logaxis.java

java图形利器

     * axis covers the specified <code>edge</code> of the <code>area</code>.
     * 
     * @param java2DValue  the Java2D coordinate.
     * @param area  the area.
     * @param edge  the edge that the axis belongs to.
     * 
     * @return A value along the axis scale.
     */
    public double java2DToValue(double java2DValue, Rectangle2D area, 
            RectangleEdge edge) {
        
        Range range = getRange();
        double axisMin = calculateLog(range.getLowerBound());
        double axisMax = calculateLog(range.getUpperBound());

        double min = 0.0;
        double max = 0.0;
        if (RectangleEdge.isTopOrBottom(edge)) {
            min = area.getX();
            max = area.getMaxX();
        }
        else if (RectangleEdge.isLeftOrRight(edge)) {
            min = area.getMaxY();
            max = area.getY();
        }
        double log = 0.0;
        if (isInverted()) {
            log = axisMax - (java2DValue - min) / (max - min) 
                    * (axisMax - axisMin);
        }
        else {
            log = axisMin + (java2DValue - min) / (max - min) 
                    * (axisMax - axisMin);
        }
        return calculateValue(log);
    }

    /**
     * Converts a value on the axis scale to a Java2D coordinate relative to 
     * the given <code>area</code>, based on the axis running along the 
     * specified <code>edge</code>.
     * 
     * @param value  the data value.
     * @param area  the area.
     * @param edge  the edge.
     * 
     * @return The Java2D coordinate corresponding to <code>value</code>.
     */
    public double valueToJava2D(double value, Rectangle2D area, 
            RectangleEdge edge) {
        
        Range range = getRange();
        double axisMin = calculateLog(range.getLowerBound());
        double axisMax = calculateLog(range.getUpperBound());
        value = calculateLog(value);
        
        double min = 0.0;
        double max = 0.0;
        if (RectangleEdge.isTopOrBottom(edge)) {
            min = area.getX();
            max = area.getMaxX();
        }
        else if (RectangleEdge.isLeftOrRight(edge)) {
            max = area.getMinY();
            min = area.getMaxY();
        }
        if (isInverted()) {
            return max 
                   - ((value - axisMin) / (axisMax - axisMin)) * (max - min);
        }
        else {
            return min 
                   + ((value - axisMin) / (axisMax - axisMin)) * (max - min);
        }
    }
    
    /**
     * Configures the axis.  This method is typically called when an axis
     * is assigned to a new plot.
     */
    public void configure() {
        if (isAutoRange()) {
            autoAdjustRange();
        }
    }

    /**
     * Adjusts the axis range to match the data range that the axis is
     * required to display.
     */
    protected void autoAdjustRange() {
        Plot plot = getPlot();
        if (plot == null) {
            return;  // no plot, no data
        }

        if (plot instanceof ValueAxisPlot) {
            ValueAxisPlot vap = (ValueAxisPlot) plot;

            Range r = vap.getDataRange(this);
            if (r == null) {
                r = getDefaultAutoRange();
            }
            
            double upper = r.getUpperBound();
            double lower = r.getLowerBound();
            double range = upper - lower;

            // if fixed auto range, then derive lower bound...
            double fixedAutoRange = getFixedAutoRange();
            if (fixedAutoRange > 0.0) {
                lower = Math.max(upper - fixedAutoRange, this.smallestValue);
            }
            else {
                // ensure the autorange is at least <minRange> in size...
                double minRange = getAutoRangeMinimumSize();
                if (range < minRange) {
                    double expand = (minRange - range) / 2;
                    upper = upper + expand;
                    lower = lower - expand;
                }

                // apply the margins - these should apply to the exponent range
//                upper = upper + getUpperMargin() * range;
//                lower = lower - getLowerMargin() * range;
            }

            setRange(new Range(lower, upper), false, false);
        }

    }

    /**
     * Draws the axis on a Java 2D graphics device (such as the screen or a 
     * printer).
     *
     * @param g2  the graphics device (<code>null</code> not permitted).
     * @param cursor  the cursor location (determines where to draw the axis).
     * @param plotArea  the area within which the axes and plot should be drawn.
     * @param dataArea  the area within which the data should be drawn.
     * @param edge  the axis location (<code>null</code> not permitted).
     * @param plotState  collects information about the plot 
     *                   (<code>null</code> permitted).
     * 
     * @return The axis state (never <code>null</code>).
     */
    public AxisState draw(Graphics2D g2, double cursor, Rectangle2D plotArea, 
            Rectangle2D dataArea, RectangleEdge edge, 
            PlotRenderingInfo plotState) {
        
        AxisState state = null;
        // if the axis is not visible, don't draw it...
        if (!isVisible()) {
            state = new AxisState(cursor);
            // even though the axis is not visible, we need ticks for the 
            // gridlines...
            List ticks = refreshTicks(g2, state, dataArea, edge); 
            state.setTicks(ticks);
            return state;
        }
        state = drawTickMarksAndLabels(g2, cursor, plotArea, dataArea, edge);
        state = drawLabel(getLabel(), g2, plotArea, dataArea, edge, state);
        return state;
    }

    /**
     * Calculates the positions of the tick labels for the axis, storing the 
     * results in the tick label list (ready for drawing).
     *
     * @param g2  the graphics device.
     * @param state  the axis state.
     * @param dataArea  the area in which the plot should be drawn.
     * @param edge  the location of the axis.
     * 
     * @return A list of ticks.
     *
     */
    public List refreshTicks(Graphics2D g2, AxisState state, 
            Rectangle2D dataArea, RectangleEdge edge) {

        List result = new java.util.ArrayList();
        if (RectangleEdge.isTopOrBottom(edge)) {
            result = refreshTicksHorizontal(g2, dataArea, edge);
        }
        else if (RectangleEdge.isLeftOrRight(edge)) {
            result = refreshTicksVertical(g2, dataArea, edge);
        }
        return result;

    }

    /**
     * Returns a list of ticks for an axis at the top or bottom of the chart.
     * 
     * @param g2  the graphics device.
     * @param dataArea  the data area.
     * @param edge  the edge.
     * 
     * @return A list of ticks.
     */
    protected List refreshTicksHorizontal(Graphics2D g2, Rectangle2D dataArea, 
            RectangleEdge edge) {
        Range range = getRange();
        List ticks = new ArrayList();
        double start = Math.floor(calculateLog(getLowerBound()));
        double end = Math.ceil(calculateLog(getUpperBound()));
        double current = start;
        while (current <= end) {
            double v = calculateValue(current);
            if (range.contains(v)) {
                ticks.add(new NumberTick(new Double(v), createTickLabel(v), 
                        TextAnchor.TOP_CENTER, TextAnchor.CENTER, 0.0));
            }
            // add minor ticks (for gridlines)
            double next = Math.pow(this.base, current 
                    + this.tickUnit.getSize());
            for (int i = 1; i < this.minorTickCount; i++) {
                double minorV = v + i * ((next - v) / this.minorTickCount);
                if (range.contains(minorV)) {
                    ticks.add(new NumberTick(new Double(minorV), 
                        "", TextAnchor.TOP_CENTER, TextAnchor.CENTER, 0.0));
                }
            }
            current = current + this.tickUnit.getSize();
        }
        return ticks;
    }
    
    /**
     * Returns a list of ticks for an axis at the left or right of the chart.
     * 
     * @param g2  the graphics device.
     * @param dataArea  the data area.
     * @param edge  the edge.
     * 
     * @return A list of ticks.
     */
    protected List refreshTicksVertical(Graphics2D g2, Rectangle2D dataArea, 
            RectangleEdge edge) {
        Range range = getRange();
        List ticks = new ArrayList();
        double start = Math.floor(calculateLog(getLowerBound()));
        double end = Math.ceil(calculateLog(getUpperBound()));
        double current = start;
        while (current <= end) {
            double v = calculateValue(current);
            if (range.contains(v)) {
                ticks.add(new NumberTick(new Double(v), createTickLabel(v), 
                        TextAnchor.CENTER_RIGHT, TextAnchor.CENTER, 0.0));
            }
            // add minor ticks (for gridlines)
            double next = Math.pow(this.base, current 
                    + this.tickUnit.getSize());
            for (int i = 1; i < this.minorTickCount; i++) {
                double minorV = v + i * ((next - v) / this.minorTickCount);
                if (range.contains(minorV)) {
                    ticks.add(new NumberTick(new Double(minorV), "", 
                            TextAnchor.CENTER_RIGHT, TextAnchor.CENTER, 0.0));
                }
            }
            current = current + this.tickUnit.getSize();
        }
        return ticks;
    }

    /**
     * Creates a tick label for the specified value.
     * 
     * @param value  the value.
     * 
     * @return The label.
     */
    private String createTickLabel(double value) {
        if (this.numberFormatOverride != null) {
            return this.numberFormatOverride.format(value);
        }
        else {
            return this.tickUnit.valueToString(value);
        }
    }

}