[Drawkit] "not flipped" drawing issues

[Allan Daly]

Hi Graham,

I've been following your posts on the mapping program with interest --  
certainly looking forward to seeing that program when it's released.  
I'm also wondering about the DK changes / improvements you might be  
making along the way toward the v1.0 release. Can you tell me if  
you've tackled the "not flipped" issue I raised back in February and  
summarized below?

I've continued work on the DXF importer and have it working well now.  
I'm just about through with "MTEXT" entities and soon I'll reach the  
point where it sure would be nice to have "not flipped" drawings to  
display text correctly. The MTEXT development is/was the last of the  
core DXF entities that I needed to tackle before turning my attention  
to the development of the main program. (By the way, the importer now  
handles LINE, LWPOLYLINE, ARC, CIRCLE, TEXT, INSERT, and MTEXT  
entities and correctly deals with HEADER variables and BLOCKS. I can  
load quite complicated architectural CAD layouts into a DK drawing  
with these tools!)

Now that I'm focusing on text so much I'm unfortunately getting many  
crashes and freezes which I suspect are related to the text origin and  
display in the not-flipped drawings or perhaps also my use of offsets  
outside the bounding box of the DK objects. I need to figure out  
what's causing the crashes and was about to start digging into the DK  
code and thought it would make sense to ask you about your updates and  
changes and schedule first. Would you mind sending out a quick update  
as to what the near future might hold? In particular please comment on  
the text drawing issue in not-flipped drawings.

Thanks as usual.

-Allan


On Feb 8, 2009, at 4:30 PM, Graham Cox wrote:

>> With your note here you are clearly identifying that the framework  
>> is  not "flip safe" and that there are tasks to do in order to make  
>> the not-flipped world work correctly. Do you have any idea how  
>> large a task this would be and is it something you plan on tackling  
>> any time soon? For my app I just cannot see making a flipped  
>> context work. Everything in the architectural CAD world and in the  
>> world of the energy simulation programs that I'm interfacing with  
>> assume a lower left origin. I'm a bit worried that this might be a  
>> major barrier for me.
>>
>
>
> Hi Allan,
>
> I don't think it's a huge amount of work to ensure "flip safety".  
> The note there really refers to the fact that I haven't done very  
> much about the unflipped state is all, so there probably are  
> assumptions about the flipped state but not on purpose (in other  
> words the assumption might have been made without thinking rather  
> than deliberately).
>
> It's likely that text is going to be the main area of concern as you  
> have identified. I can fix the specific case you mention easily  
> enough, and I'll try and find some time to look at this in general.
>
> I guess the good news is that because DK has been largely developed  
> in the "flipped" state, contrary to the natural orientation of the  
> views and graphics system, it should be easier to now ensure  
> unflipped works given that flipped definitely does. (Hope that makes  
> sense!).
>
> --Graham
>
>