How to fast rotate a Image

[winjiadh]

Angbody can help me, I want to rotate a Image controls 360 degree in a form, and let it looks like a turntable. Who can help me, thanks frist!
How to rotate a Image and let it looks like fast.:sign0085:

 

[Erel]

One of agraham's graphics libraries includes this functionality exactly.

 

[winjiadh]

Can you tell me Where to download the library

Erel:
Can you tell me Where to download the library
I post the zip files ,Could you take a few minutes to look it .
I want the earth.jpg can rotate by itself
Thank you

 

[Erel]

I do not remember the exact library. You will need to look for it here: http://www.b4x.com/forum/additional-libraries/3314-dll-version-listings.html

 

[agraham]

The BitmapEx object in ImageLibEx has both fast and high quality rotate methods. Note that you should keep a master copy of the image and rotate a copy because rotating is a lossy process and the image quality degrades on successive rotations of the same bitmap.

 

[mjcoon]

I want the earth.jpg can rotate by itself.

Ahem, does this mean that you want it to look as if the Earth is rotating about its axis? This is not the same as rotating an image. (Unless you change your Earth image to a polar view so that all parts of the image can rotate by the same amount.)

Perhaps you could have a succession of equatorial views and transition from one to the next. I don't know how many would be needed to give the appearance of smooth rotation...

Mike.

 

[winjiadh]

I need more helps

yes , Mike is right.
I want it to look as if the Earth is rotating about its axis. And I tried Agraham method, use this additional library ImageLibEx.dll, use the BitmapEx object on successive rotations, the image quality degrades, and the programs slowly.
I am very upset for this problem, hope someone in the forum can help me.
thank you very much.
:sign0085::sign0085::sign0085::sign0085::sign0085:

 

[mjcoon]

I want it to look as if the Earth is rotating about its axis.

I have just remembered that this topic cropped up last summer (without any resolution!). See http://www.b4x.com/forum/additional-libraries/5990-graphics3d-library.html#post35646.

Mike.

 

[winjiadh]

Oh, Mike
It's a bad news
And your post the link is a 3D Graphics
I only need a 2D rotation, and It's also impossible ....... :BangHead::BangHead:

 

[derez]

Perhaps you could have a succession of equatorial views and transition from one to the next

Here is a demo, very inaccurate and incomplete, of this idea.
It is rotating but it is not 3D graphics at all.

 

[winjiadh]

It's look good
thank you.
I hope somebody have better ideas
And the successive rotation is very difficulty?
I only hope the images like a clock rotate round and round.
Who have an other good ideas?
:signOops:

 

[derez]

Actually its the idea of animated gif file.
Look here Rotating earth gif at Best Animations - Earth

 

[mjcoon]

Look here Rotating earth gif at Best Animations - Earth

Ah, I wondered whose idea it was to miss out the Americas! It would need a few more PNGs to give a complete rotation.

And I never did understand whether the compression in an animated GIF makes any use of similarity between successive pictures. I presume not since that might require some sort of fractal compression. I note that Andrew Graham has offered a library to extract GIF frames (GifDecoder 1.2), so they could be extracted directly.

Then there is the matter, inevitable with images, of matching the resolution of the device to avoid having to scale at display time. That would slow the display?

I don't understand what winjiadh means by

I only hope the images like a clock rotate round and round.

. As I said before, it's only the polar views of the Earth that rotate as a complete image; the equatorial view requires more movement at the equator and very little at the poles. Also, features at the equator expand in the centre of the view and squash at the sides. This is because a sphere is a 3D object!

Mike.

 

[winjiadh]

Thank you
I'm PS some png files, the program is OK
I mean is the image rotate by degree add, like a clock-type dial rotate round the centre of a circle

thank derez's best attachment and Mike's help!

 

[lqg2118]

Angbody can help me, I want to rotate a Image controls 360 degree in a form, and let it looks like a turntable. Who can help me, thanks frist!
How to rotate a Image and let it looks like fast.:sign0085:

i think EXTRA LIBRARIES imageedit1.4 could do this easily....