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"""This module provides a flow layout for QWidget: :class:`FlowLayout`.
"""
__authors__ = ["T. Vincent"]
__license__ = "MIT"
__date__ = "20/07/2018"
from .. import qt
[docs]
class FlowLayout(qt.QLayout):
"""Layout widgets on (possibly) multiple lines in the available width.
See Qt :class:`QLayout` for API documentation.
Adapted from C++ `Qt FlowLayout example
<http://doc.qt.io/qt-5/qtwidgets-layouts-flowlayout-example.html>`_
:param QWidget parent: See :class:`QLayout`
"""
def __init__(self, parent=None):
super(FlowLayout, self).__init__(parent)
self._items = []
self._horizontalSpacing = -1
self._verticalSpacing = -1
[docs]
def addItem(self, item):
self._items.append(item)
[docs]
def count(self):
return len(self._items)
[docs]
def itemAt(self, index):
if 0 <= index < len(self._items):
return self._items[index]
else:
return None
[docs]
def takeAt(self, index):
if 0 <= index < len(self._items):
return self._items.pop(index)
else:
return None
[docs]
def expandingDirections(self):
return qt.Qt.Orientations()
[docs]
def hasHeightForWidth(self):
return True
[docs]
def heightForWidth(self, width):
return self._layout(qt.QRect(0, 0, width, 0), test=True)
[docs]
def setGeometry(self, rect):
super(FlowLayout, self).setGeometry(rect)
self._layout(rect)
[docs]
def sizeHint(self):
return self.minimumSize()
[docs]
def minimumSize(self):
size = qt.QSize()
for item in self._items:
size = size.expandedTo(item.minimumSize())
left, top, right, bottom = self.getContentsMargins()
size += qt.QSize(left + right, top + bottom)
return size
def _layout(self, rect, test=False):
left, top, right, bottom = self.getContentsMargins()
effectiveRect = rect.adjusted(left, top, -right, -bottom)
x, y = effectiveRect.x(), effectiveRect.y()
lineHeight = 0
for item in self._items:
widget = item.widget()
spaceX = self.horizontalSpacing()
if spaceX == -1:
spaceX = widget.style().layoutSpacing(
qt.QSizePolicy.PushButton,
qt.QSizePolicy.PushButton,
qt.Qt.Horizontal,
)
spaceY = self.verticalSpacing()
if spaceY == -1:
spaceY = widget.style().layoutSpacing(
qt.QSizePolicy.PushButton, qt.QSizePolicy.PushButton, qt.Qt.Vertical
)
nextX = x + item.sizeHint().width() + spaceX
if (nextX - spaceX) > effectiveRect.right() and lineHeight > 0:
x = effectiveRect.x()
y += lineHeight + spaceY
nextX = x + item.sizeHint().width() + spaceX
lineHeight = 0
if not test:
item.setGeometry(qt.QRect(qt.QPoint(x, y), item.sizeHint()))
x = nextX
lineHeight = max(lineHeight, item.sizeHint().height())
return y + lineHeight - rect.y() + bottom
[docs]
def setHorizontalSpacing(self, spacing):
"""Set the horizontal spacing between widgets laid out side by side
:param int spacing:
"""
self._horizontalSpacing = spacing
self.update()
[docs]
def horizontalSpacing(self):
"""Returns the horizontal spacing between widgets laid out side by side
:rtype: int
"""
if self._horizontalSpacing >= 0:
return self._horizontalSpacing
else:
return self._smartSpacing(qt.QStyle.PM_LayoutHorizontalSpacing)
[docs]
def setVerticalSpacing(self, spacing):
"""Set the vertical spacing between lines
:param int spacing:
"""
self._verticalSpacing = spacing
self.update()
[docs]
def verticalSpacing(self):
"""Returns the vertical spacing between lines
:rtype: int
"""
if self._verticalSpacing >= 0:
return self._verticalSpacing
else:
return self._smartSpacing(qt.QStyle.PM_LayoutVerticalSpacing)
def _smartSpacing(self, pm):
parent = self.parent()
if parent is None:
return -1
if parent.isWidgetType():
return parent.style().pixelMetric(pm, None, parent)
else:
return parent.spacing()
