Working with mathmorphs?

Stephane Ducasse ducasse at iam.unibe.ch
Thu Mar 6 20:23:55 UTC 2003


Andreas

if I understand correclty this means that this class QuickPrint could 
be then removed from Squeak

Stef
On Thursday, March 6, 2003, at 08:53 PM, Andreas Raab wrote:

> Hi,
>
>>> (b) the Vertex class in the graph package on the mathMorphs
>>> site uses a class called "QuickPrint" which doesn't seem to
>>> exist in the current image (and about which the only hint I
>>> can find on the Swiki is an aside about "DisplayScanner's
>>> #quickPrint: variants").
>>
>> Squeak 2.7 was the last version with QuickPrint.  That class
>> implemented fast, single-line string display.
>> Squeak 2.8 is the first version with quick print protocol in class
>> DisplayScanner. (You found the right hint in the 3.4 image)
>> QuickPrint was a sublcass of CharacterScanner, which in
>> turn at that time was a subclass of BitBlt. Now CharacterScanner is
>> subclassed to Object and when you try to file in QuickPrint you will
>> be told that some instance variables (those inherited from BitBlt) are
>> undefined. So this will also not work. We have no other choice than
>> to move all this MathMorphs stuff to the new quickprint protocol
>> in DisplayScanner.
>
> QuickPrint had no longer a purpose when the "regular" display protocol 
> was
> streamlined and out-performed QuickPrint by factors of 2-5. Most users 
> of
> QuickPrint were clients who wanted to measure the width of a certain 
> string
> (QuickPrint's #stringWidth: protocol) which you can simply replace by
> querying the font itself (#widthOfString:). E.g., typically QuickPrint 
> was
> used for something like
>
> 	scanner := QuickPrint newOn: Display box: Display boundingBox font:
> aFont.
> 	aWidth := (scanner stringWidth: aString).
>
> which can be replaced trivially by
>
> 	aWidth := aFont widthOfString: aString.
>
> Displaying should always be done by going through the appropriate 
> canvas
> protocol, so unless there's some magic involved in MathMorphs (which I 
> don't
> think) the above is the only issue you need to check.
>
> Cheers,
>   - Andreas
>
>
>
Prof. Dr. Stéphane DUCASSE (ducasse at iam.unibe.ch) 
http://www.iam.unibe.ch/~ducasse/
  "if you knew today was your last day on earth, what would you do 
different? ...  especially if,
  by doing something different, today might not be your last day on 
earth" Calvin&Hobbes

"The best way to predict the future is to invent it..." Alan Kay.

Open Source Smalltalks: www.squeak.org, 
www.gnu.org/software/smalltalk/smalltalk.html
Free books for Universities at 
http://www.esug.org/sponsoring/promotionProgram.html
Free Online Book at www.iam.unibe.ch/~ducasse/FreeBooks.html



More information about the Squeak-dev mailing list