I want to add an Unicode Symbol as a list widget item in QT. (Particularly this item : http://www.fileformat.info/info/unicode/char/25B6/index.htm )
I'm using following method for this :
this->addItem( new QListWidgetItem( QString::fromUtf8("\u25B6")) ) ;
But when I open the widget I see only a blank rectangle in place of this unicode symbol. I even tried other unicode symbols too, but they too are showing only blank rectangle.
What's wrong in this method?
EDIT: After following the answer, I changed the font of QListWidgetItem to Serif and it worked.
There are several possibilities, but the most probable one is that the font you are using doesn't implement the glyph at all. Can you see the triangle in eg. an editor when using the same font as your Qt font?
Edit: The fonts (which are stored in the system's font files) are the commands to draw the images of each character on the screen). Many (if not all) fonts are incomplete, which means they are not able to represent all 2,000,000,000+ codes which are possible in the unicode (the numbers which represent the characters). The files would just be to large to be practical.
The triangles you want printed are fairly basic, and should be available in many font sets. Liberation Sans and Liberation Serif are two I just checked.
I suspect Qt uses the font set of the system, which can probably be changed in the System Settings somewhere. If you tell us which distribution you are using (i.e. Ubuntu, Debian, ...), maybe we can help.
Related
I am attempting to put the final touches on a maze program I have been writing. I have used Unicode to delimit the walls and paths however because of the (horizontal) line spacing I can't quite get it to look compact enough. I have attached two screenshots. I'm just escaping the newline "\n" in order to print each row. Can the distance between lines be adjusted or am I stuck with this "gappy" representation?
My output:
What I am trying to closely represent:
Assuming you aren't printing double newlines, this is outside the scope of standard C++, it does not provide facilities for controlling terminal in a standard way.
Solutions:
You could provide a launcher script, which opens a new terminal window with specific font and runs your app in it.
You could use some platform specific method to change background color (ANSI codes work in unixy terminals, or use Win32 API for Windows terminal, ncurses library on Unix-like environments) and print just spaces in different colors.
Use a GUI library/framework to get complete control on what is drawn (I'd use Qt for C++ GUI app).
TBH if you want pixel-accurate rendering use a proper rendering API, such as OpenGL.
From a text rendering point of view you don't say what you are rendering to. Assuming something like a terminal console or shell window then the layout beyond characters and newlines is nothing to do with your program; the visual representation is entirely determined by the shell you are rendering to.
Firstly, check that you are genuinely printing a line per maze scan line, and not interleaving with spurious newlines. Assuming that is ruled out, the problem is that the unicode glyph is not a full block. So you must somehow set the font or choose another glyph which is a full block.
Usually console windows are 80 characters wide by 22 or 24 characters high, and characters are 8 pixels wide by 19 pixels high. So it's very far from a square grid, and you might want to bias the maze to reflect that and provide a better visual appearance (eg make 2 pixel-wide vertical corridors much more common than 2-pievel wide horizontal corridors).
Do check the binary image library fonts, you might find them useful.
https://github.com/MalcolmMcLean/binaryimagelibrary
In the pluma editor (on Linux) and sometimes in a web browser, for unrecognized characters, I see a little box with the Unicode value inside. I have seen 4 digit and 6 digit code boxes.
I WANT these little boxes with numbers (as appropriate.) How do I get these to display in a C++ Qt program?
Can you get a two digit box?
Here is an example, as shown in the pluma editor:
These glyphs are produced by the default fallback font for the system/platform – they are not inherently a feature of Qt.
If you want all characters to be rendered this way, you can use the Unicode BMP Fallback font, which has glyphs for all code points in the basic multilingual plane as hex digits in a box.
I am working on an embedded platform (STM32F407) with a TFT LCD as a display (480x800px) and would like to make my user interface somewhat customizable to the end user. I figured the best source of fonts would be windows compatible as their the most common.
My current implementation uses my own custom drawn font in a binary format and a descriptor table giving the character width and ascii value but having to draw my own font bit by bit is tedious.
I would like to read in a True Type Font file from an SD card and be able to use the different sized glyphs inside it but I have not seen a strait forward implementation on how to actually achieve this magic. Can somebody point me to a good c/c++ example of what I am looking for?
Even better as a way to iron out the kinks I would like to make a simple gcc command line program that will print out my input with a selected font using '#' as pixels. That way I can just worry about implementation and not any other random bugs that might pop up.
Can anybody help me out?
Perhaps you can use the Freetype library.
As duskwuff says: TTF is primarily a vector format, would need to write a renderer. Better off using an image file to define the font, or using a bitmap font format like FNT (Windows) or BDF (UNIX).
Here is my answer to my own question: AngelCode's BMFont & Useage. This makes choosing selective characters from the installed char set, mix in a font and exports an image with a map file to each character. Simple to use.
I'm working on a Qt project and I've noticed a persistent problem with some GUI forms. The form looks fine on KDE (bottom picture) and Windows , but when the app runs on anything GNOME3-based (like Unity or GNOME3 itself) some parts of the form are hidden from view. (Top picture, everything below the Sort Ascending radio button is cut off)
The problem seems to be with how Qt layouts handle large font sizes. If the user is using normal-sized system font (<= 10pt) everything works fine. If they are using larger fonts, the form is not large enough to accommodate everything. Other forms affected by this bug are merely crowded, but that isn't as serious as having vital controls out of bounds. The layout doesn't want to resize itself to take advantage of new space if I enlarge the dialog. Is there an easy way to make it do this or do I need to hard-code it? Originally the code prevented dialog resizing during runtime, but restoring that functionality didn't fix the bug. Even if the dialog can expand, the problem is the layout won't expand with it.
Up until now, I've made all affected forms oversized to compensate for this bug, but it looks strange to have the dialogs much bigger than they need to be on Windows and KDE systems where the font is the proper size. Is there a way to cause an affected dialog/layout to resize itself so everything fits properly at runtime? If so, how would the program detect it when parts of the GUI are out of bounds? I would prefer not to force a certain font size (some people may prefer large fonts due to vision problems).
Thanks in advance for help.
The fix for this is using a different approach when displaying forms. A more dynamic way as I'll describe. I've successfully used this approach on Windows with 96 and very high DPI modes (over 120).
1.
Query the OS and get the user's chosen font for a particular system item; say the font used for the window caption or system dialog boxes. Also you could allow the user to choose their font later if they desired. Use True Type fonts when doing this if possible.
2.
Using that font, construct a string object that you'll use for a label or edit control (I don't know what this is for QT, for Windows it is GetTextExtentPoint32) and pass it to a system function to determine the width and height of the string for your environment.
3.
Given the above value, place the control and dynamically resize the form with the padding all around the control as you like. For buttons you might always add a certain percentage of pixels above and below the button to taste.
4.
For graphical elements like Bitmaps and jpegs, again query the OS for the current DPI settings of the monitor and use larger, pre-made resources. Naturally, all text around theses elements will be dynamically placed on the fly.
Note that on Windows you'll need to mark your exe as high dpi aware using a manifest.
I'm rendering some text using pangomm, but the font that I am using doesn't have glyphs for parts of the text (in this case, there is some Japanese mixed in with English). Pango seems to render the text correctly using a fallback font.
How can I determine which font is being used as the fallback?
Actually the font selection is based on the selected Pango font backend. Mostly used (I think) is Fontconfig.
You fonts are basically always chosen by looking at the fonts Unicode coverage, meaning that Fontconfig tries to choose the font that covers the letters in the text you want to render best.
Not knowing if your problem applies to Fontconfig, I won't go into to much detail. But if so, have a look at http://www.freedesktop.org/software/fontconfig/fontconfig-user.html, especially the section on 'font matching'.
Feel free to ask again.