#
##
## This file is part of pyFormex 2.0 (Mon Sep 14 12:29:05 CEST 2020)
## pyFormex is a tool for generating, manipulating and transforming 3D
## geometrical models by sequences of mathematical operations.
## Home page: http://pyformex.org
## Project page: http://savannah.nongnu.org/projects/pyformex/
## Copyright 2004-2020 (C) Benedict Verhegghe (benedict.verhegghe@ugent.be)
## 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.
"""
from OpenGL import GL
import numpy as np
import pyformex as pf
from pyformex import Path
from pyformex import utils
from pyformex import freetype as ft
from pyformex import arraytools as at
from pyformex.coords import Coords
from pyformex.formex import Formex
from pyformex.opengl.drawable import Actor
from pyformex.opengl.texture import Texture
from pyformex.plugins.imagearray import array2image, image2array
__all__ = ['FontTexture', 'Text', 'TextArray', 'Mark']
[docs]class FontTexture(Texture):
"""A Texture class for text rendering.
The FontTexture class is a texture containing the most important
characters of a font. This texture can then be used to draw text
on geometry. In the current implementation only the characters with
ASCII ordinal in the range 32..127 are put in the texture.
Parameters
----------
filename: str or Path
The name of the font file to be used. It should be the
full path of an existing monospace font on the system.
size: float
Intended font height. The actual height might differ a bit.
save: bool
If True and ``filename`` is a font file (.ttf), the generated
texture image will be saved as a .png image for later reload.
"""
# This is how we store the 96 character textures
layout = (3, 32)
def __init__(self, filename, size, save=False):
"""Initialize a FontTexture"""
nrows, ncols = FontTexture.layout
filename = Path(filename)
if not filename.is_absolute():
filename = pf.cfg['fontsdir'] / filename
if not filename.exists():
raise ValueError("Font file %s does not exist" % filename)
if filename.suffix == '.ttf':
# generate texture from .ttf file
image = self.generateFromFont(filename, size, save=False)
if save:
stem = filename.stem
fn = pf.cfg['fontsdir'] / (stem+'.%sx%s.png'%(nrows, ncols))
if not fn.exists():
print("Saving Font Texture: %s" % fn)
array2image(image, str(fn))
elif filename.suffix == '.png':
stem = filename.stem
if not stem.endswith("%sx%s" % FontTexture.layout):
raise ValueError("Invalid layout for font %s" % filename)
image = image2array(filename, flip=False) # ! no flipping for fonts
self.height = image.shape[0] / nrows
self.width = image.shape[1] / ncols
pf.debug("Image size %s, w%s, h%s, type %s" % (image.shape, self.width, self.height, image.dtype), pf.DEBUG.FONT)
Texture.__init__(self, image, format=GL.GL_ALPHA, texformat=GL.GL_ALPHA)
[docs] def generateFromFont(self, filename, size, save=False):
"""Initialize a FontTexture"""
pf.debug("Creating FontTexture(%s) in size %s" % (filename, size), pf.DEBUG.FONT)
# Load font and check it is monospace
face = ft.Face(str(filename))
try:
face.set_char_size(int(size*64))
except Exception:
raise RuntimeError("Can not load font '%s' at size %s" % (filename, size))
if not face.is_fixed_width:
raise RuntimeError("Font is not monospace")
# Determine largest glyph size
width, height, ascender, descender = 0, 0, 0, 0
for c in range(32, 128):
face.load_char(chr(c), ft.FT_LOAD_RENDER | ft.FT_LOAD_FORCE_AUTOHINT)
bitmap = face.glyph.bitmap
width = max(width, bitmap.width)
ascender = max(ascender, face.glyph.bitmap_top)
descender = max(descender, bitmap.rows-face.glyph.bitmap_top)
#print("chr %s; ord %s; width %s, ascender %s, descender %s" % (
# chr(c), c, bitmap.width, face.glyph.bitmap_top, bitmap.rows-face.glyph.bitmap_top))
height = ascender+descender
#print("width %s, ascender %s, descender %s, height %s" % (
# width, ascender, descender, height ))
# Generate texture data
nrows, ncols = FontTexture.layout
image = np.zeros((height*nrows, width*ncols), dtype=np.ubyte)
for j in range(nrows):
for i in range(ncols):
k = 32+j*ncols+i
face.load_char(chr(k), ft.FT_LOAD_RENDER | ft.FT_LOAD_FORCE_AUTOHINT)
bitmap = face.glyph.bitmap
x = i*width + face.glyph.bitmap_left
y = j*height + ascender - face.glyph.bitmap_top
#print("%s %s: %s %s, %s" % (k,chr(k),face.glyph.bitmap_left,x,y))
image[y:y+bitmap.rows, x:x+bitmap.width].flat = bitmap.buffer
return image
[docs] def activate(self, mode=None):
"""Bind the texture and make it ready for use.
Returns the texture id.
"""
GL.glEnable(GL.GL_BLEND)
Texture.activate(self, filtr=1)
[docs] def texCoords(self, char):
"""Return the texture coordinates for a character or string.
Parameters:
- `char`: integer or ascii string. If an integer, it should be in the range
32..127 (printable ASCII characters). If a string, all its characters
should be ASCII printable characters (have an ordinal value in the
range 32..127).
If `char` is an integer, returns a tuple with the texture coordinates
in the FontTexture corresponding with the specified character. This is a
sequence of four (x,y) pairs corresponding respectively with the
lower left, lower right, upper right, upper left corners of the character
in the texture. Note that values for the lower corners are higher than those
for the upper corners. This is because the FontTextures are (currently)
stored from top to bottom, while opengl coordinates are from bottom to top.
If `char` is a string of length `ntext`, returns a float array with shape
(ntext,4,2) holding the texture coordinates needed to display
the given text on a grid of quad4 elements.
"""
nrows, ncols = FontTexture.layout
if at.isInt(char):
dx, dy = 1./ncols, 1./nrows
k = char-32
x0, y0 = (k%ncols)*dx, (k//ncols)*dy
return (x0, y0+dy), (x0+dx, y0+dy), (x0+dx, y0), (x0, y0)
else:
return np.array([self.texCoords(ord(c)) for c in char])
default_font = None
[docs] @classmethod
def default(clas, size=24):
"""Set and return the default FontTexture.
"""
if clas.default_font is None:
default_font_file ='NotoSansMono-Condensed.3x32.png'
default_font_size = 24
clas.default_font = FontTexture(default_font_file, default_font_size)
return clas.default_font
#
# 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 string, 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`: a 2D or 3D position. 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`: a string that determines the adjusting 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 will center the text.
- `size`: float: size (height) of the font. This is the displayed height.
The used font can have a different height and is scaled accordingly.
- `width`: float: width of the font. This is the displayed width o a single
character (currently only monospace fonts are supported).
The default is set from the `size` 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. The font to be used.
If a string, it is the filename of an existing monospace font on
the system.
- `lineskip`: float: distance in pixels between subsequent baselines
in case of multi-line text. Multi-line text results when the input
`text` contains newlines.
- `grid`: raster geometry for the text. This is the geometry where the
generate text will be rendered on 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.
"""
def __init__(self, text, pos, gravity=None, size=18, width=None, font=None, lineskip=1.0, grid=None, texmode=4, **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("Length of text(%s) and pos(%s) should match!" % (len(text), len(pos)))
# 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:
#print("Font %s / %s" % (font.height,font.width))
aspect = float(font.width) / font.height
width = size * aspect
self.width = width
# set the alignment
if gravity is None:
gravity = 'E'
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.])
# 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, **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, **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`: a list of N strings: the texts to display. If an item is
not a string, the string representation of the object will be drawn.
- `pos`: either an [N,2] or [N,3] shaped array of 2D or 3D positions.
If 2D, the values are measured in pixels. If 3D, it is a point in
global 3D space.
- `prefix`: string. If specified, it is prepended to all drawn strings.
Other parameters can be passed to the :class:`Text` class.
"""
def __init__(self, val, pos, prefix='', **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]
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)
# 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
