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glyph_explore.py
import ui,ctypes,string,os
from objc_util import *
UIFont=ObjCClass('UIFont') # This is not used anymore
CAKeyframeAnimation=ObjCClass('CAKeyframeAnimation') # Initialize object to use in PathAnimation class
# Magic
if sizeof(ctypes.c_size_t)==8:
CGFloat=ctypes.c_double
else:
CGFloat=ctypes.c_float
CGGlyph=ctypes.c_ushort
import sys
import logging
# From line 18 to 48 is the logger. This is just for debugging right?
logger = logging.getLogger('glyph_explore')
if not logger.handlers:
hdlr = logging.FileHandler('glyphlog.txt','w')
formatter = logging.Formatter('%(asctime)s %(levelname)s %(message)s')
hdlr.setFormatter(formatter)
logger.addHandler(hdlr)
#logger.setLevel(logging.INFO)
logger.setLevel(logging.DEBUG)
logger.info('logging started')
import ctypes # Is this just doubled? Safe to delete.
class loggingCDLL(ctypes.CDLL):
'''CDLL that logs all calls and arguments'''
class _FuncPtr(ctypes._CFuncPtr):
_flags_ = ctypes._FUNCFLAG_CDECL | ctypes._FUNCFLAG_USE_ERRNO
_restype_ = ctypes.c_int
def __call__(self, *args):
logger.debug('call:'+ self.__name__)
logger.debug('. args:'+args.__repr__())
ret = ctypes._CFuncPtr.__call__(self, *args)
logger.debug('. ret:'+ret.__repr__())
return ret
def __init__(self, *args, **kw):
ctypes.CDLL.__init__(self, *args, **kw)
del self._FuncPtr
c=loggingCDLL(None)
# End of logger
# Is this important for the ctypes to work properly?
def errcheck(ret,func,args):
if func.restype==c_void_p:
if not ret:
raise Exception('{} returned void pointer with args\n{}'.format(func.__name__,args))
return ret
# Downloading the file. It would be nice to know how to pick a file already installed on the iPad. "<System>" might be a variable font too.
file='PanvariaGX_downloaded.ttf'
if not os.path.exists(file):
print('downloading font')
import requests
r=requests.get('https://www.dropbox.com/s/cbeqxxuk9dg8jz1/PanvariaGX.ttf?dl=1')
with open(file,'wb') as f:
f.write(r.content)
# Magic
c.CTFontCreatePathForGlyph.restype = c_void_p
c.CTFontCreatePathForGlyph.argtypes = [c_void_p, CGGlyph, c_void_p]
c.CTFontCreatePathForGlyph.errcheck=errcheck
c.CTFontCreateWithGraphicsFont.restype=c_void_p
c.CTFontCreateWithGraphicsFont.argtypes=[c_void_p, CGFloat, c_void_p, c_void_p]
c.CTFontCreateWithGraphicsFont.errcheck=errcheck
c.CGDataProviderCreateWithCFData.restype=c_void_p
c.CGDataProviderCreateWithCFData.argtypes=[c_void_p]
c.CGDataProviderCreateWithCFData.errcheck=errcheck
c.CGFontCreateWithDataProvider.restype=c_void_p
c.CGFontCreateWithDataProvider.argtypes=[c_void_p]
c.CGFontCreateWithDataProvider.errcheck=errcheck
c.CFRelease.argtypes=[c_void_p]
c.CFRelease.restype=None
c.CGFontCopyVariations.restype=c_void_p
c.CGFontCopyVariations.argtypes=[c_void_p]
c.CGFontCopyVariations.errcheck=errcheck
c.CGFontCopyVariationAxes.restype=c_void_p
c.CGFontCopyVariationAxes.argtypes=[c_void_p]
c.CGFontCopyVariationAxes.errcheck=errcheck
c.CGFontCreateCopyWithVariations.argtypes=[c_void_p, c_void_p]
c.CGFontCreateCopyWithVariations.restype=c_void_p
c.CGFontCreateCopyWithVariations.errcheck=errcheck
createPath=c.CTFontCreatePathForGlyph # Initiates the object to create a path for specified glyph
glyphs_list=[] # List of paths extracted from the variable font in setupGlyphs()
# Animating paths; well, we have accessed the font, can't we "just" type the letters with it instead of drawing paths like here?
class PathAnimation(object):
def __init__(self,pathList,variation_values):
a=CAKeyframeAnimation.animationWithKeyPath_('path')
a.values=ns([p.CGPath() for p in pathList])
a.duration=len(pathList)
a.removedOnCompletion=False
self.animation=a
self.variation_values=variation_values
self._len=len(pathList)
@on_main_thread
def copyToLayer(self,layer):
'''Given a CAShapeLayer, add animation'''
layer.timeOffset=0
layer.speed=0
layer.addAnimation(self.animation, forKey='a')
def __len__(self):
return self._len
import os
def setupGlyphs(size=512,axis=0, letter='a'):
'''return a list of paths for letter=letter, size=size, = variation axis =axis
returns [paths, variation_values]
'''
if not os.path.exists(file):
raise FileNotFoundError()
inData=NSData.dataWithContentsOfFile_(os.path.abspath(file)) # Some kind of data container for the file?
if not inData:
raise Exception('No data in file')
provider = ObjCInstance(c.CGDataProviderCreateWithCFData(inData)); # creating another data container/provider for use with core graphics?
basefont = c.CGFontCreateWithDataProvider(provider); # creating font object using the provider
c.CFRelease(provider) # getting rid of the provider?
vardict=ObjCInstance(c.CGFontCopyVariations(basefont)) # Variation Dictionary – why are these from Core Graphics and not from Core Text? Just a matter of choice? I understand the basefont is also a CG object but i guess i could've been a CT object as well?
varaxes=ObjCInstance(c.CGFontCopyVariationAxes(basefont)) # Variation Axes – Same as before, this could be from CT?
glphcode=ObjCInstance(c.CTFontCreateWithGraphicsFont(basefont,size,None, None)).glyphWithName_(letter) # glyph from the basefont (without taking variantions into account – this might be important because variable fonts might substitute glyphs across the axes, i might understood that wrong)
rng=(varaxes[0]['kCGFontVariationAxisMinValue'].intValue(),
varaxes[0]['kCGFontVariationAxisMaxValue'].intValue()) # Read the maximum and minimum value of axis, this could also be from CT right?: https://developer.apple.com/reference/coretext/ctfont/font_variation_axis_dictionary_keys
varvalues=[]
# Creating a list of UIBezierPaths using the variable font; i don't understand how things exactly work but i'm hoping that it's possible to use like a layout engine to set text using the variable font. This looks like going backwards to me.
for i in range(rng[0],rng[1]+1,10):
vardict.setValue_forKey_(i,str(varaxes[0]['kCGFontVariationAxisName']))
cgfont=ObjCInstance(c.CGFontCreateCopyWithVariations(basefont,vardict)) # Here it is necessary to use CG as there are no function to do this step in CT?
ctfont=ObjCInstance(c.CTFontCreateWithGraphicsFont(cgfont,size,None, None)) # When i print this, i get what looks like font instances – font width different attributes on wght axis, it is even named like that which makes sense as the weight axis is named wght in the font.
t=CGAffineTransform(1,0,0,-1,0*ctfont.advancementForGlyph(glphcode).width,ctfont.capHeight())
glyphs_list.append(UIBezierPath.bezierPathWithCGPath_(ObjCInstance(
createPath(ctfont,glphcode,pointer(t)))))
varvalues.append(i)
c.CFRelease(basefont)
return (glyphs_list, varvalues)
# Just a method to get a proper color value to use with CAShapeLayer
def _get_CGColor(color):
"""Get a CGColor from a wide range of formats."""
return UIColor.colorWithRed_green_blue_alpha_(
*ui.parse_color(color)
).CGColor()
# I understand the animation part though i'd like to set type with a layout engine. But now that i think of it there might be performance issues with this???
class AniPathView(ui.View):
'''animates a path based on touch'''
def __init__(self, ani, color="#21abed",
line_width=1, line_color="#0f210f",
*args, **kwargs):
super().__init__(self, *args, **kwargs)
self.bg_color='white'
# Draw the full path on one layer
self._layer = ObjCClass("CAShapeLayer").new()
self._layer.setStrokeColor_(_get_CGColor(line_color))
self._layer.setFillColor_(_get_CGColor(color))
self._layer.setLineWidth_(line_width)
self.setup_layer()
ani.copyToLayer(self._layer)
self.variation_values=ani.variation_values
def setup_layer(self):
ObjCInstance(self).layer().addSublayer_(self._layer)
def curpath(self):
'''get current path, interpolated'''
try:
self._layer.presentationLayer().path()
except AttributeError:
return self._path
def touch_began(self,touch):
i=(touch.location.x)/(self.width)*len(glyphs_list)
if i<0:
i=0
val=self.variation_values[i]
elif i>len(glyphs_list)-1:
i=len(glyphs_list)-1
val=self.variation_values[i]
else:
val=self.variation_values[int(i)]+(i-int(i))*(self.variation_values[int(i)+1]-self.variation_values[int(i)])
self.name='Variation value: {:0.2f}'.format(val)
self._layer.timeOffset=i
def touch_moved(self,touch):
self.touch_began(touch)
if __name__=='__main__':
[glyphs_list, variation_values]=setupGlyphs(size=512,letter='b')
a=PathAnimation(glyphs_list,variation_values)
pv=AniPathView(a)
pv.present()
@jsbain

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@jsbain jsbain commented Apr 8, 2017

18: correct. delete if desired.
50: not required, but could prevent using a null pointer in case you pass in bad arguments and a function returns null., that way, an exception is raised, rather than trying to pass on to next function, and crashing
60: i think one of the early versions used UIFont.getFontForName or something to get a system font.

If you want to type the font, i am not sure if font type animatable. it should be possible to use in a textfield.

I did not see the CT methods to do font variations, but will look

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@jsbain jsbain commented Apr 8, 2017

@dyyybek, looks like font weight or type is not animateable, in a textfield or catextlayer. weight maybe is in a webview, not sure.

I am not sure if your goal is simply to be able to change the font, say a slider for each variation axis, or trying to smoothly animate. It is also not obvious to me where font variations get used in CT

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