import numpy as np
from ... import functions as fn
from ...Qt import QtCore, QtGui
from ..GLGraphicsItem import GLGraphicsItem
__all__ = ['GLTextItem']
[docs]
class GLTextItem(GLGraphicsItem):
"""Draws text in 3D."""
[docs]
def __init__(self, parentItem=None, **kwds):
"""All keyword arguments are passed to setData()"""
super().__init__(parentItem=parentItem)
glopts = kwds.pop('glOptions', 'additive')
self.setGLOptions(glopts)
self.items = []
self.pos = [0.0, 0.0, 0.0]
self.color = QtGui.QColor(QtCore.Qt.GlobalColor.white)
self.text = ''
self.font = QtGui.QFont('Helvetica', 16)
self.alignment = QtCore.Qt.AlignmentFlag.AlignLeft | QtCore.Qt.AlignmentFlag.AlignBottom
self.setData(**kwds)
[docs]
def setData(self, **kwds):
"""
Update the data displayed by this item. All arguments are optional;
for example it is allowed to update text while leaving colors unchanged, etc.
==================== ==================================================
**Arguments:**
------------------------------------------------------------------------
pos (3,) array of floats specifying text location.
text String to display.
color QColor or array of ints [R,G,B] or [R,G,B,A]. (Default: Qt.white)
font QFont (Default: QFont('Helvetica', 16))
alignment QtCore.Qt.AlignmentFlag (Default: QtCore.Qt.AlignmentFlag.AlignLeft | QtCore.Qt.AlignmentFlag.AlignBottom)
items Optional list of dicts. Each dict specifies parameters for a single textitem:
{'pos', 'text', 'color', 'font', 'alignment'}. This allows rendering multiple
text items. 'pos' and 'text' are required keys, the rest are optional.
==================== ==================================================
"""
args = ['pos', 'text', 'color', 'font', 'alignment', 'items']
for k in kwds.keys():
if k not in args:
raise ValueError('Invalid keyword argument: %s (allowed arguments are %s)' % (k, str(args)))
for arg in args:
if arg in kwds:
value = kwds[arg]
if arg == 'pos':
if isinstance(value, np.ndarray):
if value.shape != (3,):
raise ValueError('"pos.shape" must be (3,).')
elif isinstance(value, (tuple, list)):
if len(value) != 3:
raise ValueError('"len(pos)" must be 3.')
elif arg == 'color':
value = fn.mkColor(value)
elif arg == 'font':
if isinstance(value, QtGui.QFont) is False:
raise TypeError('"font" must be QFont.')
elif arg == 'items':
if not isinstance(value, list):
raise ValueError('"items" must be list of dicts')
setattr(self, arg, value)
self.update()
def paint(self):
items = [dict(text=self.text, pos=self.pos)] if len(self.text) != 0 else self.items
if len(items) == 0:
return
self.setupGLState()
device = self.view()
rect = QtCore.QRectF(0, 0, device.width(), device.height())
project = self.compute_projection(rect)
painter = QtGui.QPainter(device)
painter.setRenderHints(QtGui.QPainter.RenderHint.Antialiasing | QtGui.QPainter.RenderHint.TextAntialiasing)
for item in items:
# text and pos must be specified
text = item['text']
pos = item['pos']
if len(text) == 0:
continue
# alignment, color, font fallback to defaults
alignment = item.get('alignment', self.alignment)
color = item.get('color')
color = fn.mkColor(color) if color is not None else self.color
font = item.get('font', self.font)
vec3 = QtGui.QVector3D(*pos)
pos_2d = self.align_text(project.map(vec3).toPointF(), text, font, alignment)
painter.setPen(color)
painter.setFont(font)
painter.drawText(pos_2d, text)
painter.end()
def compute_projection(self, rect : QtCore.QRectF):
# note that QRectF.bottom() != QRect.bottom()
ndc_to_viewport = QtGui.QMatrix4x4()
ndc_to_viewport.viewport(rect.left(), rect.bottom(), rect.width(), -rect.height())
return ndc_to_viewport * self.mvpMatrix()
[docs]
def align_text(self, pos, text, font, alignment):
"""
Aligns the text at the given position according to the given alignment.
"""
font_metrics = QtGui.QFontMetrics(font)
rect = font_metrics.tightBoundingRect(text)
width = rect.width()
height = rect.height()
dx = dy = 0.0
if alignment & QtCore.Qt.AlignmentFlag.AlignRight:
dx = width
if alignment & QtCore.Qt.AlignmentFlag.AlignHCenter:
dx = width / 2.0
if alignment & QtCore.Qt.AlignmentFlag.AlignTop:
dy = height
if alignment & QtCore.Qt.AlignmentFlag.AlignVCenter:
dy = height / 2.0
return QtCore.QPointF(pos.x() - dx, pos.y() + dy)
