Develop Reference

Render DMD in Unity3D

I want to render a custom display from an emulation. Think like a dot matrix display from pinball machines.
How would i effectively go about this? (Think about actually writing to a texture that size will probably run way too slow)
There has to be a good way to get this to render, but i have trouble finding a way that actually performs properly as well.

There are many options to do this but without further details (DMD screen resolution, number of colors, animated or not, etc) it's not easy to help. Here are a bunch of options popped into my mind, hope the one you are looking for is somewhere here :)
1) There was a similar question, you can find it along with the answer here
2) If you want to display text only, there's a wide range of sites offering DMD fonts for free, e.g. here
3) You can also edit/extend the font set you download and display 'special characters' as graphics, or just use the standard ASCII table for the purpose if that's enough for your needs. e.g. ▓ █ ╔ ═ ╗ and similar "drawing characters"
You can find inspiration and ASCII art (including animated ones) e.g. here
4) Might be slow (again, "depends") but you can go for bitmap and .SetPixels with a Texture2D and DrawTexture
5) A bit "hacky", but you can save your anim phases into either bitmap data/array (readonly/constant variables for example, or read from disc in a managed way, or draw with the help of a free asset from the store, like this one here, etc) and do Graphics.DrawTexture
6) If the thing you want to display is 100% static (i.e. it's not actual data like score, but "hardcoded" animations like "TILT" text or such), you can create a Sprite Animation
7) You can mix the above and e.g. go for a font (#2) to display dynamic data on a canvas, and play the static animation around it making it look like the whole thing is dynamic
Hm. That's all right off the top of my head :)
Hope this helps!

Simple test of image containing text in it against pre-defined template

I have a small image of a text in it, a screenshot from a small area in a console application. I need a simplest possible test to tell if it matches a pre-defined pattern. In other words, if text is exactly some specific word, let's say, "root".
Font is fixed, no rotations, but it should be robust to small offsets.
So, my template/pattern image is fixed:
And my test image can be this:
In case of negative result, I don't need to extract text from it or anything. So, I'm looking for the simplest test possible.
I tried to calculate number of white pixels in the image, but that's unreliable.

How to set "Resolution Unit" when regenerating\saving an image

I'm trying to investigate an issue I thinking I'm seeing in an application that generates a TIF image.
To do this I'm trying to regenerating\saving the image myself following this msdn Encoder.Compression example (except I'm using CompressionCCITT4).
The output file has a 'Resolution unit' = 2 but I would like to set that to 1.
Questions:
Any ideas how to do set the 'Resolution unit'?
Any ideas on the effect that would\should have on the image?
Thanks!

Disclaimer: Being a Java guy, I don't know how to set it using the library you describe. So I'll only answer question part 2:
Any ideas on the effect that would\should have on the image?
The quick answer is: None. It only matters when you import the image into a page-setting/layout program, word processor, print it, etc. But a lot of software simply assumes 72dpi in both x/y dimensions regardless.
Here's what the TIFF spec says:
Typically, TIFF pixel- editors do not care about the resolution, but applications (such as page layout programs) do care.
And:
1 = No absolute unit of measurement. Used for images that may have a non-square aspect ratio, but no meaningful absolute dimensions.
The drawback of ResolutionUnit=1 is that different applications will import the image
at different sizes. Even if the decision is arbitrary, it might be better to use dots per
inch or dots per centimeter, and to pick XResolution and YResolution so that the aspect ratio is correct and the maximum dimension of the image is about four inches (the “four” is arbitrary.)

How to detect image orientation (text)

My program is working with fax documents stored as separate bitmaps
I wonder if there is a way to detect automatically page orientation (vertical or horizontal) to show image preview for user in right order (meant rotate if neccesary)
Any advices much appreciated!
EDIT: Clarification:
When Faxmachine receives multi-page document it saves each page as separate TIFF file.
My app has built-in viewer displaying those files. All files are scaled to A4 format and saved in TIFF (so there is no change to detect orientation by height/width parameters)
My viewer displays images in portrait mode by default
What I'd like to do is automagically detect situation when org document was printed in landscape mode (eg wide Excel tables) then I'd like to show rotated preview for end user to speed up preview process
Obviously there are 4 possible fax orientation portrait / landscape x 2 kinds of rotations.
I'm even interested simplified solution detecting when org doc was landscape or portrait (I've noticed most of landscape docs needs to be rotated clockwise)
EDIT2: Idea
I think it might be some idea:
If I could draw horizontal and vertical lines and check if line doesn't cut any (black) point. Then we can compare what are more type of lines (horizontal or vertical) and his decides about page orientation.
What do you think ?

You could perform a Fast Fourier Transform (FFT) to convert your spatial image to a frequency/angle representation. Then find the angle with the most prominent frequency. It sounds complicated but it's not that hard, it's pretty efficient, and in effect it tests every possible angle at once, instead of being a hard-coded hack that only works for specific angles. Search for a sample implementation with search terms like Numerical Recipes and FFT.

You'd need OCR for that. Rolling your own OCR would be a bit difficult, but there might be library or something out there worth looking into? Also, even with good OCR, it's not a 100% reliable solution.

I wonder if there are some properties of text you could use to help you do this.
For instance based on a quick glance, there are far more vertical lines in text (l,j,k,m,n etc) than horizontal ones so maybe you could start with this.
But even detecting these isn't straightforward, you'd need to use some sort of filter like a Sobel or Prewitt. They both have horizontal and vertical versions, see here for more info.
Of course the vertical/horizontal lines of an excel spreadsheet would be the strongest edges so you'd have to ignore these and look only at the text.
Alternative: Can you not just give the user an easy way to rotate the images, like the arrows in Windows Picture viewer or just show 4 thumbnail previews they can click on. You might need to cache the 4 versions (if you are rotating) so it's quick, but only if speed turns out to be an issue?

Here's a paper entitled "Combined Script and Page Orientation Estimation using
the Tesseract OCR engine" [pdf]
I haven't been able to find an implementation of their work, but the approach looks good to me:
The basic idea behind the proposed approach is simple.
A shape classifier is trained on characters (classes) from all the scripts of interest. At run-time, the classifier is run independently on each connected component (CC) in the image and the process is repeated after rotating each CC into three other candidate orientations (90°, 180° and 270° from the input orientation).
The algorithm keeps track of the estimated number of characters in each script for a given orientation, and the accumulated classifier confidence score across all candidate orientations. The estimate of page orientation is chosen as the one with the highest cumulative confidence score, and the estimate of script is chosen as the one with the highest number of characters in that script for the best orientation estimate.

GraphicsUnit.Point, isn't converting well to PDF... GraphicsUnit.World is, but how can I convert it to Point?

I have some code in .Net to draw some text content using GDI+. I used GraphicsUnit.Point to size the text. It's working wonderfully on-screen, and even if Print it.
I've been asked to make a system that generates a PDF, and I got ComponentOne's PDF control. It has got similar interface to GDI+.
The problem is: Font sizes are not working. If I use GraphicsUnit.Point, the text is much smaller, and I am getting empty space below the text. When I use GraphicsUnit.World, the text is still small, but there's no extra empty space below the text.
I want to understand how to convert GraphicsUnit.World to GraphicsUnit.Point.
All help will be appreciated.
Thanks

After some Googeling and from what I know from personal experience with GDI+ and String drawing it comes down to DPI (Dots per Inch). Basically the different devices (and as far as GDI+ is concerned, PDF is probably a device) have different DPI values. Displays usually have something like 70 DPI. Printers use 72. I don't know what PDFs use, but it might be 100 (as this is a common value for device independence and would explain the smaller text).
Now, Points are defined as being 72 DPI. This is always true. What GDI+ should do, when drawing to a PDF with a different DPI is, to transform the string drawing accordingly. But this does not always work, especially with text.
The GraphicsUnit.World should (according to some googeling) be device independent and should look the same on all devices.

You're right, GraphicsUnit.World looks the same on print, and also on screen. My final solution was to use GraphicsUnit.World as the unit of measure, and shun points. I still don't know the conversion ratio, but I approximated the value till the look was okay.
For my purpose this was enough.