#
##
## SPDX-FileCopyrightText: © 2007-2024 Benedict Verhegghe <bverheg@gmail.com>
## SPDX-License-Identifier: GPL-3.0-or-later
##
## This file is part of pyFormex 3.5 (Thu Feb 8 19:11:13 CET 2024)
## pyFormex is a tool for generating, manipulating and transforming 3D
## geometrical models by sequences of mathematical operations.
## Home page: https://pyformex.org
## Project page: https://savannah.nongnu.org/projects/pyformex/
## Development: https://gitlab.com/bverheg/pyformex
## Distributed under the GNU General Public License version 3 or later.
##
## This program is free software: you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program. If not, see http://www.gnu.org/licenses/.
##
"""Text rendering on the OpenGL canvas.
This module uses textures on quads to render text on an OpenGL canvas.
It is dependent on freetype and the Python bindings freetype-py. These
bindings come included with pyFormex.
"""
from itertools import cycle
import numpy as np
import pyformex as pf
from pyformex import arraytools as at
from pyformex.opengl.drawable import Actor
from pyformex.opengl.fonttexture import FontTexture
from pyformex.coords import Coords
from pyformex.formex import Formex
__all__ = ['Text', 'TextArray', 'Mark']
#
# TODO: Docstring of Text should be extended (include grid parameter),
# or TextArray should be merged into Text.
#
[docs]class Text(Actor):
"""A text drawn at a 2D or 3D position.
Parameters
----------
text: string
The text to display. If not a str, the string
representation of the object will be drawn. Newlines in the string
are supported. After a newline, the remainder of the string is continued
from a lower vertical position and the initial horizontal position.
The vertical line offset is determined from the font.
pos: tuple
Position where render the text: either a 2D (x,y) or a 3D (x,y,z) tuple.
If 2D, the values are measured in pixels. If 3D, it is a point in
global 3D space. The text is drawn in 2D, inserted at the specified
position.
gravity: str, optional
Specifies the adjustment of the text with respect to the insert position.
It can be a combination of one of the characters 'N or 'S' to specify
the vertical positon, and 'W' or 'E' for the horizontal.
The default(empty) string centers the text.
size: float, optional
The height of the font. This is the displayed height.
The used font can have a different height and is scaled accordingly.
width: float, optional
The width of the font. This is the displayed width of a single
character (currently only monospace fonts are supported).
The default is set from the ``size`` parameter and the aspect ratio
of the font.
Setting this to a different value allows the creation of condensed and
expanded font types. Condensed fonts are often used to save space.
font: :class:`FontTexture` or string, optional.
The font to be used. If a string, it is the filename of an monospace
font file existing on the system.
lineskip: float, loptional
The distance in pixels between subsequent baselines
in case of multi-line text. Multi-line text results when the input
``text`` contains newlines.
grid: Geometry, optional
A grid geometry for rendering the text upon as a Texture.
The default is a grid of rectangles of size (``width``,``size``) which
are juxtaposed horizontally. Each rectangle will be rendered with a
single character on it.
colors: list, optional
A list of N color specifications, allowing to draw the subsequent
strings in different colors. If provided, it overrides a ``color``
parameter specified in kargs. If all strings are to be displayed with
the same color, the ``color`` parameter instead.
**kargs:
Other parameters (like color) to be passed to the Actor initalization.
"""
def __init__(self, text, pos, gravity=None, size=18, width=None, font=None,
lineskip=1.0, grid=None, texmode=4, rotate=None, colors=None,
**kargs):
"""Initialize the Text actor."""
# split the string on newlines
text = str(text).split('\n')
# set pos and offset3d depending on pos type (2D vs 3D rendering)
pos = at.checkArray(pos)
if pos.shape[-1] == 2:
rendertype = 2
pos = [pos[0], pos[1], 0.]
offset3d = None
else:
rendertype = 1
offset3d = Coords(pos)
pos = [0., 0., 0.]
if offset3d.ndim > 1:
if offset3d.shape[0] != len(text[0]):
raise ValueError(f"Length of text({len(text)}) and "
f"pos({len(pos)}) should match!")
# Flag vertex offset to shader
rendertype = -1
# set the font characteristics
if font is None:
font = FontTexture.default(size)
if isinstance(font, str):
font = FontTexture(font, size)
if width is None:
aspect = float(font.width) / font.height
width = size * aspect
self.width = width
# set the alignment
if gravity is None:
gravity = 'E'
else:
gravity = gravity.upper()
alignment = ['0', '0', '0']
if 'W' in gravity:
alignment[0] = '+'
elif 'E' in gravity:
alignment[0] = '-'
if 'S' in gravity:
alignment[1] = '+'
elif 'N' in gravity:
alignment[1] = '-'
alignment = ''.join(alignment)
# record the lengths of the lines, join all characters
# together, create texture coordinates for all characters
# create a geometry grid for the longest line
lt = [len(t) for t in text]
text = ''.join(text)
texcoords = font.texCoords(text)
if grid is None:
grid = Formex('4:0123').replic(max(lt))
grid = grid.scale([width, size, 0.])
if rotate is not None:
grid = grid.rotate(rotate)
color = kargs.pop('color', pf.cfg['canvas/textcolor'])
if colors is None:
colors = [color]
# cycle line colors if not enough
colors = cycle(colors)
# create the actor for the first line
l = lt[0]
g = grid.select(range(l)).align(alignment, pos)
Actor.__init__(self, g, rendertype=rendertype, texture=font,
texmode=texmode, texcoords=texcoords[:l],
opak=False, ontop=True, mode='flat', offset3d=offset3d,
color=next(colors), **kargs)
for k in lt[1:]:
# lower the canvas y-value
pos[1] -= font.height * lineskip
g = grid.select(range(k)).align(alignment, pos)
C = Actor(g, rendertype=rendertype, texture=font,
texmode=texmode, texcoords=texcoords[l:l+k],
opak=False, ontop=True, mode='flat', offset3d=offset3d,
color=next(colors), **kargs)
self.children.append(C)
# do next line
l += k
[docs]class TextArray(Text):
"""An array of texts drawn at a 2D or 3D positions.
The text is drawn in 2D, inserted at the specified (2D or 3D) position,
with alignment specified by the gravity (see class :class:`Text`).
Parameters
----------
text: list of str
A list containing N strings to be displayed. If an item is
not a string, the string representation of the object will be drawn.
pos: float array
Either an [N,2] or [N,3] shaped array with the 2D or 3D positions
where to display the strings. If 2D, the values are measured in pixels.
If 3D, it is a point in the global 3D space.
prefix: str, optional
If specified, it is prepended to all drawn strings.
colors: list, optional
A list of N color specifications, allowing to draw the subsequent
strings in different colors. If provided, it overrides a ``color``
parameter specified in kargs. If all strings are to be displayed with
the same color, the ``color`` parameter instead.
**kargs:
Other parameters (like color) to be passed to the Actor initalization.
"""
def __init__(self, val, pos, prefix='', colors=None, **kargs):
# Make sure we have strings
val = [str(i) for i in val]
pos = at.checkArray(pos, shape=(len(val), -1))
if len(val) != pos.shape[0]:
raise ValueError("val and pos should have same length")
# concatenate all strings
val = [prefix+str(v) for v in val]
cs = at.cumsum0([len(v) for v in val])
val = ''.join(val)
nc = cs[1:] - cs[:-1] # lengths of the strings including prefix
pos = [at.multiplex(p, n, 0) for p, n in zip(pos, nc)]
pos = np.concatenate(pos, axis=0)
pos = at.multiplex(pos, 4, 1)
# multiplex the colors
if colors is not None:
if isinstance(colors, str) and colors == 'range':
colors = np.arange(len(val))
mcolors = []
for n, c in zip(nc, cycle(colors)):
mcolors.extend([c] * n)
kargs['color'] = mcolors
# Create the grids for the strings
F = Formex('4:0123')
grid = Formex.concatenate([F.replic(n) for n in nc])
# Create a text with the concatenation
Text.__init__(self, val, pos=pos, grid=grid, **kargs)
[docs]class Mark(Actor):
"""A 2D drawing inserted at a 3D position of the scene.
The minimum attributes and methods are:
- `pos` : 3D point where the mark will be drawn
"""
def __init__(self, pos, tex, size, opak=False, ontop=True, **kargs):
self.pos = pos
F = Formex([[[0, 0], [1, 0], [1, 1], [0, 1]]]).scale(size).align('000')
Actor.__init__(self, F, rendertype=1, texture=tex, texmode=4,
offset3d=pos, opak=opak, ontop=ontop, mode='flat',
**kargs)
# End