通过itext找出pdf页面的内容百分比 [英] Find out what percentage of a pdf page is content with itext

问题描述

我如何知道使用itext有多少页面是文本？即文本占整个页面的50％？或25％？有没有办法可以得到文本完成位置的Y坐标？那么你知道在哪里写下一段文字。

How do I know using itext how much of a page is text? ie does the text take up 50% of the whole page? or 25%? is there a way you can get the Y co-ordinate of where the text finishes? So then you know where to write the next bit of text to.

谢谢你

推荐答案

这绝对不是小事。
但最简单的实现（做了很多假设）有点像这样：

This is definitely not trivial. But the easiest implementation (which makes a lot of assumptions) goes a little bit like this:

class TextMeasurementListener implements IEventListener {

    private float space = 0.0f;

    public TextMeasurementListener(PdfDocument pdfDocument, int pageNr)
    {
        new PdfDocumentContentParser(pdfDocument).processContent(pageNr, this);
    }

    @Override
    public void eventOccurred(IEventData data, EventType type) {
        if(type != EventType.RENDER_TEXT)
            return;

        TextRenderInfo textRenderInfo = (TextRenderInfo) data;
        for(TextRenderInfo charInfo : textRenderInfo.getCharacterRenderInfos())
        {
            CharacterRenderInfo characterRenderInfo = new CharacterRenderInfo(charInfo);
            space += characterRenderInfo.getBoundingBox().getWidth() * characterRenderInfo.getBoundingBox().getHeight();
        }
    }

    public float getReservedSpaceInPoints()
    {
        return space;
    }

    @Override
    public Set<EventType> getSupportedEvents() {
        return null;
    }
}

此方法实际上处理单个页面，并计算每个角色的每个边界框的区域。

This method essentially processes a single page, and counts the area of each bounding box of each character.

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