Пример #1
0
class TextAnnotation(Annotation):
    """Text annotation item for the canvas scheme.

    """
    editingFinished = Signal()
    """Emitted when the editing is finished (i.e. the item loses focus)."""

    textEdited = Signal()
    """Emitted when the edited text changes."""
    def __init__(self, parent=None, **kwargs):
        Annotation.__init__(self, parent, **kwargs)
        self.setFlag(QGraphicsItem.ItemIsMovable)
        self.setFlag(QGraphicsItem.ItemIsSelectable)

        self.setFocusPolicy(Qt.ClickFocus)

        self.__textMargins = (2, 2, 2, 2)

        rect = self.geometry().translated(-self.pos())
        self.__framePen = QPen(Qt.NoPen)
        self.__framePathItem = QGraphicsPathItem(self)
        self.__framePathItem.setPen(self.__framePen)

        self.__textItem = GraphicsTextEdit(self)
        self.__textItem.setPlaceholderText(self.tr("Enter text here"))
        self.__textItem.setPos(2, 2)
        self.__textItem.setTextWidth(rect.width() - 4)
        self.__textItem.setTabChangesFocus(True)
        self.__textItem.setTextInteractionFlags(Qt.NoTextInteraction)
        self.__textItem.setFont(self.font())
        self.__textInteractionFlags = Qt.NoTextInteraction

        layout = self.__textItem.document().documentLayout()
        layout.documentSizeChanged.connect(self.__onDocumentSizeChanged)

        self.__updateFrame()

    def adjustSize(self):
        """Resize to a reasonable size.
        """
        self.__textItem.setTextWidth(-1)
        self.__textItem.adjustSize()
        size = self.__textItem.boundingRect().size()
        left, top, right, bottom = self.textMargins()
        geom = QRectF(self.pos(), size + QSizeF(left + right, top + bottom))
        self.setGeometry(geom)

    def setFramePen(self, pen):
        """Set the frame pen. By default Qt.NoPen is used (i.e. the frame
        is not shown).
        """
        if pen != self.__framePen:
            self.__framePen = QPen(pen)
            self.__updateFrameStyle()

    def framePen(self):
        """Return the frame pen.
        """
        return QPen(self.__framePen)

    def setFrameBrush(self, brush):
        """Set the frame brush.
        """
        self.__framePathItem.setBrush(brush)

    def frameBrush(self):
        """Return the frame brush.
        """
        return self.__framePathItem.brush()

    def __updateFrameStyle(self):
        if self.isSelected():
            pen = QPen(QColor(96, 158, 215), 1.25, Qt.DashDotLine)
        else:
            pen = self.__framePen

        self.__framePathItem.setPen(pen)

    def setPlainText(self, text):
        """Set the annotation plain text.
        """
        self.__textItem.setPlainText(text)

    def toPlainText(self):
        return self.__textItem.toPlainText()

    def setHtml(self, text):
        """Set the annotation rich text.
        """
        self.__textItem.setHtml(text)

    def toHtml(self):
        return self.__textItem.toHtml()

    def setDefaultTextColor(self, color):
        """Set the default text color.
        """
        self.__textItem.setDefaultTextColor(color)

    def defaultTextColor(self):
        return self.__textItem.defaultTextColor()

    def setTextMargins(self, left, top, right, bottom):
        """Set the text margins.
        """
        margins = (left, top, right, bottom)
        if self.__textMargins != margins:
            self.__textMargins = margins
            self.__textItem.setPos(left, top)
            self.__textItem.setTextWidth(
                max(self.geometry().width() - left - right, 0))

    def textMargins(self):
        """Return the text margins.
        """
        return self.__textMargins

    def document(self):
        """Return the QTextDocument instance used internally.
        """
        return self.__textItem.document()

    def setTextCursor(self, cursor):
        self.__textItem.setTextCursor(cursor)

    def textCursor(self):
        return self.__textItem.textCursor()

    def setTextInteractionFlags(self, flags):
        self.__textInteractionFlags = flags

    def textInteractionFlags(self):
        return self.__textInteractionFlags

    def setDefaultStyleSheet(self, stylesheet):
        self.document().setDefaultStyleSheet(stylesheet)

    def mouseDoubleClickEvent(self, event):
        Annotation.mouseDoubleClickEvent(self, event)

        if event.buttons() == Qt.LeftButton and \
                self.__textInteractionFlags & Qt.TextEditable:
            self.startEdit()

    def startEdit(self):
        """Start the annotation text edit process.
        """
        self.__textItem.setTextInteractionFlags(self.__textInteractionFlags)
        self.__textItem.setFocus(Qt.MouseFocusReason)

        # Install event filter to find out when the text item loses focus.
        self.__textItem.installSceneEventFilter(self)
        self.__textItem.document().contentsChanged.connect(self.textEdited)

    def endEdit(self):
        """End the annotation edit.
        """
        self.__textItem.setTextInteractionFlags(Qt.NoTextInteraction)
        self.__textItem.removeSceneEventFilter(self)
        self.__textItem.document().contentsChanged.disconnect(self.textEdited)
        cursor = self.__textItem.textCursor()
        cursor.clearSelection()
        self.__textItem.setTextCursor(cursor)
        self.editingFinished.emit()

    def __onDocumentSizeChanged(self, size):
        # The size of the text document has changed. Expand the text
        # control rect's height if the text no longer fits inside.
        try:
            rect = self.geometry()
            _, top, _, bottom = self.textMargins()
            if rect.height() < (size.height() + bottom + top):
                rect.setHeight(size.height() + bottom + top)
                self.setGeometry(rect)
        except Exception:
            log.error("error in __onDocumentSizeChanged", exc_info=True)

    def __updateFrame(self):
        rect = self.geometry()
        rect.moveTo(0, 0)
        path = QPainterPath()
        path.addRect(rect)
        self.__framePathItem.setPath(path)

    def resizeEvent(self, event):
        width = event.newSize().width()
        left, _, right, _ = self.textMargins()
        self.__textItem.setTextWidth(max(width - left - right, 0))
        self.__updateFrame()
        QGraphicsWidget.resizeEvent(self, event)

    def sceneEventFilter(self, obj, event):
        if obj is self.__textItem and event.type() == QEvent.FocusOut:
            self.__textItem.focusOutEvent(event)
            self.endEdit()
            return True

        return Annotation.sceneEventFilter(self, obj, event)

    def itemChange(self, change, value):
        if change == QGraphicsItem.ItemSelectedHasChanged:
            self.__updateFrameStyle()

        return Annotation.itemChange(self, change, value)

    def changeEvent(self, event):
        if event.type() == QEvent.FontChange:
            self.__textItem.setFont(self.font())

        Annotation.changeEvent(self, event)
Пример #2
0
class OWAxis(QGraphicsItem):

    Role = OWPalette.Axis

    def __init__(self,
                 id,
                 title='',
                 title_above=False,
                 title_location=AxisMiddle,
                 line=None,
                 arrows=AxisEnd,
                 plot=None):
        QGraphicsItem.__init__(self)
        self.setFlag(QGraphicsItem.ItemHasNoContents)
        self.setZValue(AxisZValue)
        self.id = id
        self.title = title
        self.title_location = title_location
        self.data_line = line
        self.plot = plot
        self.graph_line = None
        self.size = None
        self.scale = None
        self.tick_length = (10, 5, 0)
        self.arrows = arrows
        self.title_above = title_above
        self.line_item = QGraphicsLineItem(self)
        self.title_item = QGraphicsTextItem(self)
        self.end_arrow_item = None
        self.start_arrow_item = None
        self.show_title = False
        self.scale = None
        path = QPainterPath()
        path.setFillRule(Qt.WindingFill)
        path.moveTo(0, 3.09)
        path.lineTo(0, -3.09)
        path.lineTo(9.51, 0)
        path.closeSubpath()
        self.arrow_path = path
        self.label_items = []
        self.label_bg_items = []
        self.tick_items = []
        self._ticks = []
        self.zoom_transform = QTransform()
        self.labels = None
        self.auto_range = None
        self.auto_scale = True

        self.zoomable = False
        self.update_callback = None
        self.max_text_width = 50
        self.text_margin = 5
        self.always_horizontal_text = False

    def update_ticks(self):
        self._ticks = []
        major, medium, minor = self.tick_length
        if self.labels is not None and not self.auto_scale:
            for i, text in enumerate(self.labels):
                self._ticks.append((i, text, medium, 1))
        else:
            if self.scale and not self.auto_scale:
                min, max, step = self.scale
            elif self.auto_range:
                min, max = self.auto_range
                if min is not None and max is not None:
                    step = (max - min) / 10
                else:
                    return
            else:
                return

            if max == min:
                return

            magnitude = int(3 * log10(abs(max - min)) + 1)
            if magnitude % 3 == 0:
                first_place = 1
            elif magnitude % 3 == 1:
                first_place = 2
            else:
                first_place = 5
            magnitude = magnitude / 3 - 1
            step = first_place * pow(10, magnitude)
            val = ceil(min / step) * step
            while val <= max:
                self._ticks.append((val, "%.4g" % val, medium, step))
                val = val + step

    def update_graph(self):
        if self.update_callback:
            self.update_callback()

    def update(self, zoom_only=False):
        self.update_ticks()
        line_color = self.plot.color(OWPalette.Axis)
        text_color = self.plot.color(OWPalette.Text)
        if not self.graph_line or not self.scene():
            return
        self.line_item.setLine(self.graph_line)
        self.line_item.setPen(line_color)
        if self.title:
            self.title_item.setHtml('<b>' + self.title + '</b>')
            self.title_item.setDefaultTextColor(text_color)
        if self.title_location == AxisMiddle:
            title_p = 0.5
        elif self.title_location == AxisEnd:
            title_p = 0.95
        else:
            title_p = 0.05
        title_pos = self.graph_line.pointAt(title_p)
        v = self.graph_line.normalVector().unitVector()

        dense_text = False
        if hasattr(self, 'title_margin'):
            offset = self.title_margin
        elif self._ticks:
            if self.should_be_expanded():
                offset = 55
                dense_text = True
            else:
                offset = 35
        else:
            offset = 10

        if self.title_above:
            title_pos = title_pos + (v.p2() - v.p1()) * (
                offset + QFontMetrics(self.title_item.font()).height())
        else:
            title_pos = title_pos - (v.p2() - v.p1()) * offset
        ## TODO: Move it according to self.label_pos
        self.title_item.setVisible(self.show_title)
        self.title_item.setRotation(-self.graph_line.angle())
        c = self.title_item.mapToParent(
            self.title_item.boundingRect().center())
        tl = self.title_item.mapToParent(
            self.title_item.boundingRect().topLeft())
        self.title_item.setPos(title_pos - c + tl)

        ## Arrows
        if not zoom_only:
            if self.start_arrow_item:
                self.scene().removeItem(self.start_arrow_item)
                self.start_arrow_item = None
            if self.end_arrow_item:
                self.scene().removeItem(self.end_arrow_item)
                self.end_arrow_item = None

        if self.arrows & AxisStart:
            if not zoom_only or not self.start_arrow_item:
                self.start_arrow_item = QGraphicsPathItem(
                    self.arrow_path, self)
            self.start_arrow_item.setPos(self.graph_line.p1())
            self.start_arrow_item.setRotation(-self.graph_line.angle() + 180)
            self.start_arrow_item.setBrush(line_color)
            self.start_arrow_item.setPen(line_color)
        if self.arrows & AxisEnd:
            if not zoom_only or not self.end_arrow_item:
                self.end_arrow_item = QGraphicsPathItem(self.arrow_path, self)
            self.end_arrow_item.setPos(self.graph_line.p2())
            self.end_arrow_item.setRotation(-self.graph_line.angle())
            self.end_arrow_item.setBrush(line_color)
            self.end_arrow_item.setPen(line_color)

        ## Labels

        n = len(self._ticks)
        resize_plot_item_list(self.label_items, n, QGraphicsTextItem, self)
        resize_plot_item_list(self.label_bg_items, n, QGraphicsRectItem, self)
        resize_plot_item_list(self.tick_items, n, QGraphicsLineItem, self)

        test_rect = QRectF(self.graph_line.p1(),
                           self.graph_line.p2()).normalized()
        test_rect.adjust(-1, -1, 1, 1)

        n_v = self.graph_line.normalVector().unitVector()
        if self.title_above:
            n_p = n_v.p2() - n_v.p1()
        else:
            n_p = n_v.p1() - n_v.p2()
        l_v = self.graph_line.unitVector()
        l_p = l_v.p2() - l_v.p1()
        for i in range(n):
            pos, text, size, step = self._ticks[i]
            hs = 0.5 * step
            tick_pos = self.map_to_graph(pos)
            if not test_rect.contains(tick_pos):
                self.tick_items[i].setVisible(False)
                self.label_items[i].setVisible(False)
                continue
            item = self.label_items[i]
            item.setVisible(True)
            if not zoom_only:
                if self.id in XAxes or getattr(self, 'is_horizontal', False):
                    item.setHtml('<center>' + Qt.escape(text.strip()) +
                                 '</center>')
                else:
                    item.setHtml(Qt.escape(text.strip()))

            item.setTextWidth(-1)
            text_angle = 0
            if dense_text:
                w = min(item.boundingRect().width(), self.max_text_width)
                item.setTextWidth(w)
                if self.title_above:
                    label_pos = tick_pos + n_p * (
                        w + self.text_margin
                    ) + l_p * item.boundingRect().height() / 2
                else:
                    label_pos = tick_pos + n_p * self.text_margin + l_p * item.boundingRect(
                    ).height() / 2
                text_angle = -90 if self.title_above else 90
            else:
                w = min(
                    item.boundingRect().width(),
                    QLineF(self.map_to_graph(pos - hs),
                           self.map_to_graph(pos + hs)).length())
                label_pos = tick_pos + n_p * self.text_margin - l_p * w / 2
                item.setTextWidth(w)

            if not self.always_horizontal_text:
                if self.title_above:
                    item.setRotation(-self.graph_line.angle() - text_angle)
                else:
                    item.setRotation(self.graph_line.angle() - text_angle)

            item.setPos(label_pos)
            item.setDefaultTextColor(text_color)

            self.label_bg_items[i].setRect(item.boundingRect())
            self.label_bg_items[i].setPen(QPen(Qt.NoPen))
            self.label_bg_items[i].setBrush(self.plot.color(OWPalette.Canvas))

            item = self.tick_items[i]
            item.setVisible(True)
            tick_line = QLineF(v)
            tick_line.translate(-tick_line.p1())
            tick_line.setLength(size)
            if self.title_above:
                tick_line.setAngle(tick_line.angle() + 180)
            item.setLine(tick_line)
            item.setPen(line_color)
            item.setPos(self.map_to_graph(pos))

    @staticmethod
    def make_title(label, unit=None):
        lab = '<i>' + label + '</i>'
        if unit:
            lab = lab + ' [' + unit + ']'
        return lab

    def set_line(self, line):
        self.graph_line = line
        self.update()

    def set_title(self, title):
        self.title = title
        self.update()

    def set_show_title(self, b):
        self.show_title = b
        self.update()

    def set_labels(self, labels):
        self.labels = labels
        self.graph_line = None
        self.auto_scale = False
        self.update_ticks()
        self.update_graph()

    def set_scale(self, min, max, step_size):
        self.scale = (min, max, step_size)
        self.graph_line = None
        self.auto_scale = False
        self.update_ticks()
        self.update_graph()

    def set_tick_length(self, minor, medium, major):
        self.tick_length = (minor, medium, major)
        self.update()

    def map_to_graph(self, x):
        min, max = self.plot.bounds_for_axis(self.id)
        if min == max:
            return QPointF()
        line_point = self.graph_line.pointAt((x - min) / (max - min))
        end_point = line_point * self.zoom_transform
        return self.projection(end_point, self.graph_line)

    @staticmethod
    def projection(point, line):
        norm = line.normalVector()
        norm.translate(point - norm.p1())
        p = QPointF()
        type = line.intersect(norm, p)
        return p

    def continuous_labels(self):
        min, max, step = self.scale
        magnitude = log10(abs(max - min))

    def paint(self, painter, option, widget):
        pass

    def boundingRect(self):
        return QRectF()

    def ticks(self):
        if not self._ticks:
            self.update_ticks()
        return self._ticks

    def bounds(self):
        if self.labels:
            return -0.2, len(self.labels) - 0.8
        elif self.scale:
            min, max, _step = self.scale
            return min, max
        elif self.auto_range:
            return self.auto_range
        else:
            return 0, 1

    def should_be_expanded(self):
        self.update_ticks()
        return self.id in YAxes or self.always_horizontal_text or sum(
            len(t[1]) for t in self._ticks) * 12 > self.plot.width()
Пример #3
0
class TextAnnotation(Annotation):
    """Text annotation item for the canvas scheme.

    """
    editingFinished = Signal()
    """Emitted when the editing is finished (i.e. the item loses focus)."""

    textEdited = Signal()
    """Emitted when the edited text changes."""

    def __init__(self, parent=None, **kwargs):
        Annotation.__init__(self, parent, **kwargs)
        self.setFlag(QGraphicsItem.ItemIsMovable)
        self.setFlag(QGraphicsItem.ItemIsSelectable)

        self.setFocusPolicy(Qt.ClickFocus)

        self.__textMargins = (2, 2, 2, 2)

        rect = self.geometry().translated(-self.pos())
        self.__framePathItem = QGraphicsPathItem(self)
        self.__framePathItem.setPen(QPen(Qt.NoPen))

        self.__textItem = GraphicsTextEdit(self)
        self.__textItem.setPlaceholderText(self.tr("Enter text here"))
        self.__textItem.setPos(2, 2)
        self.__textItem.setTextWidth(rect.width() - 4)
        self.__textItem.setTabChangesFocus(True)
        self.__textItem.setTextInteractionFlags(Qt.NoTextInteraction)
        self.__textItem.setFont(self.font())
        self.__textInteractionFlags = Qt.NoTextInteraction

        layout = self.__textItem.document().documentLayout()
        layout.documentSizeChanged.connect(self.__onDocumentSizeChanged)

        self.__updateFrame()

    def adjustSize(self):
        """Resize to a reasonable size.
        """
        self.__textItem.setTextWidth(-1)
        self.__textItem.adjustSize()
        size = self.__textItem.boundingRect().size()
        left, top, right, bottom = self.textMargins()
        geom = QRectF(self.pos(), size + QSizeF(left + right, top + bottom))
        self.setGeometry(geom)

    def setFramePen(self, pen):
        """Set the frame pen. By default Qt.NoPen is used (i.e. the frame
        is not shown).

        """
        self.__framePathItem.setPen(pen)

    def framePen(self):
        """Return the frame pen.
        """
        return self.__framePathItem.pen()

    def setFrameBrush(self, brush):
        """Set the frame brush.
        """
        self.__framePathItem.setBrush(brush)

    def frameBrush(self):
        """Return the frame brush.
        """
        return self.__framePathItem.brush()

    def setPlainText(self, text):
        """Set the annotation plain text.
        """
        self.__textItem.setPlainText(text)

    def toPlainText(self):
        return self.__textItem.toPlainText()

    def setHtml(self, text):
        """Set the annotation rich text.
        """
        self.__textItem.setHtml(text)

    def toHtml(self):
        return self.__textItem.toHtml()

    def setDefaultTextColor(self, color):
        """Set the default text color.
        """
        self.__textItem.setDefaultTextColor(color)

    def defaultTextColor(self):
        return self.__textItem.defaultTextColor()

    def setTextMargins(self, left, top, right, bottom):
        """Set the text margins.
        """
        margins = (left, top, right, bottom)
        if self.__textMargins != margins:
            self.__textMargins = margins
            self.__textItem.setPos(left, top)
            self.__textItem.setTextWidth(
                max(self.geometry().width() - left - right, 0)
            )

    def textMargins(self):
        """Return the text margins.
        """
        return self.__textMargins

    def document(self):
        """Return the QTextDocument instance used internally.
        """
        return self.__textItem.document()

    def setTextCursor(self, cursor):
        self.__textItem.setTextCursor(cursor)

    def textCursor(self):
        return self.__textItem.textCursor()

    def setTextInteractionFlags(self, flags):
        self.__textInteractionFlags = flags

    def textInteractionFlags(self):
        return self.__textInteractionFlags

    def setDefaultStyleSheet(self, stylesheet):
        self.document().setDefaultStyleSheet(stylesheet)

    def mouseDoubleClickEvent(self, event):
        Annotation.mouseDoubleClickEvent(self, event)

        if event.buttons() == Qt.LeftButton and \
                self.__textInteractionFlags & Qt.TextEditable:
            self.startEdit()

    def startEdit(self):
        """Start the annotation text edit process.
        """
        self.__textItem.setTextInteractionFlags(self.__textInteractionFlags)
        self.__textItem.setFocus(Qt.MouseFocusReason)

        # Install event filter to find out when the text item loses focus.
        self.__textItem.installSceneEventFilter(self)
        self.__textItem.document().contentsChanged.connect(
            self.textEdited
        )

    def endEdit(self):
        """End the annotation edit.
        """
        self.__textItem.setTextInteractionFlags(Qt.NoTextInteraction)
        self.__textItem.removeSceneEventFilter(self)
        self.__textItem.document().contentsChanged.disconnect(
            self.textEdited
        )
        self.editingFinished.emit()

    def __onDocumentSizeChanged(self, size):
        # The size of the text document has changed. Expand the text
        # control rect's height if the text no longer fits inside.
        try:
            rect = self.geometry()
            _, top, _, bottom = self.textMargins()
            if rect.height() < (size.height() + bottom + top):
                rect.setHeight(size.height() + bottom + top)
                self.setGeometry(rect)
        except Exception:
            log.error("error in __onDocumentSizeChanged",
                      exc_info=True)

    def __updateFrame(self):
        rect = self.geometry()
        rect.moveTo(0, 0)
        path = QPainterPath()
        path.addRect(rect)
        self.__framePathItem.setPath(path)

    def resizeEvent(self, event):
        width = event.newSize().width()
        left, _, right, _ = self.textMargins()
        self.__textItem.setTextWidth(max(width - left - right, 0))
        self.__updateFrame()
        QGraphicsWidget.resizeEvent(self, event)

    def sceneEventFilter(self, obj, event):
        if obj is self.__textItem and event.type() == QEvent.FocusOut:
            self.__textItem.focusOutEvent(event)
            self.endEdit()
            return True

        return Annotation.sceneEventFilter(self, obj, event)

    def itemChange(self, change, value):
        if change == QGraphicsItem.ItemSelectedHasChanged:
            if self.isSelected():
                self.setFramePen(QPen(Qt.DashDotLine))
            else:
                self.setFramePen(QPen(Qt.NoPen))

        return Annotation.itemChange(self, change, value)

    def changeEvent(self, event):
        if event.type() == QEvent.FontChange:
            self.__textItem.setFont(self.font())

        Annotation.changeEvent(self, event)
Пример #4
0
class OWAxis(QGraphicsItem):

    Role = OWPalette.Axis

    def __init__(self, id, title = '', title_above = False, title_location = AxisMiddle, line = None, arrows = 0, plot = None):
        QGraphicsItem.__init__(self)
        self.setFlag(QGraphicsItem.ItemHasNoContents)
        self.setZValue(AxisZValue)
        self.id = id
        self.title = title
        self.title_location = title_location
        self.data_line = line
        self.plot = plot
        self.graph_line = None
        self.size = None
        self.scale = None
        self.tick_length = (10, 5, 0)
        self.arrows = arrows
        self.title_above = title_above
        self.line_item = QGraphicsLineItem(self)
        self.title_item = QGraphicsTextItem(self)
        self.end_arrow_item = None
        self.start_arrow_item = None
        self.show_title = False
        self.scale = None
        path = QPainterPath()
        path.setFillRule(Qt.WindingFill)
        path.moveTo(0, 3.09)
        path.lineTo(0, -3.09)
        path.lineTo(9.51, 0)
        path.closeSubpath()
        self.arrow_path = path
        self.label_items = []
        self.label_bg_items = []
        self.tick_items = []
        self._ticks = []
        self.zoom_transform = QTransform()
        self.labels = None
        self.auto_range = None
        self.auto_scale = True

        self.zoomable = False
        self.update_callback = None
        self.max_text_width = 50
        self.text_margin = 5
        self.always_horizontal_text = False

    @staticmethod
    def compute_scale(min, max):
        magnitude = int(3*log10(abs(max-min)) + 1)
        if magnitude % 3 == 0:
            first_place = 1
        elif magnitude % 3 == 1:
            first_place = 2
        else:
            first_place = 5
        magnitude = magnitude // 3 - 1
        step = first_place * pow(10, magnitude)
        first_val = ceil(min/step) * step
        return first_val, step

    def update_ticks(self):
        self._ticks = []
        major, medium, minor = self.tick_length
        if self.labels is not None and not self.auto_scale:
            for i, text in enumerate(self.labels):
                self._ticks.append( ( i, text, medium, 1 ) )
        else:
            if self.scale and not self.auto_scale:
                min, max, step = self.scale
            elif self.auto_range:
                min, max = self.auto_range
                if min is not None and max is not None:
                    step = (max - min)/10
                else:
                    return
            else:
                return

            if max == min:
                return

            val, step = self.compute_scale(min, max)
            while val <= max:
                self._ticks.append( ( val, "%.4g" % val, medium, step ) )
                val += step

    def update_graph(self):
        if self.update_callback:
            self.update_callback()


    def update(self, zoom_only = False):
        self.update_ticks()
        line_color = self.plot.color(OWPalette.Axis)
        text_color = self.plot.color(OWPalette.Text)
        if not self.graph_line or not self.scene():
            return
        self.line_item.setLine(self.graph_line)
        self.line_item.setPen(line_color)
        if self.title:
            self.title_item.setHtml('<b>' + self.title + '</b>')
            self.title_item.setDefaultTextColor(text_color)
        if self.title_location == AxisMiddle:
            title_p = 0.5
        elif self.title_location == AxisEnd:
            title_p = 0.95
        else:
            title_p = 0.05
        title_pos = self.graph_line.pointAt(title_p)
        v = self.graph_line.normalVector().unitVector()

        dense_text = False
        if hasattr(self, 'title_margin'):
            offset = self.title_margin
        elif self._ticks:
            if self.should_be_expanded():
                offset = 55
                dense_text = True
            else:
                offset = 35
        else:
            offset = 10

        if self.title_above:
            title_pos = title_pos + (v.p2() - v.p1())*(offset + QFontMetrics(self.title_item.font()).height())
        else:
            title_pos = title_pos - (v.p2() - v.p1())*offset
        ## TODO: Move it according to self.label_pos
        self.title_item.setVisible(self.show_title)
        self.title_item.setRotation(-self.graph_line.angle())
        c = self.title_item.mapToParent(self.title_item.boundingRect().center())
        tl = self.title_item.mapToParent(self.title_item.boundingRect().topLeft())
        self.title_item.setPos(title_pos - c + tl)

        ## Arrows
        if not zoom_only:
            if self.start_arrow_item:
                self.scene().removeItem(self.start_arrow_item)
                self.start_arrow_item = None
            if self.end_arrow_item:
                self.scene().removeItem(self.end_arrow_item)
                self.end_arrow_item = None

        if self.arrows & AxisStart:
            if not zoom_only or not self.start_arrow_item:
                self.start_arrow_item = QGraphicsPathItem(self.arrow_path, self)
            self.start_arrow_item.setPos(self.graph_line.p1())
            self.start_arrow_item.setRotation(-self.graph_line.angle() + 180)
            self.start_arrow_item.setBrush(line_color)
            self.start_arrow_item.setPen(line_color)
        if self.arrows & AxisEnd:
            if not zoom_only or not self.end_arrow_item:
                self.end_arrow_item = QGraphicsPathItem(self.arrow_path, self)
            self.end_arrow_item.setPos(self.graph_line.p2())
            self.end_arrow_item.setRotation(-self.graph_line.angle())
            self.end_arrow_item.setBrush(line_color)
            self.end_arrow_item.setPen(line_color)

        ## Labels

        n = len(self._ticks)
        resize_plot_item_list(self.label_items, n, QGraphicsTextItem, self)
        resize_plot_item_list(self.label_bg_items, n, QGraphicsRectItem, self)
        resize_plot_item_list(self.tick_items, n, QGraphicsLineItem, self)

        test_rect = QRectF(self.graph_line.p1(),  self.graph_line.p2()).normalized()
        test_rect.adjust(-1, -1, 1, 1)

        n_v = self.graph_line.normalVector().unitVector()
        if self.title_above:
            n_p = n_v.p2() - n_v.p1()
        else:
            n_p = n_v.p1() - n_v.p2()
        l_v = self.graph_line.unitVector()
        l_p = l_v.p2() - l_v.p1()
        for i in range(n):
            pos, text, size, step = self._ticks[i]
            hs = 0.5 * step
            tick_pos = self.map_to_graph( pos )
            if not test_rect.contains(tick_pos):
                self.tick_items[i].setVisible(False)
                self.label_items[i].setVisible(False)
                continue
            item = self.label_items[i]
            item.setVisible(True)
            if not zoom_only:
                if self.id in XAxes or getattr(self, 'is_horizontal', False):
                    item.setHtml( '<center>' + Qt.escape(text.strip()) + '</center>')
                else:
                    item.setHtml(Qt.escape(text.strip()))

            item.setTextWidth(-1)
            text_angle = 0
            if dense_text:
                w = min(item.boundingRect().width(), self.max_text_width)
                item.setTextWidth(w)
                if self.title_above:
                    label_pos = tick_pos + n_p * (w + self.text_margin) + l_p * item.boundingRect().height()/2
                else:
                    label_pos = tick_pos + n_p * self.text_margin + l_p * item.boundingRect().height()/2
                text_angle = -90 if self.title_above else 90
            else:
                w = min(item.boundingRect().width(), QLineF(self.map_to_graph(pos - hs), self.map_to_graph(pos + hs) ).length())
                label_pos = tick_pos + n_p * self.text_margin - l_p * w/2
                item.setTextWidth(w)

            if not self.always_horizontal_text:
                if self.title_above:
                    item.setRotation(-self.graph_line.angle() - text_angle)
                else:
                    item.setRotation(self.graph_line.angle() - text_angle)

            item.setPos(label_pos)
            item.setDefaultTextColor(text_color)

            self.label_bg_items[i].setRect(item.boundingRect())
            self.label_bg_items[i].setPen(QPen(Qt.NoPen))
            self.label_bg_items[i].setBrush(self.plot.color(OWPalette.Canvas))

            item = self.tick_items[i]
            item.setVisible(True)
            tick_line = QLineF(v)
            tick_line.translate(-tick_line.p1())
            tick_line.setLength(size)
            if self.title_above:
                tick_line.setAngle(tick_line.angle() + 180)
            item.setLine( tick_line )
            item.setPen(line_color)
            item.setPos(self.map_to_graph(pos))

    @staticmethod
    def make_title(label, unit = None):
        lab = '<i>' + label + '</i>'
        if unit:
            lab = lab + ' [' + unit + ']'
        return lab

    def set_line(self, line):
        self.graph_line = line
        self.update()

    def set_title(self, title):
        self.title = title
        self.update()

    def set_show_title(self, b):
        self.show_title = b
        self.update()

    def set_labels(self, labels):
        self.labels = labels
        self.graph_line = None
        self.auto_scale = False
        self.update_ticks()
        self.update_graph()

    def set_scale(self, min, max, step_size):
        self.scale = (min, max, step_size)
        self.graph_line = None
        self.auto_scale = False
        self.update_ticks()
        self.update_graph()

    def set_tick_length(self, minor, medium, major):
        self.tick_length = (minor, medium, major)
        self.update()

    def map_to_graph(self, x):
        min, max = self.plot.bounds_for_axis(self.id)
        if min == max:
            return QPointF()
        line_point = self.graph_line.pointAt( (x-min)/(max-min) )
        end_point = line_point * self.zoom_transform
        return self.projection(end_point, self.graph_line)

    @staticmethod
    def projection(point, line):
        norm = line.normalVector()
        norm.translate(point - norm.p1())
        p = QPointF()
        type = line.intersect(norm, p)
        return p

    def continuous_labels(self):
        min, max, step = self.scale
        magnitude = log10(abs(max-min))

    def paint(self, painter, option, widget):
        pass

    def boundingRect(self):
        return QRectF()

    def ticks(self):
        if not self._ticks:
            self.update_ticks()
        return self._ticks

    def bounds(self):
        if self.labels:
            return -0.2, len(self.labels) -0.8
        elif self.scale:
            min, max, _step = self.scale
            return min, max
        elif self.auto_range:
            return self.auto_range
        else:
            return 0, 1

    def should_be_expanded(self):
        self.update_ticks()
        return self.id in YAxes or self.always_horizontal_text or sum(len(t[1]) for t in self._ticks) * 12 > self.plot.width()