TdxForm.ScaleFactor Property

Returns the form’s scale factor.

Declaration

property ScaleFactor: TdxScaleFactor read;

Property Value

Type	Description
TdxScaleFactor	The scale factor for the current monitor DPI

Remarks

The ScaleFactor property value changes every time your application accepts the WM_DPICHANGED^[1] system message. You can use this property to obtain the current scale factor or call the ScaleFactor.Apply function to apply the scale factor to custom-drawn UI elements within the form.

Code Example

The following code example demonstrates an OnCustomDraw event handler of a TcxButton component that draws a button with custom scaled geometry:

Delphi

procedure TMyForm.btnColorCustomDraw(Sender: TObject; ACanvas: TcxCanvas;
          AViewInfo: TcxButtonViewInfo; var AHandled: Boolean);
var
  AColorBoxOffset, ALineWidth: Integer;
  AColorBoxRect: TRect;
begin
  AViewInfo.Painter.LookAndFeelPainter.DrawScaledButton(ACanvas, AViewInfo.Bounds, '', AViewInfo.State, ScaleFactor);
  ALineWidth := ScaleFactor.Apply(1);  // Applies the form's scale factor to the line width
  AColorBoxOffset := ScaleFactor.Apply(6);  // Applies the form's scale factor to the box offset
  AColorBoxRect := cxRectInflate(AViewInfo.Bounds, -AColorBoxOffset);
  ACanvas.FrameRect(AColorBoxRect, clBlack, ALineWidth);  // Draws the red square's outline
  AColorBoxRect := cxRectInflate(AColorBoxRect, -ALineWidth);  // Fits the color-filled square into the outline
  ACanvas.FillRect(AColorBoxRect, clRed);  // Fills the outline with the red color
  AHandled := True;
end;

C++

void __fastcall TMyForm::btnColorCustomDraw(TObject *Sender, TcxCanvas *ACanvas,
                TcxButtonViewInfo *AViewInfo, bool &AHandled)
{
  int AColorBoxOffset = ScaleFactor->Apply(6);  // Applies the form's scale factor to the box offset
  int ALineWidth = ScaleFactor->Apply(1);  // Applies the form's scale factor to the line width
  AViewInfo->Painter->LookAndFeelPainter->DrawScaledButton(ACanvas, AViewInfo->Bounds, "", AViewInfo->State, ScaleFactor);
  TRect AColorBoxRect = cxRectInflate(AViewInfo->Bounds, -AColorBoxOffset);
  ACanvas->FrameRect(AColorBoxRect, clBlack, ALineWidth);  // Draws the red square's outline
  AColorBoxRect = cxRectInflate(AColorBoxRect, -ALineWidth);  // Fits the color-filled square into the outline
  ACanvas->FillRect(AColorBoxRect, clRed);  // Fills the outline with the red color
  AHandled = true;
}

Footnotes

1. An application accepts the WM_DPICHANGED system message only if the application manifest includes the permonitor or permonitorv2 item.