I am trying to convert a string into Code39 barcode. To increase the reliability I am trying to increase the font size of barcode from 40 to 60. Would this cause any issue as the width and height of the bars will change compared to the previous version of font 40?
No, the scanner reads the ratio between the width of the symbols. As long as they both scale the same way, you're fine. I doubt that you'll see increased reliability. I hope you'll post results.
Related
I've been looking at this page, as well as this code example and I've noticed that the x_advance, y_advance, x_offset and y_offset fields in hb_glyph_position_t are of the type hb_position_t, which is an alias to int32_t. I haven't found any documentation about which units are used for these fields. The examples above suggest that they're 64ths of something, but that's all I can infer.
Does anyone else know the exact unit implied by hb_position_t?
It is in input font size units (say pixels).
The idea there is you multiply the input font size by 64 then you divide the position by 64 after the shaping so you will be in control of how much sub pixel precision you need.
I am new to the field of medical imaging - and trying to solve this (potentially basic problem). For a machine learning purpose, I am trying to standardize and normalize a library of DICOM images, to ensure that all images have the same rotation and are at the same scale (e.g. in mm). I have been playing around with the Mango viewer, and understand that one can create transformation matrices that might be helpful in this regard. I have however the following basic questions:
I would have thought that a scaling of the image would have changed the pixel spacing in the image header. Does this tag not provide the distance between pixels, and should this not change as a result of scaling?
What is the easiest way to standardize a library of images (ideally in python)? Is it possible and should one extract a mean pixel spacing across all images, and then scaling all images to match that mean? or is there a smarter way to ensure consistency in scaling and rotation?
Many thanks in advance, W
Does this tag not provide the distance between pixels, and should this
not change as a result of scaling?
Think of the image voxels as fixed units of space, which are sampling your image. When you apply your transform, you are translating/rotating/scaling your image around within these fixed units of space. That is, the size and shape of the voxels doesn't change. They just sample different parts of your image.
You can resample your image by making your voxels bigger or smaller or changing their shape (pixel spacing), but this can be independent of the transform you are applying to the image.
What is the easiest way to standardize a library of images (ideally in
python)?
One option is FSL-FLIRT, although it only accepts data in NIFTI format, so you'd have to convert your DICOMs to NIFTI. There is also this Python interface to FSL.
Is it possible and should one extract a mean pixel spacing across all
images, and then scaling all images to match that mean? or is there a
smarter way to ensure consistency in scaling and rotation?
I think you'd just to have pick a reference image to register all your other images too. There's no right answer: picking the highest resolution image/voxel dimensions or an average or some resampling into some other set of dimensions all sound reasonable.
I am going to print from the browser to a receipt printer. I want to support 58mm --> full size paper using responsive design. I used: http://www.unitconversion.org/typography/pixels-x-to-millimeters-conversion.html and it says 58 mm is approx. 219 pixels.
Is this an accurate way to measure pixels in the browser?
That converter is misleading - it can produce only approximations (or at the very best, results that work for your specific display), but never generally accurate results.
The number of pixels per mm (or any other physical unit) will vary from display to display, as different displays will have a different number of differently sized pixels. See "Pixel Density" in Wikipedia.
You can specify physical measures in CSS and when printing they should come out OK if the browser and the printer driver are handling things right:
.mysheet { width: 19.2cm; height: 8cm; }
Some Browser/OS/display combinations (I don't know which protocols do this) apparently also can interpret physical measures and render them in their correct size on screen.
I have my own video source and using VMR7. When I use 24 color depth, my graph contains Color Space Converter filter which converts 24 bits to ARGB32. Everything works fine. When I use 32 bit color depth, my image looks desintegrated. In this case my source produces RGB32 images and passes them directly to VMR7 without color conversion. During window sizing I noticed that when destination height is changing the image becomes "integrated" (normal) in some specific value of destination height. I do not know where is the problem. Here are the example photos: http://talbot.szm.com/desintegrated.jpg and http://talbot.szm.com/integrated.jpg
Thank you for your help.
You need to check for a MediaType change in your FillBuffer method.
HRESULT hr = pSample->GetMediaType((AM_MEDIA_TYPE**)&pmt);
if (S_OK == hr)
{
SetMediaType(pmt);
DeleteMediaType(pmt);
}
Depending on your graphic you get different width for your buffer. This means, you connect with an image width of 1000 pixels but with the first sample you get a new width for your buffer. In my example it was 1024px.
Now you have the new image size in the BitmapInfoHeader.biWidth and got the old size in the VideoInfoHeader.rcSource. So one line of your image has a size of 1024 pixels and not 1000 pixels. If you don't remember this you can sometimes get pictures like you.
How do I determine the number of characters in a particular font will fit to the screen?
Have a look at QFontMetrics. Using this, you can determine, among other things, the width of a particular string:
QFontMetrics metrics(myFont);
int width = metrics.width(myString);
Is this what you want?
Note: It is not possible to find the number of characters of a particular font that will fit on the screen since not all fonts are monospace. So the number of characters will depend on the actual characters.
you can also use QFontMetrics::elidedText passing available space (remember to reduce it with margins/paddings. Then call length on result string