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Diffstat (limited to 'silx/gui/_glutils/font.py')
-rw-r--r-- | silx/gui/_glutils/font.py | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/silx/gui/_glutils/font.py b/silx/gui/_glutils/font.py new file mode 100644 index 0000000..566ae49 --- /dev/null +++ b/silx/gui/_glutils/font.py @@ -0,0 +1,152 @@ +# coding: utf-8 +# /*########################################################################## +# +# Copyright (c) 2016-2017 European Synchrotron Radiation Facility +# +# Permission is hereby granted, free of charge, to any person obtaining a copy +# of this software and associated documentation files (the "Software"), to deal +# in the Software without restriction, including without limitation the rights +# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +# copies of the Software, and to permit persons to whom the Software is +# furnished to do so, subject to the following conditions: +# +# The above copyright notice and this permission notice shall be included in +# all copies or substantial portions of the Software. +# +# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +# THE SOFTWARE. +# +# ###########################################################################*/ +"""Text rasterisation feature leveraging Qt font and text layout support.""" + +__authors__ = ["T. Vincent"] +__license__ = "MIT" +__date__ = "13/10/2016" + + +import logging +import sys +import numpy +from .. import qt +from .._utils import convertQImageToArray + + +_logger = logging.getLogger(__name__) + + +def getDefaultFontFamily(): + """Returns the default font family of the application""" + return qt.QApplication.instance().font().family() + + +# Font weights +ULTRA_LIGHT = 0 +"""Lightest characters: Minimum font weight""" + +LIGHT = 25 +"""Light characters""" + +NORMAL = 50 +"""Normal characters""" + +SEMI_BOLD = 63 +"""Between normal and bold characters""" + +BOLD = 74 +"""Thicker characters""" + +BLACK = 87 +"""Really thick characters""" + +ULTRA_BLACK = 99 +"""Thickest characters: Maximum font weight""" + + +def rasterText(text, font, + size=-1, + weight=-1, + italic=False, + devicePixelRatio=1.0): + """Raster text using Qt. + + It supports multiple lines. + + :param str text: The text to raster + :param font: Font name or QFont to use + :type font: str or :class:`QFont` + :param int size: + Font size in points + Used only if font is given as name. + :param int weight: + Font weight in [0, 99], see QFont.Weight. + Used only if font is given as name. + :param bool italic: + True for italic font (default: False). + Used only if font is given as name. + :param float devicePixelRatio: + The current ratio between device and device-independent pixel + (default: 1.0) + :return: Corresponding image in gray scale and baseline offset from top + :rtype: (HxW numpy.ndarray of uint8, int) + """ + if not text: + _logger.info("Trying to raster empty text, replaced by white space") + text = ' ' # Replace empty text by white space to produce an image + + if not isinstance(font, qt.QFont): + font = qt.QFont(font, size, weight, italic) + + metrics = qt.QFontMetrics(font) + size = metrics.size(qt.Qt.TextExpandTabs, text) + bounds = metrics.boundingRect( + qt.QRect(0, 0, size.width(), size.height()), + qt.Qt.TextExpandTabs, + text) + + if (devicePixelRatio != 1.0 and + not hasattr(qt.QImage, 'setDevicePixelRatio')): # Qt 4 + _logger.error('devicePixelRatio not supported') + devicePixelRatio = 1.0 + + # Add extra border and handle devicePixelRatio + width = bounds.width() * devicePixelRatio + 2 + # align line size to 32 bits to ease conversion to numpy array + width = 4 * ((width + 3) // 4) + image = qt.QImage(width, + bounds.height() * devicePixelRatio, + qt.QImage.Format_RGB888) + if (devicePixelRatio != 1.0 and + hasattr(image, 'setDevicePixelRatio')): # Qt 5 + image.setDevicePixelRatio(devicePixelRatio) + + # TODO if Qt5 use Format_Grayscale8 instead + image.fill(0) + + # Raster text + painter = qt.QPainter() + painter.begin(image) + painter.setPen(qt.Qt.white) + painter.setFont(font) + painter.drawText(bounds, qt.Qt.TextExpandTabs, text) + painter.end() + + array = convertQImageToArray(image) + + # RGB to R + array = numpy.ascontiguousarray(array[:, :, 0]) + + # Remove leading and trailing empty columns but one on each side + column_cumsum = numpy.cumsum(numpy.sum(array, axis=0)) + array = array[:, column_cumsum.argmin():column_cumsum.argmax() + 2] + + # Remove leading and trailing empty rows but one on each side + row_cumsum = numpy.cumsum(numpy.sum(array, axis=1)) + min_row = row_cumsum.argmin() + array = array[min_row:row_cumsum.argmax() + 2, :] + + return array, metrics.ascent() - min_row |