How to create a Filters plugin in Delphi[]
To see how to create a FiltersPlugin, we will create a new one ! This new Plugin will be very basic : it adds noise on a input image.
1 - Create a new Delphi project :
a/ choose the type 'DLL'
b/ save it with the name 'FiltersPlugin_Noise.dpr'
2 - Copy and add this files in your project :
FiltersTutorial/FiltersPlugin_/Delphi/dllInterface.pas
FiltersTutorial/FiltersPlugin_/Delphi/main.pas
FiltersTutorial/FiltersPlugin_/Delphi/image.pas
(all this files are not necessary to create a FilterPlugin, but it can help a lot !)
3 - In the project source (the unit with 'library' at the top', add this lines : After "{$R *.res}"
exports getVersion, createFilter, deleteFilter, run, runCommand, getParametersCount, getParameterName, getParameterHelp, setParameterInteger, setParameterFloat, setParameterBoolean, setParameterString, setParameterImage, setParameterPointer, setParameterImagesCount, setParameterImagesImageAtIndex, getOutputsCount, getOutputName, getOutputImage, getOutputImagesCount, getOutputImagesImageAtIndex, getOutputInteger, getOutputFloat, getOutputArrayPointersCount, getOutputArrayPointersPointerAtIndex, setRegionOfInterest, unsetRegionOfInterest;
->It is the only functions exported by our DLL
4 - Change the project options to set the destination directory to the location of Filters
->Example : set the destination path to 'C:\FiltersTutorial\Bin'
5 - Build the project
->Actually the new Plugin do nothing, but we can already test it in a Delphi project !
(for a final example, you can have a look on the project 'testplugin')
6 - Now we will add 2 parameters of our plugin :
The parameter 'inImage' : the input image
The parameter 'outImage' : the image where we have to draw the result
->it's always a good practice to provide output images as parameters
(of course, when the size of output images can't be known, the filter must create it and provide it as a 'Output')
a/ Well, in the unit 'main.pas', add this protected variable :
...
protected _inImageParameter : PBitmap32; _outImageParameter : PBitmap32;
...
b/ Set it to nil in the constructor :
... constructor TFiltersPlugin.Create; begin
_inImageParameter := nil; _outImageParameter := nil; unsetRegionOfInterest();
end; ...
c/ Our Plugin has to declare this 2 parameters:
... function TFiltersPlugin.getParametersCount() : Integer; begin
Result := 2;
end;
procedure TFiltersPlugin.getParameterName( const aIndex : Integer; var aName : String ); begin
case aIndex of 0 : aName := 'inImage'; 1 : aName := 'outImage'; end;
end;
procedure TFiltersPlugin.getParameterHelp( const aIndex : Integer; var aHelp : String ); begin
case aIndex of 0 : aHelp := 'the input image'; 1 : aHelp := 'the output image (must be of the same size than [inImage])'; end;
end;
procedure TFiltersPlugin.setParameterImage( const aName : String; const aImage : PFBitmap32 ); begin
if aName='inImage' then _inImageParameter := aImage else if aName='outImage' then _outImageParameter := aImage;
end; ...
7 - Now we do the real job of our plugin : add noise ! ... // It's a scholar example, and not a good and fast method ! procedure TFiltersPlugin.run(); var
x, xMin, xMax, y, yMin, yMax : Integer; pDest : PColor32Array; roi : TFRect; r : Integer;
begin
// if we have input images
if (_inImageParameter<>nil) and (_outImageParameter<>nil) then begin
// both input images must be of the same size
if image.isSameSize( _inImageParameter, _outImageParameter )=True then begin
// we start by copy the [inImage] to [outImage]
image.copyImageToImage( _inImageParameter, _outImageParameter );
// we get the ROI (if ROI=(-1,-1)(-1,-1), then getValidROI return the full image)
roi := image.getValidROI( _inImageParameter, _roi );
// for each pixel in the ROI
xMin := Round( roi.Left );
xMax := Round( roi.Right );
yMin := Round( roi.Top );
yMax := Round( roi.Bottom );
pDest := _outImageParameter.Bits;
for y:=yMin to yMax do begin
for x:=xMin to xMax do begin
// sometime we add salt and pepper noise
r := Random(2*100);
if r=0 then begin
pDest^[0] := clBlack32;
end else if r=1 then begin
pDest^[0] := clWhite32;
end;
Inc( pDest );
end;
end;
end;
end;
end; ...
8 - We can add a parameter to add more or less noise.
a/ We add the parameter 'scale'
...
protected _scale : Integer;
...
b/ Set it to a default value in the constructor :
... constructor TFiltersPlugin.Create; begin
_inImageParameter := nil; _outImageParameter := nil; _scale := 100; unsetRegionOfInterest();
end; ...
c/ Our Plugin has now to declare 3 parameters:
... function TFiltersPlugin.getParametersCount() : Integer; begin
Result := 3;
end;
procedure TFiltersPlugin.getParameterName( const aIndex : Integer; var aName : String ); begin
case aIndex of 0 : aName := 'inImage'; 1 : aName := 'outImage'; 2 : aName := 'scale'; end;
end;
procedure TFiltersPlugin.getParameterHelp( const aIndex : Integer; var aHelp : String ); begin
case aIndex of 0 : aHelp := 'the input image'; 1 : aHelp := 'the output image (must be of the same size than [inImage])'; 2 : aHelp := 'if scale=100, then for each pixel, there is 1/scale chance to have noise'; end;
end;
procedure TFiltersPlugin.setParameterInteger( const aName : String; const aValue : Int64 ); begin
if aName='scale' then _scale := aValue;
end; ...
d/ And we use it in our process
... procedure TFiltersPlugin.run();
...
r := Random(2*_scale);
...
end; ...
by edurand
->for any question : filters@edurand.com
the final code[]
unit main;
interface
uses
image;
type
TFiltersPlugin = class(TObject)
protected
_inImageParameter : PBitmap32;
_outImageParameter : PBitmap32;
_scale : Integer;
// Region Of Interest
_roi : TFRect;
public
constructor Create;
destructor Destroy;
procedure run();
procedure runCommand( const aCommand : String);
function getParametersCount() : Integer;
procedure getParameterName( const aIndex : Integer; var aName : String );
procedure getParameterHelp( const aIndex : Integer; var aHelp : String );
procedure setParameterBoolean( const aName : String; const aValue : Boolean );
procedure setParameterInteger( const aName : String; const aValue : Int64 );
procedure setParameterFloat( const aName : String; const aValue : Single );
procedure setParameterString( const aName : String; const aValue : String );
procedure setParameterImage( const aName : String; const aImage : PBitmap32 );
procedure setParameterImagesCount( const aName : String; const aCount : Integer );
procedure setParameterImagesImageAtIndex( const aName : String; const aImage : PBitmap32; const aIndex : Integer );
procedure setParameterPointer( const aName : String; const aPointer : Pointer );
function getOutputsCount() : Integer;
procedure getOutputName( const aIndex : Integer; var aName : String );
function getOutputImage( const aName : String ) : PFBitmap32;
function getOutputImages( const aName : String ) : PArrayOfPFBitmap32;
function getOutputInteger( const aName : String ) : Integer;
function getOutputFloat( const aName : String ) : Single;
function getOutputArrayPointers( const aName : String ) : PArrayOfPointers;
procedure setRegionOfInterest( const roi : PFRect );
procedure unsetRegionOfInterest( );
end;
var
FiltersPlugin_Version : String = 'V20061204';
implementation
uses
SysUtils, Math;
constructor TFiltersPlugin.Create;
begin
_inImageParameter := nil;
_outImageParameter := nil;
_scale := 100;
unsetRegionOfInterest();
Randomize();
end;
destructor TFiltersPlugin.Destroy;
begin
end;
// It's a scholar example, and not a good and fast method !
procedure TFiltersPlugin.run();
var
x, xMin, xMax, y, yMin, yMax : Integer;
pDest : PColor32Array;
roi : TFRect;
r : Integer;
begin
// if we have input images
if (_inImageParameter<>nil) and (_outImageParameter<>nil) then begin
// both input images must be of the same size
if image.isSameSize( _inImageParameter, _outImageParameter )=True then begin
// we start by copy the [inImage] to [outImage]
image.copyImageToImage( _inImageParameter, _outImageParameter );
// we get the ROI (if ROI=(-1,-1)(-1,-1), then getValidROI return the full image)
roi := image.getValidROI( _inImageParameter, _roi );
// for each pixel in the ROI
xMin := Round( roi.Left );
xMax := Round( roi.Right );
yMin := Round( roi.Top );
yMax := Round( roi.Bottom );
pDest := _outImageParameter.Bits;
for y:=yMin to yMax do begin
for x:=xMin to xMax do begin
// sometime we add salt and pepper noise
r := Random(2*_scale);
if r=0 then begin
pDest^[0] := clBlack32;
end else if r=1 then begin
pDest^[0] := clWhite32;
end;
Inc( pDest );
end;
end;
end;
end;
end;
procedure TFiltersPlugin.runCommand( const aCommand : String );
begin
run();
end;
function TFiltersPlugin.getParametersCount() : Integer;
begin
Result := 2;
end;
procedure TFiltersPlugin.getParameterName( const aIndex : Integer; var aName : String );
begin
case aIndex of
0 : aName := 'inImage';
1 : aName := 'outImage';
2 : aName := 'scale';
end;
end;
procedure TFiltersPlugin.getParameterHelp( const aIndex : Integer; var aHelp : String );
begin
case aIndex of
0 : aHelp := 'the input image';
1 : aHelp := 'the output image (must be of the same size than [inImage])';
2 : aHelp := 'if scale=100, then for each pixel, there is 1/scale chance to have noise';
end;
end;
procedure TFiltersPlugin.setParameterBoolean( const aName : String; const aValue : Boolean );
begin
end;
procedure TFiltersPlugin.setParameterInteger( const aName : String; const aValue : Int64 );
begin
if aName='scale' then _scale := aValue;
end;
procedure TFiltersPlugin.setParameterFloat( const aName : String; const aValue : Single );
begin
end;
procedure TFiltersPlugin.setParameterString( const aName : String; const aValue : String );
begin
end;
procedure TFiltersPlugin.setParameterImage( const aName : String; const aImage : PFBitmap32 );
begin
if aName='inImage' then _inImageParameter := aImage
else if aName='outImage' then _outImageParameter := aImage;
end;
procedure TFiltersPlugin.setParameterImagesCount( const aName : String; const aCount : Integer );
begin
end;
procedure TFiltersPlugin.setParameterImagesImageAtIndex( const aName : String; const aImage : PBitmap32; const aIndex : Integer );
begin
end;
procedure TFiltersPlugin.setParameterPointer( const aName : String; const aPointer : Pointer );
begin
end;
function TFiltersPlugin.getOutputsCount() : Integer;
begin
Result := 0;
end;
procedure TFiltersPlugin.getOutputName( const aIndex : Integer; var aName : String );
begin
end;
function TFiltersPlugin.getOutputImage( const aName : String ) : PFBitmap32;
begin
end;
function TFiltersPlugin.getOutputImages( const aName : String ) : PArrayOfPFBitmap32;
begin
end;
function TFiltersPlugin.getOutputInteger( const aName : String ) : Integer;
begin
end;
function TFiltersPlugin.getOutputFloat( const aName : String ) : Single;
begin
end;
function TFiltersPlugin.getOutputArrayPointers( const aName : String ) : PArrayOfPointers;
begin
end;
procedure TFiltersPlugin.setRegionOfInterest( const roi : PFRect );
begin
_roi := roi^;
end;
procedure TFiltersPlugin.unsetRegionOfInterest();
begin
_roi.Left := -1;
_roi.Top := -1;
_roi.Right := -1;
_roi.Bottom := -1;
end;
end.