FIX: Wrong scaling (Gtk3)

src/doublecmd.lpi

@@ -170,14 +170,14 @@ begin
   UnitPath += 'platform/$(SrcOS)/qt6;platform/$(SrcOS)/wayland;';
 end;
 
-if (LCLWidgetType = 'gtk2') and (SrcOS = 'unix') and (TargetOS <> 'darwin') then
+if ((LCLWidgetType = 'gtk2') or (LCLWidgetType = 'gtk3')) and (SrcOS = 'unix') then
 begin
   UnitPath += 'platform/$(SrcOS)/$(LCLWidgetType);';
 end;
 
 if (SrcOS = 'unix') and (TargetOS <> 'darwin') and (TargetOS <> 'haiku') then
 begin
-  CustomOptions += '-dXDG -dRabbitVCS';
+  CustomOptions += ' -dXDG -dRabbitVCS';
 end;"/>
           <Parsing>
             <SyntaxOptions>
@@ -2219,6 +2219,11 @@ begin
   UnitPath += &apos;platform/$(SrcOS)/qt6;platform/$(SrcOS)/wayland;&apos;;
 end;
 
+if ((LCLWidgetType = &apos;gtk2&apos;) or (LCLWidgetType = &apos;gtk3&apos;)) and (SrcOS = &apos;unix&apos;) then
+begin
+  UnitPath += &apos;platform/$(SrcOS)/$(LCLWidgetType);&apos;;
+end;
+
 if (SrcOS = &apos;unix&apos;) and (TargetOS &lt;> &apos;darwin&apos;) and (TargetOS &lt;> &apos;haiku&apos;) then
 begin
   CustomOptions += &apos;-dXDG -dRabbitVCS&apos;;

src/doublecmd.lpr

@@ -56,6 +56,9 @@ uses
   {$IFDEF LCLGTK2}
   uGtk2FixCursorPos,
   {$ENDIF}
+  {$IFDEF LCLGTK3}
+  uGtk3WSControls,
+  {$ENDIF}
   {$IFDEF darwin}
   uDarwinApplication,
   uiCloudDriveConfig,

src/platform/unix/gtk3/interfaces.pas

@@ -0,0 +1,95 @@
+unit Interfaces;
+
+{$mode objfpc}{$H+}
+
+interface
+
+uses
+  InterfaceBase, LCLType, Gtk3Int;
+
+type
+
+  { TGtk3WidgetSetEx }
+
+  TGtk3WidgetSetEx = class(TGtk3WidgetSet)
+  public
+    function GetDpiForMonitor(hMonitor: HMONITOR; dpiType: TMonitorDpiType; out dpiX: UINT; out dpiY: UINT): HRESULT; override;
+  end;
+
+implementation
+
+uses
+  Forms, LazGLib2, LazGdk3;
+
+{ TGtk3WidgetSetEx }
+
+function TGtk3WidgetSetEx.GetDpiForMonitor(hMonitor: HMONITOR;
+  dpiType: TMonitorDpiType; out dpiX: UINT; out dpiY: UINT): HRESULT;
+var
+  ADisplay: PGdkDisplay;
+  AMonitor: PGdkMonitor;
+  AMonitorRect: TGdkRectangle;
+  AWmm, AHmm, AMonitorIdx, ANMon: gint;
+  AScreenDpi: gdouble;
+  AFallback: UINT;
+begin
+  Result := S_OK;
+  AScreenDpi := gdk_screen_get_resolution(gdk_screen_get_default);
+
+  if AScreenDpi > 0 then
+    AFallback := Round(AScreenDpi)
+  else
+    AFallback := 96;
+
+  dpiX := AFallback;
+  dpiY := AFallback;
+
+  if hMonitor = 0 then
+    Exit;
+
+  AMonitorIdx := Integer(hMonitor) - 1;
+  ADisplay := gdk_display_get_default;
+
+  if ADisplay = nil then
+    Exit;
+
+  ANMon := gdk_display_get_n_monitors(ADisplay);
+  if (AMonitorIdx < 0) or (AMonitorIdx >= ANMon) then
+  begin
+    Result := S_FALSE;
+    Exit;
+  end;
+
+  AMonitor := gdk_display_get_monitor(ADisplay, AMonitorIdx);
+  if AMonitor = nil then
+  begin
+    Result := S_FALSE;
+    Exit;
+  end;
+
+  case dpiType of
+    MDT_RAW_DPI:
+    begin
+      gdk_monitor_get_geometry(AMonitor, @AMonitorRect);
+      AWmm := gdk_monitor_get_width_mm(AMonitor);
+      AHmm := gdk_monitor_get_height_mm(AMonitor);
+      if AWmm > 0 then
+        dpiX := Round(AMonitorRect.width * 25.4 / AWmm)
+      else
+        dpiX := 96;
+      if AHmm > 0 then
+        dpiY := Round(AMonitorRect.height * 25.4 / AHmm)
+      else
+        dpiY := 96;
+    end;
+  end;
+end;
+
+initialization
+  CreateWidgetset(TGtk3WidgetSetEx);
+
+finalization
+  FreeWidgetSet;
+
+end.
+

src/platform/unix/gtk3/ugtk3wscontrols.pas

@@ -0,0 +1,51 @@
+unit uGtk3WSControls;
+
+{$mode ObjFPC}{$H+}
+
+interface
+
+uses
+  Classes, SysUtils, Controls, Gtk3WSControls;
+
+type
+
+  { TGtk3WSWinControlEx }
+
+  TGtk3WSWinControlEx = class(TGtk3WSWinControl)
+  published
+    class function GetCanvasScaleFactor(const AControl: TControl): Double; override;
+  end;
+
+implementation
+
+uses
+  WSLCLClasses, WSControls, Gtk3Widgets, Gtk3Procs, LazGdk3;
+
+procedure Initialize;
+begin
+  WSControls.RegisterControl;
+  WSControls.RegisterWinControl;
+  RegisterWSComponent(TWinControl, TGtk3WSWinControlEx);
+end;
+
+{ TGtk3WSWinControlEx }
+
+class function TGtk3WSWinControlEx.GetCanvasScaleFactor(const AControl: TControl): Double;
+var
+  W: TGtk3Widget;
+begin
+  Result := 1;
+
+  if TWinControl(AControl).HandleAllocated then
+  begin
+    W := TGtk3Widget(TWinControl(AControl).Handle);
+    if Gtk3IsGdkWindow(W.GetWindow) then
+      Result := gdk_window_get_scale_factor(W.GetWindow);
+  end;
+end;
+
+initialization
+  Initialize;
+
+end.
+