[etoys-dev] Re: [JIRA] Commented: (SQ-682) 'forward by' when snap to grid is true move one gridspace forward.

karl ramberg karlramberg at gmail.com
Mon Mar 22 14:59:16 EDT 2010

On Mon, Mar 22, 2010 at 5:37 PM, Steve Thomas <sthomas1 at gosargon.com> wrote:
> There are other ways to accomplish the same tasks (ie: move "forward" one
> grid space et al) without being able to specify movement in "grid units"
> (ie: move forward grid size).
> What exactly is the problem we are trying to solve?

Movement of players now are pretty abstract and measuring area is awkward.
A pixel is kind  of a weird unit and being able to use others would be nice.
I suggest that we could change the behavior of forward based on the grid
of the playfield.
If the grid is 200 by 200 units a step forward would be 1/200 th

I made a snake game project that use a grid and liked the simplicity it gave in
dealing with area and movement in turtle graphic.
By using smaller units it's also easier for younger kids to deal with the
numbers when the numbers are in in range up to 10 or 20 instead of 200 or 500.

DrGeo solves many of these issues though with distance, perimeter and area etc.


> Randy did a beautiful example of moving across a grid in his Lesson
> 7 showing how moving across a grid can be used to measure area. In fact I
> believe he did it without using gridding.
> Now one thing I have been struggling with is how to measure perimeter. I saw
> Randy do it using Polygons.
> But not sure how to do it when placing Squares in a Playfield to create a
> shape.
> Any suggestions or a script would be appreciated.
> Stephen
> On Mon, Mar 22, 2010 at 12:28 PM, Rita Freudenberg
> <rita at isg.cs.uni-magdeburg.de> wrote:
>> 'forward by' when snap to grid is true move one gridspace forward.
>> ------------------------------------------------------------------
>>              Key: SQ-682
>>              URL: http://tracker.squeakland.org/browse/SQ-682
>>          Project: squeakland
>>       Issue Type: Feature
>>       Components: etoys
>>         Reporter: Karl Ramberg
>> When snap to grid is turned on it would be nice if forward by moved the
>> player one grid space forward. Like wise for all the height, width turn
>> etc
>> that they reflected the preference griding and showed the grid values
>> instead of the pixel values.
>>>>>> Bert Freudenberg commented on SQ-682:
>>>>>> -------------------------------------
>>>>>> I don't think this would be a good idea. The gridding is for manual
>>>>>> placement of objects.
>>>>>> But feel free to discuss on the squeakland list (since this is
>>>>>> changing
>>>>>> behavior, it's not just for developers).
>>>>> I agree it's a big change and maybe you are right.
>>>>> Maybe it' just complicates stuff unnecessary.
>>>>> But we kind of do this on the pixel grid already by moving one pixel
>>>>> forward ;-)
>>>>> Another related change is defining movement to for example centimeters
>>>>> instead of pixels.
>>>>> But it is a fundamental change and need more discussion.
>> Randy, what do you think, would you like to have that for your perimeter
>> lessons? Maybe to write a script to calculate the perimeter?
>> Rita
>> _______________________________________________
>> etoys-dev mailing list
>> etoys-dev at squeakland.org
>> http://lists.squeakland.org/mailman/listinfo/etoys-dev
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