Dequeue Data In Paint Event Of A UserControl To Show Continuously Moving Waveform?
May 11, 2011
Given this illustration and basic code, how do I dequeue and draw the data that has been inserted into the User Control's Preperty queue? The graph/chart will need to show anywhere from 1 to 120 seconds of data, with each second representing electrical waveform data that arrives each second with a variable amount of sample data..The timer interval will have to vary with the amount of incoming data so that it shows a continuously moving waveform from right to left and the rate of drawing keeps up with the amount of data arriving. (so the queue doesn't get backed up)
I have a picturebox set to move when the arrow keys are pressed. How do I prevent it from continously moving if the arrow key is HELD DOWN. I want to make it so the user has to press the key each time manually to move the picturebox.
I want to know the codes to show numbers one by one continuously from 1 to 20 on clicking a button, and it should keep on doing it till a Button is clicked.I know how to get a Random number to for it but I don't know how to do for numbers in normal order .
I have a UserControl that has a ProgressBar on it. The purpose of the UserControl is to be able to show the progress % on the ProgressBar as text. To do this it uses the MyBase.Paint event. To make it work the ProgressBar is made invisible and the UserControl is 'painted' with an image of the ProgressBar and then the text is painted on top. The UserControl has a Value property that is passed through to the ProgressBar.Value property.
I use this UserControl in two places, on a Splash form (not a standard Splash Screen) and also on the main form of the application. It works on the Splash form but not on the main form - by work I mean that changes to the ProgressBar.Value property cause the ProgressBar to show its progress. The cause appears to be that in the Splash form case the MyBase.Paint event is called as a consequence of calling Me.Refresh in the Set procedure of the UserControl.Value property, in the main form case it isn't, i.e. Me.Refresh isn't causing MyBase.Paint to run.
The main form has two BackgroundWorker components. The first gets called (RunWorkerAsync) from Form_Load after the Splash form has been shown. The BackgroundWorker.ProgressChanged event updates the Value property of the UserControl and it works exactly as intended. The second gets called as a result of a user starting an operation and again the BackgroundWorker.ProgressChanged event updates the Value property of the UserControl but MyBase.Paint doesn't run so the ProgressBar remains resolutely static.
Any ideas why it won't respond to Me.Refresh in one case but does in the other? Happy to make any of the code avaialble but didn't want to fllod the first post with reams of it. Here's what I think are the most relevant code sections. First the UserControl
I'm using 2 System.Timers, which spawns a worker process during its elapsed event. If 1 of the events is busy doing something, the other thread elapsed event doesnt fire until the 1st thread has completed.Is there any way I can make both threads continuously fire its elapsed event??
How can I play a sound based on waveform data that my .Net program is generating from user input and mathematical functions? By "waveform data" I am mean SPL values in a fixed interval time-series (probably 44.1 kHz). I presume that this requires some kind of streaming buffer arrangement.Note, that this has to be live/real-time, so just creating a .wav file and then playing that will not be sufficient. VB.net is preferred, but C# is acceptable also.
How can I cause the Paint event to fire from a Form_Click() event? This is what I'm trying to do...
Public Class StrTests01 Private Sub StrTests01_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Click Dim ps As Graphics = Me.CreateGraphics()
The only way I know to force a paint event in my pictureboxes is to do a 'Picturebox1.invalidate'. I read that this isn't the best way to do it though, so what's the best way to make my picture boxes repaint?
Weird issue: I have application that I fire some code in the Form_Paint event for the main form, it works fine on my machine, but on other machines is not working at all.
I tried to debug the code on the other machine, and Form_Paint event is not triggered at all!
I was wondering how i would go about threading a paint event. I know the basic multithreading but i cant figure out how i would go about applying this on a paint event. This is the way i know how to go about multithreading.
however it will draw it behind objects for example if i have a groupbox it will draw(i assume its still drawing at leaste) behind the group box and i cant see it
[url]... I managed to figure out how to paint a bitmap on a form. With some slight modification, I managed to make it so that the position of the bitmap can change based on key strokes.However, for some reason, it only does this once. It can't be that the xPosition and yPosition aren't responding since I rigged two labels to tell me their values and they are changing. So how can I make the bitmap respond.[code]...
I want to create a track bar using paint event, but the problem is on mouse move event<Me.Invalidate()> is very slow since the graphic become unvisible for milli seconds and then return back, is there a way to make it faster?(doesn't become invisible)
correct way to draw rectangles onto a picturebox, and also to explain the paint event more clearly.Basically I have an application where a picturebox contains an image, this image is a small computer monitor as such:
The idea of this part of my application is that the user can draw small window size rectangles which represent windows later on. I have already used some excellent code on this forum to be able to draw the rectangles on the picturebox (As pictured above), the rectangle outline is drawn from MouseDown and MouseUp respectivley.
The problem I am encountering is with the 'repainting' of this rectangle. I have included code to repaint the rectangle in the Paint event of the picturebox. This works when you move the picturebox 'off screen' and bring it back. However when the form is re-sized or other various things occur the rectangle is not re-drawn? even though the picturebox 'appears' to be clean and always there!
My code is below, it is not full and complete, but the few main subs listed should give an indication as to how I am currently creating the rectangle:
Private Sub picboxAdvDisplay_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles picboxAdvDisplay.MouseDown 'Set the flag for Drawing enabled
[code]....
1. What is the CORRECT way to draw a rectangle onto a Picturebox?
2. How do you code so that the rectangle is ALWAYS visible/drawn on a form re-size, minimise, window overlap etc etc.
during the development of my project, i've the need to raise the paint event of a form, to make it with rounded angle.The strange thing is that, when i use the invalidate comand on it, the repaint event (that sometimes doesn't go and i don't know why), doesn't make it like i need, that is, the dimension of the side is one instead of six pixel, and the angle are rounded, but the border is not visible.
I've got a bug in my program that I can't work out, during a paint event. The only way I can think to solve it is to watch the screen being updated one thing at a time. Problem is, I've put a break in and then I try stepping through the program one line at a time, but when I go to look at the screen it's blank - probably because I'm in the middle of a paint event? Is there some way that I can get my screen to update after each command?
From jmchillihiney's most excellent code bank sumission on Drawing:Quote:The way GDI+ works, controls get repainted on screen over and over again, sometimes many times in quick succession. On each of these occasions the control's Paint event is raised. You need to use the Paint event of the control to perform your own drawing or else, the next time the control is repainted, your drawing will just disappear as the control paints over it.
When you're creating a custom control you should override the OnPaint method and perform your drawing there. When you're designing a form or user control and you want to add custom drawing to a child control you handle that control's Paint event, then perform your drawing in the event handler.
You may have seen, or heard people talk about, controls flickering on screen. That's caused by repainting large areas of the control repeatedly and happens because painting on screen is actually quite a slow process. As such, you should try to do as little of it as possible.So, I am attempting to draw part of a custom control. I have placed a SplitContainer on a UserControl, and oriented it vertically. I then shrunk to top panel to 15 pixels in height. I have two Methods which each draw a different type of Path + fill into the panel, and then draw a border around it (One is a gradient fill, and the other is just a plain color). The idea is that when the user clicks on this panel, it switches from one to the other (a "Selected State" and "Not-Selected" state).
I have also created an icon which looks like the +/- widget on a treeview (or more specifically, on the vs2008 Toolbox, which is essentially what I am trying to emulate here . . .) which toggles as the control is selected/unselected. Not that ultimately, the selected state will change when the user selects OTHER controls, but the Expand/Collapse gizmo will toggle when the user clicks on the panel in question.
Again, check out the vs2008 toolbox. The Group "headers" are what I am after here. Believe it or not, all of this now WORKS (gee me, look what I did!) EXCEPT the initialization. If I "Handle" the paint event of the SplitCOntainer.Panel1 object in any way which prevents the flickering jmc alludes to above, any redrawing required by either initialization OR hiding/unhiding of the host form is prevented. And it seems like the SplitContainer panel is constantly redraing (probably checking to see if the splitter has been moved).
I can post some code, but it is a little confusing, since I am dealing with some semi-complex interaction here. Also, It is not necssecarily structured well ()yet). AFTER I figured out the drawing bits, THEN I was going to try to do some refactoring and restructuring. Code Follows in next post.
I have serial port object which continuously receiving data from weighing device, which sends data in 0001450= format (8 Bytes). I read about datareceived event, and implement that, but i must use Thred.Sleep to get all data and read with serial.ReadExisting. Does the ReadBytesTreshold=8 raised DataReceived event after 8 bytes of data??
Is there any way to cancel, abort, stop DataReceived event?
I have the following code for a gradient form below. When I step through my code it seems to fire constantly. Does this mean that it fires constantly at run-time? If so, is there a way to stop it from firing constantly
Private Sub Form1_Paint(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint Dim Mybrush As New System.Drawing.Drawing2D.LinearGradientBrush(Me.ClientRectangle, Color.LightSkyBlue, _ Color.Snow, Drawing2D.LinearGradientMode.Vertical) e.Graphics.FillRectangle(Mybrush, Me.ClientRectangle) End Sub
In my attempts to understand vb.NET, one of the problems I have encountered is that I have not been able to find a concise definition anywhere for the Paint Event. So after many hours of researching and forum posts (and my own personal tests), here is my own definition (but it seems to fail in one instance, mentioned after the definition). I would like to create a final definition based on everyone's input, but keep in mind, the idea here is to STAY CONCISE. So here goes:
Explanation of the Paint Event
Whenever any portion of a control is UNCOVERED (except by the mouse pointer), the paint event fires. Covering of the control does not fire the event, because the covered area is not visible to the user, and is therefore irrelevant. The paint event is a messenger that alerts the program, via message, that some portion of the control has been uncovered and this message launches an OPTIONAL paint event handler (paint event procedure) written by the programmer, if one is needed to handle those situations when the event occurs. One possible situation is the most obvious...the need to redraw the uncovered region. A paint event procedure is the programmer's counterpart to vb6's automatic property, "AutoRedraw". But whereas vb6's solution was a simple and automatic redraw of the control, vb.NET's equivalent requires the programmer to define explicitly how the event is to be handled, whether it be a simple redraw or something more elaborate. This puts this event in a special category; it is not a user-desired event fired by some user-desired action...it is an internally generated event that acts more as a housekeeping "watchdog" to alert the program that housekeeping chores may have to be implemented because the user did something that was NOT DIRECTLY RELATED to a desired action. For example, when the user moves a window over a control in such a manner that a portion of the control is covered, then uncovered, this causes the state of the control to change even though the user did not specifically request it. It nonetheless may have to be dealt with, and this is managed via the paint event handler procedure.
The problem I have with this definition of mine, is that if the above is true, then why does the mouse moving across the control NOT cause the paint event to fire? After all, it is causing areas of the control to be covered and then uncovered. Is it because the mouse is a special case where the system puts the mouse pointer on a separate layer above the screen graphics, in order to prevent constant paint event messaging?
This is a working example which draws a rectangle on different location every timer_tick and I fully understand now how it's working:
Code: Dim i, timercount As Integer Private Sub PictureBox1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles PictureBox1.Paint
[code]....
Now I'm looking for a way to draw this rectangles without refreshing them every single tick. I've just started using Visual Basic and I really don't know how to call/raise PictureBox1_Paint event every timer_tick or how to store drawing data in member variables?
I have a panel in my mainform and need to display a jpg file on it using a paint event. Any suggestion how can i go about doing it. I have to use a menu item to open a folder i.e. OpenDiaolgFolder to open a jpg file.
I've created a schedule panel,drawing some lines,and adding some labels,as in image(blue,red and green are labels added by code).Now I've put some code to show the number for each cells,for that I've used Paint event of the panel but this slow the paint event,and after some investigation I found that the paint event was raised for some 20 time on my first form shown.Is there a place to put this code to run only once ?
I have a Windows form UserControl that receives electrical signal waveform data into a 128 element byte array Property every 1,000 ms.
I would like to have the Paint event draw a a subset of the 128 sample points of the array every 100ms (12-13 graphic.drawline operations) to simulate a rolling waveform display such as one would see on an oscilloscope or a medical monitoring device. Is it possible, and if so, how would I set the paint event handler to fire every 100 ms?
