c# - How to crop bitmap in UWP app? -

there many similar questions, none of them seem answer problem.

i working on uwp app (with syncfusion), can generate pdf. pdf, need syncfusion.pdf.graphics.pdfbitmap, before that, need crop little bit.

this doing, diagram , transform pdfbitmap:

 var diagrambitmap = new pdfbitmap(diagram); 

then need draw pdf by:

 document.pages[0].graphics.drawimage(diagrambitmap, x, y, width, height); 

problem is, none of solutions found worked in uwp crop pdfbitmap before drawing it. solved problem without cropping diagram, it's working, crop more better , nicer solution.

thanks or advice!

problem is, none of solutions found worked in uwp crop pdfbitmap before drawing it. solved problem without cropping diagram, it's working, crop more better , nicer solution.

you can crop before pdfbitmap creation.there sample project cropping images in uwp. please refer uwp-imagecropper. can modify core function below let meet requirement:

/// <param name="originalimgfile">image file want crop</param> /// <param name="startpoint">from point want crop</param> /// <param name="corpsize">the crop size of image</param> /// <param name="scale">the scale of cropped image</param> async public static task<stream> getcroppedbitmapasync(storagefile originalimgfile, system.drawing.point startpoint, system.drawing.size corpsize, double scale) {     if (double.isnan(scale) || double.isinfinity(scale))     {         scale = 1;     }       // convert start point , size integer.      uint startpointx = (uint)math.floor(startpoint.x * scale);     uint startpointy = (uint)math.floor(startpoint.y * scale);     uint height = (uint)math.floor(corpsize.height * scale);     uint width = (uint)math.floor(corpsize.width * scale);       using (irandomaccessstream stream = await originalimgfile.openreadasync())     {           // create decoder stream. decoder, can           // properties of image.          bitmapdecoder decoder = await bitmapdecoder.createasync(stream);          // scaledsize of original image.          uint scaledwidth = (uint)math.floor(decoder.pixelwidth * scale);         uint scaledheight = (uint)math.floor(decoder.pixelheight * scale);            // refine start point , size.           if (startpointx + width > scaledwidth)         {             startpointx = scaledwidth - width;         }          if (startpointy + height > scaledheight)         {             startpointy = scaledheight - height;         }           // create cropping bitmaptransform , define bounds.          bitmaptransform transform = new bitmaptransform();         bitmapbounds bounds = new bitmapbounds();         bounds.x = startpointx;         bounds.y = startpointy;         bounds.height = height;         bounds.width = width;         transform.bounds = bounds;           transform.scaledwidth = 100;         transform.scaledheight = 100;          // cropped pixels within bounds of transform.          pixeldataprovider pix = await decoder.getpixeldataasync(             bitmappixelformat.bgra8,             bitmapalphamode.straight,             transform,             exiforientationmode.ignoreexiforientation,             colormanagementmode.colormanagetosrgb);         byte[] pixels = pix.detachpixeldata();           // stream bytes writeablebitmap          writeablebitmap cropbmp = new writeablebitmap((int)width, (int)height);         stream pixstream = cropbmp.pixelbuffer.asstream();         pixstream.write(pixels, 0, (int)(width * height * 4));           return pixstream;     } } 

then can use pdfbitmap creation:

var imagefile = await storagefile.getfilefromapplicationuriasync(new uri("ms-appx:///assets/image03.jpg")); stream  bitmap = await getcroppedbitmapasync(imagefile, new system.drawing.point(100, 100), new system.drawing.size(100, 100), 1); pdfbitmap image = new pdfbitmap(bitmap);