Combining multiple image effect filters in your C++ FireMonkey applications

In previous blogs and videos, I showed you how to use the FireMonkey image effect components and image effect filters in your C++Builder XE3 Windows and Mac applications. "January 14 - Using Pixel Shader Image Effects in your C++Builder XE3 Windows and Mac apps" showed you how to use an image effect component in the UI of your application.  "January 19 - Using Image Effect Filters in your C++Builder XE3 Windows and Mac apps" showed you how to use a single effect filter and save the output bitmap to a file.  To use two or more image effect filters together to produce the desired bitmap output you can set an image filter's InputFilter property.  According to the Embarcadero DocWiki entry: "Use InputFilter with a stack of filters when you want to put the result of one filter in the input of another filter. For example, if the result of Filter1 is used in Filter2, use the statement Filter2->InputFilter = Filter1;".

Here is an example C++ FireMonkey HD application source code and header file for a simple example that connects two image effects:  Sepia Filter and Magnify Filter.

[caption id="attachment_42508" align="alignnone" width="300" caption="Multiple Image Effect Demo Forms Designer and Structure Window"][/caption]

MainForm.h:

//---------------------------------------------------------------------------



#ifndef MainFormH

#define MainFormH

//---------------------------------------------------------------------------

#include <System.Classes.hpp>

#include <FMX.Controls.hpp>

#include <FMX.Forms.hpp>

#include <FMX.Objects.hpp>

#include <FMX.Types.hpp>

#include <FMX.Dialogs.hpp>

//---------------------------------------------------------------------------

class TForm1 : public TForm

{

__published:	// IDE-managed Components

	TImage *Image1;

	TImage *Image2;

	TButton *OpenButton;

	TOpenDialog *OpenDialog1;

	TSaveDialog *SaveDialog1;

	TTrackBar *SepiaTrackBar;

	TLabel *Label1;

	TButton *SaveButton;

	TLabel *Label2;

	TTrackBar *MagnifyTrackBar;

	void __fastcall OpenButtonClick(TObject *Sender);

	void __fastcall FormCreate(TObject *Sender);

	void __fastcall SepiaTrackBarChange(TObject *Sender);

	void __fastcall SaveButtonClick(TObject *Sender);

private:	// User declarations

public:		// User declarations

    TFilterSepia * MySepiaFilter;

    TFilterMagnify * MyMagnifyFilter;

	__fastcall TForm1(TComponent* Owner);

};

//---------------------------------------------------------------------------

extern PACKAGE TForm1 *Form1;

//---------------------------------------------------------------------------

#endif

MainForm.cpp:

//---------------------------------------------------------------------------



#include <fmx.h>

#pragma hdrstop

#include "FMX.Filter.hpp"

#include "FMX.Filter.Effects.hpp"

#include "MainForm.h"

//---------------------------------------------------------------------------

#pragma package(smart_init)

#pragma resource "*.fmx"

TForm1 *Form1;

//---------------------------------------------------------------------------

__fastcall TForm1::TForm1(TComponent* Owner)

	: TForm(Owner)

{

}

//---------------------------------------------------------------------------

void __fastcall TForm1::OpenButtonClick(TObject *Sender)

{

	if (OpenDialog1->Execute()) {

		Image1->Bitmap->LoadFromFile(OpenDialog1->FileName);

		SaveButton->Enabled = true;

		MySepiaFilter->Input = Image1->Bitmap;

		MySepiaFilter->Amount = SepiaTrackBar->Value / 100;

		MyMagnifyFilter->Center = TPointF(Image1->Bitmap->Width/2,Image1->Bitmap->Height/2);

		MyMagnifyFilter->Radius = 0.35;

		MyMagnifyFilter->InputFilter = MySepiaFilter; // set the Magnify Filter's input to the Sepia output

		MyMagnifyFilter->Magnification = MagnifyTrackBar->Value;

		Image2->Bitmap = MyMagnifyFilter->Output;

	}

}

//---------------------------------------------------------------------------

void __fastcall TForm1::FormCreate(TObject *Sender)

{

	MySepiaFilter = new TFilterSepia(this);

	MyMagnifyFilter = new TFilterMagnify(this);

}

//---------------------------------------------------------------------------

void __fastcall TForm1::SepiaTrackBarChange(TObject *Sender)

{

	MySepiaFilter->Amount = SepiaTrackBar->Value / 100;

	MyMagnifyFilter->InputFilter = MySepiaFilter;

	MyMagnifyFilter->Magnification = MagnifyTrackBar->Value;

	Image2->Bitmap = MyMagnifyFilter->Output;

}

//---------------------------------------------------------------------------

void __fastcall TForm1::SaveButtonClick(TObject *Sender)

{

	if (SaveDialog1->Execute()) {

		Image2->Bitmap->SaveToFile(SaveDialog1->FileName);

	}

}

//---------------------------------------------------------------------------

The following are screen captures of the demo application and the resulting saved bitmap:





I have also uploaded the complete project to CodeCentral at http://cc.embarcadero.com/item/29314