Fix TX spectrum filter alpha accumulation

SpectrumView.pas

@@ -19,7 +19,7 @@ interface
 
 uses
   Classes, SysUtils, Graphics, ExtCtrls, Controls, Math,
-  LCLIntf, LCLType, AppTheme,
+  AppTheme,
   AlertOverlay, SampleRateOverlay, VfoOverlay,
   WaterfallView, SMeterView, RulerView;
 
@@ -98,6 +98,7 @@ type
     procedure DrawSpectrumGradient(const SpPts: array of TPoint; W, H: Integer);
     procedure DrawMarkerLine(C: TCanvas; W, H: Integer);
     procedure BlendBand(X1, X2, H: Integer; R, G, B, Alpha: Byte);
+    procedure CopyGridToSpectrum(W, H: Integer);
     procedure DrawADCOverloadOverlay(C: TCanvas; W, H: Integer);
     procedure CalcFilterBandX(VfoFreq: Double; W: Integer;
                               out X1, X2, VfoX: Integer);
@@ -282,6 +283,7 @@ begin
   FSpectrumBitmap  := TBitmap.Create;
   FSpectrumBitmap.PixelFormat := pf32bit;
   FGridBitmap      := TBitmap.Create;
+  FGridBitmap.PixelFormat := pf32bit;
   FGridBitmapW     := 0; FGridBitmapH := 0;
   FFMGridLastCenter := -1.0; FFMGridLastStepHz := -1.0; FFMGridLastSpan := -1.0;
   FFMGridStepHz    := 0.0;
@@ -503,6 +505,27 @@ begin
   end;
 end;
 
+procedure TSpectrumView.CopyGridToSpectrum(W, H: Integer);
+var
+  Y: Integer;
+  Src, Dst: PByte;
+begin
+  if (FSpectrumBitmap = nil) or (FGridBitmap = nil) then Exit;
+  if (W <= 0) or (H <= 0) then Exit;
+  FSpectrumBitmap.BeginUpdate(False);
+  try
+    for Y := 0 to H - 1 do
+    begin
+      Src := PByte(FGridBitmap.ScanLine[Y]);
+      Dst := PByte(FSpectrumBitmap.ScanLine[Y]);
+      if (Src <> nil) and (Dst <> nil) then
+        Move(Src^, Dst^, W * 4);
+    end;
+  finally
+    FSpectrumBitmap.EndUpdate(False);
+  end;
+end;
+
 procedure TSpectrumView.DrawADCOverloadOverlay(C: TCanvas; W, H: Integer);
 begin
   if not FADCOverloadVisible then Exit;
@@ -761,7 +784,7 @@ begin
       end;
     end;
   end;
-  LCLIntf.BitBlt(C.Handle, 0, 0, W, H, FGridBitmap.Canvas.Handle, 0, 0, $CC0020);
+  CopyGridToSpectrum(W, H);
 
   // ── 2. Полоса фильтра ─────────────────────────────────────────────────────
   if FActiveVfo = 0 then CalcFilterBandX(FVfoA, W, X1, X2, VfoX)