textutilities.java

来自「JfreeChart 常用图表例子」· Java 代码 · 共 885 行 · 第 1/3 页

     * @param g2  the graphics device.
     * @param x  the x coordinate for the anchor point.
     * @param y  the y coordinate for the anchor point.
     * @param textAnchor  the text anchor.
     * @param angle  the angle.
     * @param rotationAnchor  the rotation anchor.
     * 
     * @return The bounds (possibly <code>null</code>).
     */
    public static Shape calculateRotatedStringBounds(final String text, 
            final Graphics2D g2, final float x, final float y,
            final TextAnchor textAnchor, final double angle,
            final TextAnchor rotationAnchor) {

        if (text == null || text.equals("")) {
            return null;
        }
        final float[] textAdj = deriveTextBoundsAnchorOffsets(
            g2, text, textAnchor
        );
        if (logger.isDebugEnabled()) {
            logger.debug(
                "TextBoundsAnchorOffsets = " + textAdj[0] + ", " + textAdj[1]
            );   
        }
        final float[] rotateAdj = deriveRotationAnchorOffsets(
            g2, text, rotationAnchor
        );
        if (logger.isDebugEnabled()) {
            logger.debug(
                "RotationAnchorOffsets = " + rotateAdj[0] + ", " + rotateAdj[1]
            );   
        }
        final Shape result = calculateRotatedStringBounds(
            text, g2, x + textAdj[0], y + textAdj[1],
            angle, x + textAdj[0] + rotateAdj[0], y + textAdj[1] + rotateAdj[1]
        );
        return result;
            
    }
    
    /**
     * A utility method that calculates the anchor offsets for a string.  
     * Normally, the (x, y) coordinate for drawing text is a point on the 
     * baseline at the left of the text string.  If you add these offsets to 
     * (x, y) and draw the string, then the anchor point should coincide with 
     * the (x, y) point.
     *
     * @param g2  the graphics device (not <code>null</code>).
     * @param text  the text.
     * @param anchor  the anchor point.
     *
     * @return  The offsets.
     */
    private static float[] deriveTextBoundsAnchorOffsets(final Graphics2D g2, 
            final String text, final TextAnchor anchor) {

        final float[] result = new float[2];
        final FontRenderContext frc = g2.getFontRenderContext();
        final Font f = g2.getFont();
        final FontMetrics fm = g2.getFontMetrics(f);
        final Rectangle2D bounds = TextUtilities.getTextBounds(text, g2, fm);
        final LineMetrics metrics = f.getLineMetrics(text, frc);
        final float ascent = metrics.getAscent();
        final float halfAscent = ascent / 2.0f;
        final float descent = metrics.getDescent();
        final float leading = metrics.getLeading();
        float xAdj = 0.0f;
        float yAdj = 0.0f;

        if (anchor == TextAnchor.TOP_CENTER
                || anchor == TextAnchor.CENTER
                || anchor == TextAnchor.BOTTOM_CENTER
                || anchor == TextAnchor.BASELINE_CENTER
                || anchor == TextAnchor.HALF_ASCENT_CENTER) {
                    
            xAdj = (float) -bounds.getWidth() / 2.0f;
            
        }
        else if (anchor == TextAnchor.TOP_RIGHT
                || anchor == TextAnchor.CENTER_RIGHT
                || anchor == TextAnchor.BOTTOM_RIGHT
                || anchor == TextAnchor.BASELINE_RIGHT
                || anchor == TextAnchor.HALF_ASCENT_RIGHT) {
                    
            xAdj = (float) -bounds.getWidth();
            
        }

        if (anchor == TextAnchor.TOP_LEFT
                || anchor == TextAnchor.TOP_CENTER
                || anchor == TextAnchor.TOP_RIGHT) {
                    
            yAdj = -descent - leading + (float) bounds.getHeight();
            
        }
        else if (anchor == TextAnchor.HALF_ASCENT_LEFT
                || anchor == TextAnchor.HALF_ASCENT_CENTER
                || anchor == TextAnchor.HALF_ASCENT_RIGHT) {
                    
            yAdj = halfAscent;
            
        }
        else if (anchor == TextAnchor.CENTER_LEFT
                || anchor == TextAnchor.CENTER
                || anchor == TextAnchor.CENTER_RIGHT) {
                    
            yAdj = -descent - leading + (float) (bounds.getHeight() / 2.0);
            
        }
        else if (anchor == TextAnchor.BASELINE_LEFT
                || anchor == TextAnchor.BASELINE_CENTER
                || anchor == TextAnchor.BASELINE_RIGHT) {
                    
            yAdj = 0.0f;
            
        }
        else if (anchor == TextAnchor.BOTTOM_LEFT
                || anchor == TextAnchor.BOTTOM_CENTER
                || anchor == TextAnchor.BOTTOM_RIGHT) {
                    
            yAdj = -metrics.getDescent() - metrics.getLeading();
            
        }
        result[0] = xAdj;
        result[1] = yAdj;
        return result;

    }

    /**
     * A utility method that calculates the rotation anchor offsets for a 
     * string.  These offsets are relative to the text starting coordinate 
     * (BASELINE_LEFT).
     *
     * @param g2  the graphics device.
     * @param text  the text.
     * @param anchor  the anchor point.
     *
     * @return  The offsets.
     */
    private static float[] deriveRotationAnchorOffsets(final Graphics2D g2, 
            final String text, final TextAnchor anchor) {

        final float[] result = new float[2];
        final FontRenderContext frc = g2.getFontRenderContext();
        final LineMetrics metrics = g2.getFont().getLineMetrics(text, frc);
        final FontMetrics fm = g2.getFontMetrics();
        final Rectangle2D bounds = TextUtilities.getTextBounds(text, g2, fm);
        final float ascent = metrics.getAscent();
        final float halfAscent = ascent / 2.0f;
        final float descent = metrics.getDescent();
        final float leading = metrics.getLeading();
        float xAdj = 0.0f;
        float yAdj = 0.0f;

        if (anchor == TextAnchor.TOP_LEFT
                || anchor == TextAnchor.CENTER_LEFT
                || anchor == TextAnchor.BOTTOM_LEFT
                || anchor == TextAnchor.BASELINE_LEFT
                || anchor == TextAnchor.HALF_ASCENT_LEFT) {

            xAdj = 0.0f;

        }
        else if (anchor == TextAnchor.TOP_CENTER
                || anchor == TextAnchor.CENTER
                || anchor == TextAnchor.BOTTOM_CENTER
                || anchor == TextAnchor.BASELINE_CENTER
                || anchor == TextAnchor.HALF_ASCENT_CENTER) {
                    
            xAdj = (float) bounds.getWidth() / 2.0f;
           
        }
        else if (anchor == TextAnchor.TOP_RIGHT
                || anchor == TextAnchor.CENTER_RIGHT
                || anchor == TextAnchor.BOTTOM_RIGHT
                || anchor == TextAnchor.BASELINE_RIGHT
                || anchor == TextAnchor.HALF_ASCENT_RIGHT) {
                    
            xAdj = (float) bounds.getWidth();
            
        }

        if (anchor == TextAnchor.TOP_LEFT
                || anchor == TextAnchor.TOP_CENTER
                || anchor == TextAnchor.TOP_RIGHT) {
                    
            yAdj = descent + leading - (float) bounds.getHeight();
            
        }
        else if (anchor == TextAnchor.CENTER_LEFT
                || anchor == TextAnchor.CENTER
                || anchor == TextAnchor.CENTER_RIGHT) {
                    
            yAdj = descent + leading - (float) (bounds.getHeight() / 2.0);
            
        }
        else if (anchor == TextAnchor.HALF_ASCENT_LEFT
                || anchor == TextAnchor.HALF_ASCENT_CENTER
                || anchor == TextAnchor.HALF_ASCENT_RIGHT) {
                    
            yAdj = -halfAscent;
            
        }
        else if (anchor == TextAnchor.BASELINE_LEFT
                || anchor == TextAnchor.BASELINE_CENTER
                || anchor == TextAnchor.BASELINE_RIGHT) {
                    
            yAdj = 0.0f;
            
        }
        else if (anchor == TextAnchor.BOTTOM_LEFT
                || anchor == TextAnchor.BOTTOM_CENTER
                || anchor == TextAnchor.BOTTOM_RIGHT) {
                    
            yAdj = metrics.getDescent() + metrics.getLeading();
            
        }
        result[0] = xAdj;
        result[1] = yAdj;
        return result;

    }

    /**
     * Returns a shape that represents the bounds of the string after the 
     * specified rotation has been applied.
     * 
     * @param text  the text (<code>null</code> permitted).
     * @param g2  the graphics device.
     * @param textX  the x coordinate for the text.
     * @param textY  the y coordinate for the text.
     * @param angle  the angle.
     * @param rotateX  the x coordinate for the rotation point.
     * @param rotateY  the y coordinate for the rotation point.
     * 
     * @return The bounds (<code>null</code> if <code>text</code> is 
     *         </code>null</code> or has zero length).
     */
    public static Shape calculateRotatedStringBounds(final String text,
                                                     final Graphics2D g2,
                                                     final float textX,
                                                     final float textY,
                                                     final double angle,
                                                     final float rotateX,
                                                     final float rotateY) {

        if ((text == null) || (text.equals(""))) {
            return null;
        }
        final FontMetrics fm = g2.getFontMetrics();
        final Rectangle2D bounds = TextUtilities.getTextBounds(text, g2, fm);
        final AffineTransform translate = AffineTransform.getTranslateInstance(
            textX, textY
        );
        final Shape translatedBounds = translate.createTransformedShape(bounds);
        final AffineTransform rotate = AffineTransform.getRotateInstance(
            angle, rotateX, rotateY
        );
        final Shape result = rotate.createTransformedShape(translatedBounds);
        return result;

    }

    /** 
     * A flag that controls whether the FontMetrics.getStringBounds() method 
     * is used or a workaround is applied.
     */
    private static boolean useFontMetricsGetStringBounds = true;

    /**
     * Returns the flag that controls whether the FontMetrics.getStringBounds() 
     * method is used or not.  If you are having trouble with label alignment
     * or positioning, try changing the value of this flag.
     * 
     * @return A boolean.
     */
    public static boolean getUseFontMetricsGetStringBounds() {
        return useFontMetricsGetStringBounds;    
    }
    
    /**
     * Sets the flag that controls whether the FontMetrics.getStringBounds() 
     * method is used or not.  If you are having trouble with label alignment 
     * or positioning, try changing the value of this flag.
     * 
     * @param use  the flag.
     */
    public static void setUseFontMetricsGetStringBounds(final boolean use) {
        useFontMetricsGetStringBounds = use;   
    }
    
}