Re: [Sketch-devel] How to use a PixmapHandles ?

[Daniel K. <dk...@me...>]

Hi:
> Is this a plugin-object?
Nop, I'm writing a script for my pattern maker.
Sorry for the bad descriptions. I'll try to explain what I need
again in a diferent maner and hope I explain myself better:

I want a draggable pixmap drag the canvas to point to the
center of a pattern to be. This pixmap should not be part of the drawing,
for example it shouldn't change it's size if I zoom in or out. It would be
a draggable shape  that would be a little cross like the + symbol. It will
remain viewable at all  times (like a crosshair) and the user will
position it in the canvas where he wants the  center of a pattern (like
a rosetter) to be.
In pseudo code using my imaginary simplified commands it would look like:

control_point = CreateControlPoint(bitmap = mysymbol.xpm)
context.main_window.canvas.DrawControlPoint(control_point,(0,0))

I could then drag a the little cross wherever with my mouse in the canvas,
and when I'd want his position I would put:

position_control_point = control_point.pos()

and It would return:

>position_control_point
(65,78)

I tried to do this with an image but it has several problems:
	- It's can be zoomed in or zoomed out while the size of my control
	point should remain constant indepently of the zoom (like a
	handle)
	- It's printable, a control point would be an auxiliary for
	drawing (like the grid or a guideline) it is not to be printed.

	Sorry if this mail was too long but I tried to be more
	descriptive than the previous one.

	Thanks.

					Daniel.

> Is this a plugin-object? A plugin-object is the only real way to do it.
>
> The basic approach is to make that plugin object editable. This means
> that the has_edit_mode attribute has to be true and the Editor method
> has to return an editor for the object. All actual interaction is then
> done through that editor.
>
> The canvas calls the editor's GetHandles method to find out which
> handles to draw and the canvas also tests whether mouse clicks would
> select a handle. If mouse clicks occur the canvas calls the editor's
> SelectHandle or SelectPoint methods to indicate that where the user has
> clicked and when the user drags the mouse it calls ButtonDown, ButtonUp
> and MouseMove and a few other methods.
>
> Some of this is documented in the comments in Sketch/Graphics/base.py.
> The editing of builting objects is implemented this way too, so their
> code is also a good start.
>
> I'll also try to write a simple example of an editable plugin object. I
> hope to have it ready this weekend, but I can't really promise this.
>
>    Bernhard
>
> --
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> MapIt!                                               http://mapit.de/
>