In my WPF application I have a control that acts like a zoom box. You can zoom and drag its content. In my case this content is a grid that contains an image and some UserControls. These UserControls have to be positioned ontop of the image to highlight some segments of that image.
Here is an example (this is not an actual use case):
My question is, how should I position those red rectangles (what is the better practise here)?
By replacing the grid with a canvas and use Canvas.SetLeft resp. Canvas.SetTop?
or
By manipulating the RenderTransform of those rectangles?
Note: The rectangles are interactive (they have to interact with the mouse and maybe some other input devices).
Related
I have a scrollable set of toggles partially hidden under png image. The image serves as a "border" for the toggles. The problem is that if the image is in hierarchy on top of the toggle (what I want for composition reasons) the toggles stop to work. Is there a way to make image ignore touches and not prevent touches of toggles under it? I know that I can cut image into borders and get rid of the transparent hole but maybe there is simpler way?
Thank you
I typically solve this problem by adding a Canvas Group component to the transparent element.
Canvas Group Documentation - http://docs.unity3d.com/Manual/class-CanvasGroup.html
It has a property that allows you to set a UI Element to a "Non-Interactable" state, which will allow you to click / touch through it with your event system.
I have an array of picture boxes that are arranged in a square. I want to put a larger, mostly transparent picture box over the top. But when I do it covers the other picture boxes and just draws the background of the form.
Is there a way to get it to have all the other picture boxes show where it is transparent?
Transparency in WinForms isn't great. Some controls have transparency support, others don't. Some controls can be subclassed to enable this (by calling Control.SetStyle() with the SupportsTransparency flag). I believe this can be done with PictureBox.
However, transparency in all WinForms controls works by having the transparent control call its parent control to draw the background before the child control draws. This means that you cannot have two sibling controls and expect transparency on one to show through to the other. Sorry!
All that said, it would be possible to code your own workaround to support this. It would involve subclassing PictureBox and clever coding in the OnPaint override to locate sibling controls and manually trigger painting of them into in-memory bitmaps. Lots of gotchas with this approach.
Try WPF!
Here's a tip to get the desired result:
Create multiple copies of your top image.
Add each copy to the Controls of each picture box it should cover.
Adjust location of each copy according to the offset of each picture box to be covered.
So you will see every copy of your big image covering each picture box as if they were a single image.
I'm using WPF shapes to create Hexagons (for a game map) on a Canvas. After some playing around with ScrollViewer, I've decided to implement the scrolling and zoom of the map myself rather than using WPF functionality, just using WPF to get the events for mouse wheel, arrow keys etc. I'm placing the (Hex Map) Canvas as the last child inside a Dock Panel so it will get all the available remaining space. The Dock Panel will be set to be the content of the Main Window. But I want to find out how big the Canvas can be before I put any Children on the Canvas so that I can centre the screen over the Hex I want and only add the Shapes (Hexs) that can actually be seen. When zoomed out, a long way I will remove Polygons altogether and use another method of rendering and when zoomed in a long way I will add more details.
Is there any neat way of getting the available space? The only way that I can think of that will hopefully work is to get the current dimensions of the windows and subtract the dimensions of the outer elements of the Dock Panel, but that feels rather messy.
You may use the ActualWidth and ActualHeight properties of Canvas to determine size available to it. Be sure that HorizontalAlignment and VerticalAlignment are set to Stretch.
How can i create a canvas of this kind - http://www.silverdiagram.net/Projects/SilverDiagram/SilverDiagram_Demo.aspx? I want to position the controls exactly aligned to each other. I want to help users to align it properly using auto-alignment (like visual studio) and by providing user the scale.
The Canvas is the right container to use as you can position its child control by coordinates. Your problem is more about moving elements around, which is in fact drag & drop.
You'll have to handle mouse events: MouseDown to select an item, MouseMove to detect a drag and MouseUp to drop it. During the move or at the drop, you can change the element's coordinates to auto-align it on a grid or compared to surrounding elements.
I successfully made such a project in Silverlight and used Adorners to add resize handlers to the elements.
I solved the panning and zooming question by putting the Canvas into a Viewbox, which was in a ScrollViewer. If you want to let the user control the zoom factor, apply a LayoutTransform to the Canvas (available in the Toolkit).
I'm trying to write a very simple photo editor using C# 2008 or QT4.
How to make a resizeable rectangle selection tool like the photoshop did?
If you are talking about the "classic" "rubber band" type of selection rectangle, check out How to draw a rubber band rectangle or a focus rectangle in Visual C#.
WPF Code Example: http://www.codeproject.com/KB/WPF/wpfmarchingants.aspx?display=Print
This one is a bit more complicated because it involves image cropping, but if you scroll down to the selection rectangle, you can see the basic formulas for calculating the rectangle: http://69.10.233.10/KB/WPF/ImageCropper.aspx
Lastly, another one using GDI: http://codelog.blogial.com/2008/10/31/rubber-band-selection-rectangle-in-c/
If you provide more specifics, I'm sure we can help you out more.
Qt has a class for that:
http://doc.trolltech.com/4.5-snapshot/qrubberband.html
I don't know the specific calls, but the idea is this:
You want to draw a transparent rectangle with an opaque or dotted border. The rectangle appears when the mouse button is clicked. While the button is held, the dimension of the rectangle will change as the mouse moves, with the top-left point at the position where the button was clicked and the bottom-right following the mouse as it moves. Releasing the button causes the rectangle to fix its position over the selection area.
You should be able to figure out the particulars from a resource on the C# Drawing namespace.