"""
iconfont provides a barebones system to get QIcons from icon fonts (like Font Awesome).
The inspiration and methodology come from the 'QtAwesome' module, which does exactly this, but
is a little too big, complicated, and flexible for PyDM's needs.
"""
import json
import os
import sys
from typing import Optional
from qtpy import QtGui, QtWidgets
from qtpy.QtCore import QPoint, QRect, Qt, qRound
from qtpy.QtGui import QColor, QFont, QFontDatabase, QIcon, QIconEngine, QPainter, QPixmap
if sys.version_info[0] == 3:
unichr = chr
[docs]class IconFont(object):
"""IconFont represents an icon font. Users will generally want
to use IconFont.icon() to get a QIcon object for the character they want."""
__instance = None
def __init__(self):
if self.__initialized:
return
self.font_file = "fontawesome.otf" # specify these relative to this file.
self.charmap_file = "fontawesome-charmap.json"
self.font_name = None
self.char_map = {}
self.loaded_fonts = {}
self.__initialized = True
def __new__(cls, *args, **kwargs):
if cls.__instance is None:
cls.__instance = object.__new__(IconFont)
cls.__instance.__initialized = False
return cls.__instance
[docs] def load_font(self, ttf_filename, charmap_filename):
"""
Load font from ``ttf_filename`` with a mapping defined in
``charmap_filename``.
"""
def hook(obj):
result = {}
for key in obj:
result[key] = unichr(int(obj[key], 16))
return result
if self.char_map:
return
cache_key = ttf_filename + "|" + charmap_filename
ttf_fname = os.path.join(os.path.dirname(os.path.realpath(__file__)), ttf_filename)
font_id = QFontDatabase.addApplicationFont(ttf_fname)
if font_id >= 0:
font_families = QFontDatabase.applicationFontFamilies(font_id)
else:
cache = self.loaded_fonts.get(cache_key, None)
if cache is None:
raise OSError("Could not load ttf file for icon font.")
self.char_map = cache["char_map"]
self.font_name = cache["font_name"]
return
self.font_name = font_families[0]
filename = os.path.join(os.path.dirname(os.path.realpath(__file__)), charmap_filename)
with open(filename, "r") as codes:
self.char_map = json.load(codes, object_hook=hook)
self.loaded_fonts[cache_key] = {
"char_map": self.char_map,
"font_name": self.font_name,
}
[docs] def get_char_for_name(self, name: str) -> str:
"""
Get a character icon for the given name from the character map.
Parameters
----------
name : str
The user-friendly icon name.
Returns
-------
str
The Qt-facing icon text to use with the font.
"""
if name in self.char_map:
return self.char_map[name]
raise ValueError("Invalid icon name for font.")
def _load_font_if_needed(self) -> bool:
"""
Load the configured font if a QApplication is available
and the font was not already loaded.
Returns
-------
bool
Readiness indicator - return True if the font has been loaded.
"""
if QtWidgets.QApplication.instance() is None:
return False
if not self.char_map:
self.load_font(self.font_file, self.charmap_file)
# If it was loaded correctly, the char map will be populated:
return bool(self.char_map)
[docs] def font(self, size: int) -> Optional[QtGui.QFont]:
"""
Load the font at a given pixel size.
Returns
-------
QtGui.QFont or None
The font, if available. If a QApplication is not yet created,
None will be returned.
"""
if not self._load_font_if_needed():
return None
font = QFont(self.font_name)
font.setPixelSize(int(size))
return font
[docs] def icon(self, name, color=None) -> Optional[QtGui.QIcon]:
"""
Retrieve the icon given a name and color.
Parameters
----------
name : str
The Icon string identifier.
Icon strings can be found at: https://fontawesome.com/icons?d=gallery
color : QColor, Optional
The base color to use when constructing the Icon. Default is QColor(90, 90, 90).
Returns
-------
QIcon
The desired Icon. ``None`` if a QApplication is not yet available.
"""
if not self._load_font_if_needed():
return None
char = self.get_char_for_name(name)
engine = CharIconEngine(self, char, color)
return QIcon(engine)
class CharIconEngine(QIconEngine):
"""Subclass of QIconEngine that is designed to draw characters from icon fonts."""
def __init__(self, icon_font, char, color=None):
super(CharIconEngine, self).__init__()
self.icon_font = icon_font
self.char = char
if color is None:
self._base_color = QColor(90, 90, 90)
else:
self._base_color = color
self._disabled_color = QColor.fromHslF(
self._base_color.hueF(),
self._base_color.saturationF(),
max(min(self._base_color.lightnessF() + 0.25, 1.0), 0.0),
)
def paint(self, painter, rect, mode, state):
painter.save()
if mode == QIcon.Disabled:
color = self._disabled_color
else:
color = self._base_color
painter.setPen(color)
scale_factor = 1.0
draw_size = 0.875 * qRound(rect.height() * scale_factor)
painter.setFont(self.icon_font.font(draw_size))
painter.setOpacity(1.0)
painter.drawText(rect, int(Qt.AlignCenter | Qt.AlignVCenter), self.char)
painter.restore()
def pixmap(self, size, mode, state):
pm = QPixmap(size)
pm.fill(Qt.transparent)
self.paint(QPainter(pm), QRect(QPoint(0, 0), size), mode, state)
return pm