I have used the gestures code based on the provided Kivy examples to record and recognize single touch gestures. However, I am not sure how to extend this code to recognize multi-touch gestures. Let's say, for example, a pinch.
My problem becomes specially complicated because I use a laptop with zero multi-touch functionality. How do I combine two single gestures? Is there any example available?
From 1.9.0, Kivy got a multi-touch gesture recognizer integrated: have a look at kivy.multistroke. I personally didn't got time to test it yet.
If you want to map or act depending of the gesture, you might be interested by the Scatter. Pinch can be done with 2 to N touch, with rotation and translation integrated. You can restrict the transformation to just scale and not rotation / translation. And, when all the touches are released, you could animate the scale to the closest wanted value. You can also set a limit for the minimum scale and maximum scale.
With few parameters and code, you can pinch to zoom, de/un pinch to unzoom, etc. Maybe that's what you want :) (like pinch to zoom in a image, or put an image in fullscreen).
You can also just use the Scatter's scale parameters, or Scale's matrix to do your own things :)
Related
I would like to write a 2D QT application. The goal is to be able to draw rectangles and resize them and drag them around with the mouse. QT offers functionality to do that. The QGraphicsXxx classes natively operate with pixels, but I would like to be able to specify the items' dimensions and positions in length dimensions like meters.
I am looking for a good strategy for constructing an abstraction layer that allows object dimension representation in meters independent of pixels. I was thinking about extending QRectangle with with zoom information, for example, and methods to convert between real-world and screen, i.e. pixel, representation.
That should certainly be possible, but also smells like a road to coordinate-mapping hell. And like a lot of work for a problem that I wouldn't be surprised if it had already been solved more globally/elegantly and that I'm just not finding or understanding from the QT documentation.
Use a QGraphicsScene to layout your objects, all sizes and positions are float and unit independent. Pixel come into play when displaying your Scene using a QGraphicsView. The zooming should be handled by the View so there is no need to do any coordinate transformation in your Scene. You just alter the transformation of your view to show whatever you want.
You can read more about it in the GraphicsView Framework documentation: http://doc.qt.io/qt-4.8/graphicsview.html
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 would like draw a filled polygon on iPhone with Google map (Version 1.1.1, the last one).
Anyone knows how to do like that on ios :
(My code on Android)
mMap.addPolygon(new PolygonOptions()
.addAll(latLngList)
.fillColor(Color.BLUE)
.strokeColor(Color.RED)
.strokeWidth(3));
Regards,
PS : If you have many solutions, keep in mind that I have many Polygon to draw.
The SDK currently doesn't support filled polygons, however there is a feature request to add them here:
https://code.google.com/p/gmaps-api-issues/issues/detail?id=5070
In the meantime, one option could be to draw your polygons into an image, and then add them as a ground overlay. This would be very limiting, but might work as a temporary workaround.
Another option is to add another view over the top of the map view and draw the polygons into it, and then update them whenever the map view moves. It isn't possible to perfectly synchronize another view with the map view, so your polygons will lag behind a bit as you pan/zoom around, but this might also be okay for you as a temporary workaround.
UPDATE
These are just some random ideas to try for the ground overlay approach, I'm not sure if they would work, but they might get you started:
I would suggest converting the lat/lon corners of the rectangle into MKMapPoint (using MKMapPointForCoordinate). These are equivalent to Google's coordinate system at zoom level 20.
You can then use the aspect ratio of the width/height of the rectangle in MKMapPoint coordinates to determine the aspect ratio of your ground overlay UIImage. Once you have the aspect ratio, you'll just need to experiment with actual sizes (ie guess a width, calculate the height from the aspect ratio) to find one which looks okay. The bigger it is, the finer the detail of your rectangle will be, but the more memory it will use, and probably the slower the performance will be. Also you might hit a hard limit at some size - I'm guessing the UIImage gets converted by the Google Maps SDK into a texture, and textures have a max size of 2048x2048 on iPhone 3GS+.
Then, use something similar to How to setRegion with google maps sdk for iOS? to calculate a zoom level and centre lat/lon. Instead of the map view width/height you would use your UIImage width/height, and you'd use the bounds of your rectangle instead of the bounds of the desired view. You also wouldn't need to calculate the scale from both the width and height (as the scale should be the same) - so just use one of them. Instead of creating a camera with the zoom level and centre lat/lon, set them on the GMSGroundOverlayOptions. Also set the ground overlay's anchor to the centre of the image (ie 0.5, 0.5).
The above describes how to add one GroundOverlay per rectangle. If you have lots of overlapping or nearby rectangles you could probably combine them into a single UIImage, but that would be a bit more complicated.
I am using wxWidgets to draw a large flow chart, i.e. 625 x 26329 pixels. The program was transported from Qt to wxWidgets. It is easy in layout with a main frame which has a customized scroll window inside. The scroll window draws part of the chart every time within updated client region.
Now Qt and wxWidgets make much difference. When scrolling vertically with mouse rolling, Qt refreshs painting the chart very smoothly, while wxWidgets is slowly with flicker.
Can anyone tell me how to make the painting efficiently?
Are you sure it's slow? I would be wondering, I encounterd a different experience.
You mention flickering. Flickering is mostly result of too many refresh calls.
To prevent this you must use double buffering and this is the key.
Double buffering means to draw all stuff offscreen into a image / bitmap and after everything is drawn the image/bitmap is drawn fully (this is done really fast so no flickering :)! ).
Qt uses for default double buffering. That's why it looks everytime smooth.
However the downside of this approach is that it consumes performance.
wxWidgets doesn't bound you to that. Instead it says, it's your task to get double buffering.
Also you should look whether you aren't clipping the region you're drawing. Clipping under Windows with wxWidgets gave me a really better performance.
PS:
Yes, old question but I think it's still needed to know how the facts are.
I'm developing a Flex 2 application, and I noticed that part of the library which is responsible for moving GUI windows (TitleWindows) around when you drag them with the mouse gets confused if there is a clickable (buttonMode = true) sprite beneath them. When I say confused, I mean that the window is moved around normally for a while, but then at some point "jumps" into the upper left corner of the flash app, and makes very minor movement there. Then at some other point it jumps back. It is more difficult to explain than to experience, so please go and see for yourself. Here's how to reproduce the problem:
Go to http://www.panocast.com
In the left sidebar, choose "Real Estate"
Just below the bottom right corner of the flash window, choose "high res" by clicking on the rightmost icon.
When (part of) the video loads, click on the staircase. A TitleWindow will pop up.
Try dragging it around the screen. When the mouse cursor is moved above one of the clickable areas (like the staircase), the window is misplaced.
(Sorry, but can't give you a direct link, part of the page is generated dynamically.)
(What's makes the problem even more interesting is that for me, in "low res" mode, the problem does not occur! There is very little difference between the various modes.) I would really appreciate if someone told me what was going on here and how it can be fixed.
I'm not sure if it matters, but the underlying sprite is actually not just plain sprite, rather it is a Papervision3D renderer object with some 3D elements in it. I'm telling this because it is possible that the incorrect mouse coordinates somehow come from the texture UV mapped on the clickable objects.
I've managed to replicate this on the low res mode as well, so I don't think it's related to the resolution.
This looks to be because the MouseEvent is being handled by the TitleWindow AND the Papervision3D window. Perhaps you need to force stopImmediatePropagation() on one or the other? Or maybe switch off the MouseEvent handling for the Pv3D window when the TitleWindow pops up?
That's a tough one to debug without some source; something's apparently calling either move() or setting x and y properties on that TitleWindow and scheduling it be moved.
When I first read the post, it "smelled" like maybe a rotation miscalculation somewhere (using Math.atan vs. Math.atan2 can sometimes have that kind of effect), so you're right, it could have something to do with PaperVision, assuming you're not using Math.atan or setting rotation properties yourself anywhere. Just thought I'd mention it, though it's probably not happening in your case. You never know, though. ;)
More likely the LayoutManager is moving the component in response to a property change on the component. The Flex docs explain that in addition to setting its x and y properties, and explicit calls to move(), a UIComponent's move event can also be triggered when any of the following other properties change:
minWidth
minHeight
maxWidth
maxHeight
explicitWidth
explicitHeight
PaperVision or no, maybe that info might help you isolate the source of the move. Good luck.
I got this figured out. Apparently, this is a Papervision3D problem. There is a class deep inside Papervision3D called VirtualMouse, which is supposed to generate MouseEvents programmatically. This happens, for example, when the user interacts with any of the interactive objects on stage, e.g., a Plane with an interactive material on it (as in my case).
The problem is that the x and y coordinates of the generated event represent texture UV coordinates (just as I suspected) and not real world screen coordinates. When a TitleWindow (or any Panel object) is dragged, a "mouseMove" handler (among others) is added to the SystemManager, which then uses the stageX and stageY properties of the event object to determine the new position of the window. Unfortunately for VirtualMouse's mouse events, these are invalid, since the original x,y coordinates, which are probably used to determine the global stage coordinates are, as I said, not screen coordinates.
Honestly, I'm still unsure whether the events dispatched by VirtualMouse are used anywhere within Papervision3D itself, or they are just offered for convenience, but they sure make it difficult to integrate a viewport into a Flex program. Assuming that such events aren't necessary for PV3D itself, there is a one-liner fix for my problem, which must be added right after the creation of the viewport:
viewport.interactiveSceneManager.virtualMouse.
disableEvent(MouseEvent.MOUSE_MOVE);
BTW., there was a very similar (or rather, as it turns out, the same) bug with dragging sliders, also fixed by this line.