Versions up to 1.3 can be opened by version 4 of Adobe Acrobat.If it was used intentionally, check that the chosen files haveĬheck that the PDF version is suitable for your PDF viewer. I see jumbled text or pictures on the page, with items on top of each otherĬheck that overlay was not used during PDF creation. I see unwanted text or pictures in the background or foregroundĬheck that a watermark is not enabled by mistake. Welcome > Troubleshooting > Troubleshooting for PDF Create Troubleshooting for PDF Create I do not see any controls in my PDF viewer Note that operators cannot be used as search terms: + - * : ~ ^ ' " (Example: port~1 matches fort, post, or potr, and other instances where one correction leads to a match.) To use fuzzy searching to account for misspellings, follow the term with ~ and a positive number for the number of corrections to be made.(Example: shortcut^10 group gives shortcut 10 times the weight as group.) Follow the term with ^ and a positive number that indicates the weight given that term. For multi-term searches, you can specify a priority for terms in your search.(Example: title:configuration finds the topic titled “Changing the software configuration.”) Type title: at the beginning of the search phrase to look only for topic titles.(Example: inst* finds installation and instructions.) The wildcard can be used anywhere in a search term. Use * as a wildcard for missing characters.(Example: user +shortcut –group finds shortcut and user shortcut, but not group or user group.) Type + in front of words that must be included in the search or - in front of words to exclude.To refine the search, you can use the following operators: The results appear in order of relevance, based on how many search terms occur per topic. The search also uses fuzzy matching to account for partial words (such as install and installs). If you type more than one term, an OR is assumed, which returns topics where any of the terms are found. as described by Tilman Hausherr in his answer to "how to add unicode in truetype0font on pdfbox 2.0.0".ĭepending on the number of different fonts you have to create the mappings for, this approach might easily require way too much time and effort.The search returns topics that contain terms you enter. You can try to interactively add manually created ToUnicode maps to the PDF, e.g. in your "PDF copy text issue-Text layer workaround.pdf" the header "Chapter 1: Derivative Securities" has been recognized as "Chapter1: Deratve Securites". Unless you have a contract with that source that requires them to supply the PDFs in a machine readable form or the source is otherwise obligated to do so, they usually will decline, though.ĭepending on the quality of the OCR software and the glyphs in the PDF, the results can be of a questionable quality e.g. There are multiple options, more or less feasible depending on your concrete case:Īsk the source of the PDF for a version that contains proper information for text extraction. The heuristics used by those programs differ relevantly and Okular's heuristics work best for your document. Your PDF does not contain the information required for the algorithm above from the PDF specification and That the different programs you tried returned so different results shows that This is where the text extraction implementations differ, they try to determine the matching Unicode value by using heuristics or information from beyond the PDF or applying OCR to the glyph in question. What happens if the algorithm above fails to produce a Unicode value If these methods fail to produce a Unicode value, there is no way to determine what the character code represents in which case a conforming reader may choose a character code of their choosing. In PDFs which don't contain the information required for text extraction, you eventually get to this point in the algorithm: It has been quoted very often in other stack overflow answers (see here, here, here, here, here, or here), so I won't quote it here again.Įssentially this is the algorithm used by Adobe Acrobat during copy&paste and also by many other text extractors. The PDF specification ISO 32000-1 (and similarly ISO 32000-2, too) describes an algorithm for mapping character codes to Unicode values using information available directly inside the PDF. Mapping character codes to Unicode as described in the PDF specification Depending on the exact nature of your task, you might try to add the required information to the existing text objects and fonts or you might go for OCR. In short: The (original) PDF does not contain the information required for regular text extraction as described in the PDF specification.
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