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class FlowLayout(QLayout): |
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def __init__(self, parent=None, margin=-1, h_spacing=-1, v_spacing=-1): |
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QLayout.__init__(self, parent) |
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self.setContentsMargins(margin, margin, margin, margin) |
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self.m_h_space = h_spacing |
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self.m_v_space = v_spacing |
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self.item_list = [] |
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|
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def addItem(self, item): |
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self.item_list.append(item) |
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|
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def horizontalSpacing(self): |
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if self.m_h_space >= 0: |
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return self.m_h_space |
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else: |
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return self.smart_spacing(QStyle.PM_LayoutHorizontalSpacing) |
|
|
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def verticalSpacing(self): |
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if self.m_v_space >= 0: |
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return self.m_v_space |
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else: |
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return self.smart_spacing(QStyle.PM_LayoutVerticalSpacing) |
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|
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def count(self): |
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return len(self.item_list) |
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|
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def itemAt(self, index): |
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if index >= 0 and index < len(self.item_list): |
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return self.item_list[index] |
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else: |
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return None |
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|
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def takeAt(self, index): |
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if index >= 0 and index < len(self.item_list): |
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return self.item_list.pop(index) |
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else: |
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return None |
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|
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def expandingDirections(self): |
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return Qt.Orientations(0) |
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|
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def hasHeightForWidth(self): |
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return True |
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|
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def heightForWidth(self, width): |
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return self.do_layout(QRect(0,0, width, 0), True) |
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|
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def setGeometry(self, rect): |
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super(FlowLayout, self).setGeometry(rect) |
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self.do_layout(rect, False) |
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|
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def sizeHint(self): |
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return self.minimumSize() |
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|
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def minimumSize(self): |
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size = QSize() |
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for item in self.item_list: |
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size = size.expandedTo(item.minimumSize()) |
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#size += QSize(2*self.margin(), 2*self.margin()) |
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size += QSize(2*8, 2*8) |
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return size |
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|
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def do_layout(self, rect, test_only): |
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(left, top, right, bottom) = self.getContentsMargins() |
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effective_rect = rect.adjusted(left, top, -right, -bottom) |
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x = effective_rect.x() |
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y = effective_rect.y() |
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line_height = 0 |
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for item in self.item_list: |
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wid = item.widget() |
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space_x = self.horizontalSpacing() |
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if space_x == -1: |
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space_x = wid.style().layoutSpacing(QSizePolicy.PushButton, QSizePolicy.PushButton, Qt.Horizontal) |
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space_y = self.verticalSpacing() |
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if space_y == -1: |
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space_y = wid.style().layoutSpacing(QSizePolicy.PushButton, QSizePolicy.PushButton, Qt.Vertical) |
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next_x = x + item.sizeHint().width() + space_x |
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if next_x - space_x > effective_rect.right() and line_height > 0: |
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x = effective_rect.x() |
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y = y + line_height + space_y |
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next_x = x + item.sizeHint().width() + space_x |
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line_height = 0 |
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if not test_only: |
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item.setGeometry(QRect(QPoint(x, y), item.sizeHint())) |
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x = next_x |
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line_height = max(line_height, item.sizeHint().height()) |
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return y + line_height - rect.y() + bottom |
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|
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def smart_spacing(self, pm): |
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parent = self.parent() |
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if not parent: |
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return -1 |
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elif parent.isWidgetType(): |
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return parent.style().pixelMetric(pm, None, parent) |
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else: |
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return parent.spacing() |
What's the problem this feature will solve?
MEDM widgets are placed by absolute positioning. MEDM users are accustomed to changing the screen size and the widgets will stretch accordingly. In Qt, the stretchable feature is provided by a layout manager which re-positions its widgets as the layout changes size.
The widgets from the
adl2pydmconverter are not stretchable and this is a popular feature that is missed in MEDM screens converted for use in PyDM.Describe the solution you'd like
Internal widgets proportionally should stretch as the window changes size. (note: These example screens are rendered with caQtDM, a C++/Qt application, showing the idea is possible in Qt.)
original size
stretched
Additional context
After some research, it seems a good candidate case for a Qt Custom Layout Manager. The new custom layout would accept widgets placed in absolute coordinates and then adjust the geometry (x,y,h,w) of each to fit the containing QFrame.
The PyDM project already has an existing custom layout manager (
FlowLayout()) that would be a good example for a new layout manager for this feature:pydm/pydm/widgets/template_repeater.py
Lines 17 to 112 in 5740b1a
The
adl2pydmconverter would use this new layout for each of the MEDM screens it converts.