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Try this article: Simple Zoom.
Trinity: Neo... nobody has ever done this before.
Neo: That's why it's going to work.
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Hi, we're a couple of students on our internship, and we're kinda stuck in the project we're doing. I'll first try to explain what it is we are expected to make.
You have to imagine a white empty 2D paper which is virtually unlimited in size. An admin can place a question on this paper, users can then reply on the active question. The admin can also zoom in and zoom out and drag the paper around and post new questions. So we have to work with an environment that contains a fair amount of questions linked to answers. Every question can be differently scaled, so this means that you have to zoom in more on some questions than others.
Basic functionality would have to be panning the paper, by that I mean hold mouse down and dragging it to another position, thus moving all objects on the paper in that direction.
We've tried this with the following code, however the performance was really bad.
void Window_MouseUp(object sender, System.Windows.Input.MouseButtonEventArgs e)<br />
{<br />
if (mbMouseDown)<br />
{<br />
Point bNew = e.GetPosition(Window);<br />
foreach (UIElement oObject in LayoutRoot.Children)<br />
{<br />
Canvas.SetTop(oObject, bNew.X - mpBegin.X);<br />
Canvas.SetLeft(oObject, bNew.Y - mpBegin.Y);<br />
}<br />
}<br />
mbMouseDown = false;<br />
}<br />
<br />
void LayoutRoot_MouseMove(object sender, System.Windows.Input.MouseEventArgs e)<br />
{<br />
if (mbMouseDown)<br />
{<br />
Point bNew = e.GetPosition(Window);<br />
foreach (UIElement oObject in LayoutRoot.Children)<br />
{<br />
Canvas.SetTop(oObject, bNew.X - mpBegin.X);<br />
Canvas.SetLeft(oObject, bNew.Y - mpBegin.Y);<br />
}<br />
}<br />
}<br />
<br />
void LayoutRoot_MouseDown(object sender, System.Windows.Input.MouseButtonEventArgs e)<br />
{<br />
mbMouseDown = true;<br />
mpBegin = e.GetPosition(Window);<br />
}
With the zooming we tried the scaling functionality of wpf.
private void Window_MouseWheel(object sender, MouseWheelEventArgs e)<br />
<br />
{<br />
<br />
if (e.Delta > 0)<br />
<br />
{<br />
<br />
mpScaleSize = new Point((mpScaleSize.X - 0.05), (mpScaleSize.Y - 0.05));<br />
<br />
grdCanvas.LayoutTransform = new ScaleTransform(mpScaleSize.X, mpScaleSize.Y);<br />
<br />
zoomX.Content = mpScaleSize.X.ToString();<br />
<br />
zoomY.Content = mpScaleSize.Y.ToString();<br />
<br />
}<br />
<br />
else<br />
<br />
{<br />
<br />
mpScaleSize = new Point((mpScaleSize.X + 0.05), (mpScaleSize.Y + 0.05));<br />
<br />
grdCanvas.LayoutTransform = new ScaleTransform(mpScaleSize.X, mpScaleSize.Y);<br />
<br />
zoomX.Content = mpScaleSize.X.ToString();<br />
<br />
zoomY.Content = mpScaleSize.Y.ToString();<br />
<br />
}<br />
<br />
}
This again wasn't going smoothly.
(My laptop is a IBM Thinkpad r50p, 1,7Ghrz Centrino, 1gig RAM, maybe it's just not fast enough?)
Anyway , I've posted this same question on the msdn forums. One person with little experience with the subject suggested me that I should try to work with visualBrushes and use it as some kind of view. I've been playing around with the VisualBrushes for a while now.
I've managed to get controls from code onto the VisualBrush(which is on a rectangle in the center of my app), however working with VisualBrush as some kind of view isn't working for me.What I "discovered"is that working with the viewbox property of the visualbrush might be the solution, but I can't seem to get it to work.
To my understanding the viewbox is a rectangle with it's x & y as panning values, and it's with & height as crop/stretch values (zoom).
Anyone with some experience in the area, I would really appreciate the help.
Thanks,
Tobias
-- modified at 8:14 Tuesday 24th April, 2007
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I am working on a drawing application using OpenGl and C#. I want to use the whole form as Drawing area, i have added menus to my application but these menus does not show at run time, help required
thanks
David
david
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Hi
I want to do some limited filters on an image (like converting RGB to MonoColor)
I do this now by to inner loop on image scales and use GetPixel method on this but it's real Slow.
Who can help me to do that with realtime speed (like Adobe Photoshop).
Tanx
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Christian Graus has written a very good set of articles describing image processing with C#. Yo ucan find them here[^] under the GDI+ section.
Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007
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Thanks for the plug, mate 
Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
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After Mark Salsbery showed me the wonders of DirectShow Editing Services (Thanks Mark!) i was able to take a bunch of mpegs, put them on after the other and add background music and save the output to an avi file.
One problem. I am having problems Compressing it. The output file is huge since i am not compressing it.
The following example from the DirectShow documentation shows this:
long NumGroups;
pTimeline->GetGroupCount(&NumGroups);
// Loop through the groups and get the output pins.
for (i = 0; i < NumGroups; i++)
{
IPin *pPin;
if (pRender->GetGroupOutputPin(i, &pPin) == S_OK)
{
IBaseFilter *pCompressor;
// Create a compressor filter. (Not shown.)
// Set compression parameters. (Not shown.)
// Connect the pin.
pBuilder->RenderStream(NULL, NULL, pPin, pCompressor, pMux);
pCompressor->Release();
pPin->Release();
}
}
They do not show how to create a compression filter. So meanwhile my compressor is NULL, this is why my output is so huge.
Anyone have any idea how to create a compressor filter? Show me some code xample?
Thanks,
Michael
mjmimmm@hotmail.com
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I had no idea that stuff actually worked!! 
The only compressor that comes with directshow is for writing ASF (.wma,.wmv, etc) files.
I believe MPEG-4 is built-in to that but other flavors of MPEG are license-protected.
If you can live with an ASF file, a method is shown here (note you'll need the Windows Media
Format SDK to use the WM ASF Writer Filter, which is a mux.writer combo filter):
Writing a Windows Media File in DES[^]
If you need to output MPEG-1, and you have a MPEG-1 mux filter, you should be able to add it to the graph before the file writer. I'm pretty sure we discussed this before but I'm not sure
exactly how it works since I've never used any third-party filters. I would expect a mux filter
to have multiple input pins and one compressed format output pin.
Hope that helps a little!
Mark
"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder
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I forgot to ask - What filter(s) are you using to write the AVI file??
Mark
"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder
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Hey Mark, Nice to talk to you again....
I don't know how much experience you have with DirectShow Editing Services.
The truth is i don't really know what filters i am currently using.
I guess it automatically uses the default filters since i did not manually order it to use any specific filters.
I have an open source mpeg-2 decoder and an open source ac3 filter (for the sound).
I am guessing that underneath it uses the mpeg-2 splitter and both of these decoders for video and sound.
For the mux, i saw that i have an avi muxer through the graphedit tool - didn't this come with windows?
1. Is is the avi muxer i have a third party tool?
2. Is there a way for me to definitely know which filters DES is using?
3. Do asf decoders come by default on windows systems?
4. The reason you think we already had this conversation was because in the past i wanted to ouput to mpeg-2, but there were no built-in muxers and now i have this avi-muxer "qcap.dll" if i recall correctly.
5. There is something called smart-rendering in DirectShow Editing Services have you had any experience with it?(ISmartRenderEngine).
6. In my other post i explained that my output file is huge because i am not compressing. I do not know how to create a compressor filter, not with the basicengine and not with the smartengine.
Thanks,
Michael
mjmimmm@hotmail.com
p.s. really sorry for the long post.
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I have no problem sending you or posting you my entire class. It's not that much, that way i can show you the place where i am supposed ot have a compressor filter and instead i place NULL because i do not know how ot create one...
Thnx
michael
mjmimmm@hotmail.com
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The AVI muxer comes with DirectShow.
I have lots of experience with Windows Media Format (ASF) - that's what I use in my software.
The Windows Media Format compression works well for my needs, including realtime streaming.
I haven't used the AVI muxer but I know it is configurable for various compression settings.
I see it uses the Video Compression Manager but I'm not sure what types of compressors are
included with Windows - I'm looking into that.
The Windows Media stuff comes with windows starting in XP. The SDK comes with (or you can
download) a redistributable install package for previous Windows versions. Pretty much the same
deal as DirectX installation (but alot smaller).
I'll definitely take a look at your code - I'll send an email you can reply to.
Mark
"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder
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Hey Mark,
I sent you an email with my code... take a look whenever you can.
Thanks,
Michael
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I have succesfully created compression filters also for my audio and also for my video.
The problem is that i do not know which codec to use now.
The Divx codec that i have does not allow me to control the frame rate or quality because it does not support this.
The codecs that do allow me to have control give me bad quality\file size ratio.
What codec can i use will allow me to control the frame rate and quality for Avi compression and have a reasonable size for the output file.
Reminder: i am compressing from mpeg-2 to avi.
Thanks,
Michael
mjmimmm@hotmail.com
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More information on why i cannot use the Divx codec:
When using the IAMVideoCompression:GetInfo on the codec it returns 0 for capabilities. Meaning that it does support controlling the codec through this interface and I cannot control the frame rate, quality etc....
Is there a way around this? or another codec that does allow me to control this?
Thank you,
Michael
mjmimmm@hotmail.com
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Hey Mark,
Haven't heard from you since i sent you the example code?
I still appreciate any help i can get.
Thnx,
Michael
mjmimmm@hotmail.com
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Hi,
I have a number of still images containing concentric circles and I would like to be able to detect the centre point of the circles. Are there any algorithms out there that would allow me to do this?
Cheers,
Tony
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For future readers who stumble upon this post and are curious about the solution, a few responses to this question were posted here[^].
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hey...
currently working on a graphics application using C# and openGL....intially the whole from was used for drawing...but now I want to refine my application by adding controls and drawing in a picture box but having problems properly defining a drawing area in a picture-box....kindly help me in this regard
thanks
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I am writing a program that does, among other things, authoring to mpeg-2.
I am currently using an sdk that throws an exception if i give it a corrupt mpeg-2 file.
Are there any directshow functions\open source code\applications that give me the option to verify an mpeg-2 to see if it is corrupt or not?
Thank you,
Michael
mjmimmm@hotmail.com
mjmimmm
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There's nothing that will test it for you, no. You've pretty much found the only way to find out. Pass the MPEG inside a Try/Catch block. If it fails, then you know!
Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007
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Hello..
i'm beginner in c# and have problems with implementing some things in my project...
i need to draw circle (ellipse) as car and different roads (from couple segments) on some map
and to be able to choose a road and navigate such car on this road and also noise if the car gets out from the road... something like this..
I tried to read some good articles here.. but i missed the main idea of such design and also do i need directx?
Thanks for any help...
Shimon
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i want to control serialport with wpf form.i mean i want to send datas and get some datas from outside.i cant add serialport component.but i create serialport component with code.System.io.ports.serialport myserial;
but when i write its datareceived event so i cant exit from datareceived event.i ll save some datas in received event and i ll call another function.how can i do it?
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Dear All
How to use OpenGl with C#, please explain in detail
thanks
david
david
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Look here - very good explanation on integrating OpenGL and C#.
-------------------------
Listen up! Teamwork means staying out of my way! (Seifer, Final Fantasy 8).
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