[Newbie] Form dotOfSize: 5. What am I missing?

John-Reed Maffeo rlpa80 at email.sps.mot.com
Wed Feb 23 15:38:44 UTC 2000


agree at carltonfields.com wrote:
---snip
> #displayOn:at: uses copyBits with the combination rule "Form over", which simply copies the form over the specified bitmap.  The rule to use depends upon your particular needs.  Perhaps:
> 
> (Form dotOfSize: 20)    displayOn: Display
>         at: 200 at 200
>         clippingBox: Display boundingBox
>         rule: Form and
>         fillColor: nil
> 
> Many other combinations are possible, depending upon the particular results desired.

Bob Arning wrote:
---snip
> Here's one way:
> 
> ((Form dotOfSize: 200) asFormOfDepth: Display depth)
>         replaceColor: Color white withColor: Color transparent;
>         displayOn: Display at: 40 at 40 rule: Form paint

It seems that the part I was missing (and still am to a certain extent)
is the relationships
among class Form, display methods, and rules.

The basic displayOn: family of methods all use the rule Form over. As we
see in the examples,
different rules need to be used (depending on depth?). I haven't looked
yet, but I expect that
the display method that I am invoking in class LinearFit uses Form over
as well.

Thanks for the pointers. It has helped. I will continue plodding my way
through MVC graphics
hopeful in the knowledge that the Squeak List is there to help when I
get stuck.

John-Reed Maffeo
Mesa, AZ





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