[Kstars-devel] Kstars-devel Digest, Vol 143, Issue 3

[M.S. Adityan]

Hi,

Here are a few proposed ideas to solve the clipping problem with
constellation art.

1. Draw a opaque black rectangle with a hollow center for the sphere. This
black rectangle will cover any 'part' of the constellation image that is
drawn beyond the sphere.

2. Note down the coordinates of the 4 corners of the rectangle for each
constellation image. Then draw the image ONLY if all the 4 corners are
visible on the sky. This will ensure that the image is drawn only if the
entire rectangle lies on the sky.

3. The clipping happens when FOV>180. So we get FOV center() and then find
the minimum and maximum values by adding or subtracting 90 from it. Then
check the midpoint Aziumth and add the width of the constellation image in
degrees to it. If this value is greater than fov_center+90 or less than
fov_center-90 then it needs to be clipped.

Can anyone help solve this issue?

Thanks.

M.S.Adityan
Website: www.msadityan.com
https://www.linkedin.com/in/msadityan

On Sat, Jul 18, 2015 at 5:30 PM, <kstars-devel-request at kde.org> wrote:

> Send Kstars-devel mailing list submissions to
>         kstars-devel at kde.org
>
> To subscribe or unsubscribe via the World Wide Web, visit
>         https://mail.kde.org/mailman/listinfo/kstars-devel
> or, via email, send a message with subject or body 'help' to
>         kstars-devel-request at kde.org
>
> You can reach the person managing the list at
>         kstars-devel-owner at kde.org
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Kstars-devel digest..."
>
>
> Today's Topics:
>
>    1. Clipping artwork on the border of skymap (M.S. Adityan)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 17 Jul 2015 21:25:01 +0530
> From: "M.S. Adityan" <msadityan at gmail.com>
> To: KStars Development Mailing List <kstars-devel at kde.org>
> Subject: [Kstars-devel] Clipping artwork on the border of skymap
> Message-ID:
>         <CA+T53Rq-pXzfJeetiDbsyw3K=k22FaOBBHOxKRp8gqC6w-v=
> 3w at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hi,
>
> I have completed Western and Inuit sky culture artwork in KStars. The
> artwork is currently displaying completely on the border of the sky map. I
> want to make it clip such that it displays only the portion of the artwork
> which is "on" the sky map and not the one that goes out of the sphere. How
> can this be achieved? To see how KStars looks currently please see this
> <http://www.msadityan.com/wp-content/uploads/2015/07/kstars.png>.
>
> Also another issue was regarding pixelation of the artwork at high zoom
> levels. To solve this, I scaled every constellation image to 1024x1024
> pixels using Qt::SmoothTransformation. Is this a right way to solve the
> problem? (please refer to the latest git commit on
> gsoc2015-constellationart branch for this)
>
> Regards
> M.S.Adityan
> Website: www.msadityan.com
> https://www.linkedin.com/in/msadityan
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> http://mail.kde.org/pipermail/kstars-devel/attachments/20150717/4b6d89fb/attachment-0001.html
> >
>
> ------------------------------
>
> Subject: Digest Footer
>
> _______________________________________________
> Kstars-devel mailing list
> Kstars-devel at kde.org
> https://mail.kde.org/mailman/listinfo/kstars-devel
>
>
> ------------------------------
>
> End of Kstars-devel Digest, Vol 143, Issue 3
> ********************************************
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.kde.org/pipermail/kstars-devel/attachments/20150721/c3b5a921/attachment.html>