How to detect and “fix” DPI settings with Inno Setup?

Question

I created a setup with custom wizard pages and custom background images. The problem is with non-standard DPI systems.

When I run this setup the background images ar

Answer 1

Deanna mentioned that the DPI can be detected like so:

You can detect the DPI size using the TGraphicsObject.PixelsPerInch property and load a different image.

However, the InnoSetup documentation suggests that TGraphicsObject has no PixelsPerInch attribute, it is instead an attribute of TFont objects.

The DPI can therefore be detected and custom settings be implemented using code similar to this:

procedure CheckDPI;
var
  CurrentDPI, StandardDPI, MediumDPI, LargeDPI: Integer;
begin
  { Get the current DPI }
  CurrentDPI  := WizardForm.Font.PixelsPerInch;

  { Store defaults determined from Windows DPI settings }
  StandardDPI := 96;  { 100% }
  MediumDPI   := 120; { 125% }
  LargeDPI    := 144; { 150% }

  if (CurrentDPI >= StandardDPI) and (CurrentDPI < MediumDPI) then 
  begin
    { Execute some custom code for small to medium DPI }
  end
  else if (CurrentDPI >= MediumDPI) and (CurrentDPI < LargeDPI) then
  begin
    { Execute some custom code for medium to large DPI }
  end
  else if (CurrentDPI >= LargeDPI) then
  begin
    { Execute some custom code for large DPI or above }
  end;
end;