Using a UIlabel as a diffuse texture works great in Scenekit but when I rotate the device it breaks and the materials go blank. I've tried also adding the labels to a view offscreen but unfortunately the problem persists. Is there a way around that other than unloading the views and reloading them back into every material every time the orientation changes?
Related
I am using xamarin forms map for a tracking application, so the view tends to move across the landscape and tiles need to be loaded to show the new area. I am scrolling using map.MoveToRegion
Sometimes the map tiles are loading extremely slowly, to the point where the entire region is just white with no graphics. Initially I thought it was a data speed issue, but it turns out that if I rotate the device, changing the layout landscape/portrait, this makes the map instantly refresh, so the data was apparently available, it was just not being rendered. Zooming can have the same effect, albeit not quite as effectively.
How can I force a refresh, or alternatively just make the map refresh more quickly?
Turns out the issue is that the way to move the forms.map is by MoveToRegion, and that animates the motion. If the animation takes one second and new positions are being set at a higher, or equal, frequency, the map is effectively always in the middle of an animation.
When the map is animating, it is not willing to refresh the tiles, and so the map eventually becomes blank.
When I rotated the device, this constant animation was interrupted, and it could refresh the tile graphics.
The solution was to make a custom renderer with an alternative - non animated - method to move map focus.
private void moveToFast(Location location)
{
var update = CameraUpdateFactory.NewLatLng(new
Android.Gms.Maps.Model.LatLng(location.Latitude, location.Longitude));
googleMap.MoveCamera(update);
}
There are plenty of examples of custom map renderes, so I will not post that here. The main takeaway is really just that...
while the map is animating, it will not refresh its tiles, so if you constantly update the map location, you should do so in a non-animated way.
I am using Qt 5.7 and have a QGraphicsView in which I have added a QSceneView. At the program start, I fit the scene into the view with fitinview and Qt::IgnoreAspectRatio (maybe this is relevant?). I am trying to create an interface for zooming in and out with 4 simple buttons. To zoom out horizontally for example I call view.scale(0.5,1).
However, if I try to zoom on in any axis by using scale factors larger than 1, nothing happens. It's as if I didn't even click the button, as no matter how often I pressed zoomed in, I can zoom out with one click. Somehow the scale method is being completely ignored if the value is greater than 1.
The Problem was using fitinview and Qt::IgnoreAspectRatio. I removed the call and everything works perfectly now.
I am building a node graph in a QGraphicsView and I am currently implementing panning.
I used the following question "how to pan images in QGraphicsView" to start but the panning is limited by the scrollbar range.
I also tried the translate method but it gives the same result. The view is limited to a certain rectangle.
I would like to pan without limits, the graph can becomes quite large and it is useful to be able to work in different area of the scene (one graph here, another graph over there, etc).
If you take a look at this video, at the 3 minute mark you'll see the demonstration panning the screen. The application here is one I developed and although it doesn't show it, the real estate of the board appears limitless when panning.
What I did for this was to create a QGraphicsScene of 32000 x 32000 and start the application with the view at the centre of the QGraphicsScene. The test team spent ages trying to pan to the edge of the graphics scene and everyone gave up before getting there - perhaps the scene could have been smaller!
The scroll bar policies are set to off and translation is done by moving the QGraphicsView via its translate function, passing in the delta of either touch, or mouse movement that is applied in the mouseMoveEvent.
Done this way, you need not worry about exceeding the scroll bar range and there was no problem creating a very large QGraphicsScene as it's just a coordinate space.
I came across the same issue. However, setting the scene to something big and leaving it I do not think is the best option. I have developed a dynamic way of changing the scene size so it lets you move freely. You can find it in this other stack overflow answer.
You want to plot graphs. Try out this Qt library - QCustomPlot , it will save you hours of hard work.
I am making an app using Qt (currently 4.8) which displays a literal map from a large number of QGraphicsScene items. I would like to annotate the view with a scale. My requirement for the scale is that it is permanently fixed w.r.t the viewport widget. It needs to be updated whenever the view scale changes (zoom in, etc). There are other possible overlay items as well (compass, etc) so I'd prefer a generic solution.
I have looked at earlier questions around this which suggest:
using the ItemIgnoresTransform
using an overlay pixmap.
I tried IgnoresTransform but that way didn't work right: I couldn't figure out how to fix it in place in (say) the bottom corner of the viewport and was having some difficulty getting the text and lines always displaying in the correct size.
I scrapped that and subclassed QGraphicsView, adding an overlay pixmap by reimplementing the paintEvent (calls original one, then paints the overlay pixmap on top), and an alignment option to indicate where it goes. Coding some pixmap paint code produces a usable scale on the view. Yay! ... but it doesn't work with scrolls - I get "shattered" renderings of the scale all over, or sometimes no scale at all. I think this is because QGraphicsView::scrollViewportBy() uses viewport()->scroll() so I wondered if switching to ViewportSmartUpdate would help, but it doesn't help enough. I'd prefer not to switch to ViewportFullUpdate as that would likely slow the app down too much (there are millions of items in the scene and that would require a full repaint just to move around).
So. Any ideas from here? Would adapting my pixmap code to write to a new mostly-transparent Widget that is overlaid on the viewport be a better way?
Thanks for any help...
Though it may not be the best way of doing this, in the past I've added custom widgets to the window that holds the QGraphicsView / QGraphicsScene, which have the same graphic style as the QGraphicObjects in the scene. When the view is then used to move objects in the scene, or the scene itself, the items on the window remain in the same place.
Hope that helps.
I'm scaling my application to fit the browser window. I'm also defining my own cursor using a bitmap and CursorManager.setCursor.
The problem: when my app scales, the cursor bitmap is jagged. Is there a way to smooth the bitmap that is use?
I believe your problem is that you're scaling your root display object(e.g., stage), which means the cursor also gets scaled. You probably want to scale a child container instead, which means the cursor won't scale. I'm guessing you don't want the cursor to change sizes anyway.
Otherwise, you can look at using an svg file (or a swf image) since they're based on vectors and scale properly. You can also look at trying to smooth the bitmap using the bitmapData draw function. (http://livedocs.adobe.com/flex/3/langref/flash/display/BitmapData.html#draw())