[DUG] Image manipulation

[Conor Boyd]

Yeah, those issues are what drove my choice of Graphics32 (image quality
and scaling).
 
Here's some code which uses Graphics32 to resample an image.
 
OldBitmap, TempBitmap are of type Graphics32.TBitmap32
NewBitmap is of type Graphics.TBitmap;
 
  OldBitmap.Assign(a regular Graphics.TBitmap here which you could load
using GraphicEx);
 
  TempBitmap := TBitmap32.Create;
  try
    TempBitmap.Width := Trunc(OldBitmap.Width * Scale);
    TempBitmap.Height := Trunc(OldBitmap.Height * Scale);
 
    rs := TKernelResampler.Create(OldBitmap);
 
    if FastResamplingWanted then
      rs.Kernel := THermiteKernel.Create
    else
      rs.Kernel := TLanczosKernel.Create;
 
    GR32_Resamplers.StretchTransfer(TempBitmap,
                                    Rect(0, 0, TempBitmap.Width,
TempBitmap.Height),
                                    Rect(0, 0, TempBitmap.Width,
TempBitmap.Height),
                                    OldBitmap,
                                    Rect(0, 0, OldBitmap.Width,
OldBitmap.Height),
                                    rs, dmBlend, Nil);
 
    NewBitmap.Assign(TempBitmap);
  finally
    TempBitmap.Free;
  end;

I've paraphrased this from some code of mine, but hopefully that's the
gist of a high-quality resample for you using Graphics32.
 
Cheers,
 
Conor

________________________________

From: delphi-bounces at delphi.org.nz [mailto:delphi-bounces at delphi.org.nz]
On Behalf Of Jeremy Coulter
Sent: Tuesday, 13 October 2009 4:09 p.m.
To: NZ Borland Developers Group - Delphi List
Subject: Re: [DUG] Image manipulation


I have some code that I wrote form bits of other code off the net that
resizes images so they dont loose any quality. But like how Photoshop
does it etc.....well nearly.
I needed one that did scaling so that the aspect ratio was retained. It
seems to work ok.

Jeremy


On Tue, Oct 13, 2009 at 4:05 PM, Kyley Harris <Kyley at harrissoftware.com>
wrote:


	GraphicsEx is great.. but I do everything with BMP and JPG only
	
	
	On Tue, Oct 13, 2009 at 3:43 PM, Robert martin
<rob at chreos.co.nz> wrote:
	

		Hi
		
		We want to do some basic image manipulation.
Specifically the following
		
		1) open and dipslay Gif, jpg, and png image formats.
		2) Resize the above file format
		3) Save file back in resized format.
		
		Does anyone have or recommend any code for doing such?
		
		I have seen GraphixEx but it states it does not support
saving of images.
		
		Cheers
		Rob
		
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	-- 
	Kyley Harris
	Harris Software
	+64-21-671-821
	
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