C++ Axis::getAlignment方法代码示例

//
// Draw track line with axis labels
//
void TrackAxis::trackLineAxis(XYChart *c, int mouseX)
{
    // Clear the current dynamic layer and get the DrawArea object to draw on it.
    DrawArea *d = c->initDynamicLayer();

    // The plot area object
    PlotArea *plotArea = c->getPlotArea();

    // Get the data x-value that is nearest to the mouse, and find its pixel coordinate.
    double xValue = c->getNearestXValue(mouseX);
    int xCoor = c->getXCoor(xValue);

    // The vertical track line is drawn up to the highest data point (the point with smallest
    // y-coordinate). We need to iterate all datasets in all layers to determine where it is.
    int minY = plotArea->getBottomY();

    // Iterate through all layers to find the highest data point
    for(int i = 0; i < c->getLayerCount(); ++i) {
        Layer *layer = c->getLayerByZ(i);

        // The data array index of the x-value
        int xIndex = layer->getXIndexOf(xValue);

        // Iterate through all the data sets in the layer
        for(int j = 0; j < layer->getDataSetCount(); ++j) {
            DataSet *dataSet = layer->getDataSetByZ(j);

            double dataPoint = dataSet->getPosition(xIndex);
            if ((dataPoint != Chart::NoValue) && (dataSet->getDataColor() != (int)Chart::Transparent))
                minY = min(minY, c->getYCoor(dataPoint, dataSet->getUseYAxis()));
        }
    }

    // Draw a vertical track line at the x-position up to the highest data point.
    d->vline(max(minY, plotArea->getTopY()), plotArea->getBottomY() + 6, xCoor, d->dashLineColor(
        0x000000, 0x0101));

    // Draw a label on the x-axis to show the track line position
    ostringstream xlabel;
    xlabel << "<*font,bgColor=000000*> " << c->xAxis()->getFormattedLabel(xValue, "mmm dd, yyyy")
        << " <*/font*>";
    TTFText *t = d->text(xlabel.str().c_str(), "arialbd.ttf", 8);
    t->draw(xCoor, plotArea->getBottomY() + 6, 0xffffff, Chart::Top);
    t->destroy();

    // Iterate through all layers to build the legend array
    for(int i = 0; i < c->getLayerCount(); ++i) {
        Layer *layer = c->getLayerByZ(i);

        // The data array index of the x-value
        int xIndex = layer->getXIndexOf(xValue);

        // Iterate through all the data sets in the layer
        for(int j = 0; j < layer->getDataSetCount(); ++j) {
            DataSet *dataSet = layer->getDataSetByZ(j);

            // The positional value, axis binding, pixel coordinate and color of the data point.
            double dataPoint = dataSet->getPosition(xIndex);
            Axis *yAxis = dataSet->getUseYAxis();
            int yCoor = c->getYCoor(dataPoint, yAxis);
            int color = dataSet->getDataColor();

            // Draw the axis label only for visible data points of named data sets
            if ((dataPoint != Chart::NoValue) && (color != (int)Chart::Transparent) && (yCoor >=
                plotArea->getTopY()) && (yCoor <= plotArea->getBottomY())) {
                // The axis label consists of 3 parts - a track dot for the data point, an axis label,
                // and a line joining the track dot to the axis label.

                // Draw the line first. The end point of the line at the axis label side depends on
                // whether the label is at the left or right side of the axis (that is, on whether the
                // axis is on the left or right side of the plot area).
                int xPos = yAxis->getX() + ((yAxis->getAlignment() == Chart::Left) ? -4 : 4);
                d->hline(xCoor, xPos, yCoor, d->dashLineColor(color, 0x0101));

                // Draw the track dot
                d->circle(xCoor, yCoor, 4, 4, color, color);

                // Draw the axis label. If the axis is on the left side of the plot area, the labels
                // should right aligned to the axis, and vice versa.
                ostringstream axisLabel;
                axisLabel << "<*font,bgColor=" << hex << color << "*> "
                    << c->formatValue(dataPoint, "{value|P4}")	<< " <*/font*>";
                t = d->text(axisLabel.str().c_str(), "arialbd.ttf", 8);
                t->draw(xPos, yCoor, 0xffffff,
                    ((yAxis->getAlignment() == Chart::Left) ? Chart::Right : Chart::Left));
                t->destroy();
            }
        }
    }
}