Drawing LaTeX Improvements

[TheCedarPrince]

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Link to relevant issue(s)
#161

How did you address these issues with this PR? What methods did you use?

The draw LaTeX PR was good (#206 ) but I noticed that the drawing animation seems to "swoop" into the frame. This is a result of using the circle object to cover up/uncover the LaTeX being animated. I propose to add additional shapes (such as rectangles) to modify this behavior.

[TheCedarPrince]

@Wikunia, I noticed that there seems to be a strange behavior in my code in providing a rectangular glide. Here is my code:

function animate_latex(text, pos::Point, t, action)
    svg = get_latex_svg(text)
    action == :stroke && (action = :fill)
    if t >= 1
        translate(pos)
        pathsvg(svg)
        do_action(action)
        translate(-pos)
        return
    end

    pathsvg(svg)
    polygon = pathtopoly()
    w, h = polywh(polygon)

    translate(pos)
    pathsvg(svg)
    do_action(:clip)
    rect(O, t * w, h, :fill)
    translate(-pos)
end

And here is the output:

Somehow, the h "height" return from polywh does not completely cover the LaTeX. Any thoughts as to why this is? Is this a bug in polywh?

[Wikunia]

It gives you the width and height but not the starting point. You assume the starting point is the origin but this seems to be wrong in this case. You should be able to see it when drawing the rectangle in red and on top the latex.

[TheCedarPrince]

Hey @Wikunia I tested this again and, though I changed the presumed point, I still have the same problem. Here is what the output of my modified code is now:

function animate_latex(text, pos::Point, t, action)
    svg = get_latex_svg(text)
    action == :stroke && (action = :fill)
    if t >= 1
        translate(pos)
        pathsvg(svg)
        do_action(action)
        translate(-pos)
        return
    end 
    
    pathsvg(svg)
    polygon = pathtopoly()
    w, h = polywh(polygon)
    sethue("red")
    rect(pos, t * w, h, :fill)
    pathsvg(svg)
    do_action(:clip)
    translate(-pos)
end

and output:

It's almost like the LaTeX is being shifted somehow... Thoughts?

[Wikunia]

I can't see anything to be honest. Why don't you draw the latex on top of the rectangle to see where it is exactly and why it doesn't match.

[Wikunia]

Will you continue trying to tackle this @TheCedarPrince ?

[TheCedarPrince]

Yes @Wikunia - it is on my radar to be worked on in v0.3.x. So, should be one of the first ones I tackle.