[vtkusers] 2D API- Image Drawing

[Marcus D. Hanwell]

On Wed, Aug 4, 2010 at 2:59 AM, Krishna Katamneni <
krishna.katamneni at gmail.com> wrote:

> Dear All
> I have several 2D  images with different dimensions, origins and
> resolutions.
> I want to draw them using 2D API (class vtkImageItem) etc and also want the
> images to be drawn in windows screen coordinates.
>
> I'm also confused with parameters for DrawImage method in the 2D API(are
> these screen coordinates or should be in-terms of image dimensions).
> When using this method, all my images are upside down.
>

These are screen coordinates by default, but they can be transformed.

> .
> For example , my window size is 600x400
>
> and have many 2D images(  details of few examples are given below)
>
> Image  Details
>
>                         Resolution
> Dimensions                          Origin
>
>    1.               0.1 x 0.1 x 1             930   x  700   x
>    1                -78.3 x 0  x 0
>    2.               0.2 x 0.2 x 1             1560 x  750   x
>    1                -78.3 x 0  x 0
>    3.               0.5 x 0.2 x 1             3100 x  1560 x
>    1                -100  x 20 x 0
>    4.               0.1 x 0.2 x 1             360   x  180   x
>    1               -14.3 x 0  x 0
>
> and also would like my image to be to fit to the available window size(I
> can resize my window dynamically).
>

I have just added some API to scale the images drawn by a scale factor.

>
> I think we should be able to create 2D Transform that handles all these
> cases in one go, but I'm not sure how to achieve it using vtkTransform2D.
>

The 2D API has a scene, and you can build up a tree, making a vtkImageItem
the child item of a vtkContextTransform would allow you to them transform
the child items (translation, scale, rotation), see the TestContextScene
code for some examples.

There are still issues with test not being transformed correctly, I am
working on that. Most other stuff should get transformed, and I could likely
give you a few pointers. I am not sure why your images would be upside down,
I did not encounter that in my tests.

>
> Could anybody help me how to handle these situations?
>

Hopefully that clears some of this up. It would be good to come up with an
example that could be added to the wiki, and possibly as a new test. I am
pretty busy right now, but will try to give you further pointers if anything
is not clear.

Thanks,

Marcus
--
Marcus D. Hanwell, Ph.D.
R&D Engineer, Kitware Inc.
(518) 881-4937
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