Java TextLayout.getVisibleAdvance方法代碼示例

import java.awt.font.TextLayout; //導入方法依賴的package包/類
public void test() {

        // construct a paragraph as follows: MIXED + [SPACING + WORD] + ...
        StringBuffer text = new StringBuffer(MIXED);
        for (int i=0; i < NUM_WORDS; i++) {
            text.append(SPACING);
            text.append(WORD);
        }

        AttributedString attrString = new AttributedString(text.toString());
        attrString.addAttribute(TextAttribute.SIZE, new Float(24.0));

        LineBreakMeasurer measurer = new LineBreakMeasurer(attrString.getIterator(),
                                                           DEFAULT_FRC);

        // get width of a space-word sequence, in context
        int sequenceLength = WORD.length()+SPACING.length();
        measurer.setPosition(text.length() - sequenceLength);

        TextLayout layout = measurer.nextLayout(10000.0f);

        if (layout.getCharacterCount() != sequenceLength) {
            throw new Error("layout length is incorrect!");
        }

        final float sequenceAdvance = layout.getVisibleAdvance();

        float wrappingWidth = sequenceAdvance * 2;

        // now run test with a variety of widths
        while (wrappingWidth < (sequenceAdvance*NUM_WORDS)) {
            measurer.setPosition(0);
            checkMeasurer(measurer,
                          wrappingWidth,
                          sequenceAdvance,
                          text.length());
            wrappingWidth += sequenceAdvance / 5;
        }
    }
 

import java.awt.font.TextLayout; //導入方法依賴的package包/類
/**
 * Iterate through measurer and check that every line is
 * not too long and not too short, but just right.
 */
private void checkMeasurer(LineBreakMeasurer measurer,
                           float wrappingWidth,
                           float sequenceAdvance,
                           int endPosition) {

    do {
        TextLayout layout = measurer.nextLayout(wrappingWidth);
        float visAdvance = layout.getVisibleAdvance();

        // Check that wrappingWidth-sequenceAdvance < visAdvance
        // Also, if we're not at the end of the paragraph,
        // check that visAdvance <= wrappingWidth

        if (visAdvance > wrappingWidth) {
            // line is too long for given wrapping width
            throw new Error("layout is too long");
        }

        if (measurer.getPosition() < endPosition) {
            if (visAdvance <= wrappingWidth - sequenceAdvance) {
                // line is too short for given wrapping width;
                // another word would have fit
                throw new Error("room for more words on line.  diff=" +
                                (wrappingWidth - sequenceAdvance - visAdvance));
            }
        }
    } while (measurer.getPosition() != endPosition);
}