Contents - Methods - Properties

Helper class for image manipulations (wrapper to PLPict23.dll)

Description
Internal representation - truecolor device-independent bitmap (DIB).

Loading an image from file/stream - BMP, JPEG, TIFF, PNG, GIF, TGA, PCX, ....

Saving an image to file/stream - BMP, JPEG, TIFF, PNG.

Drawing directly into the image canvas (or HDC) - usable as offscreen bitmap.

Drawing an image into another canvas (or into HDC) - 1:1 or zoomed by factor.

Thread-safe (locking mechanism for using with unsafe VCL version).

At runtime, TPLPicture requires PLPict23.dll on search path ( Windowsetc).

Contents - TPLPicture - Properties

~TPLPicture

Destructor

C++ declaration
__fastcall virtual ~TPLPicture(void)

BeginPaint

Begin painting into image canvas

Delphi declaration
function BeginPaint(bLockedPaint: Boolean): Boolean;
C++ declaration
bool __fastcall BeginPaint(bool bLockedPaint)

Description
bLockedPaint - Lock TPLPicture painting operations. Important in the case of multithreading.

Set bLockedPaint to TRUE, if your VCL graphics is not thread-safe (CBuilder1, Delphi2),

Otherwise set to FALSE (starting from CBuilder 4 and Delphi 4; we have not tested CBuilder 3 yet).

Don't forget to call EndPaint after your drawing is finished!

CheckPaintLibDllOk

Internal

Delphi declaration
function CheckPaintLibDllOk: Boolean;
C++ declaration
bool __fastcall CheckPaintLibDllOk(void)

Create

Create a new empty image object

Delphi declaration
constructor Create;

Description
The size is not determined (1x1 pixels).

Usage: before loading from file/stream.

CreateSize

Create a new empty image with determined width and height

Delphi declaration
constructor CreateSize(AWidth: Longint; AHeight: Longint);

Description
Usable before drawing into the image canvas.

Destroy

Destructor

Delphi declaration
destructor Destroy;

Draw

Draws an image into the canvas

Delphi declaration
procedure Draw(ACanvas: TCanvas; x: Integer; y: Integer);
C++ declaration
void __fastcall Draw(Graphics::TCanvas *ACanvas, int x, int y)

Description
ACanvas - where to draw

x,y - left upper corner in ACanvas

DrawDC

Draws an image into HDC

Delphi declaration
procedure DrawDC(dc: HDC; x: Integer; y: Integer);
C++ declaration
void __fastcall DrawDC(HDC dc, int x, int y)

Description
dc - device context, where to draw

x,y - left upper corner

EndPaint

End painting o n the image canvas

Delphi declaration
procedure EndPaint;
C++ declaration
void __fastcall EndPaint(void)

Description
At this point Canvas and dc are freed.

If previously BeginPaint was called requiring locking (BeginPaint(TRUE)), then this will also unlock other threads.

GetCanvas

Delphi declaration
function GetCanvas: TCanvas;
C++ declaration
Graphics::TCanvas *__fastcall GetCanvas(void)

GetFileLoadFilter

Delphi declaration
function GetFileLoadFilter: string;
C++ declaration
System::AnsiString __fastcall GetFileLoadFilter(void)

GetFileSaveFilter

Delphi declaration
function GetFileSaveFilter: string;
C++ declaration
System::AnsiString __fastcall GetFileSaveFilter(void)

GetHandle

Delphi declaration
function GetHandle: HBITMAP;
C++ declaration
HBITMAP __fastcall GetHandle(void)

GetHeight

Delphi declaration
function GetHeight: Longint;
C++ declaration
long __fastcall GetHeight(void)

GetWidth

Delphi declaration
function GetWidth: Longint;
C++ declaration
long __fastcall GetWidth(void)

LoadFromFile

Load (decode) image from file

Delphi declaration
function LoadFromFile(const FileName: string): Boolean;
C++ declaration
bool __fastcall LoadFromFile(const System::AnsiString FileName)

Description
Image type is detected automatically.

Warning: previous content and size will be overwritten.

LoadFromStream

Load (decode) image from stream

Delphi declaration
function LoadFromStream(InStream: TCustomMemoryStream): Boolean;
C++ declaration
bool __fastcall LoadFromStream(Classes::TCustomMemoryStream *InStream)

Description
Image type is detected automatically.

Warning: previous content and size will be overwritten.

Lock

Another way to lock an image before a thread-unsafe operation

Delphi declaration
procedure Lock;
C++ declaration
void __fastcall Lock(void)

Description
Don't forget to call UnLock, if the required operation is done!

SaveToBMPStream

Save (encode) an image into stream as BMP

Delphi declaration
function SaveToBMPStream(OutStream: TStream): Boolean;
C++ declaration
bool __fastcall SaveToBMPStream(Classes::TStream *OutStream)

SaveToFile

Save (encode) an image into a file

Delphi declaration
function SaveToFile(const FileName: string): Boolean;
C++ declaration
bool __fastcall SaveToFile(const System::AnsiString FileName)

Description
Image type will b e determined from t he filename extension (default BMP)

SaveToJPEGStream

Save (encode) an image into steam as JPEG with default quality

Delphi declaration
function SaveToJPEGStream(OutStream: TStream): Boolean;
C++ declaration
bool __fastcall SaveToJPEGStream(Classes::TStream *OutStream)

SaveToJPEGStreamQ

Save (encode) an image into steam as JPEG with custom quality

Delphi declaration
function SaveToJPEGStreamQ(OutStream: TStream; iQuality: Integer): Boolean;
C++ declaration
bool __fastcall SaveToJPEGStreamQ(Classes::TStream *OutStream, int iQuality)

Description
Parameter iQuality is t he BMP->JPEG conversion quality in percentages (0...100) - better quality means bigger size.

SaveToPNGStream

Save (encode) an image into steam as PNG

Delphi declaration
function SaveToPNGStream(OutStream: TStream): Boolean;
C++ declaration
bool __fastcall SaveToPNGStream(Classes::TStream *OutStream)

SaveToTIFFStream

Save (encode) an image into steam as TIFF

Delphi declaration
function SaveToTIFFStream(OutStream: TStream): Boolean;
C++ declaration
bool __fastcall SaveToTIFFStream(Classes::TStream *OutStream)

StretchDraw

Draws a n image into t he canvas, zoomed by factor

Delphi declaration
procedure StretchDraw(ACanvas: TCanvas; x: Integer; y: Integer; Factor: Double);
C++ declaration
void __fastcall StretchDraw(Graphics::TCanvas *ACanvas, int x, int y, double Factor)

Description
ACanvas - where to draw

x,y - left upper corner

StretchDrawDC

Draws a n image into HDC, zoomed by factor

Delphi declaration
procedure StretchDrawDC(dc: HDC; x: Integer; y: Integer; Factor: Double);
C++ declaration
void __fastcall StretchDrawDC(HDC dc, int x, int y, double Factor)

Description
dc - where to draw

x,y - left upper corner

TPLPicture

Constructor

C++ declaration
__fastcall virtual TPLPicture(void)

__fastcall virtual TPLPicture(long AWidth, long AHeight)

Description
Constructor without parameters creates a new empty image - usable before loading from file/stream.

Paramet e rized constructor creates a new empty image with a determined size - usable before drawing into the image canvas.

UnLock

Unlocking an image after a thread-unsafe operation

Delphi declaration
procedure UnLock;
C++ declaration
void __fastcall UnLock(void)

Contents - TPLPicture - Methods

Canvas

Canvas for drawing o n the image

Delphi declaration
property Canvas: TCanvas read GetCanvas;
C++ declaration
__property Graphics::TCanvas *Canvas={ read=GetCanvas, nodefault }

Description
Canvas is available only between BeginPaint and EndPaint !

dc

Image's device context (HDC) for drawing

Delphi declaration
property dc: HDC read hMemDC;
C++ declaration
__property HDC dc={ read=hMemDC, nodefault }

Description
dc is available only between BeginPaint and EndPaint !

FileLoadFilter

Supported imagefiles filter for OpenFile dialog

Delphi declaration
property FileLoadFilter: string read GetFileLoadFilter;
C++ declaration
__property System::AnsiString FileLoadFilter={ read=GetFileLoadFilter, nodefault }

FileSaveFilter

Supported imagefiles filter for SaveFile dialog

Delphi declaration
property FileSaveFilter: string read GetFileSaveFilter;
C++ declaration
__property System::AnsiString FileSaveFilter={ read=GetFileSaveFilter, nodefault }

Handle

Handle to image's internal representation (Windows HBITMAP)

Delphi declaration
property Handle: HBITMAP read GetHandle;
C++ declaration
__property HBITMAP Handle={ read=GetHandle, nodefault }

Height

Image height in pixels

Delphi declaration
property Height: Longint read GetHeight;
C++ declaration
__property long Height={ read=GetHeight, nodefault }

Description
Value is not changeable (set in t he constructor or when loaded from file/stream)

Locked

Check if image is locked

Delphi declaration
property Locked: Boolean read FLocked;
C++ declaration
__property bool Locked={ read=FLocked, nodefault }

Width

Image width in pixels

Delphi declaration
property Width: Longint read GetWidth;
C++ declaration
__property long Width={ read=GetWidth, nodefault }

Description
Value is not changeable (set in t he constructor or or when loaded from file/stream)