We are working on an angular SPA which allow users to draw elements like rectangle, lines, elipses...
User must be able to rotate, drag, resize all those elements.
For that we use the snap BBox angles, to place some grips, to be able to resize for example.
All grips are so identified as NordWestPoint, NordEastPoint, SouthWestPoint, SouthEastPoint.
This is working fine if we don't use the rotation: drag and resize are working fine.
But as soon as we use rotate, for example to reverse a rectangle upside down, and then try to resize, the NordWestPoint is now in the SouthEastPoint place, and this is a mess, the resize is not working anymore and have some weird behaviour as the positioning functions return wrong results...
Is there any library that we can use, any pattern, any good practice, any example that someone can show to handle that easily?
Thx
Related
I really want to create circular slider. I've been searching, but I can't find any information. So any tutorial, guide or if someone already created like this. Please post their XML code.
Instead of making a circular slider (which as #auburg points out) would be a little unintutive to use (think the old telephone dials), consider making it a dial like a thermostat:
It's functionally very similar, but has a much larger hit-test area and is therefore less easy to mess-up for the user.
Try this guide: https://blogs.msdn.microsoft.com/jerrynixon/2012/12/06/walkthrough-building-a-sweet-dial-in-xaml-for-windows-8/
A circular slider can be implemented just like a normal horizontal or vertical slider. The only difference would be that in the MouseMove event handler of the thumb during the drag operation you cannot just handle the horizontal or vertical position. Instead you have to calculate the angle relative to the center of the slider and map that to the value of the slider.
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.
I have an ximage which I want to zoom in on, and display. I'm currently taking the naive approach:
allocate bigger image
use nearest-neighbor interpolation to fill it in.
put the whole image on a pixmap.
Which works, but slowly, and crawls once I approach bigger zoom levels, like 800%. The gimp, however, can zoom in to 3200% and still feel snappy. What's the approach taken here? Should I only fill one screen at a time? But then what about scrolling: wouldn't performing interpolation, and an XPutImage, and an XCopyArea on each expose kill performance?
I'm not expert in Xlib, but in my opinion a good approach would be to draw only the zoomed part, instead of computing the interpolation of the entire image.
For scrolling, if you are looking for performances, you may copy the part of the old zoom which is still visible in the new position, and compute the interpolation of the "discovered" pixels. For example, when scrolling down, you may copy the bottom of the previous image and paste it higher, and then compute/draw the new visible stuff at the bottom.
Most modern X11 applications don't use Xlib directly much, if at all. My guess would be that Gimp is rendering the zoomed image into a buffer itself and drawing that to the window, rather than working with the image in an XImage.
I currently have a Silverlight canvas that exceeds the viewable area of the screen (I'm letting the users drag the viewable areas around to navigate). I'm trying to display a modal popup that always shows up in the middle of the viewable area, and I can't seem to find any property that tells me what currently is on the screen. Basically if the user has panned down to the bottom and clicks something that causes a modal popup to appear it is stuck at the far top of the screen.
Any ideas anyone?
Thanks
~Steve
I don't think this is possible since the visibility isn't being surfaced. Perhaps with some fun JavaScript to figure out where the panning is?
Quite true. I wound up creating a holding canvas, making that full screen, and putting everything else as a child canvas within that. The modal popup now comes up in the holding canvas.
Gabriel Guimarães one works good.
App.Current.Host.Content.ActualHeight(and ActualWidth) does bring the browser size inside. Good for calculating position. And of course you can use LayoutUpdated on your main control to double check the sizes and resize stuff if need be.