ldo/harfpy

Python wrapper for HarfBuzz

harfpy's Issues

Access violation

I store a hb.Font and reuse it to redo shaping on new inputs, and it seems I randomly get bad access or garbage results after a few times reusing the hb.Font.

Traceback (most recent call last):
  File "c:\users\admin\downloads\trufont\lib\trufont\controls\glyphCanvasView.py", line 342, in keyPressEvent
    self._redirectEvent(event, self._currentTool.keyPressEvent)
  File "c:\users\admin\downloads\trufont\lib\trufont\controls\glyphCanvasView.py", line 465, in _redirectEvent
    callback(event)
  File "c:\users\admin\downloads\trufont\lib\trufont\drawingTools\textTool.py", line 119, in keyPressEvent
    self.layoutLine.insert(text)
  File "c:\users\admin\downloads\trufont\lib\trufont\objects\layoutLine.py", line 99, in insert
    self.updateView()
  File "c:\users\admin\downloads\trufont\lib\trufont\objects\layoutLine.py", line 164, in updateView
    self._shapeAndSetText()
  File "c:\users\admin\downloads\trufont\lib\trufont\objects\layoutLine.py", line 142, in _shapeAndSetText
    records = self.engine.process(self._inputString.tounicode())
  File "c:\users\admin\downloads\trufont\lib\trufont\objects\layoutEngine.py", line 165, in process
    hb.shape(self._hbFont, buf)
  File "c:\users\admin\downloads\harfpy\harfbuzz.py", line 4009, in shape
    hb.hb_shape(font._hbobj, buffer._hbobj, c_features, nr_features)
OSError: exception: access violation reading 0x130945F6

segfault on python exit if I don't manually del hb_font instance

Take this simple helloworld.py snippet:

import freetype2
import harfbuzz as hb

ft = freetype2.Library()
text_line = "abc"
buf = hb.Buffer.create()
buf.add_str(text_line, 0, len(text_line))
buf.guess_segment_properties()
ft_face = ft.new_face("/Users/cosimolupo/Desktop/test.ttf")
ft_face.set_char_size(size=1, resolution=72)
hb_font = hb.Font.ft_create(ft_face)
hb.shape(hb_font, buf)
print(
    "buf.glyph_infos = %s\n\n"
    "glyph_positions = %s" % (
        buf.glyph_infos, buf.glyph_positions
    )
)
# if I don't delete hb_font, I get "Segmentation fault: 11"
del hb_font

I noticed that, if I don't manually delete the hb_font instance myself, python will abort with a Segmentation fault 11 immediately before exit, while it's destroying the __main__ module.

The signature of python font funcs callbacks is different from C

Take for example glyph advance function, the documentation says:

def get_glyph_v_advance(self, font_data, glyph, user_data)

where self is the FontFuncs instance and font_data was what was passed to set_font_funcs for the Font, and return a float.

But in C the first argument in the font itself, which is needed here since the glyph advance (in font units) should be multiplied by the font scale.

'HARFBUZZ' has no attribute 'message_func_t'

I got this error message while trying to set up a debugger function on the Buffer object:

Traceback (most recent call last):
  File "harfbuzz__.py", line 47, in <module>
    shape_dat(*sys.argv[1:])
  File "harfbuzz__.py", line 28, in shape_dat
    buf.set_message_func(debugger, None, None)
  File "c:\users\admin\downloads\harfpy\harfbuzz.py", line 772, in set_callback
    wrap_callback_func = def_wrap_callback_func(self, callback_func, user_data)
  File "c:\users\admin\downloads\harfpy\harfbuzz.py", line 2484, in def_wrap_message_func
    @HB.message_func_t
AttributeError: type object 'HARFBUZZ' has no attribute 'message_func_t'

Maybe I'm misusing the API, but thought I would post this.

Could you upload to PyPI?

Hi there!

I am using harfpy and python_freetype in the example code for a book I am writing. You can read it at https://ralsina.gitlab.io/boxes-book/ and I was wondering if you could upload them to PyPI? Makes explaining requirements.txt simpler.

Thanks in advance!

Which harfbuz shared library version should be used with harfpy?

When run I am receiving function not found error.

Porting to OSX

Making this binding work in OSX requires a tiny change. When dynamically loading the library
on OSX the name is different:

hb = ct.cdll.LoadLibrary("libharfbuzz.0.dylib")

Other than that, it works. If you are interested in this working I can provide a PR.
There is a similar issue in the freetype binding.

Cannot import the module

File "/home/frappe/frappe-bench/apps/asterisk_erp/asterisk_erp/codimd/codimd_pdf.py", line 4, in <module>
    import harfbuzz as hb
  File "/home/frappe/frappe-bench/env/lib/python3.6/site-packages/harfbuzz.py", line 1535, in <module>
    hb.hb_face_count.restype = ct.c_uint
  File "/usr/lib/python3.6/ctypes/__init__.py", line 361, in __getattr__
    func = self.__getitem__(name)
  File "/usr/lib/python3.6/ctypes/__init__.py", line 366, in __getitem__
    func = self._FuncPtr((name_or_ordinal, self))
AttributeError: /usr/lib/x86_64-linux-gnu/libharfbuzz.so.0: undefined symbol: hb_face_count

Line 1535( hb.hb_face_count.restype = ct.c_uint ) of the script throws error.

OS: Ubuntu 18.04.

Blob from bytes?

Are the following Blob declarations equivalent?

table = b'..' # the font table in bytes
blob = hb.Blob.create(
    table, len(table), HB.MEMORY_MODE_READONLY, None, None)

import array

table = b'..' # the font table in bytes
a = array.array('B')
a.frombytes(table)
value = hb.Blob.create_for_array(a, HB.MEMORY_MODE_READONLY)

The second example works, but the first one produces bad access. Am I missing something?

Proposal: “universal” text shaping result JSON notation based on hb-shape

See: OpenType/opentype-layout#4

(Apologies for "spamming".)

Support for MCUs?

Hi,

I have a very important project to render Devnagiri text using Arduino Uno/Mega or ESP32.

I was looking for solutions and came across this. As you have clearly mentioned this library is for linux environment.

But the code is in python. ESP32 supports micro python.

Is there any way to port this to ESP32/Arduino environment with MicroPython?

If not, do you have any ideas how to achieve this? Thanks!

Where is main development happening? Github or Gitlab?

I saw the Github repo went down yesterday and noticed that there is an equivalent one at https://gitlab.com/ldo/harfpy

Which one is the mirror of the other, and where would you like pull request to be sent to?

64 scale factor should only apply to FT funcs

So I did port the hb_ot python example from the harfbuzz repo:

import array
import os

from harfbuzz import HARFBUZZ as HB
import harfbuzz as hb

def shape_dat(path, text):
    a = array.array('B')
    size = os.path.getsize(path)
    with open(path, 'rb') as f:
        a.fromfile(f, size)

    blob = hb.Blob.create_for_array(a, HB.MEMORY_MODE_READONLY)
    face = hb.Face.create(blob, 0)
    del blob
    font = hb.Font.create(face)
    upem = face.upem
    del face
    font.scale = (upem, upem)
    font.ot_set_funcs()

    buf = hb.Buffer.create()
    class Debugger(object):
        def message(self, buf, font, msg, data):
            print(msg)
            return True
    debugger = Debugger()
    #buf.set_message_func(debugger, None, None)

    buf.add_str(text)
    buf.guess_segment_properties()
    hb.shape(font, buf)

    for info, pos in zip(buf.glyph_infos, buf.glyph_positions):
        gid = info.codepoint
        cluster = info.cluster
        x_advance = pos.x_advance
        x_offset = pos.x_offset
        y_offset = pos.y_offset

        print("gid%d=%d@%d,%d+%d" % (
            gid, cluster, x_advance, x_offset, y_offset))

if __name__ == "__main__":
    import sys
    assert len(sys.argv) == 3
    shape_dat(*sys.argv[1:])

Yet the x_advance values that I get back seem very small, e.g. with Bitstream Vera:

PS C:\Users\Admin\Documents> python harfbuzz__.py C:\Vera.ttf "Hello World!"
gid43=0@24,0+0
gid72=1@19,0+0
gid79=2@8,0+0
gid79=3@8,0+0
gid82=4@19,0+0
gid3=5@10,0+0
gid58=6@31,0+0
gid82=7@19,0+0
gid85=8@13,0+0
gid79=9@8,0+0
gid71=10@20,0+0
gid4=11@12,0+0

Is this expected?

cc @khaledhosny