I'm looking at creating a panel that takes all the children and wraps them inside of a ViewBox so it can scale them down to a certain uniform size.
I'm not sure if this is even possible to do, but I thought I'd ask. The reason why I'm not sure if this is possible is because Panel's don't have any xaml associated to them. They measure and arrange children in code. Any tips?
After not being clear enough, I figure I'll be more specific:
I want a Panel because I want to arrange and measure my children.
The measure find the AVERAGE height/width of all the children elements.
The arrange puts them into a grid-like pattern and scales them to the average height/width. I don't want them cliptobounds, I want them scaled up or scaled down appropriately.
I already got the measureoverride function working to find the average height/width, but I can't figure out how to scale them in my arrangeoverride.
You haven't completely specified how you want your panel to work so I can't give you a sample panel, but I can point you to a working panel that does something similar to what you want to do:
Making a Viewbox scale vertically but stretch horizontally
In the example you can see that we can simulate a Viewbox by just scaling the children of the panel ourselves. As I mentioned, exactly how you want to scale them is up to you.
Even after your update, I agree with Markus. It doesn't seem you need a custom panel. What you need is an ItemsControl with UniformGrid as ItemsPanel and ViewBox as ItemsContainer. UniformGrid decides how your items container are arranged. ViewBox handles stretch and scale of each item.
Related
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.
I implemented a usercontrol, but i have a problem with rescaling the window. I know when i make the window smaller, everything scales, and every textbox and label becomes also smaller. But this is not what i want, i just want that when i make the screen smaller, everything stays the same size, and that scrollbars appear ( vertical and horizontal ). How do i do that?
Thanks
Assumption
The behaviour you describe, is not mandatory the default layout-behaviour of WPF. It depends on the layout-controls you use. I assume, you're using a Grid with setting it's columns and rows to the Start (*)-GridLengths. This would have more or less such an effect as you describe (without scaling). Or maybe you are using a ViewBox, this control scales the whole content based on the available layout size.
Solution
I guess that wrapping your whole content into a ScrollViewer will probably do what you desire. If not, I suggest that you post some XAML-code to show us how you have built your content.
<ScrollViewer>
<YourContent>
</YourContent>
</ScrollViewer>
Update
If you really scale your window (applying a ScaleTransformation) and you want your UserControl to be the only control within that does not scale, you have to scale your UserControl in the opposite direction as you have done it with your window. Apply a ScaleTransformation and set the scale values to 1/scale. Or try to use the ViewBox to blow up the content of your UserControl, but this will not be very exact.
I have a XamDataGrid in one of my user controls, inside of a stackpanel. I want the grid to maintain the same height regardless of how many rows are present in the grid. To do that, I set the grid's Height property to an explicit value.
Is that how things are done in WPF? Every time I do explicit sizing I feel like I am doing WinForms and not using WPF properly. Is setting the Height directly the only/correct solution?
There's nothing wrong with setting an explicit Height in situations where you want an element to always stay the same height. Where it's less appropriate is in situations where sizing is better handled by the parent layout Panel or the element's child content which can use the available space dynamically.
WPF uses a relative measurement system which at first glance is not intuitive. I have never found an example when I was forced to use explicit sizes ( once when I paint something on Canvas). I use styles in 90% cases where I define Padding, Margin, Aligment etc. Sometimes I use MinHeight and MinWidth for simple things.
About that Grid you can put it in the ScrollViewer or ViewBox to have dynamic sizing, yet If it won't be trouble set the explicit Height.
I would like use a panel whose children have coordinates specified as percentage of total panel's width/height. Moreover, I should be able to animate the coordinate property, for example to make a button move from 10% to 50% panel's width.
I've made 2 attempts:
Use a Grid and specify size as stars - this was not enough, because AFAIK by default WPF cannot animate distance properties specified by stars. I've found somewhere a custom class that enabled me to do so, it even worked, hovewer I consider that solution overly complicated an I am looking for something simpler.
Use a Canvas with fixed width and height and put it inside a Viewbox - this is a simple solution, but when resizing the Viewbox the whole content of Canvas is resized too. I want the content to have fixed size.
Is there a simple solution or should I implement my own panel (or maybe extend one of the existing ones, i.e. Canvas)?
Cheers!
I would:
subclass Canvas, perhaps calling it RelativeCanvas or RatioCanvas
add two attached properties: XRatio and YRatio
override ArrangeOverride and loop over all children. For each child, use their XRatio and YRatio along with the ActualWidth and ActualHeight of the RelativeCanvas to calculate and apply values for their Canvas.Left and Canvas.Top attached properties
You would use it as follows:
<local:RelativeCanvas>
<!-- the top-left of this button will be center of panel -->
<Button local:RelativeCanvas.XRatio="50" local:RelativeCanvas.YRatio="50"/>
</local:RelativeCanvas>
One thing you might like to add after you get that working is control over alignment. For example, I might to align the center of a control to the specified ratio, not its top-left corner.
There's one here: WPF Proportional Panel
Been checking the web and this site, but couldn't come up with any descent results.
Is there a way to make a canvas in WPF show scrollbars on overflow ? Been trying the scrollviewer, but can't get it to work :(
Thanks in advance..
The problem you're running into is that Canvas, unlike many WPF panels and containers, does not size to contents. That means if you add an element which goes outside the canvas boundaries it will not update it's size. Hence embedding a Canvas in a ScrollViewer will do no good unless you manually update the size of the Canvas.
It sounds like what you want is a Canvas which supports size to contents. This blog entry has exactly that control.
http://themechanicalbride.blogspot.com/2008/11/auto-sizing-canvas-for-silverlight-and.html
I took a different approach and abandoned the Canvas for Grid. The Canvas is more performant but for my purposes at least I haven't noticed a difference. The grid can mimic the behavior of canvas by doing the following.
Create a single row,single column grid.
Set the HorizontalAlignment to Left
Set the VerticalAlignment to Top
Use Margin "x,y,0,0" to set the position.
Bam..works just like canvas and it works great in a Scrollviewer.