i use EASYBMP library and i want to know the most effective way to scale , rotate , shear and reflect algorithm. i want the most optimized to do it.
The most effective way to scale, rotate, shear and reflect is to use the power of your graphics card - for example through OpenGL.
If you still want to do bitmap pixel operations yourself, typically you do this using linear algebra. This is not super easy to figure out, so I recommend finding some good study material, for example this book.
Instead of telling you how to use EASYBMP (which looks like crap), I'm going to suggest you use Magick++ instead. It supports BMP and has all the methods you ask for built-in.
Please refer to the Wikipedia link for the transformation matrices
Related
I am looking for a way of approximating a surface based on a set of 3D data points. For this purpose I would like to use a method based on radial basis functions but I cannot find a free implementation in C++.
I looked in ITK, VTK and open CV but I did not find anything...
Does anyone knows a free implementation of such an algorithm ?
Any suggestion about the reconstruction of a surface based on a set of 3D data points is also more than welcome ! :)
3D surface reconstruction can be challenging. I would first recommend taking a look at PCL. The Point Cloud Library has grown into a nice set of tools for 3D point management and interpretation, and its license and API sound compatible with your needs. The surface reconstruction features of the library appear to be most applicable. In fact, RBF reconstruction is supported.
If PCL doesn't work, there are other options:
MeshLab,
This SO post provides a nice summary, and
of course, Wikipedia provides some links
Finally, you might search CiteSeerX, Google Scholar, etc. for papers like this one. As an example, a search for "3D Surface Reconstruction" at CiteSeerX yields many hits. RBF-based reconstruction is just one of many methods: is your application truly limited to radial basis functions? If not, there are many choices, (i.e. Ball Pivoting Algorithm). See this survey paper for some comparisons.
Im looking for a way to warp an image similar to how the liquify/IWarp tool works in Photoshop/Gimp.
I would like to use it to move a few points on an image to make it look wider than it was originally.
Anyone have any ideas on libraries that could be used to do this? I'm currently using OpenCV in the same project so if theres a way using that it would be easiest but I'm open to anything really
Thanks.
EDIT: Heres an example of what im looking to do http://i.imgur.com/wMOzq.png
All I've done there is pulled a few points out sideways and thats what im looking to do from inside my application
From this search 'image warp operator source c++' i get:
..... Added function 'CImg ::[get_]warp()' that can warp an image using a deformation .... Added function 'CImg ::save_cpp()' allowing to save an image directly as a C/C++ source code. ...
then CImg could do well for you.
OpenCV's remap can accomplish this. You only have to provide x and y displacement maps. I would suggest you can create the displacement map directly if you are clever, and this would be good for brush-stroke manipulation similar to Photoshop's liquify. The mesh warp and sparse point map approach is another option, but essentially computes the displacement map based on interpolation.
You may want to take a look at http://code.google.com/p/imgwarp-opencv/. This library seems to be exactly what you need: image warping based on a sparse grid.
Another option is, of course, generate displacements yourself and use cv::Remap() function of OpenCV.
I need code for rotating an image in C++ which functions like imrotate function of matlab.
Please suggest a good link. Or if someone can provide the code for imrotate.
Or at least please explain the algorithm.
Its not a homework. I need this code for my project. And we can use any external library or code.
OpenCV2.0 has several computer vision and image processing tools. Specifically warpAffine (by defining the rotation matrix) will solve your problem with rotating an image.
The 2x3 transformation matrix mentioned in the documentation is as follows:
where θ is the angle of rotation and tx and ty is the translation along the x and y axes respectively.
You can get the source code here.
Also, OpenCV2.0 has many MATLAB-esque functions like imread, etc.
Magick can help you. Read this PDF and search for rotate.
Check this hope it helps .
Other questions on stack overflow on the same topic experts opinion on it.
libgd has image rotation functions.
There is no built-in way of accomplishing this in C++, short of writing your own function for manipulating binary data, which yields other problems like "How do I decompress a jpg/png in C++?"
Your best bet is a 3rd party graphics library such as libSDL
I am writing a very simple 3d particle software rendering system, but I am only really interested in coding the particle system and the rasterizer, so what I am looking for, is the easiest way to go from 3d particle coordinates, through camera, to screen coordinates, but with features like variable FOV, and targeted (look at) camera.
Any additional features such as distance from point to point, bounding volumes etc. would be a bonus, but ease of use is more important to me than features.
The only license requirement is that it's free (as in beer).
You probably want a scenegraph library. Many C++ scene graph libraries exist. OpenScenegraph is popular, Coin3D (free for non-commercial use) is an implementation of the OpenInventor spec, any of them would probably fit your need as it doesn't sound like you need any cutting-edge support. There is also Panda3D, which I've heard is good if you're into Python.
You could do all of this in a straight low-level toolkit like OpenGL but without prior experience it takes a lot longer to get a handle on using OpenGL than any of the scenegraph libraries.
When choosing a scenegraph library it will probably just come down to personal preference as to which API you prefer.
Viewing is done with elementary transformations, the same way that model transformations are done. If you want some convenience functions like gluLookAt() in GLU, then I don't know, but it would be really easy to make your own.
If you do want to make your own Look At function etc. then I can recommend eigen which is a really easy to use linear algebra library for C++.
If you're trying to just focus on the rendering portion of a particle system, I'd go with an established 3D rendering library.
Given your description, you could consider trying to just add your particle rasterization to one or both of the software renderers in Irrlicht. One other advantage of this would be that you could compare your results to the DX/OGL particle effect renderers that already exist. All of the plumbing/camera management/etc would be done for you.
You may also want to have a look at the Armadillo C++ library
Does anyone know of a graphing library for simple transformation of a point from one coordinate system to another coordinate system which is rotated by a angle and some point transformation and just for 2d?
And any graphing tool for plotting and verifying the same visually?
double[3][3]
GDAL includes pretty much every graphic transform you could ask for, and while it is big and hence takes some time to get used to, it is a great framework to move forward with.
This isn't a library, but it's a blog by someone who does this kind of thing:
http://polymathprogrammer.com/
It's got some good theory if you want to know the "behind the scenes".
The Angtigrain Geometry library contains code that can do this, and you can also go farther and use it for drawing as well, but you don't have to. You should look at the agg::trans_affine class in the agg_trans_affine.h file.
Dave