Use GDI + to create watermark image for Delphi Program

Using GDI +, you can easily create images with watermark effects.ArticleThere are also many, but there are few Delphi, this article refer to the online article http://www.codeproject.com/kb/gdi-plus/watermark.aspxintroduction, using Delphi 2007 to create a watermark, the originalCodeAs follows:

Unit Main;

Interface

Uses
Windows, messages, sysutils, variants, classes, graphics, controls, forms,
Dialogs, gdiplus, stdctrls;

Type
Tmainform = Class (tform)
Button1: tbutton;
Procedure formpaint (Sender: tobject );
Procedure formcreate (Sender: tobject );
Procedure formdestroy (Sender: tobject );
Procedure button1click (Sender: tobject );
Private
{Private Declarations}
Phot tgpimage;
Phwidth: integer;
Phheight: integer;
Watermark: tgpimage;
Wmwidth: integer;
Wmheight: integer;
BMP: tgpbitmap;
Public
{Public declarations}
End;

VaR
Mainform: tmainform;

Implementation

Uses gdiptypes;

{$ R *. DFM}

Procedure tmainform. button1click (Sender: tobject );
VaR
CLSID: tguid;
Parameters: tencoderparameters;
Quality: integer;
Begin
// Set image quality encoding Parameters
Parameters. Count: = 1;
Parameters. Parameter [0]. guid: = encoderquality;
Parameters. Parameter [0]. valuetype: = encoderparametervaluetypelong;
Parameters. Parameter [0]. numberofvalues: = 1;
// Set the parameter value: quality level, up to 100. The image file size is proportional to the quality.
Quality: = 100;
Parameters. Parameter [0]. Value: = @ quality;

If getencoderclsid ('image/JPEG ', CLSID) then
BMP .save('watermarkphoto.jpg ', CLSID, @ parameters );
End;

Procedure tmainform. formcreate (Sender: tobject );
Const
Colormatrix: tcolormatrix =
(
(1.0, 0.0, 0.0, 0.0, 0.0 ),
(0.0, 1.0, 0.0, 0.0, 0.0 ),
(0.0, 0.0, 1.0, 0.0, 0.0 ),
(0.0, 0.0, 0.0, 0.3, 0.0 ),
(0.0, 0.0, 0.0, 0.0, 1.0)
);
Workingdirectory = '... media ';
Copyright = 'copyright 2008-maozefa ';
VaR
GP: tgpgraphics;
Imageattr: tgpimageattributes;
Strformat: tgpstringformat;
Font: tgpfont;
X, Y: single;
Begin
// Read the original image
Photo: = tgpimage. Create (workingdirectory + '100_0349.jpg ');
Phwidth: = photo. width;
Phheight: = photo. height;
// Read the watermark image
Watermark: = tgpimage. Create (workingdirectory + 'watermark.bmp ');
Wmwidth: = watermark. width;
Wmheight: = watermark. height;
// Create a new bitmap with a resolution of 72
BMP: = tgpbitmap. Create (phwidth, phheight, pf32bppargb );
BMP. setresolution (72, 72 );
// Create a new bitmap canvas and set the image display quality and text display quality.
GP: = tgpgraphics. Create (BMP );
GP. smoothingmode: = smantialias;
GP. textrenderinghint: = thantialias;
// Draw the original image on the canvas
GP. drawimage (photo, gprect (0, 0, phwidth, phheight ),
0, 0, phwidth, phheight, utpixel );
// Create an image display helper class
Imageattr: = tgpimageattributes. Create;
// Set the transparent color to the base color of the watermark image at four corners. The watermark image is displayed as a rounded corner image.
Imageattr. setcolorkey ($ ff00ff00, $ ff00ff00, ctbitmap );
// Set the watermark image opacity to 0.3
Imageattr. setcolormatrix (colormatrix, cfdefault, ctbitmap );
// Watermark in the upper left corner of the canvas
GP. drawimage (watermark, gprect ({phwidth-wmwidth-} 10, 10, wmwidth, wmheight ),
0, 0, wmwidth, wmheight, utpixel, imageattr );
// Set the text font and display format
Font: = tgpfont. Create ('arial', 16, [fsbold]);
Strformat: = tgpstringformat. Create;
Strformat. Alignment: = sacenter;
// Center the shadow text under the canvas
X: = phwidth/2;
Y: = phheight-26;
GP. drawstring (copyright, Font, brushs [$99000000], x + 1, Y + 1, strformat );
GP. drawstring (copyright, Font, brushs [$99 ffffff], X, Y, strformat );

Font. Free;
Strformat. Free;
Imageattr. Free;
GP. Free;
End;

Procedure tmainform. formdestroy (Sender: tobject );
Begin
Photo. Free;
Watermark. Free;
BMP. Free;
End;

Procedure tmainform. formpaint (Sender: tobject );
VaR
G: tgpgraphics;
Begin
G: = tgpgraphics. Create (canvas. Handle );
// Display the original image
G. drawimage (photo, 0, 0, phwidth, phheight );
// Display the original watermark image
G. translatetransform (0, phheight + 5 );
G. drawimage (watermark, 0, 0, wmwidth, wmheight );
// Display images with watermarks and text
G. translatetransform (phwidth,-(phheight + 5 ));
G. drawimage (BMP, 0, 0, phwidth, phheight );
G. Free;
End;

End.