feat: upgrade DPI awareness to Per-Monitor v2, add TMainForm.FormChangeBounds as a replacement for the missing OnAfter/OnBeforeMonitorDpiChanged events

ansgarbecker · ansgarbecker · commit 9eab28ea642b · 2026-01-22T19:12:10.000+01:00
diff --git a/heidisql.lpi b/heidisql.lpi
@@ -11,7 +11,7 @@
       <ResourceType Value="res"/>
       <UseXPManifest Value="True"/>
       <XPManifest>
-        <DpiAware Value="True"/>
+        <DpiAware Value="True/PM_V2"/>
         <AnsiUTF8 Value="True"/>
         <TextName Value="HeidiSQL"/>
         <TextDesc Value="A lightweight, fast and flexible interface to MySQL"/>
diff --git a/source/main.lfm b/source/main.lfm
@@ -10,6 +10,7 @@ object MainForm: TMainForm
   Menu = MainMenu1
   Position = poMainFormCenter
   OnActivate = FormActivate
+  OnChangeBounds = FormChangeBounds
   OnCloseQuery = FormCloseQuery
   OnCreate = FormCreate
   OnDestroy = FormDestroy
diff --git a/source/main.pas b/source/main.pas
@@ -1192,11 +1192,8 @@   TMainForm = class(TExtForm)
     procedure actSynMoveUpExecute(Sender: TObject);
     procedure actCopyTabsToSpacesExecute(Sender: TObject);
     procedure actCopyUpdate(Sender: TObject);
-    //procedure FormBeforeMonitorDpiChanged(Sender: TObject; OldDPI,
-    //  NewDPI: Integer);
+    procedure FormChangeBounds(Sender: TObject);
     procedure menuToggleAllClick(Sender: TObject);
-    //procedure FormAfterMonitorDpiChanged(Sender: TObject; OldDPI,
-    //  NewDPI: Integer);
     procedure menuCloseTabOnDblClickClick(Sender: TObject);
     procedure TimerRefreshTimer(Sender: TObject);
     procedure SynCompletionProposalChange(Sender: TObject);
@@ -1278,6 +1275,7 @@   TMainForm = class(TExtForm)
     FMatchingBraceBackgroundColor: TColor;
     //FHelpData: TSimpleKeyValuePairs;
     FMainWinMaximized: Boolean;
+    FCurrentPixelsPerInch: Integer;
 
     // Host subtabs backend structures
     FHostListResults: TDBQueryList;
@@ -1697,23 +1695,21 @@ procedure TMainForm.StoreLastSessions;
 end;
 
 
-{procedure TMainForm.FormAfterMonitorDpiChanged(Sender: TObject; OldDPI,
-  NewDPI: Integer);
-begin
-  // DPI settings change finished
-  FormResize(Sender);
-end;}
-
-{procedure TMainForm.FormBeforeMonitorDpiChanged(Sender: TObject; OldDPI,
-  NewDPI: Integer);
+procedure TMainForm.FormChangeBounds(Sender: TObject);
 var
   Factor: Extended;
+  NewDPI, OldDPI: Integer;
 begin
-  // Moving window to different screen or user changed DPI setting for current screen
-  Factor := 100 / PixelsPerInchDesigned * NewDPI;
-  LogSQL(f_('Scaling controls to screen DPI: %d%%', [Round(Factor)]));
-  //LogSQL('PixelsPerInchDesigned:'+PixelsPerInchDesigned.ToString+' OldDPI:'+OldDPI.ToString+' NewDPI:'+NewDPI.ToString);
-end;}
+  NewDPI := Monitor.PixelsPerInch;
+  OldDPI := FCurrentPixelsPerInch;
+  if NewDPI <> OldDPI then begin
+    // Moving window to different screen or user changed DPI setting for current screen
+    FCurrentPixelsPerInch := NewDPI;
+    Factor := 100 / 96 * NewDPI;
+    LogSQL(f_('Scaling controls to screen DPI: %d%%', [Round(Factor)]));
+    //LogSQL('PixelsPerInchDesigned:'+PixelsPerInchDesigned.ToString+' OldDPI:'+OldDPI.ToString+' NewDPI:'+NewDPI.ToString);
+  end;
+end;
 
 
 procedure TMainForm.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
@@ -2093,6 +2089,7 @@ procedure TMainForm.FormCreate(Sender: TObject);
 
   FLastMouseButtonUpOnGrid := mbLeft;
   FLastCaptionChange := 0;
+  FCurrentPixelsPerInch := 0;
   FFormatSettings := DefaultFormatSettings;
   FFormatSettings.DecimalSeparator := '.';
   FFormatSettings.ThousandSeparator := ' ';;
