[RQt-devel] scale of view for some primitive doesn't work

[Tengfei Yin]

On Thu, Nov 11, 2010 at 5:39 PM, Michael Lawrence <lawrence.michael at gene.com
> wrote:

> This is by design. If this didn't work that way, then when the user zoomed
> into a chromosome, for example, the text labels would get really stretched
> out. Glyphs are the same way (they're essentially fancy characters). Zooming
> into a scatterplot should not make the glyphs larger. Circles (after much
> debate inside my head) behave the same as glyphs. This is because their
> radius, like in a bubble plot, is derived from something other than the X
> and Y axes.
>
> Shapes however, like rectangles, polygons and paths, are zoomed. You expect
> a mosaic plot rectangle or a map polygon to scale with the plot.
>
>
This make sense to me, in most cases, i guess people won't expect the circle
or text to be  zoomed in.

Are you sure you really need the text to scale with the zoom? Deepayan and I
> decided a long time ago that zooming does not behave like a "magnifying
> glass." It rescales the plot.
>
>
No, you don't have to change that, it's convenient so far, I am just curious
why this doesn't work for text and circle, because in other rare case, I
will draw very small text as labels of axis for one circular track, or if I
draw points around the circular track, I am still expecting the points will
be zoomed in when I rescale the view. I guess I am confused the "rescale of
the view" with the one you defined with Deepayan, but it make sense to me.

There are some ways to get around this if you really want to:
> - Draw the text as a path.
> - Use the "render" method on the scene to render to a QPicture, rescale
> that and display it. This is how I imagined someone making a magnifying
> glass. QPicture is a vectorized representation, so no nasty scaling
> artifacts are introduced.
>

Thanks, I think I need to do it in this way, if I really need them to be
rescaled.  I never try QPicture before, I will take a look at it.


> Michael
>
> On Thu, Nov 11, 2010 at 3:24 PM, Tengfei Yin <yintengfei at gmail.com> wrote:
>
>> Hi
>>
>> Here comes another question with text, please see the attached  code
>> below, only rect could be resized,  when I call v$scale()
>>
>> text, circle doesn't change. it happens to visnab, the circular view, when
>> I scale the view, every thing resize but the text, it's still in the same
>> size.
>>
>> library(qtpaint)
>> s <- qscene()
>> test_layer <- qlayer(s,function(layer,painter){
>>   qdrawRect(painter,30,30,70,70,stroke="blue")
>>   qdrawCircle(painter,50,50,20,stroke="red")
>>   qdrawText(painter,"TEST",50,50)
>> },limits=qrect(0,0,100,100))
>> v <- qplotView(s)
>> v$show()
>>
>> v$scale(1.5,1.5)
>>
>> Thanks
>>
>> Tengfei
>> --
>> Tengfei Yin
>> MCDB PhD student
>> 1620 Howe Hall, 2274,
>> Iowa State University
>> Ames, IA,50011-2274
>> Homepage: www.tengfei.name
>>
>>
>>
>> _______________________________________________
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>> Qtinterfaces-devel at lists.r-forge.r-project.org
>>
>> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/qtinterfaces-devel
>>
>>
>


-- 
Tengfei Yin
MCDB PhD student
1620 Howe Hall, 2274,
Iowa State University
Ames, IA,50011-2274
Homepage: www.tengfei.name
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