I am working on a touch screen application (WinRT) and currently draw some graphics to the screen. Because it is touch, I want to enable pinch-to-zoom for scaling the entire content. For a better experience, I only want to redraw the graphics, once the pinch gesture is complete. For the intermediate scalings, I would like to reuse the current bitmap, and perform (if possible) a gpu-only scaling (enlarge bitmap).
Basically, I want to do exactly what iOS and Windows Phone have been doing for years now.
How can I implement this in Direct2D?
As a bonus, If you know a good ressource for reading on Direct2D, please tell me. The MSDN documentation is really poor and I have to hunt different blogs and magazine articles to learn :(
What I tried so far:
m_target->SetTransform(
D2D1::Matrix3x2F::Scale(
D2D1::Size(1.5f, 1.5f),
D2D1::Point2F(500.0f, 500.0f))
);
However, if I do this for interactive elements (like page zoom-in/zoom-out), all objects are rendered (which is also slow).
Another option could be to draw into a BITMAP and use that as the base for the transforms. However, I am not sure if this is a good approach.
Note: I am currently debugging on a Desktop but want to target tablets. I have to consider that tablets are orders of magnitude slower. That's why I try to optimize this functionality.
Thanks!
Related
I'm trying to graph some things in C++ and Koolplot seems like a very simple and suitable library to do so with. I'm stuck, however, on finding some documentation about it that allows me to fullscreen the application (or resize it like you can do so on lots of applications, chrome, word, discord...). As well as this, I can't find or see how i can allow the user to drag the graph around with the mouse as well as zooming into a point of a scatterplot or function. If anyone has any ideas about these things i'd appreciate it, thanks.
The short reply is: cannot do.
Koolplot uses for drawings of the charts a modernized version of the venerable BGI driver. It was invented once upon a time, when personal computers were still running on some DOS version. Those times the graphics were full screen, hence of fixed size. This particularity was kept in the modernized WinBGIm library.
Zooming or panning properly a chart present on the screen require access from the drawing/painting routines of Koolplot to the data to be shown. This is not the case. If you look once again in the source code, you will note that in the implementation efforts were made to keep separated data to be plot from the actual drawing on the screen.
In conclusion, to do what you want, you will have to modify WinBGIm such that it manages correctly a drawing surface of variable dimensions and modify koolplot such that data to be shown is owned by (or aggregated with) Plotstream class.
For Imageprocessing I want to get all pixel information from a given process.
Concrete its for testing an image hashing algorithm for identifying hearthstone cards, so i need to get a screenshot of the given process.
How can I solve it in windows?
My idea so far:
Get the process name.
Get the process ID
Get Window Handle
I have no idea how to go further from this point.
I hope it understandable what I want to achieve.
Unfortunately, there is no general method for getting the pixels of a particular window that I would be aware of. Depending on how the target application draws itself, this task can be very simple or very complicated. If we were talking about an application that uses good old GDI, then you could just get yourself an HDC to the window via GetWindowDC() and BitBlt/StretchBlt the content over into a bitmap of your own.
Unfortunately, the target application in your case appears to be a game. Games typically use 3D graphics APIs like Direct3D or OpenGL for drawing. Assuming that you cannot simply modify the target application to just send the desired data over to you out of its own free will, the only way to specifically record output from such applications that I'm aware of is to hook into the graphics API and capture the data from underneath the API. This can be done. However, implementing such a system is quite involved. There might be existing libraries to aid with writing such applications, but I don't know any that I could recommend here. If you don't have to capture the game content in real-time, you could just use a screen recording application to, e.g., record a video and then use that video as input for your algorithm. There are also graphics debugging tools like NSight Graphics or RenderDoc that you could use. Be aware that games, particularly online games, these days often have cheat protection systems that are likely to get very angry at you if you attempt to hook into the game…
Apart from all that, one alternative approach might be to use DXGI Output Duplication to just capture the entire desktop. While you won't be able to target one specific application (as far as I know), this would potentially have several advantages: First of all, it's only moderately complex to set up compared to a fully-fledged API-hook-based approach. Second, it should work regardless of what API the target application uses and even if the application is in fullscreen mode. Third, since you will have the data delivered straight from the operating system, you shouldn't have any issues with cheat protection. You can use MonitorFromWindow() to get the monitor your target window appears on and then enumerate all outputs of all DXGI adapters to find the one that corresponds to that HMONITOR…
I am trying to make a simple QT android app, but basically my problem is that on my main screen I have about 250 little images that i want to scroll. But I really need the scrolling to be fluent and fast. First I tried it using QML but it wasnt really fast, then I tried to make the app in qt designer and use widgets but that was very slow. Then I tried using openGL but on android I can only use openGL ES and I cant find so much examples because every example that I find is much more advanced than I need.
But basically my main question is, what do you think is the best way to solve my problem and if its openGL which way of using it is the best that could solve it?
Thank you.
Neither approach should have problems when scrolling when compared to a native application on the same device. Check the following:
Make sure to measure performance only in release-builds, with QML debugging disabled and no debugger attached.
Maybe your device simply can't keep up with so many images in one view - then it's not a Qt problem. Compare with a 'native' java-App to see if this is the case.
Check if you implemented everything correctly; e.g. check if theres anything running in your main-loop or some events happenening repeatedly which consumes CPU time
And some more general advice:
Downscale your images to the appropriate view-size before giving them to the UI, as they might have to be re-scaled on every frame-update and/or consume graphics memory otherwise. E.g. dont set the source to a 1024x1024 image when it's going to show in a 64x64 view
Remove transparency from the images if they are going to display on solid-colored background anyway.
Dont overlay the images with other widgets/controls
If you're still getting a 'slow' UI, maybe try to merge all or multiple images and their surrounding UI/Controls into one or more bigger images
Very long views are not user-friendly. Maybe implement a pager or tab-view etc. to divide your list into multiple views. This way you can also decrease load-time
Dont try to implement an interface in openGL yourself. It's unlikely you'll make a better one than you already get with QtWidgets and QtQuick.
I would like to have a tool to debug 2D planar meshes. I would like to be able to display them and debug to be able to debug certain things.
Is there a widget (for any toolkit on Linux - QT, GTK+Cairo, ...) which would display the images, scroll them and zoom it. Is there any widget which would handle it (without need to implement zooming, scrolling etc. by hand)?
Side requirements:
Needs to work on CentOS 6
I need it for C++. Unfortunately changing the build system in my situation is harder then it sounds.
The Qt Graphics View is certainly a useful tool, it gives you scrolling, zooming, rotating easily. You probably want to learn the basics of Qt before. (and Qt is in C++).
Here's an off the wall suggestion.
This would be fairly easy to implement in a web browser. Web browser engines already have the base functionality for resizing and scrolling over images. You may need a little JavaScript to bind it together, of course.
So why not use WebKit? There are bindings for many of the leading toolkits (e.g. QWebView for Qt), so you could take your pick of which one you're most comfortable with.
Yes, it's overkill. But it's code you don't have to write, and time is money.
Could anyone suggest me a particular way to implement animation in my Dialog-based mfc program? The animation that I am intending to add is like a construction digger machine graphic that would read the values of the machine parameters and change the shape of the graphic accordingly. Most of the information is read from a text file in terms of the parameters, so I just need to be able to get the animation working.
Thanks for your help in advance.
Well, GDI is easy but ugly and quite slow, GDI+ is also easy, but nicer although generally slower. OpenGL or DirectX are much, much faster but quite hard to program. Other libraries, such as cairo, are also available.
I'd suggest to start with the easiest (maybe GDI+) and see if it is fast enough for you.
Do do that, just Invalidate() the control where you are drawing in a timer, (or when you receive new data), and paint the whole graphic in the OnPaint() function. A basic improvement is to Invalidate() only the region where the new data affects the picture.
If then you notice that your code is not fast enough, come back and ask how to improve it. A concrete example will make it easier to get a more useful answer.
there are lot of articles. Most of them based on drawing in device context
http://www.codeproject.com/KB/GDI/flickerfree.aspx
http://www.codeguru.com/cpp/g-m/bitmap/article.php/c4879
http://www.codersource.net/mfc/mfc-gdi-plus/animation-control-mfc.aspx