Here is an example.....shows the original larger image and the resized one. You can see the ragged border when the image is on a darker background, as the offending pixels are not the same as the transparent colour of the rest of the square image out to the edges - they have been altered in colour by the resizing. Hope I am making sense.
The original image was a png, and it has been resized then converted to BMP using Irfanview. As far as I recall I didn't use the Lanczos option, just the defaults. http://sites.google.com/site/jbclnz2/delphistuff/delphimiscissues John ----- Original Message ----- From: "Conor Boyd" <conor.b...@trimble.co.nz> To: "NZ Borland Developers Group - Delphi List" <delphi@delphi.org.nz> Sent: Tuesday, January 19, 2010 11:31 AM Subject: Re: [DUG] Resizing images > What I think you're seeing (without seeing your example) is the softness > introduced by most resampling algorithms (when used for downsampling). > > Something like Bicubic Sharper in PS or Lanczos Kernel in Irfanview > might help. > > However, most of these sharpening algorithms probably work better on > photographic images than they will on graphics. Maybe a more "dumb" > program like Paint would resample a graphic better. Or reducing the > color depth of the image before resizing will also help. > > Post an example, and I'll see what I would do with it. > > C. > > -----Original Message----- > From: delphi-boun...@delphi.org.nz [mailto:delphi-boun...@delphi.org.nz] > On Behalf Of John Bird > Sent: Tuesday, 19 January 2010 11:15 a.m. > To: NZ Borland Developers Group - Delphi List > Subject: Re: [DUG] Resizing images > > More specifically - does the GIMP or any other resizing method allow me > to specify this?: > > Where say an image with a a white background (the transparent colour) > meets a grey border, and the image is resized (especially if resized > smaller), there will be on this edge a new pixel that has part of the > grey border and > the white background. Most resizing operations will change the pixel > to > light grey/cream whereas I want to tell it to either use the original > grey or the white background only for any pixels on the edge. > > John > >> The GiMP is always handy for image manipulation. Generally I draw my >> images in a really old version of Corel Draw, then use GiMP for >> transparance, shadows and so on. >> > > > _______________________________________________ > NZ Borland Developers Group - Delphi mailing list > Post: delphi@delphi.org.nz > Admin: http://delphi.org.nz/mailman/listinfo/delphi > Unsubscribe: send an email to delphi-requ...@delphi.org.nz with Subject: > unsubscribe > > _______________________________________________ > NZ Borland Developers Group - Delphi mailing list > Post: delphi@delphi.org.nz > Admin: http://delphi.org.nz/mailman/listinfo/delphi > Unsubscribe: send an email to delphi-requ...@delphi.org.nz with Subject: > unsubscribe _______________________________________________ NZ Borland Developers Group - Delphi mailing list Post: delphi@delphi.org.nz Admin: http://delphi.org.nz/mailman/listinfo/delphi Unsubscribe: send an email to delphi-requ...@delphi.org.nz with Subject: unsubscribe
