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https://issues.apache.org/jira/browse/PDFBOX-611?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andreas Lehmkühler updated PDFBOX-611:
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Fix Version/s: (was: 0.8.0-incubator)
> PDSimpleFont. Font height reported as zero.
> --------------------------------------------
>
> Key: PDFBOX-611
> URL: https://issues.apache.org/jira/browse/PDFBOX-611
> Project: PDFBox
> Issue Type: Bug
> Components: PDModel
> Affects Versions: 0.8.0-incubator
> Environment: Win and Linux
> Reporter: Peter Costello
> Original Estimate: 1h
> Remaining Estimate: 1h
>
> The logic for PDSimpleFont.getFontHeight() can return a value of zero.
> This will corrupt or compromise text extraction and layout.
> In particular, test with
> 'http://www.encana.com/investor/financial/shareholder/pdfs/info-circular-french.pdf',
> pg 12
> When a PDFontDescriptor is used, the current logic uses:
> 1) an average of xHeight and capHeight.
> xHeight is the height from the baseline to the top of a lower
> case letter like 'x'.
> CapHeight is the height from the baseline to the top of an upper
> case latin char.
> 2) xHeight
> 3) capHeight
> 4) ascent
> 5) zero
> This is really bizarre. 'xHeight' is an optional parameter, and 'capHeight'
> is often missing.
> The font bounding box is a required parameter and is the height that is used
> by Acrobat Reader when you select a line of text.
> The bounding box is not perfect, because it often overlaps the line above,
> but it is a consistent value. The problem with the
> current logic is that the reported height varies way too much, and a zero
> value can be reported.
> I have modified the logic as follows. The goal was to make the nominal values
> the same as the current logic,
> but return a very similar number when parameters go missing.
> PDFontDescriptor desc = getFontDescriptor();
> if( desc != null ) {
> float height = desc.getCapHeight();
> // Top of Cap to baseline (eg 715)
> if (height==0) {
> height=desc.getAscent();
> // Max height from baseline (eg 715);
> if (height==0) {
> PDRectangle bbox = desc.getFontBoundingBox();
> height = bbox.getHeight()/2;
> // Max height less max depth (eg (1006-(-325))=1331/2=665)
> if (height==0) {
> height=desc.getXHeight();
> // Top of lower-case to baseline (eg 518)
> height-=desc.getDescent();
> // Depth below baseline (eg 209, to get total of 727)
> }
> }
> }
> retval=height;
> }
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