build/windows: Make Installer aware of Install, Reinstall and Update modes

Closes #12998.

On Install mode, we correctly allow users to customize the installation.
This is the expected use case of the "Customize" button: the first user be
able to decide if the installation will be system-wide or on local user,
to see the license, to choose the install dir, to select components etc.

On Reinstall and Update mode, however, some options choosen byf the first
user can't be undone, mainly components, since Inno never had support to
"modify" installs (it can only not install the unchecked components).
So, in our current scenario (before this commit):
- If python support was installed but on the update the user uncheck it,
  the old python and all old gimp python plug-ins will remain installed
- The same applies for postscript (.ps) component and 32-bit TWAIN

So, the chances of breaking the install are very high. Inno knows that
and displays a built-in warning, but even that dialog have limitations.
So, let's not keep that false impression of being able to modify the
install, let's fix that by hidding "Customize" on Reinstall and Update.

build/windows/installer/base_gimp3264.iss

@@ -483,6 +483,7 @@ const
 
 var
 	//pgSimple: TWizardPage;
+  InstallType: String;
   InstallMode: (imNone, imSimple, imCustom, imRebootContinue);
   ConfigOverride: (coUndefined, coOverride, coDontOverride);
 	Force32bitInstall: Boolean;
@@ -600,6 +601,47 @@ begin
 		Result := True;
 end;
 
+//Check what type of installation is being done
+procedure CheckInstallType;
+var
+	isInstalled: String;
+	InstallLocation: String;
+	Installed_AppVersion: String;
+	Installed_AppVersionInt: Int64;
+	Installer_AppVersionInt: Int64;
+begin
+	isInstalled := 'notInstalled';
+	if RegQueryStringValue(HKCU, 'Software\Microsoft\Windows\CurrentVersion\Uninstall\GIMP-{#GIMP_MUTEX_VERSION}_is1',
+                           'DisplayVersion', Installed_AppVersion) then begin
+	    RegQueryStringValue(HKCU, 'Software\Microsoft\Windows\CurrentVersion\Uninstall\GIMP-{#GIMP_MUTEX_VERSION}_is1',
+                           'InstallLocation', InstallLocation);
+		StrToVersion(Installed_AppVersion, Installed_AppVersionInt);
+		isInstalled := 'Installed';
+	end;
+	if RegQueryStringValue(HKLM, 'Software\Microsoft\Windows\CurrentVersion\Uninstall\GIMP-{#GIMP_MUTEX_VERSION}_is1',
+                           'DisplayVersion', Installed_AppVersion) then begin
+	    RegQueryStringValue(HKLM, 'Software\Microsoft\Windows\CurrentVersion\Uninstall\GIMP-{#GIMP_MUTEX_VERSION}_is1',
+                           'InstallLocation', InstallLocation);
+	    StrToVersion(Installed_AppVersion, Installed_AppVersionInt);
+		isInstalled := 'Installed';
+	end;
+
+	StrToVersion('{#FULL_GIMP_VERSION}', Installer_AppVersionInt);
+
+	if (isInstalled = 'Installed') and (not DirExists(InstallLocation)) then begin
+        InstallType := 'itRepair';
+    end else if isInstalled = 'notInstalled' then begin
+	    InstallType := 'itInstall';
+	end else if ComparePackedVersion(Installer_AppVersionInt, Installed_AppVersionInt) = 0 then begin
+		InstallType := 'itReinstall';
+    end else if ComparePackedVersion(Installer_AppVersionInt, Installed_AppVersionInt) > 0 then begin
+	    InstallType := 'itUpdate';
+    end else begin
+	    InstallType := 'itDowngrade';
+	end;
+	DebugMsg('CheckInstallType','Installed GIMP {#GIMP_MUTEX_VERSION} is: ' + Installed_AppVersion + ', installer is: {#FULL_GIMP_VERSION}. So Install type is: ' + InstallType);
+end;
+
 function InitializeSetup(): Boolean;
 #if (Defined(GIMP_UNSTABLE) && GIMP_UNSTABLE != "") || (Defined(GIMP_RC_VERSION) && GIMP_RC_VERSION != "") || Defined(DEVEL_WARNING)
 var Message,Buttons: TArrayOfString;
@@ -715,7 +757,9 @@ begin
 
 		btnInstall.Visible := True;
 		btnInstall.TabOrder := 1;
-		btnCustomize.Visible := True;
+		if InstallType = 'itInstall' then begin
+		    btnCustomize.Visible := True;
+		end;
 
 		WizardForm.Bevel.Visible := False;
 		WizardForm.WelcomeLabel1.Visible := False;
@@ -729,7 +773,9 @@ procedure CleanUpCustomWelcome();
 begin
 	WizardForm.NextButton.Visible := True;
 	btnInstall.Visible := False;
-	btnCustomize.Visible := False;
+	if InstallType = 'itInstall' then begin
+	     btnCustomize.Visible := False;
+    end;
 
 	WizardForm.Bevel.Visible := True;
 	WelcomeBitmapBottom.Visible := False;
@@ -771,7 +817,14 @@ begin
 		Height := WizardForm.NextButton.Height;
 		Left := WizardForm.NextButton.Left;
 		Top := WizardForm.NextButton.Top;
-		Caption := CustomMessage('Install');
+	    CheckInstallType;
+		if InstallType = 'itInstall' then begin
+		    Caption := CustomMessage('Install');
+	    end else if InstallType = 'itReinstall' then begin
+		    Caption := CustomMessage('Reinstall');
+	    end else if InstallType = 'itUpdate' then begin
+		    Caption := CustomMessage('Update');
+		end;
 		Default := True;
 		Visible := False;
 
@@ -810,6 +863,7 @@ begin
 	end;
 
 	MeasureLabel.Free;
+	
 end;
 
 

build/windows/installer/lang/setup.isl.xml.in

@@ -50,6 +50,12 @@
     <config name="Install">
       <value>&amp;Install</value>
     </config>
+    <config name="Reinstall">
+      <value>&amp;Reinstall</value>
+    </config>
+    <config name="Update">
+      <value>&amp;Update</value>
+    </config>
     <config name="Customize">
       <value>&amp;Customize</value>
     </config>