src/Mod/CAM/Path/Tool/shape/ui/flowlayout.py

# SPDX-License-Identifier: LGPL-2.1-or-later

# ***************************************************************************
# *   Copyright (c) 2025 Samuel Abels <knipknap@gmail.com>                  *
# *                                                                         *
# *   This program is free software; you can redistribute it and/or modify  *
# *   it under the terms of the GNU Lesser General Public License (LGPL)    *
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# *   for detail see the LICENCE text file.                                 *
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# *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
# *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
# *   GNU Library General Public License for more details.                  *
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from PySide.QtCore import *
from PySide.QtGui import *


class FlowLayout(QLayout):
    widthChanged = Signal(int)

    def __init__(self, parent=None, margin=0, spacing=-1, orientation=Qt.Horizontal):
        super(FlowLayout, self).__init__(parent)

        if parent is not None:
            self.setContentsMargins(margin, margin, margin, margin)

        self.setSpacing(spacing)
        self.itemList = []
        self.orientation = orientation

    def __del__(self):
        item = self.takeAt(0)
        while item:
            item = self.takeAt(0)

    def addItem(self, item):
        self.itemList.append(item)

    def count(self):
        return len(self.itemList)

    def itemAt(self, index):
        if index >= 0 and index < len(self.itemList):
            return self.itemList[index]

        return None

    def takeAt(self, index):
        if index >= 0 and index < len(self.itemList):
            return self.itemList.pop(index)

        return None

    def expandingDirections(self):
        return Qt.Orientations(Qt.Orientation(0))

    def hasHeightForWidth(self):
        return True

    def heightForWidth(self, width):
        if self.orientation == Qt.Horizontal:
            return self.doLayoutHorizontal(QRect(0, 0, width, 0), True)
        elif self.orientation == Qt.Vertical:
            return self.doLayoutVertical(QRect(0, 0, width, 0), True)

    def setGeometry(self, rect):
        super(FlowLayout, self).setGeometry(rect)
        if self.orientation == Qt.Horizontal:
            self.doLayoutHorizontal(rect, False)
        elif self.orientation == Qt.Vertical:
            self.doLayoutVertical(rect, False)

    def sizeHint(self):
        return self.minimumSize()

    def minimumSize(self):
        size = QSize()

        for item in self.itemList:
            size = size.expandedTo(item.minimumSize())

        margin, _, _, _ = self.getContentsMargins()

        size += QSize(2 * margin, 2 * margin)
        return size

    def doLayoutHorizontal(self, rect, testOnly):
        # Get initial coordinates of the drawing region (should be 0, 0)
        x = rect.x()
        y = rect.y()
        lineHeight = 0
        i = 0
        for item in self.itemList:
            wid = item.widget()
            # Space X and Y is item spacing horizontally and vertically
            spaceX = self.spacing() + wid.style().layoutSpacing(
                QSizePolicy.PushButton, QSizePolicy.PushButton, Qt.Horizontal
            )
            spaceY = self.spacing() + wid.style().layoutSpacing(
                QSizePolicy.PushButton, QSizePolicy.PushButton, Qt.Vertical
            )
            # Determine the coordinate we want to place the item at
            # It should be placed at : initial coordinate of the rect + width of the item + spacing
            nextX = x + item.sizeHint().width() + spaceX
            # If the calculated nextX is greater than the outer bound...
            if nextX - spaceX > rect.right() and lineHeight > 0:
                x = rect.x()  # Reset X coordinate to origin of drawing region
                y = y + lineHeight + spaceY  # Move Y coordinate to the next line
                nextX = (
                    x + item.sizeHint().width() + spaceX
                )  # Recalculate nextX based on the new X coordinate
                lineHeight = 0

            if not testOnly:
                item.setGeometry(QRect(QPoint(x, y), item.sizeHint()))

            x = nextX  # Store the next starting X coordinate for next item
            lineHeight = max(lineHeight, item.sizeHint().height())
            i = i + 1

        return y + lineHeight - rect.y()

    def doLayoutVertical(self, rect, testOnly):
        # Get initial coordinates of the drawing region (should be 0, 0)
        x = rect.x()
        y = rect.y()
        # Initialize column width and line height
        columnWidth = 0
        lineHeight = 0

        # Space between items
        spaceX = 0
        spaceY = 0

        # Variables that will represent the position of the widgets in a 2D Array
        i = 0
        j = 0
        for item in self.itemList:
            wid = item.widget()
            # Space X and Y is item spacing horizontally and vertically
            spaceX = self.spacing() + wid.style().layoutSpacing(
                QSizePolicy.PushButton, QSizePolicy.PushButton, Qt.Horizontal
            )
            spaceY = self.spacing() + wid.style().layoutSpacing(
                QSizePolicy.PushButton, QSizePolicy.PushButton, Qt.Vertical
            )
            # Determine the coordinate we want to place the item at
            # It should be placed at : initial coordinate of the rect + width of the item + spacing
            nextY = y + item.sizeHint().height() + spaceY
            # If the calculated nextY is greater than the outer bound, move to the next column
            if nextY - spaceY > rect.bottom() and columnWidth > 0:
                y = rect.y()  # Reset y coordinate to origin of drawing region
                x = x + columnWidth + spaceX  # Move X coordinate to the next column
                nextY = (
                    y + item.sizeHint().height() + spaceY
                )  # Recalculate nextX based on the new X coordinate
                # Reset the column width
                columnWidth = 0

                # Set indexes of the item for the 2D array
                j += 1
                i = 0

            # Assign 2D array indexes
            item.x_index = i
            item.y_index = j

            # Only call setGeometry (which place the actual widget using coordinates) if testOnly is false
            # For some reason, Qt framework calls the doLayout methods with testOnly set to true (WTF ??)
            if not testOnly:
                item.setGeometry(QRect(QPoint(x, y), item.sizeHint()))

            y = nextY  # Store the next starting Y coordinate for next item
            columnWidth = max(
                columnWidth, item.sizeHint().width()
            )  # Update the width of the column
            lineHeight = max(lineHeight, item.sizeHint().height())  # Update the height of the line

            i += 1  # Increment i

        # Only call setGeometry (which place the actual widget using coordinates) if testOnly is false
        # For some reason, Qt framework calls the doLayout methods with testOnly set to true (WTF ??)
        if not testOnly:
            self.calculateMaxWidth(i)
            self.widthChanged.emit(self.totalMaxWidth + spaceX * self.itemsOnWidestRow)
        return lineHeight

    # Method to calculate the maximum width among each "row" of the flow layout
    # This will be useful to let the UI know the total width of the flow layout
    def calculateMaxWidth(self, numberOfRows):
        # Init variables
        self.totalMaxWidth = 0
        self.itemsOnWidestRow = 0

        # For each "row", calculate the total width by adding the width of each item
        # and then update the totalMaxWidth if the calculated width is greater than the current value
        # Also update the number of items on the widest row
        for i in range(numberOfRows):
            rowWidth = 0
            itemsOnWidestRow = 0
            for item in self.itemList:
                # Only compare items from the same row
                if item.x_index == i:
                    rowWidth += item.sizeHint().width()
                    itemsOnWidestRow += 1
                if rowWidth > self.totalMaxWidth:
                    self.totalMaxWidth = rowWidth
                    self.itemsOnWidestRow = itemsOnWidestRow