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Embedded svg canvas in WContainerWidget

Added by denis Bertini over 6 years ago

Hi

I have embedded an svg canvas ( javascript standalone code ) within

a WContainerWidget. When i used Auto Sizing of the container the embedded

svg canvas is not able to resize properly and get distorted .

Is there a way to force repaint() of all existing element in a WContainerWidget

in an automatically way ?

Thanks in advance

Denis


Replies (4)

RE: Embedded svg canvas in WContainerWidget - Added by Koen Deforche over 6 years ago

What do you mean with 'Auto Sizing'?

I think there's only one way to react to the container resizing and that's by:

  • setting a layout (e.g. WFitLayout) on the container
  • setting a custom widget (e.g. WContainerWidget) inside the fit layout
  • reimplementing the virtual layoutResized() function.

RE: Embedded svg canvas in WContainerWidget - Added by denis Bertini over 6 years ago

Hi Koen,

Thanks for your answer. will look at this !

What i meant is that the svg canvas put inside a WGridLayout

do not resize properly like if a repaint() is missing when changing

at the size of an element in the grid layout.

I attached a screen shot showing exactly this.

Ciao

Denis

RE: Embedded svg canvas in WContainerWidget - Added by denis Bertini over 6 years ago

Hi Koen,

I could not find out how to use WFitLayout from within a WGridLayout to solve the

sizing problem.

On the other hand, reimplementing the LayoutResized() function worked fine for me!

My concern is when having a lot of histogram to display ( client side ) any resizing of the

layout will cause a repaint() of all the histograms and may be can be a performance

penalty.

Since i am not experience with web graphics, what is the "good practice" to have

performant graphics on the web ( client or server side ) ?

Best regards,

Denis

RE: Embedded svg canvas in WContainerWidget - Added by Koen Deforche over 6 years ago

In that case you were already using layouts and then the additional WFitLayout is not necessary.

As to performance: that is a bit of an open-ended question. Wt does it's best to have performant graphics rendering (to HTML5 Canvas, SVG, VML, or PNG). But since it's server-side it cannot offer the same kind of interactivity as a client-side solution. On the other hand, if a lot of data is required for the rendering, then rendering a PNG server-side can be the fastest solution, and with WPaintedWidget you can easily switch between the two. So it's not an easy choice.

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