C # watermark A picture to set transparency

C # to the picture watermark, you can set the transparency, set the location of the watermark can see the previous article ha

/// <summary>    ///Creating a watermarked photograph with GDI + for. NET/// </summary>    /// <param name= "Rsrcimgpath" >Physical path of the original picture</param>    /// <param name= "Rmarkimgpath" >the physical path of the watermark picture</param>    /// <param name= "Rmarktext" >Watermark text (does not display watermark text set to empty string)</param>    /// <param name= "Rdstimgpath" >the physical path to the output of the synthesized picture</param>     Public voidBuildwatermark (stringRsrcimgpath,stringRmarkimgpath,stringRmarktext,stringRdstimgpath) {     //the following (code) creates an image object from a specified file, and then defines the variable for its Width and height. //these lengths will be used to create a bitmap object that uses the format of the bits per pixel as the color data. Image Imgphoto =Image.FromFile (Rsrcimgpath); intPhwidth =Imgphoto.width; intPhheight =Imgphoto.height; Bitmap Bmphoto=NewBitmap (Phwidth, Phheight, Pixelformat.format24bpprgb); Bmphoto.setresolution ( the, the); Graphics Grphoto=graphics.fromimage (Bmphoto); //This code is loaded into the watermark image, the watermark image has been saved as a BMP file, with green (a=0,r=0,g=255,b=0) as the background color. //once again, a variable is defined for its width and height. Image Imgwatermark =NewBitmap (Rmarkimgpath); intWmwidth =Imgwatermark.width; intWmheight =Imgwatermark.height; //This code draws imgphoto to the (x=0,y=0) position of the Graphics object at 100% of its original size. //all subsequent drawings will take place at the top of the original photo. Grphoto.smoothingmode =Smoothingmode.antialias; Grphoto.drawimage (Imgphoto,NewRectangle (0,0, Phwidth, phheight),0,          0, Phwidth, Phheight, GraphicsUnit.Pixel); //to maximize the size of the copyright information, we will test 7 different font sizes to determine the maximum possible size we can use for our photo widths. //to do this effectively, we will define an integer array and then traverse these integer values to measure the different size of the copyright string. //Once we determine the maximum possible size, we exit the loop and draw the text    int[] sizes =New int[] { -, -, A,Ten,8,6,4 }; Font Crfont=NULL; SizeF crsize=NewSizeF ();  for(inti =0; I <7; i++) {Crfont=NewFont ("Arial", Sizes[i], fontstyle.bold); Crsize=grphoto.measurestring (Rmarktext, Crfont); if((ushort) Crsize.width < (ushort) phwidth) Break; }     //because all the photos have a variety of heights, it is decided to start at the bottom of the image at the beginning of the 5% position. //Use the height of the Rmarktext string to determine the appropriate y-axis for the drawing string. //The x-axis is determined by the center of the computed image, then a StringFormat object is defined, and the stringalignment is set to center.     intYpixlesfrombottom = (int) (Phheight *. to); floatYposfrombottom = ((Phheight-ypixlesfrombottom)-(Crsize.height/2)); floatXcenterofimg = (Phwidth/2); StringFormat Strformat=NewStringFormat (); Strformat.alignment=Stringalignment.center; //now we have all the coordinates we need to create a solidbrush with a color of 60% black (alpha value 153). //draw a copyright string at the right 1 pixels from the right and 1 pixels at the bottom. //This deviation will be used to create a shadow effect.    Use the brush to repeat a process that draws the same text at the top of the previous drawn text. SolidBrush SEMITRANSBRUSH2 =NewSolidBrush (Color.FromArgb (153,0,0,0)); Grphoto.drawstring (Rmarktext, Crfont, SemiTransBrush2,NewPointF (xcenterofimg +1, Yposfrombottom +1), Strformat); SolidBrush Semitransbrush=NewSolidBrush (Color.FromArgb (153,255,255,255)); Grphoto.drawstring (Rmarktext, Crfont, Semitransbrush,NewPointF (xcenterofimg, Yposfrombottom), Strformat); //Create a bitmap based on the previously modified photo.    Load this bitmap into a new graphic object. Bitmap Bmwatermark =NewBitmap (Bmphoto);     Bmwatermark.setresolution (Imgphoto.horizontalresolution, imgphoto.verticalresolution); Graphics Grwatermark=graphics.fromimage (Bmwatermark); //by defining a ImageAttributes object and setting its two properties, we are implementing two colors to achieve a translucent watermark effect. //the first step in handling the watermark image is to turn the background pattern transparent (alpha=0, r=0, g=0, b=0).        We use a colormap and define a remaptable to do this. //as shown earlier, my watermark is defined as 100% green background, we will search for this color and replace it with transparency. ImageAttributes ImageAttributes =NewImageAttributes (); ColorMap ColorMap=NewColorMap (); Colormap.oldcolor= Color.FromArgb (255,0,255,0); Colormap.newcolor= Color.FromArgb (0,0,0,0); Colormap[] Remaptable={COLORMAP}; //the second color processing is used to change the opacity of the watermark. //do this by applying a 5x5 matrix that contains the RGBA space that provides the coordinates. //by setting the third row and the third column 0.3f we have reached an opaque level.    The result is that the watermark appears slightly below the image. imageattributes.setremaptable (remaptable, Coloradjusttype.bitmap); float[] colormatrixelements = {                                                  New float[] {1.0f,0.0f,0.0f,0.0f,0.0f},                                                 New float[] {0.0f,1.0f,0.0f,0.0f,0.0f},                                                 New float[] {0.0f,0.0f,1.0f,0.0f,0.0f},                                                 New float[] {0.0f,0.0f,0.0f,0.3f,0.0f},                                                 New float[] {0.0f,0.0f,0.0f,0.0f,1.0f}                                            }; ColorMatrix Wmcolormatrix=NewColorMatrix (colormatrixelements);     Imageattributes.setcolormatrix (Wmcolormatrix, Colormatrixflag.default, Coloradjusttype.bitmap); //with two color processing added to the ImageAttributes object, we can now draw a watermark on the right hand side of the photo. //we will deviate from the 10 pixel to the bottom, 10 pixels to the left.     intMarkwidth; intMarkheight; //mark is wider than the original figure.    if(Phwidth <=wmwidth) {Markwidth= Phwidth-Ten; Markheight= (Markwidth * wmheight)/Wmwidth; }     Else if(Phheight <=wmheight) {Markheight= Phheight-Ten; Markwidth= (Markheight * wmwidth)/Wmheight; }     Else{markwidth=Wmwidth; Markheight=Wmheight; }     intXPOSOFWM = ((phwidth-markwidth)-Ten); intYPOSOFWM =Ten; Grwatermark.drawimage (Imgwatermark,NewRectangle (XPOSOFWM, YPOSOFWM, Markwidth, markheight),0,          0, Wmwidth, Wmheight, GraphicsUnit.Pixel, ImageAttributes); //The final step will be to replace the original image with the new bitmap.    Destroys two graphic objects and then saves the image to the file system. Imgphoto =Bmwatermark;     Grphoto.dispose ();     Grwatermark.dispose ();     Imgphoto.save (Rdstimgpath, imageformat.jpeg);     Imgphoto.dispose (); Imgwatermark.dispose (); }

C # watermark A picture to set transparency