;
+
+  // Overlay Style Scroller Knob Shrunk Size, in Dots
+  CocoaScrollerOverlayStyleKnobShrunkSize : Double = 6;
+
+  // in extreme cases, the normally calculated Knob size of Overlay Scroller
+  // may be too small, keep the min size.
+  // min height for the Knob of VerticalScroller
+  // min width for the Knob of HorizontalScroller
+  CocoaScrollerOverlayStyleKnobMinSize : Double = 25;
+
+
   // for compatiblity with LCL 1.8 release. The macOS base is 72ppi
   CocoaBasePPI : Integer = 96;
 
@@ -38,6 +109,11 @@ var
 
 implementation
 
+function getCocoaScrollerDefaultKnobColor: NSColor;
+begin
+  Result:= NSColor.controlTextColor;
+end;
+
 initialization
   CocoaDefaultCheckMenuImageName:= NSSTR('NSMenuCheckmark');
   CocoaDefaultRadioMenuImageName:= NSSTR('NSDatePickerCalendarHome');

lcl/interfaces/cocoa/cocoawinapi.inc

@@ -1678,11 +1678,10 @@ begin
   begin
     mn := TCocoaManualScrollView(obj);
     case SBStyle of
-      SB_Vert: Result := mn.hasVerticalScroller and not mn.verticalScroller.isHidden;
-      SB_Horz: Result := mn.hasHorizontalScroller and not mn.horizontalScroller.isHidden;
+      SB_Vert: Result := mn.hasVerticalScroller;
+      SB_Horz: Result := mn.hasHorizontalScroller;
     else
-      Result := mn.hasHorizontalScroller and not mn.horizontalScroller.isHidden
-                and mn.hasVerticalScroller and not mn.verticalScroller.isHidden;
+      Result := mn.hasHorizontalScroller and mn.hasVerticalScroller;
     end;
   end
   else

lcl/interfaces/cocoa/cocoawsstdctrls.pas

@@ -2270,7 +2270,12 @@ begin
     prm.Height:=ScrollBase;
   end;
 
-  scr:=NSView(TCocoaScrollBar.alloc).lclInitWithCreateParams(prm);
+  // for the Scroller created separately through TCocoaWSScrollBar.CreateHandle(),
+  // due to the lack of the control over the Layout by TCocoaManualScrollView,
+  // only the Legacy Style can be used for compatibility.
+  // it's the same logical relationship as NSScrollView and NSScroller.
+  scr:= createLegacyScroller;
+  scr.lclInitWithCreateParams(prm);
   scr.callback:=TLCLCommonCallback.Create(scr, AWinControl);
 
   // OnChange (scrolling) event handling