class Callout(QGraphicsItem): def __init__(self, chart): QGraphicsItem.__init__(self, chart) self._chart = chart self._text = "" self._textRect = QRectF() self._anchor = QPointF() self._font = QFont() self._rect = QRectF() def boundingRect(self): anchor = self.mapFromParent(self._chart.mapToPosition(self._anchor)) rect = QRectF() rect.setLeft(min(self._rect.left(), anchor.x())) rect.setRight(max(self._rect.right(), anchor.x())) rect.setTop(min(self._rect.top(), anchor.y())) rect.setBottom(max(self._rect.bottom(), anchor.y())) return rect def paint(self, painter, option, widget): path = QPainterPath() path.addRoundedRect(self._rect, 5, 5) anchor = self.mapFromParent(self._chart.mapToPosition(self._anchor)) if not self._rect.contains(anchor) and not self._anchor.isNull(): point1 = QPointF() point2 = QPointF() # establish the position of the anchor point in relation to _rect above = anchor.y() <= self._rect.top() aboveCenter = (anchor.y() > self._rect.top() and anchor.y() <= self._rect.center().y()) belowCenter = (anchor.y() > self._rect.center().y() and anchor.y() <= self._rect.bottom()) below = anchor.y() > self._rect.bottom() onLeft = anchor.x() <= self._rect.left() leftOfCenter = (anchor.x() > self._rect.left() and anchor.x() <= self._rect.center().x()) rightOfCenter = (anchor.x() > self._rect.center().x() and anchor.x() <= self._rect.right()) onRight = anchor.x() > self._rect.right() # get the nearest _rect corner. x = (onRight + rightOfCenter) * self._rect.width() y = (below + belowCenter) * self._rect.height() cornerCase = ((above and onLeft) or (above and onRight) or (below and onLeft) or (below and onRight)) vertical = abs(anchor.x() - x) > abs(anchor.y() - y) x1 = (x + leftOfCenter * 10 - rightOfCenter * 20 + cornerCase * int(not vertical) * (onLeft * 10 - onRight * 20)) y1 = (y + aboveCenter * 10 - belowCenter * 20 + cornerCase * vertical * (above * 10 - below * 20)) point1.setX(x1) point1.setY(y1) x2 = (x + leftOfCenter * 20 - rightOfCenter * 10 + cornerCase * int(not vertical) * (onLeft * 20 - onRight * 10)) y2 = (y + aboveCenter * 20 - belowCenter * 10 + cornerCase * vertical * (above * 20 - below * 10)) point2.setX(x2) point2.setY(y2) path.moveTo(point1) path.lineTo(anchor) path.lineTo(point2) path = path.simplified() painter.setBrush(QColor(255, 255, 255)) painter.drawPath(path) painter.drawText(self._textRect, self._text) def mousePressEvent(self, event): event.setAccepted(True) def mouseMoveEvent(self, event): if event.buttons() & Qt.LeftButton: self.setPos( mapToParent(event.pos() - event.buttonDownPos(Qt.LeftButton))) event.setAccepted(True) else: event.setAccepted(False) def setText(self, text): self._text = text metrics = QFontMetrics(self._font) self._textRect = QRectF( metrics.boundingRect(QRect(0.0, 0.0, 150.0, 150.0), Qt.AlignLeft, self._text)) self._textRect.translate(5, 5) self.prepareGeometryChange() self._rect = self._textRect.adjusted(-5, -5, 5, 5) def setAnchor(self, point): self._anchor = QPointF(point) def updateGeometry(self): self.prepareGeometryChange() self.setPos(self._chart.mapToPosition(self._anchor) + QPointF(10, -50))
class MandelbrotWidget(QWidget): def __init__(self, parent=None): super(MandelbrotWidget, self).__init__(parent) self.thread = RenderThread() self.pixmap = QPixmap() self.pixmapOffset = QPointF() self.lastDragPos = QPointF() self.centerX = DefaultCenterX self.centerY = DefaultCenterY self.pixmapScale = DefaultScale self.curScale = DefaultScale self.thread.renderedImage.connect(self.updatePixmap) self.setWindowTitle("Mandelbrot") self.setCursor(Qt.CrossCursor) self.resize(550, 400) def paintEvent(self, event): painter = QPainter(self) painter.fillRect(self.rect(), Qt.black) if self.pixmap.isNull(): painter.setPen(Qt.white) painter.drawText(self.rect(), Qt.AlignCenter, "Rendering initial image, please wait...") return if self.curScale == self.pixmapScale: painter.drawPixmap(self.pixmapOffset, self.pixmap) else: scaleFactor = self.pixmapScale / self.curScale newWidth = int(self.pixmap.width() * scaleFactor) newHeight = int(self.pixmap.height() * scaleFactor) newX = self.pixmapOffset.x() + (self.pixmap.width() - newWidth) / 2 newY = self.pixmapOffset.y() + (self.pixmap.height() - newHeight) / 2 painter.save() painter.translate(newX, newY) painter.scale(scaleFactor, scaleFactor) exposed, _ = painter.transform().inverted() exposed = exposed.mapRect(self.rect()).adjusted(-1, -1, 1, 1) painter.drawPixmap(exposed, self.pixmap, exposed) painter.restore() text = "Use mouse wheel or the '+' and '-' keys to zoom. Press and " \ "hold left mouse button to scroll." metrics = painter.fontMetrics() textWidth = metrics.horizontalAdvance(text) painter.setPen(Qt.NoPen) painter.setBrush(QColor(0, 0, 0, 127)) painter.drawRect((self.width() - textWidth) / 2 - 5, 0, textWidth + 10, metrics.lineSpacing() + 5) painter.setPen(Qt.white) painter.drawText((self.width() - textWidth) / 2, metrics.leading() + metrics.ascent(), text) def resizeEvent(self, event): self.thread.render(self.centerX, self.centerY, self.curScale, self.size()) def keyPressEvent(self, event): if event.key() == Qt.Key_Plus: self.zoom(ZoomInFactor) elif event.key() == Qt.Key_Minus: self.zoom(ZoomOutFactor) elif event.key() == Qt.Key_Left: self.scroll(-ScrollStep, 0) elif event.key() == Qt.Key_Right: self.scroll(+ScrollStep, 0) elif event.key() == Qt.Key_Down: self.scroll(0, -ScrollStep) elif event.key() == Qt.Key_Up: self.scroll(0, +ScrollStep) else: super(MandelbrotWidget, self).keyPressEvent(event) def wheelEvent(self, event): numDegrees = event.angleDelta().y() / 8 numSteps = numDegrees / 15.0 self.zoom(pow(ZoomInFactor, numSteps)) def mousePressEvent(self, event): if event.buttons() == Qt.LeftButton: self.lastDragPos = event.position() def mouseMoveEvent(self, event): if event.buttons() & Qt.LeftButton: pos = event.position() self.pixmapOffset += pos - self.lastDragPos self.lastDragPos = pos self.update() def mouseReleaseEvent(self, event): if event.button() == Qt.LeftButton: self.pixmapOffset += event.position() - self.lastDragPos self.lastDragPos = QPointF() deltaX = (self.width() - self.pixmap.width()) / 2 - self.pixmapOffset.x() deltaY = (self.height() - self.pixmap.height()) / 2 - self.pixmapOffset.y() self.scroll(deltaX, deltaY) def updatePixmap(self, image, scaleFactor): if not self.lastDragPos.isNull(): return self.pixmap = QPixmap.fromImage(image) self.pixmapOffset = QPointF() self.lastDragPosition = QPointF() self.pixmapScale = scaleFactor self.update() def zoom(self, zoomFactor): self.curScale *= zoomFactor self.update() self.thread.render(self.centerX, self.centerY, self.curScale, self.size()) def scroll(self, deltaX, deltaY): self.centerX += deltaX * self.curScale self.centerY += deltaY * self.curScale self.update() self.thread.render(self.centerX, self.centerY, self.curScale, self.size())