Class: XftFontDescription

• Inheritance
• Description
• Related information
• Class protocol
  • change & update
  • examples
  • initialization
  • instance creation
  • primitives
  • queries
  • utilities
• Instance protocol
  • accessing
  • accessing-private
  • converting
  • displaying
  • error reporting
  • finalization
  • getting a device font
  • initialization
  • primitives
  • queries-dimensions
  • release
  • testing
• Private classes

Inheritance:

   Object
   |
   +--FontDescription
      |
      +--XftFontDescription

Package:

stx:libview

Category:

Graphics-Support

Version:

rev: 1.131 date: 2019/06/21 21:51:35

user: cg

file: XftFontDescription.st directory: libview

module: stx stc-classLibrary: libview

Author:

Jan Vrany <jan.vrany@fit.cvut.cz>

Description:

WARNING: Unfinished.

Experimental implementation of custom font rendered using
Xft library (UNIX / X Window only), To actually use it,
add following definitions to the end of stx/configurations/myConf
(works on Ubuntu 12.10)

--- snip ---
XDEFS+=-DXFT
XINCLUDE+=$(shell pkg-config --cflags xft)
LIB_XFT=-l:libXft.so.2 -l:libfontconfig.so.1
--- snip --

NOTE: This class should be named XftFont, however then
there would be a name clash with XftFont structure
defined in Xft.h - therefore the class is named
XftFontDescription to avoid that name clash.



[instance variables:]

[class variables:]

Related information:

Class protocol:

 aboutToDestroyViewWithDevice: aDevice id: aWindowId

a view is going to be destroyed.
Have to disassociate the XftDrawId from the drawableId aWindowId

 example1

XftFontDescription example1

 example2

XftFontDescription example2

 example3

XftFontDescription example2

 flushListOfAvailableFonts

XftFontDescription flushListOfAvailableFonts

 initialize

Invoked at system start or when the class is dynamically loaded.

 for: aFontOrFontDescription

 new

 xftAvailable

 xftFontClose: fontIdArg displayId: displayId

 xftFontGetAscent: fontIdArg

 xftFontGetDescent: fontIdArg

 xftFontGetHeight: fontIdArg

 xftFontGetMaxAdvanceWidth: fontIdArg

 xftFontGetPattern: fontIdArg

 listOfAvailableFonts

uses fc-list to get a list of available fontDescriptions

usage example(s):

XftFontDescription flushListOfAvailableFonts. XftFontDescription listOfAvailableFonts

 fixedLC_CTYPE

to suppress the disturbing warning messages from fontconfig,
if LC_CTYPE is wrong (osx problem only?)

Instance protocol:

 encoding

 face

 fullName

 graphicsDevice

(comment from inherited method)
return the device I am on

 maxCode

 maxCode: something

 minCode

 minCode: something

 style

 weight: aNumber

set the weight. The face is the string representation of weight.

 getXftFontId

 setFontId: fontIdArg

 asNonXftFont

in some situations, we do not want an Xft font.
Return an abstract fontDescription corresponding to the receiver

 displayString: aString from: index1 to: index2 x: x y: y in: aGC opaque: opaque

this is only called for fonts which have a nil fontId,
and therefore use the replacementFont. Should never be called
for non-replacement fonts.

 primitiveFailed

 primitiveFailed: errorString

 finalize

 installInDeviceForGCId: aGCId

install the font for aGCId

 onDevice: aGraphicsDevice

Create a new XftFont representing the closes font as
myself on aDevice; if one already exists, return the one.

 onDevice: aGraphicsDevice ifAbsent: aBlock

Create a new XftFont representing the closest font as
myself on aDevice; if one already exists, return the one.

usage example(s):

(XftFontDescription family:'monospace' size:16) onDevice:Screen current ifAbsent:[self halt].

 initialize

Invoked when a new instance is created.

 isScaledFont

 setDevice: deviceArg patternId: patternIdArg fontId: fontIdArg

name := patternIdArg get: 'fullname' index: 0.

 xftTextExtents: displayIdArg string: aString from: start to: stop into: extentsArrayOrNil

get the extents of aString.
Answer thr width of aString (in reality the xOff).
If extentArrayOrNil is an Array, fill is with the extent info:
#(width height x y xOff yOff ascent descent).

 ascent

return the ascent - the number of pixels above the baseLine.

 descent

return the descent - the number of pixels below the baseLine.

 getFontMetrics

 getFontResolution

 height

return the height - the number of pixels above plus below the baseLine.

 isFixedWidth

return true, if this is a fixed pitch font
(i.e. all characters are of the same width).
Also called monospaced fonts

 maxAscent

return the font's maximum-ascent (i.e. the maximum of all characters);
That is the number of units (usually pixels) above the baseline.

 maxDescent

return the font's maximum-descent (i.e. the maximum of all characters);
That is the number of units (usually pixels) below the baseline.

 maxWidth

return the font's maximum-width character (i.e. the maximum of all characters);
That is a number of units (usually pixels).

 patternStringForId: patternIdArg

 width

return the font's characters width;
That is a number of units (usually pixels).
For variable pitch fonts, the width of the space character is returned.
For fixed fonts, this is the same as minWidth or maxWidth (or any character).
The receiver must be associated to a device, for this query to be legal.

 widthOf: aString from: start to: stop

return the width of a sub string

 releaseFromDevice

I am no longer available on the device

 restored

flush device handles when restored

 isAlienFont

my GraphicsContext knows how to disply strings in my font.
Alien fonts are eg. Hershey or Bitmap fonts, which are drawn by st/x itself.

 isXftFont

anwer true, if this is an Xft font.
Sure, I am

Private classes:

    FCFontListParser
    FCPatternHandle
    XftDrawHandle
    XftFontHandle