qt - 我如何从 Maya 复制这个 2D 相机变焦？

Question

我正在尝试重新创建 Mayas 捏缩放我正在做的项目，但我无法让它工作......我目前正在使用 python，但这里的语言实际上是不敬的。如果您知道如何实现这一点，请用适合您的任何语言进行解释（包括数学）。如果您可以在我当前来源的上下文中编写它；这将是惊人的。

我当前的实现看起来像这样（从资源下链接的 repo 中的 Inari.py 中的第 160 行开始）：

    def mousePressEvent(self, event: QtGui.QMouseEvent) -> None:
        if event.button() == QtCore.Qt.RightButton:
            self._lastRightMousePressPosition = event.pos()
            self._initialRightMousePressHorizontalScalingFactor = self.matrix().m11()
            self._initialRightMousePressVerticalScalingFactor = self.matrix().m22()

    def mouseMoveEvent(self, event: QtGui.QMouseEvent) -> None:
        # Camera panning and zooming
        ...
        if self._lastRightMousePressPosition == None:
            self._lastRightMousePressPosition = event.pos()
        if bool(QtWidgets.QApplication.queryKeyboardModifiers() & QtCore.Qt.KeyboardModifier.AltModifier):
            if bool((event.buttons() & QtCore.Qt.MiddleButton) or (event.buttons() & QtCore.Qt.LeftButton)):
                ...
            elif bool(event.buttons() & QtCore.Qt.RightButton):
                self.setTransformationAnchor(QtWidgets.QGraphicsView.NoAnchor)
                # TODO: Make zooming slower when distanceToOrigin increases
                # Capture data for correcting view translation offset.
                oldSceneSpaceOriginPoint = self.mapToScene(self._lastRightMousePressPosition)
                ### Calculate scaleing factor
                cursorPoint = np.array((self.mapToScene(event.pos()).x(), self.mapToScene(event.pos()).y()))
                originPoint = np.array((self.mapToScene(self._lastRightMousePressPosition).x(), self.mapToScene(self._lastRightMousePressPosition).y()))
                orientationPoint = np.add(originPoint, np.array((1, 1)))
                orientationVector = np.subtract(orientationPoint, originPoint)
                cursorVector = np.subtract(orientationPoint, cursorPoint)
                # Introduce a small constant value if the vector length is 0.
                # This is needed since the vector normalization calulation will cause an error if the vector has a length of 0
                orientationVector = np.add(orientationVector, np.array((0.001, 0.001))) if bool(np.linalg.norm(orientationVector) == 0) else orientationVector
                cursorVector = np.add(cursorVector, np.array((0.001, 0.001))) if bool(np.linalg.norm(cursorVector) == 0) else cursorVector
                orientationUnitVector = orientationVector/np.linalg.norm(orientationVector) # Normalization calulation
                cursorUnitVector = cursorVector/np.linalg.norm(cursorVector) # Normalization calulation
                dotProduct = np.dot(orientationUnitVector, cursorUnitVector)
                distanceToOrigin = np.linalg.norm(cursorPoint - originPoint)
                globalScaleFactor = (dotProduct * distanceToOrigin * 0.01) # dot * dist * zoomSensitivity
                ### Create the actial matrix for applying the scale; the initial scaleing factors should be set on mouse putton pressed.
                print(globalScaleFactor)
                horizontalScalingFactor = self._initialRightMousePressHorizontalScalingFactor + globalScaleFactor # FIXME: This should possibly not by multiplying since it wont be linear; i think...
                verticalScalingFactor = self._initialRightMousePressVerticalScalingFactor + globalScaleFactor # FIXME: If addition or subtraction is the correct way to go, the globalScaleFactor range need to change.
                verticalShearingFactor = self.matrix().m12()
                horizontalShearingFactor = self.matrix().m21()
                self.setMatrix(QtGui.QMatrix(horizontalScalingFactor, verticalShearingFactor, horizontalShearingFactor, verticalScalingFactor, self.matrix().dx(), self.matrix().dy()))
                # Correct view translation offset.
                newSceneSpaceOriginPoint = self.mapToScene(self._lastRightMousePressPosition)
                translationDelta = newSceneSpaceOriginPoint - oldSceneSpaceOriginPoint;
                self.translate(translationDelta.x(), translationDelta.y())
        ...

资源：

• 想要的效果：https ://i.gyazo.com/244ca7976de59712198e6cd671c8094c.mp4
• 我目前的实现：https ://gyazo.com/34540d57f5ba74f59fe533d5bdb00334
• 我的整个源代码（如 Inari.py 中的 300 行）：https ://github.com/KhaosSystems/Inari

标签： qtmathvector3dcamera