There are proportional fonts (i.e. not monospaced) that nevertheless provide monospaced numbers. E.g. see this Excel screenshot using Arial:
Note how the numbers are nicely aligned. How can I find out programmatically (probably WinAPI) if a font supports this feature?
You won't find an API for that because there isn't any specific metadata value within the font file to indicate "the glyphs for digits in this font have fixed width". Some fonts may support both proportional and fixed-width ("lining") digits, in which case the font is likely to support the 'lnum' OpenType Layout feature. You should pick a font that supports this feature and then explicitly activate that feature when drawing the text.
Related
Windows has font substitution logic - if you try to render a character which isn't in the currently selected font, Windows would quietly pull a glyph from another font where a glyph
for that character is present.
Imagine the current font is, for example, a serif one. When picking the source for substitution, will Windows prefer serif fonts to sans-serif ones and vice versa?
As far as I know Windows uses the PANOSE values of a font to find a suitable replacement. Those values categorise the font into descriptive values, and there are in fact multiple values to describe the serif style.
The problem is, that only font with PANOSE values can be replaced by fonts with PANOSE values.
So if the font you’re using doesn’t have PANOSE values, Windows can’t find a replacement. Also, if it does and there are no fonts with fitting PANOSE values in your collection, you will get bad substitutions.
However, the PANOSE system was established for font replacement for PostScript printers.
I’m not sure how other people do it but I don’t provide all the information to the PANOSE values in fonts I produce (unless its explicitly asked). I stick to familytype, weight and letterform (though I use this only to decide between upright or italic).
I am now converting a project's render engine from GDI to D2D. The GDI use "CreateFontIndirect" to assign font size "-13", font family "Segeo UI". The D2D use "CreateTextFormat" to assign font size "13", font family "Segeo UI". The effect is shown as follow picture:
In GDI case, the system didn't find chinese character in "Segeo UI", it will find in regedit "SystemLink" to locate the chinese font, on my machine is "YaHei". But In D2D case, the system didn't find "YaHei", Which chinese font it will choose to draw, How does it work?
It works according to DirectWrite layout logic. See IDWriteTextLayout2::SetFontFallback(), you'll be able to provide your own fallback implementation, if default configuration is not satisfactory.
Basically, layout object will call your custom fallback methods to map characters to fonts, you can then detect which characters you want to map to which font, potentially reusing system fallback implementation for cases you don't care about.
FreeType has font metrics for the underline position, but I can't seem to find any metrics for the strikethrough position. How do text engines usually compute this value? Should I just put it at 1/3*ascent or whatever looks good? I suppose that for Latin at least this should be 1/2*height of "m" but I'm looking for a more general solution.
This information is not provided for all the various font formats supported by Freetype; so it is not exposed on the "main" interface.
In the (common but not universal) case of TrueType or OpenType fonts it can be retrieved in the TT_OS2 table, fields yStrikeoutSize and yStrikeoutPosition; you should be prepared for the table to be lacking, or yStrikeoutSize to be null or negative thus unusable.
I do not remember of an equivalent for plain Postscript fonts (.pfb/.pfa, even in .afm.)
The various bitmap formats might have the information available; an example is strike_out in Windows FNT; notice this is the position, while the size defaults to be the same as underlining. Basically every format is alone here.
I have a NSPopUpButton which contains either English or Japanese Strings read from a plist file according to the System's Language. Now when the Language is English I am able to change the font size by using code such as -
[auxStatePopup setFont: [NSFont fontWithName:#"Helvetica-BoldOblique" size:10.0]];
but Using such technique I am not able to change Japanese font size even if I tried by setting some Japanese font name which I googled and found out.
I want to do that because Japanese characters move slightly up when used. I intend to manipulate that upward movement by decreasing font size.
Thanks for any help..
OR
any way to move text in NSPopupButton downwards?
My impression is that the two samples are not using the same font. Please try to put a text with characters from both sets and see what happens.
Also try not to customize the font size and even the font face.
I also suspect that the text rendering engine may had overridden some of your changes due to the text length. iOS text rendering may try to change the font size of letter spacing if the text does not fit the control. So make some tests with shorter texts.
BTW, I think that you were mean to say that you want bigger font size for Japanese not smaller. In the screenshots the Japanese text is already too small to be properly read by anyone.
Suppose you have a string with text in two or more scripts. When you use a GDI function like TextOut, (modern versions of) Windows will do "font-linking". That is, GDI will draw what it can with your selected font and draw the rest in an appropriate font that it chooses automagically. For example, if part of your text is in English (using the Roman alphabet), and part of it is Chinese (using CJK characters), and you have Arial selected, the English portion will be drawn in Arial, and the Chinese portion will be drawn in another font that has the CJK glyphs.
My question is, is there a way to determine which fonts TextOut will choose (or did choose) for the font linking?
I have to draw some text with the low-level Uniscribe API, which doesn't do automatic font-linking. I've implemented my own font-linking, but sometimes my algorithm chooses a different font than TextOut does for the same text. I'm trying to understand the Windows algorithm better, but I'm not real good at identifying fonts on sight (especially in unfamiliar scripts).
The font is selected by a registry entry. It is well described in this article. Quoting the relevant part:
If font linking is enabled on your
device, you can examine the registry
by enumerating the subkeys of the
registry key at
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows
NT\CurrentVersion\FontLink\SystemLink
to determine the mappings of linked
fonts to base fonts. You can add links
by using Regedit to create additional
subkeys.