I'm trying to make an application which allows the user to draw shapes to the canvas. Once drawn, I would like for the user to be able to select, move, resize, basically manipulate the shapes in any which way.
I have done something similar in XNA and that was quite easy due to the fact that there was a draw loop. In Silverlight there is no such thing as far as I understand and I am having trouble figuring out how to manage the objects on the canvas. As in what is the best way to manage the canvas' children collection to ensure appropriate response of the UI to what the user does.
Most examples out there are pretty basic and do not go anywhere near this kind of thing. I would be grateful if somebody who has done this before could tell me how they approached the problem.
Thinking about it for a while I think I figured out how it works.
There is a draw loop for the canvas, which is the draw loop of the top level parent container which it lives on.
The difference with XNA I guess is that the collection of items to draw on the canvas doesn't need to be explicitly drawn, since the canvas takes care of drawing its children automatically.
So, what I need is some way to hold on to any object I add to the canvas' children... I can then update the objects drawing properties and the changes will be reflected in the canvas next time it refreshes.
I guess a dictionary of some sort in which to store the items I put in the list might be best...?
Not a finished answer yet, but I guess I understand half of it now.
Related
I've modeled using helixtoolkit which is done in a wpf user control library and hosted on ElementHost. I decided to do this because my model is fairly simple (just a stick element with lineVisual3d and bunch of small spheres).
Now I want to animate it and everything I find related to animation seems too complicated for what I'm trying to accomplish. I've seen storyboard being suggested as well as transform methods.
What I have is a 3D line connected by a bunch of points3D and I want to translate them only by a series of values at a fixed time increment.
I did this in a 2D graph using a timer for winform and even a forloop did the trick.
However, I'm not sure how to do the same for a 3D line element. I was thinking that since I have a simple structure simply redrawing it would suffice.
But my problem is I want to add a slider which acts in pretty much the same way as a video player, it will increment itself as the animation runs, I want to also be able to freeze it at any point in time and use the slider to go to any point in time much like how a video player works.
My biggest question here is how do I use a slider to control the animation. Again, this animation will simply be a bunch of values that I want to translate the stick element by(a series of points).
I've already got the values but I want to add an animation for these values at every increment while being able to control it using a slider.
--I will post any code if necessary, not posting any right now because I dont know what would help explain the question better
You can use TranslationTransform3D and apply the transform onto the 3D Model
So there's this tutorial about creating a diagram in WPF.
http://www.codeproject.com/Articles/24681/WPF-Diagram-Designer-Part
I've read it, and still studying it to understand it completely.
At the end of this tutorial, you can basically add shapes, move/rotate/scale them, and since they are created in a vector form, they are keeping their resolutions, there are also connectors that can connect each shape with another.
My goal, since I need to create a simulator which shows how internet protocols are delivered, is to create a divided diagram in which Side A communicates with Side B. it could read an automata and simulate the transitions in the diagram.
I'm thinking of how to deliever this, and since I don't have a lot of knowledge in WPF, I wonder in which way should I implement it.
Should I create 2 different Canvases? or maybe dividing 1 canvas with two sides?
The main issue I'm dealing with, is that when a shape is being dragged to the end margin of the window, then the window allow me to slide it so I can see the rest of the field, this is being done by increasing the size of the Canvas, as seen in the Tutorial Part 1.
However, if my canvas is divided by two, and there's a border in the middle, how can I create two sliders for each of the sides?
I was wondering if you can give me any tips about how approaching this idea, since my knowledge in WPF is still very limited.
Here is my point of view, but it would be very useful if you would provide a more/less final sketch of your app. I recommend using Telerik AppMock but paint will also suffice ;).
From what I have understood you should need 3 canvases.
1-st is canvas on the left.
2-nd is canvas on the right.
3-rd is on top of both canvases.
When you want to drag an element, you must set opacity of the clicked element to be a bit transparent and leave it on its place(1st canvas), add copy of dragged element in to the 3rd canvas. When you do leftmousebuttonup(drop dragged item), you have to check where was it dropped and if it was droppend on the 2nd canvas you add it to this canvas. To position element on the canvas you can use Canvas.SetLeft and accordingly SetRight method.
You can put 1st and 2nd canvases into Grid. Even if Canvases will be bigger if Grid, view will be cut only to the size of the Grid.
Moreover, to allow canvases manipulation, add there (to the Grid) a scrollviewer which will Translate Transform the canvases given to their sizes.
Later, try to use MVVM pattern to fill your Canvases with data.
I would also suggest an ObservableColletion of drawable (you can use FrameworkElement as base class) and draggable objects. Different for every Canvas.
Good luck!
I need to display many markers on a WPF image. The markers can be lines, circles, squares, etc. and there can be several hundreds of them.
Both the image source and the markers data are updated every few seconds. The markers are associated with specific pixels on the image and their size should be absolute in relation to the screen (i.e. when I move the image the markers should move along with it, but if i zoom in, they should take the same space of the screen as before).
Currently, I've implemented this using the AdornerLayer. This solution has several problems but the most significant one is that the UI doesn't fare well under the load even for 120 such markers.
I wanted to ask what would be the best way to go about implementing this? I thought of two solutions:
Inherit from Canvas and make sure it is invalidated not for every
added marker but for a range of markers at once
Create a control that holds an image and change its OnDraw to draw all the markers
I would appreciate some pointers from someone with experience with a similar problem.
Your use case looks quite specialized, so a specialized solution seems in order. I'd try a variant of your second option — extend Image, overriding its OnRender method.
I'm currently playing with touch gesture support and I wired up an element that can be zoomed in, rotated, etc through manipulationdelta. The elements container is a border however whenever i gesture the element it moves across the screen and I want to keep it inside the border where they can only use that area of the screen to manipulate the element. Any ideas as to how to accomplish this? Thanks!
Seeing how nobody has replied, I'll just say I think I've come up with a workaround by hosting a window inside a grid... that way the manipulation is always bound to the child window.
So I realize that I am venturing outside of the intended use of a Canvas here and will likely have to come up with a more manual solution. However, not being overly experienced in WPF I was hoping that there may be some solution which would allow me to continue using a Canvas control and the features it gives you for free.
The issue revolves around a Canvas which is used to zoom in and out of an image and some number of child controls that belong to the Canvas. These child controls are to be placed at various positions on the image and, as such, the Canvas works nicely in that it handles all of the layout/positioning for me as I zoom in or out.
However, one drawback is that the Canvas scales these child controls up as I zoom into the image, causing them to become too large to be usable in practice. What I am looking for is a solution that allows me to zoom into an image that belongs to a canvas without also zooming up the size of the child controls, preferably handling the layout for me.
I have tried modifying the width and height of these child controls as the zoom factor increases or decreases, but there is a slight lag time and it all looks a bit 'jerky'.
If it comes down to it I will simply do all of the zooming/panning/layout myself, but I thought I would ask first just to make sure that I am not missing anything that would allow me to tell the Canvas to not scale the size of certain controls. Thanks in advance.
You can bind the children's RenderTransform to the inverse of the Canvas' transform, see my answer to this similar question on rotation.
This is more of a thought than an answer, but what if you set a transform on the element that you did not want scaled that was the opposite of the canvas itself. So for example, if the canvas had a scale transform of 2.0, set the element to have a scale transform of 0.5. You could probably accomplish this by binding the transform values together using a value converter.
You'll probably want to make sure the element has a render transform origin of 0.5,0.5 so that it scales from the center.