ui(main): fix DPI layout and theme switching

FlatDropDown.pas

@@ -32,9 +32,11 @@ type
     FItemBtns:    array of TFlatButton;
     FItemIndex:   Integer;
     FColumns:     Integer;
-    FItemBtnH:    Integer;
+    FItemBtnH96:  Integer;
     FRightInset96: Integer;
     FIsOpen:      Boolean;
+    FStyleProc:   TButtonStyleProc;
+    FPanelColor:  TColor;
     FOnSelect:    TDropDownSelectEvent;
     procedure ItemClick(Sender: TObject);
     procedure PositionPopup;
@@ -61,15 +63,17 @@ begin
   inherited Create;
   FAnchor      := AAnchor;
   FPopupParent := APopupParent;
-  FColumns     := ACols;
-  FItemBtnH    := ABtnH;
+  FColumns     := Max(1, ACols);
+  FItemBtnH96  := Max(1, ABtnH);
   FRightInset96 := Max(0, ARightInset96);
   FItemIndex   := 0;
   FIsOpen      := False;
+  FStyleProc   := nil;
+  FPanelColor  := TColor($00181818);
   FPopup := TPanel.Create(nil);
   FPopup.Parent     := APopupParent;
   FPopup.BevelOuter := bvNone;
-  FPopup.Color      := TColor($00181818);
+  FPopup.Color      := FPanelColor;
   FPopup.Visible    := False;
 end;
 
@@ -81,7 +85,7 @@ end;
 
 procedure TFlatDropDown.SetItems(const ANames: array of string);
 var
-  I, Count, BtnW, PopW: Integer;
+  I, Count, BtnW, PopW, ItemBtnH, EdgePad, ItemGap: Integer;
   B: TFlatButton;
 begin
   while FPopup.ControlCount > 0 do
@@ -93,17 +97,22 @@ begin
   // при каждом наполнении: SetItems бывает и до, и после DPI-scale формы.
   PopW := Max(1, FPopupParent.ClientWidth -
                  FPopupParent.Scale96ToForm(FRightInset96));
-  BtnW := (PopW - 4) div FColumns;
+  ItemBtnH := FPopupParent.Scale96ToForm(FItemBtnH96);
+  EdgePad := FPopupParent.Scale96ToForm(2);
+  ItemGap := FPopupParent.Scale96ToForm(2);
+  BtnW := Max(1, (PopW - 2 * EdgePad) div FColumns);
   FPopup.SetBounds(0, 0, PopW,
-                   ((Count + FColumns - 1) div FColumns) * FItemBtnH);
+                   ((Count + FColumns - 1) div FColumns) * ItemBtnH);
   for I := 0 to Count - 1 do
   begin
     B := MakeFlatBtn(FPopup, ANames[I],
-                     2 + (I mod FColumns) * BtnW,
-                     (I div FColumns) * FItemBtnH,
-                     BtnW - 2, FItemBtnH, @ItemClick);
+                     EdgePad + (I mod FColumns) * BtnW,
+                     (I div FColumns) * ItemBtnH,
+                     Max(1, BtnW - ItemGap), ItemBtnH, @ItemClick);
     B.Tag    := I;
     B.Active := (I = FItemIndex);
+    if Assigned(FStyleProc) then
+      FStyleProc(B, B.Active);
     FItemBtns[I] := B;
   end;
 end;
@@ -141,9 +150,10 @@ var
 begin
   P  := FAnchor.ClientToScreen(Point(0, FAnchor.Height));
   P  := FPopupParent.ScreenToClient(P);
-  Y0 := P.Y + 2;
+  Y0 := P.Y + FPopupParent.Scale96ToForm(2);
   if Y0 + FPopup.Height > FPopupParent.ClientHeight then
-    Y0 := P.Y - FAnchor.Height - FPopup.Height - 2;
+    Y0 := P.Y - FAnchor.Height - FPopup.Height -
+          FPopupParent.Scale96ToForm(2);
   if Y0 < 0 then Y0 := 0;
   FPopup.Top  := Y0;
   FPopup.Left := 0;
@@ -173,6 +183,8 @@ procedure TFlatDropDown.ApplyStyle(AStyleProc: TButtonStyleProc; APanelColor: TC
 var
   I: Integer;
 begin
+  FStyleProc := AStyleProc;
+  FPanelColor := APanelColor;
   FPopup.Color := APanelColor;
   for I := 0 to High(FItemBtns) do
     if FItemBtns[I] <> nil then