Pinch to Zoom

[Christopher]

Does your touch display react anyhow?

Yes, it works, but my setup doesn't enable that example to work. Tomorrow I will try the example on another setup, and if it works I can look again at the WPF issue. Apologies again for the slow pace on this issue.

[Christopher]

Hello,

New TeeChartWPFManipulation added to our GitHub repo here:
https://github.com/Steema/TeeChart-for- ... nipulation

Scroll with one finger, double-tap to reset, click on the Zoom button to zoom with two fingers, double-tap to reset. It works on this set up - it wasn't working with Win10 as a Virtual Machine, but it works fine when the touch-screen has direct access to the graphics card.

I hope this resolves your doubts!

[HCCKPM_2020]

Hello,
I downloaded the project and tested it.
It works not very well. When I set it to "zoom" it also scrolls while zooming => two fingers will scroll the graphic which should not be possible when in zoom mode.
Do you experience the same?

[HCCKPM_2020]

We have an additional issue with the zoom functionality: it will not work if you increase the amount of data.
change the code to our sample and maximize the window. Then try pinch to zoom - nothing will happen. but standard zooming works?!

Code: Select all

 public MainWindow()
    {
      InitializeComponent();

      TChart1.Header.Text += " IsManipulationEnabled";

      TChart1.IsManipulationEnabled = true;

      // your code
      //TChart1.Series.Add(typeof(Steema.TeeChart.WPF.Styles.Bar)).FillSampleValues();

      // our sample 1. this is the amount of data we are actually using!
      TChart1.Series.Add(typeof(Steema.TeeChart.WPF.Styles.ColorGrid)).FillSampleValues(420);

      // our sample 2
      //TChart1.Series.Add(typeof(Steema.TeeChart.WPF.Styles.Histogram)).FillSampleValues(1024);

      TChart1.ClickLegend += TChart1_ClickLegend;
    }

[Christopher]

Hello,

okay, I've had a look at the code and have made a few modifications - you might like to try the TeeChart.WPF.dll you can find here:

http://steema.com/files/public/support/ ... 0.8.20.zip

And let me know what you think. I'm not sure how easy it's going to be for us to greatly improve this.

[HCCKPM_2020]

Hello Christopher,

sorry for my late response.
Now I had time to test the new DLL.
Now it works a little bit better but it is absolutely not satisfying:
- When I do a "Pinch to Zoom" ist doesn't respect the location on the screen where I do this. It just zooms the center of the screen.
- zooming is way to "slow". I used your example to test the new DLL. When I zoom the changes are so small that it would take forever to zoom down to a very detailed view.

Please improve this functionality in a way that it is usefull. It has to be the same like on an iPhone or an Android device. The actual state is not "state of the art". Our customers will not accept this.

[Christopher]

It has to be the same like on an iPhone or an Android device.

No, in fact it doesn't. The WPF framework was not designed as a platform to be used on mobile phones, and so there is no expectation that WPF components behave in an identical way to those written against platforms specifically designed for those devices.

[HCCKPM_2020]

Christopher, the zoom is too slow. This hasn't to do anything with mobile phones.
Actually we are buying your product since nearly 20 years. We never had any issues except that one.
Is it that difficult to enable or realize a usefull pinch to zoom functionality like it is state of the art?

[EDIT]
Besides that, is that really your answer for my question???

[Christopher]

Christopher, the zoom is too slow. This hasn't to do anything with mobile phones.

As I say, particularly the speed of Zoom is something which is going to be extremely difficult to improve in TeeChart.WPF.dll; I think it's unlikely we are going to get significant speed improvements without a substantial rewrite of the code base, something that at this time we don't have planned.

Is it that difficult to enable or realize a usefull pinch to zoom functionality like it is state of the art?

I'm sorry to say, as I have indicated above, that the answer to this question is: yes, yes it is, and I'm afraid it's unlikely - under current plans - that we are going to make significant advances in this area in the near future.

[HCCKPM_2020]

And what's with the problem that pinch to zoom doesn't respect the point on screen it is performed? It just zooms the center of the actual view.

[Christopher]

And what's with the problem that pinch to zoom doesn't respect the point on screen it is performed? It just zooms the center of the actual view.

In the tests I made on the screen I made them on, this was not a problem. It is going to be difficult to perfect this particular aspect if the behavior varies according to the hardware on which it is run.

[HCCKPM_2020]

If I get you right, you are not willing to put the WPF product into a usefull state.
This is important to know for our future proceeding.

[Christopher]

If I get you right, you are not willing to put the WPF product into a usefull state.
This is important to know for our future proceeding.

It isn't a question of will, it is a more prosaic question of time and resource allocation. It is also worth mentioning that 'usable' is not a particularly objective measure of software functionality: opinions may differ, and indeed do in this case, as to what or what isn't 'usable'.

Please be aware that Steema Software offers consulting services, as you can read here, services which were designed to help our clients achieve their more particular aims with our software.

[Christopher]

Hello,

following your email conversations with us, some other members of the development team will be performing a code review of work done in this area - they've asked me to inform you that they will look to make improvements in this area, and we'll get back to you with any feedback.

[Marc]

Review of the current WPF touch functionality.

- Scroll mode, one finger-touch.
This seems to work correctly when tested, speed of response, ie. plot movement in relation finger location, appears correct on our test device. Scroll correctly resets on double-tap.

- Zoom mode, two finger-touch.
This appears to respond correctly, the zoom start location being the midway position between the two touch locations (not necessarily the centre of the screen). Scroll behaviour with two touch locations is also considered correct and desirable as a scroll of this type enhances a zoom, for fine-tuning or permitting a lateral shift at the same zoom level. A negative aspect of the current zoom implementation is the amount-of-plot-zoom relative to the movement of the two touch locations. On reflection we considered the current implementation as too slow, ie, too little zoom for the two-touch movement. In response to this we will increase the default sensitivity and make public the property in the API to permit fine-tuning by code. Double-tap is not resetting zoom in current build; to be resolved for upcoming builds.

Response to comments from earlier posts:

Pinch to Zoom" ist doesn't respect the location on the screen where I do this. It just zooms the center of the screen.

We did not find this to be the case in the current version, the zoom centre being the mid pint between the two touch locations.

zooming is way to "slow"

Agreed, see earlier comments in this post. We will make a property publicly available to permit change to movement response. In relation to zoom performance, there may be other factors that should be taken into account such as number of points; the more [plotted] points the slower it will be. Improvements can be made by setting unnecessary Pens to Visible false; WPF is resource costly on pen plots so setting pen.visible to false on a ColorGrid will make a large difference to plot response.

We'll include changes among the next builds we are preparing.

Regards,
Marc Meumann