How to improve quality when resizing images?

rbuser

I print a logo in the header of every page.
The logo looks good if it is displayed in it's original size.

If the report-preview (TppViewer) is resized then the image also
should be resized. This results in really bad quality.

How can i improve the quality?
- Can i set a resize-method with better quality?
- Can i draw an image by code?
- Can i change the image when the image-control is resized?
- ... any other ideas?

regards,

josef

nicocizik

Hi Josef,

ReportBuilder uses the Delphi StretchDraw routine to draw a scaled image to
the screen. One thing you might try is setting the DirectDraw property of
the image to True. This tends to help.

Another option may be to use the TppViewer.OnResize event to re-assign
another image.

--
Regards,

Nico Cizik
Digital Metaphors
http://www.digital-metaphors.com

rbuser

Hi,

For this reason we use ImageEn from HiComponents (www.hicomponents.com). We
have written wrapper around it and use it's resize methods - support for
many different resize filters.
Works great and without problems. Somehing like:

TdoppImage = class(TppImage)
private
FImageEnIO: TImageEnIO;
FImageEnIOProc: TImageEnProc;
protected
procedure PictureMenuClick(Sender: TObject);
public
procedure PopupMenuClick(Sender: TObject); //override;
constructor Create(aOwner: TComponent); override;
destructor Destroy; override;
end;

in the implementation is used our own code for loading image from file and
dynamically resizing it to correct size. The DB version is a little
complicated, but it works. It can be easily updated to support image resize
while resizing TdoppImage - but we didn't need that.

Petr Slipek


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