Manipulating images

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Steven Spencer (Spinalogic) - 04 Jan 2007 00:29 GMT

Gday guys,

We have a need in our application to manipulate around 10 images on the
screen at any one time, with the manipulations limited to zooming and
transforming.

(Vb.net .net 1.1)

Currently we have been using GDI Plus to manipulate the images, but
specifically when panning images, it has been quite slow when redrawing,
resulting in flickering. We have implemented double buffering, but the end
result is no flicker, but the refresh rate drops to around 1.5/2 full
redraws per second on a modern machine. This is unacceptable.

(We only manipulate one image at a time, but need to show up to 10 at once,
whilst the doctor manipulates a specific image of interest.)

Is there an API that we have missed for panning and zooming large images?
Or should we be looking into managed DirectX (DirectDraw) to do the
manipulations?

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Kevin Spencer - 04 Jan 2007 11:36 GMT

It is possible that you have missed something in the panning and zooming of
the images. However, your best bet would indeed be to use DirectX for
panning and zooming the images, since it uses vector graphics, which
provides much better size scalability, and faster drawing (the video card
handles the greatest part of the load in its hardware).

Signature

HTH,

Kevin Spencer
Microsoft MVP
Bit Player
http://unclechutney.blogspot.com

Where there's a Will, there's a William.

> Gday guys,
>
[quoted text clipped - 16 lines]
> Or should we be looking into managed DirectX (DirectDraw) to do the
> manipulations?

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Bob Powell [MVP] - 12 Jan 2007 06:20 GMT

GDI+ doesn't handle large images well.

A control that may help you with this is the ZoomPicBox which is
available on my site. It's support code for an article and comes in C#
and VB flavours.

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Bob Powell [MVP]
Visual C#, System.Drawing

Ramuseco Limited .NET consulting
http://www.ramuseco.com

Find great Windows Forms articles in Windows Forms Tips and Tricks
http://www.bobpowell.net/tipstricks.htm

Answer those GDI+ questions with the GDI+ FAQ
http://www.bobpowell.net/faqmain.htm

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> Gday guys,
>
[quoted text clipped - 16 lines]
> Or should we be looking into managed DirectX (DirectDraw) to do the
> manipulations?

Reply to this Message

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Manipulating images

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