How do I change the color of my progress bar in Inno Setup?

Question

I create a progress bar using TNewProgressBar.
The default color of the progress bar is green.
I would like to change the color to blue.

Answer 1

You cannot.

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The progress bar is styled by the current Windows theme. In the default Windows theme, the progress bar is green (or yellow or red, if the progress bar is in paused or error state, see TNewProgressBar.State).

You would have to completely reimplement the drawing of the progress bar or disable visual themes of whole installer.
See How to change the color of progressbar in C# .NET 3.5?

With the Inno Setup API it would very difficult if possible at all to reimplement the drawing. And you probably do not want to disable the visual themes.

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If you really need the blue color, you may consider implementing the progress bar yourself using TBitmapImage.Bitmap.Canvas (using methods like .Rectangle).

A simple example:

var
  ProgressImage: TBitmapImage;

procedure InitializeWizard();
begin
  ProgressImage := TBitmapImage.Create(WizardForm);
  ProgressImage.Parent := WizardForm;
  ProgressImage.Left := ScaleX(10);
  ProgressImage.Top := WizardForm.ClientHeight - ScaleY(34);
  ProgressImage.Width := ScaleX(200);
  ProgressImage.Height := ScaleY(20);
  ProgressImage.BackColor := clWhite;
  ProgressImage.Bitmap.Width := ProgressImage.Width;
  ProgressImage.Bitmap.Height := ProgressImage.Height;
end;

procedure DrawProgress(Image: TBitmapImage; Progress: Integer);
var
  Canvas: TCanvas;
  Width: Integer;
begin
  Log(Format('Drawing progress %d', [Progress]));
  
  Canvas := Image.Bitmap.Canvas;
  
  Canvas.Pen.Style := psClear;

  Width := Image.Bitmap.Width * Progress / 100
  Log(Format('Bar size: %d x %d', [Width, Image.Bitmap.Height]));

  Canvas.Brush.Color := clHighlight;
  Canvas.Rectangle(1, 1, Width, Image.Bitmap.Height);
  
  Canvas.Brush.Color := clBtnFace;
  Canvas.Rectangle(Width - 1, 1, Image.Bitmap.Width, Image.Bitmap.Height);

  Canvas.Pen.Style := psSolid;
  Canvas.Pen.Mode := pmCopy;
  Canvas.Pen.Color := clBlack;
  Canvas.Brush.Style := bsClear;
  Canvas.Rectangle(1, 1, Image.Bitmap.Width, Image.Bitmap.Height);
end;

procedure CurPageChanged(CurPageID: Integer);
begin
  Log(Format('CurPageChanged %d', [CurPageID]));
  DrawProgress(ProgressImage, (CurPageID * 100 / wpFinished));
end;

Answer 2

Long time passed, but I would like to share a solution to change the color of the progress bar of Inno Setup for installation progress. I guess this solution can be applied to a custom progress bar. I put in place this solution after some googling, but I have no more reference to the sources. As a side note: I do not have a solution for the uninstaller.

  if CurPageID = wpInstalling then 
  begin
    Log('PAGE: wpInstalling ' + IntToStr(CurPageID));

    // Progress bar color cannot be changed from the application: request using Win DLL shall be done
    SendMessage(wizardform.progressgauge.Handle, PBM_SETBARCOLOR, 0, $DCA939); // Foreground color
    SendMessage(wizardform.progressgauge.Handle, PBM_SETBKCOLOR, 0, $202000);  // Background color
    //SendMessage(wizardform.progressgauge.Handle, PBM_SETMARQUEE, 1, 200);
  end;