I am a little stuck with what might be a trivial question:
I have two Raphael canvas on my site, following a certain event I need to take the content of the one canvas and add it (with a different scale and position) to the second canvas.
How do I even approach that task?
Just to render this question maybe a wee bit useful, I by now succeeded.
I've gathered up all elements from the one paper (with the forEach-method) and pushed them into a set.
That set I cloned to the other paper using Shamasis' .cloneToPaper(targetPaper) method from the answer to this question.
So it turned out to be fairly simply if one were to enter the right search terms >.>
Related
I'm having trouble finding a way to solve this specific problem using MeshLab.
As you can see in the figure, the mesh with which I'm working presents some cracks in certain areas, and I would like to try to close them. The "close holes" option does not seem to work because, being technically cracks and not holes, it seems not to be able to weld them.
I managed to get a good result using the "Screened Poisson Surface Reconstruction" option, but using this operation (rebuilding the whole mesh topology), I would lose all the information about the mesh's UVs (and I can not afford to lose them).
I would need some advice to find the best method to weld these cracks, which does not change the vertices that are not along them, adding only the geometry needed to close the mesh (or, ideally, to make a weld using the existing edges along the edge).
Thanks in advance!
As answered by A.Comer in a comment to the main question, I was able to get the desired result simply by playing a bit with the parameters of the "close holes" tool.
Just for the sake of completeness, here is a copy of the comment:
The close holes option should be able to handle this. Did you try changing the max size for that filter to a much larger number? Do filters >> selection >> select border and put the number of selected faces as the max size into that filter – A.Comer
Is there an easy way to show 3D entity at all times, even when that entity is hidden behind another entity? For example, I want that lines are always shown event when they are behind mesh surface.
I use Qt3D framework.
Assuming that you are talking about the Qt3D framework I want to extend the answer of Rabbid76.
To disable depth-testing in the Qt3D framework, add a QRenderStateSet to the framegraph branch that renders things (the one that as a QViewPort for example) and add a QDepthTest to it. Then, set the depth function of the QDepthTest to always. This way, the depth test is always passed and entities in the back will also be drawn, depending on the drawing order. You can use QSortPolicy to adjust the drawing order to back-to-front.
But this won't work when the camera position changes and your entity that you always want to be drawn is in the front. I'd suggest you add another framegraph branch and use a QLayerFilter to only deactivate depth-testing for this one entity.
If your entity looks weird when deactivating depth-testing (likely for complex objects), you could replace the QDepthTest by a QClearBuffers and simply clear the depth buffer.
Have a look at my answer here, where I showed an example of a custom framegraph with depth test.
If the depth test is disabled, then the geometry (like a line) is always drawn on top of the previously drawn geometry. The depth test can be disabled by:
glDisable(GL_DEPTH_TEST)
See glEnable
As an alternative the depth test function, can be set to let a fragment always pass depth test. In Qt this can be done by the class QDepthTest, using the enumerator constant Qt3DRender::QDepthTest::Always.
In this case, you have to take care about the order in which the geometry is drawn.
You have to find a way, to render the polygons (opaque geometry) first, by using the depth test function Qt3DRender::QDepthTest::Less.
After that you have to render the lines on top, by using the depth test function Qt3DRender::QDepthTest::Always.
I have a map that I converted from a raster graphic into an SVG file by converting the differently coloured areas into paths.
I know how to do a basic point-in-polygon check given an array of edges, but the svg:path elements represent multiple polygons as well as masks (to account for seas etc) and extracting that information by parsing the d attribute seems rather heavy-handed.
Is there a JS library that allows me to simplify that check? I basically want to create random points and then check whether they are on land (i.e. inside the polygons) or water (i.e. outside).
As SVG elements seem to allow for mouse event handling, I would think that this shouldn't be much of a problem (i.e. if you can tell whether the mouse pointer is on top of an element, you are already solving the point-in-polygon problem).
EDIT: Complicating the matter a bit, I should mention that the svg:path elements seem to be based on curves rather than lines, so just parsing the d attribute to create an array of edges doesn't seem to be an option.
As the elements can take a fill attribute, a ghetto approach of rendering the SVG on a canvas and then finding the colour value of the pixel at the given point could work, but that seems like a really, really awful way to do it.
The answers on Hit-testing SVG shapes? may help you in this quest. There are issues with missing browser support, but you could perhaps use svgroot.checkIntersection to hit test a small (perhaps even 0 width/height would work?) rectangle within your polygon shape.
The approach I suggested as a last resort seems to be the easiest solution for this problem.
I found a nice JS library that makes it easy to render SVG on a canvas. With the SVG rendered, all it takes is a call to the 2D context's getImageData method for a 1x1 region at the point you want to check. I guess it helps to create a copy of the SVG with colour coding to make the check easier if your SVG is more complex than the one I'm using (you'll have to check the RGBA value byte-by-byte).
This feels terribly hackish as you're actually inspecting the pixels of a raster image, but the performance seems to be decent enough and the colour checks can be written in a way that allows for impurities (e.g. near the edges).
I guess if you want relative coordinates you could try creating a 1-to-1 sized canvas and then divide the pixel coordinates by the canvas dimensions.
If somebody comes up with a better answer, I'll accept it instead. Until then, this one serves as a placeholder in case someone comes here with the same problem looking for an easy solution.
Apologies if there is a thread for this already, I couldn't find one that I could get my teeth into.
Anyway, I'm new to WPF and want to create a custom control that will be a sort of graphic control. The graphic will always consist of a circle, containing a matrix of several squares (from several hundred to several thousand actually) The squares need to respond to mouse click and mouse over events (and ideally be possible to navigate/select via keyboard.) Each square will represent an object I've coded.
In the past I've used a grid control to display the coloured squares (with VCL in CBuilder) but I would like to make a graphical version. (Actually, another question I'd like to ask is, is there a WPF grid control where I can set the colours of individual cells?)
The question is, where to start? Do I start with a canvas and draw on it? Do I derive from an existing object? I'm just a little lacking on ideas on implementation so any pointers or advice you can offer will be greatly received.
BBz
First off I would suggest getting a decent handle on WPF and how it approaches the problem set. It is vastly different from previous .NET Desktop technologies such as WinForms. Once you have a decent understanding in regards to the separation of logic from UI and how WPF approaches the problem then you can dive in and begin making the right decisions based upon what you encounter.
The problem you mention can be solved in multiple ways. In regards to your question about making use of a Grid, that could be done as that is a layout type. It is vastly superior to the Canvas in terms of arranging your visual structure. The defined rows/columns are nothing more then containers which can hold varying UI objects. Therefore pushing a Rectangle into the Grid and coloring as desired would give you the effect you are looking for. This Rectangle could then become a custom control which would allow you to define varying properties on, as well as specific triggers for mouse overs, etc...
At a higher level you will want to encapsulate this logic as a UserControl which will also hold your custom control. Perhaps the UserControl contains the Grid which will make use of your custom control.
Hopefully this gives you some ideas around how to get started, however getting a better understanding of WPF will help you immensely in achieving your goal.
Just have a question for anyone out there who knows some sort of game engine pretty well. What I am trying to implement is some sort of script or code that will allow me to make a custom game character and textures mid-game. A few examples would be along the lines of changing facial expressions and body part positions in the game SecondLife. I don't really need a particular language, feel free to use your favorite, I'm just really looking for an example on how to go about this.
Also I was wondering if there is anyway to combine textures for optimization; for example if i wanted to add a tattoo to a character midgame, is there any code that could combine his body texture and the tattoo texture into one texture to use (this way I can simply just render one texture per body.)
Any tips would be appreciated, sorry if the question is a wee bit to vauge.
I think that "swappable tattoos" are typically done as a second render pass of the polygons. You could do some research into "detail maps" and see if they provide what you're looking for.
As for actually modifying the texture data at runtime, all you need to do is composite the textures into a new one. You could even use the rendering API to do it for you, more than likely; render the textures you want to combine in the order you want to combine them into a new texture. Mind, doing this every frame would be a disoptimization since it'll be slower to render two textures into one and then draw the new one than it would be just to draw the two sources one after the other.