I would like to write a text scroller on a micro-processor with 4 5x7 displays in ANSI-C.
Does anyone know of example source code or anything that can help me get started?
Update
This is the user manual for the micro-processor board I have. On PDF page 17 is a picture of the board with the displays.
The code is written in an IDE called "zds2_Z8Encore493.exe" and then flashed to the micro-controller over serial port.
I would like the text to cascade from one to the next to the next column-by-column, so it is smooth.
There may be a better way, but I would store the text in a block of RAM, and in the routines that update the displays I would include a value to offset the starting point, possibly with a wrap-around to the start. The you store a counter which increments the "global" offset (scrolling).
You can then use string[offset + display-width + scroll_position] as the start pointer, but you need to detect the end and wrap round or just stop.
Related
Using Windows API, I want to implement something like following:
i.e. Getting current microphone input level.
I am not allowed to use external audio libraries, but I can use Windows libraries. So I tried using waveIn functions, but I do not know how to process audio input data in real time.
This is the method I am currently using:
Record for 100 milliseconds
Select highest value from the recorded data buffer
Repeat forever
But I think this is way too hacky, and not a recommended way. How can I do this properly?
Having built a tuning wizard for a very dated, but well known, A/V conferencing applicaiton, what you describe is nearly identical to what I did.
A few considerations:
Enqueue 5 to 10 of those 100ms buffers into the audio device via waveInAddBuffer. IIRC, when the waveIn queue goes empty, weird things happen. Then as the waveInProc callbacks occurs, search for the sample with the highest absolute value in the completed buffer as you describe. Then plot that onto your visualization. Requeue the completed buffers.
It might seem obvious to map the sample value as follows onto your visualization linearly.
For example, to plot a 16-bit sample
// convert sample magnitude from 0..32768 to 0..N
length = (sample * N) / 32768;
DrawLine(length);
But then when you speak into the microphone, that visualization won't seem as "active" or "vibrant".
But a better approach would be to give more strength to those lower energy samples. Easy way to do this is to replot along the μ-law curve (or use a table lookup).
length = (sample * N) / 32768;
length = log(1+length)/log(N);
length = max(length,N)
DrawLine(length);
You can tweak the above approach to whatever looks good.
Instead of computing the values yourself, you can rely on values from Windows. This is actually the values displayed in your screenshot from the Windows Settings.
See the following sample for the IAudioMeterInformation interface:
https://learn.microsoft.com/en-us/windows/win32/coreaudio/peak-meters.
It is made for the playback but you can use it for capture also.
Some remarks, if you open the IAudioMeterInformation for a microphone but no application opened a stream from this microphone, then the level will be 0.
It means that while you want to display your microphone peak meter, you will need to open a microphone stream, like you already did.
Also read the documentation about IAudioMeterInformation it may not be what you need as it is the peak value. It depends on what you want to do with it.
I'm trying to get pixel data from my X11 instance, I've seen this thread (How do take a screenshot correctly with xlib?) and the double for loop is taking just too long for me (over a million loops, as the system I'm building requires the highest amount of efficiency possible, sitting around for 600 miliseconds is just not an option). Is there no way to just get a raw array of pixels to avoid the for loop? I know the XImage class has a "data" member which is supposed to contain all of the pixels, but the organizational system that it uses is foreign to me. Any help would be greatly appreciated! The best end game here would be for me to just be able to have X11 write directly to /dev/fb0
You can see the code there: http://jsfiddle.net/jocose/CkL5F/901/
(double click on the box and move your mouse)
NOTE: This is a simplified example that is part of a larger system. My ultimate goal is to manipulate individual vertices of a path.
Update: I crunched the numbers and the math actually apears to be correct. What I want to do is calculate the offset from each point to the mouse, and then move that point to the mouses position + the offset.
So if I have a mouse of 224 then 224-103 = 121 then I add: 121+224=345
These creates a cycle of ups and downs that I am seeing. I don't know why these is stumping me so badly, any help would be much appreciated.
I need to manually update a Raphael path element.
To do this I convert an absolute path into an array using Raphael great built in function "parsePathString"
I then loop through that array and modify the values based off the mouse position.
The update is done to the X values only, and is in real time; called each time the mouse moves.
When the element moves it flickers back and forth between the correct position and some anomalous one.
I have no clue why its doing this. I have spent almost 5 hours trying to figure this out and I'm officially stuck.
Here is a sample of the result where you can see the values jumping around:
MOUSE224
M,103.676287
MOUSE225
M,346.323713
MOUSE227
M,107.676287
MOUSE228
M,348.323713 12
MOUSE228
M,107.676287
MOUSE229
M,350.323713
MOUSE231
M,111.67S287
MOUSE232
M,3S2.323713
MOUSE233
M,113.676287
MOUSE233
M,3S2.323713
Here's my version of your fiddle modified to do what I think you need. At least, it seems to work. It's the same type of problem I had to fix for the Raphael 2 transformations here.
Basically, in your mousemove, I've changed mx to be a calculation of the offset between where your mouse is now and where it was the last time mousemove was called. Your move() function now only has to add this value to the x-coords.
Hope this helps you out somewhat
I'm currently writing an eBook reader for Windows Phone Seven, and I'm trying to style it like the Kindle reader. In order to do so, I need to split my books up into pages, and this is going to get a lot more complex when variable font sizes are added.
To do this at the moment, I just add a word at a time into the textblock until it becomes higher than its container. As you can imagine though, with a document of over 120,000 words, this takes an unacceptable period of time.
Is there a way I can find out when the text would exceed the bounds (logically dividing it into pages), without having to actually render it? That way I'd be able to run it in a background thread so the user can keep reading in the meantime.
So far, the only idea that has occurred to me is to find out how the textblock decides its bounds (in the measure call?), but I have no idea how to find that code, because reflector didn't show anything.
Thanks in advance!
From what I can see the Kindle app appears to use a similar algorithm to the one you suggest. Note that:
it generally shows the % position through the book - it doesn't show total number of pages.
if you change the font size, then the first word on the page remains the same (so that's where the % comes from) - so the Kindle app just does one page worth of repagination assuming the first word of the page stays the same.
if you change the font size and then scroll back to the first page, then actually there is a discontinuity - they pull content forwards again in order to fill the first page.
Based on this, I would suggest you do not index the whole book. Instead just concentrate on the current page based on a "position" of some kind (e.g. character count - displayed as a percentage). If you have to do something on a background thread, then just look at the next page (and maybe the prev page) in order that scrolling can be more responsive.
Further to optimise your experience, there are a couple of changes you could make to your current algorithm that you could try:
try a different starting point and search increment for your algorithm - no need to start at one word and to then only add one word at a time.
assuming most of your books are ASCII, try caching the width of the common characters, and then work out the width of textblocks yourself.
Beyond that, I'd also quite like to try using <Run> blocks within your TextBlock - it may be possible to get the relative position of each Run within the TextBlock - although I've not managed to do this yet.
I do something similar to adjust font size for individual textboxes (to ensure they all fit). Basically, I create a TextBlock in code, set all my properties and check the ActualWidth and ActualHeight properties. Here is some pseudo code to help with your problem:
public static String PageText(TextBlock txtPage, String BookText)
{
TextBlock t = new TextBlock();
t.FontFamily = txtPage.FontFamily;
t.FontStyle = txtPage.FontStyle;
t.FontWeight = txtPage.FontWeight;
t.FontSize = txtPage.FontSize;
t.Text = BookText;
Size Actual = new Size();
Actual.Width = t.ActualWidth;
Actual.Height = t.ActualHeight;
if(Actual.Height <= txtPage.ActualHeight)
return BookText;
Double hRatio = txtPage.ActualHeight / Actual.Height;
return s.Substring((int)((s.Length - 1) * hRatio));
}
The above is untested code, but hopefully can get you started. Basically it sees if the text can fit in the box, if so you're good to go. If not, it finds out what percentage of the text can fit and returns it. This does not take word breaks into account, and may not be a perfect match, but should get you close.
You could alter this code to return the length rather than the actual substring and use that as your page size. Creating the textblock in code (with no display) actually performs pretty well (I do it in some table views with no noticeable lag). I wouldn't send all 120,000 words to this function, but a reasonable subset of some sort.
Once you have the ideal length you can use a RegEx to split the book into pages. There are examples on this site of RegEx that break on word boundaries after a specific length.
Another option, is to calculate page size ahead of time for each potential fontsize (and hardcode it with a switch statement). This could easily get crazy if you are allowing any font and any size combinations, and would be awful if you allowed mixed fonts/sizes, but would perform very well. Most likely you have a particular range of readable sizes, and just a few fonts. Creating a test app to calculate the text length of a page for each of these combinations wouldn't be that hard and would probably make your life easier - even if it doesn't "feel" right as a programmer :)
I didn't find any reference to this example from Microsoft called: "Principles of Pagination".
It has some interesting sample code running in Windows Phone.
http://msdn.microsoft.com/en-us/magazine/hh205757.aspx
You can also look this article about Page Transitions in Windows Phone and this other about the final touches in the E-Book project.
The code is downloadable: http://archive.msdn.microsoft.com/mag201111UIFrontiers/Release/ProjectReleases.aspx?ReleaseId=5776
You can query the FormattedText class that is used AFAIK inside textBlock. since this is the class being used to format text in preparation for Rendering, this is the most lower-level class available, and should be fast.
I am creating printouts in WPF using flow documents. These printouts are set in separate window where DocumentViewer is placed.
When user clicks print I would like to show a progress bar that informs about current page that is sending to the printer. How can I do this?
I'm not sure exactly where your print code is, or where you want the progress bar, but I did something similar to this recently. This will be in VB.net.
First of all, create a new progressbar in the same class as the code you use to send the page to the printer. Then, we're going to take advantage of the "top-down" order in a block of code to change the progress bar.
The progress bar's value should be set to "0" be default. Now, in the code for sending the page to the printer, you're going to increase the progressbar's value (such as with the code "MyProgressBar.Value = MyProgressBar.Value + 1"). Put this code in between each line of the code you want to show progress for.
I would change the "+ 1" part of the code, however, to another value, so your progress bar progresses equally after each step. If you have three lines of code, then use "+ 33" (100\3), four lines use "+ 25", etc.
Finally, at the end of the code, set "MyProgressBar.Value = 100"
This only works, however, if you have access to a code longer than one line. For one line of code, I'm not sure how this works, unless you can get to the block of code that line points to.
If you have to use code from another class, you may need to do something like...
Dim MyWindowWhereProgressIs As New MyWindowWhereProgressIs
And then, each time you need to change the value, try...
MyWindowWhereProgressIs.MyProgressBar.Value = MyWindowWhereProgressIs.MyProgressBar.Value + 1
I'm not entirely sure whether or not those last two lines of code will work, as I'm away from Visual Studio right now, but it is worth a shot.