[Newbies] Resizing a form to specific width and height

[Matthias Korn]

Hi Bert,

thanks for your hint.

I tried WarpBlt class>>rotate:degrees:center:scaleBy:smoothing: and it
worked as expected. But I also found that I just had a slight mistake
and my initial try with Form>>magnifyBy: and aPoint (with x and y
scaling) was actually also successful. I am using this now.

Thanks,
Matthias

P.S.: I had to fix Form>>magnifyBy: in my Squeak version as it
initially did not work with Points as advertised.


Am Mon, 12 Jan 2009 11:45:43 +0100
schrieb Bert Freudenberg <bert at freudenbergs.de>:

> On 12.01.2009, at 00:16, Matthias Korn wrote:
> 
> > Hi,
> >
> > how can I resize a form to a specific width and height by either
> > stretching it on one axis or cropping it on the other axis.
> 
> 
> Forms are fixed-size. The way you do it is by creating a new form of  
> the desired extent and depth, and then copying (a part of) the old  
> form into the new form, possibly scaling the pixels while doing so.
> 
> This is done by class BitBlt (for "bit block transfer") and its  
> extension WarpBlt (which can do scaling and rotation too).
> 
> There are convenience methods hiding the details of form creation,  
> BitBlt, and WarpBlt in class Form. E.g. "copy: aRectangle" does  
> cropping, and "magnify: aRectangle by: aPoint smoothing: anInteger"  
> does cropping and scaling.
> 
> BitBlt also does bit-depth conversion, color-remapping, statistics,  
> and other image manipulations. It's well worth learning about :)
> 
> - Bert -
> 
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-- 
Matthias Korn
Institut für Wirtschaftsinformatik
Fachbereich 5 
Universität Siegen
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eMail: matthias.korn at uni-siegen.de