changing plot line color in Graph flower

[husamal...@gmail.com]

the attached example is to use Graph flower now I want to change the color during the run time I mean update the color after creating the widget I simply tried to act like the color property is kivy property and change directly but is not work ?

Thanks in advance for any help 

[Elliot Garbus]

Taking a quick look at the source code for LinePlot, this is not a capability of the library.  You would need to add an on_color event to LinePlot and update the color.

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[Tobias HT]

I've been using graph for a while now but I haven't thought of writing a graph which changes color at runtime. However I believe it can be done, you just have to implement the action yourself by subclassing the plot you want, implement the on_color property to update the graph canvas when a color changes. I'm sorry I can't elaborate more cause I've not tried it myself, but that would be the best way I think it can be done

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[husamal...@gmail.com]

do you mean modify the source code of  LinePlot widget ?

[Elliot Garbus]

Yes,  I am suggesting modifying the source code.  Another user made a good suggestion, derive a new class from LinePlot and see if you can make the modifications in the child class. 

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[husamal...@gmail.com]

can some one gives my  some hints

I tried this on Plot source code but its not working

def on_color(self.,instance,color):

    self.color.=color

the method I called but its not working

[husamal...@gmail.com]

Thanks in advance for any help

[Elliot Garbus]

Looking at the source code for LinePlot(),

https://github.com/kivy-garden/garden.graph/blob/c83c7382c47d1e0568ea3b6d5edb11bfaa609953/__init__.py#L1212

 

The method, create_drawings, creates a RenderContext, and sets the color and the Line. 

 

I have not used a RenderContext and am not familiar with the underlying OpenGL technology – but this is what I would try:

Create a new class derived from LinePlot.

In your on_color handler, you will need to run the code from create_drawnings. (super().create_drawings()) Perhaps you will need to clear the render context prior.  A quick search of the docs – I did not see a way to clear the render context.  I don’t understand the relationship between the canvas and the render context.  Do some experiments start by changing the color from black to white and white to black.

 

Try using the self._grc.clear() method on the render context, the way in works on  a canvas.

Clear the render context then create a new one with the new color.

 

Good Luck!

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