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https://github.com/JakubMelka/PDF4QT.git
synced 2025-06-05 21:59:17 +02:00
Implementation of font drawing - first part
This commit is contained in:
Jakub Melka
@@ -16,6 +16,9 @@
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// along with PDFForQt. If not, see <https://www.gnu.org/licenses/>.
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#include "pdffont.h"
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#include "pdfdocument.h"
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#include "pdfparser.h"
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#include "pdfnametounicode.h"
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namespace pdf
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{
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@@ -25,4 +28,295 @@ PDFFont::PDFFont()
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}
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PDFFontPointer PDFFont::createFont(const PDFObject& object, const PDFDocument* document)
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{
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const PDFObject& dereferencedFontDictionary = document->getObject(object);
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if (!dereferencedFontDictionary.isDictionary())
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{
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throw PDFParserException(PDFTranslationContext::tr("Font object must be a dictionary."));
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}
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const PDFDictionary* fontDictionary = dereferencedFontDictionary.getDictionary();
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PDFDocumentDataLoaderDecorator fontLoader(document);
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// TODO: Fonts - implement all types of the font
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// First, determine the font subtype
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constexpr const std::array<std::pair<const char*, FontType>, 2> fontTypes = {
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std::pair<const char*, FontType>{ "Type1", FontType::Type1 },
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std::pair<const char*, FontType>{ "TrueType", FontType::TrueType }
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};
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const FontType fontType = fontLoader.readEnumByName(fontDictionary->get("Subtype"), fontTypes.cbegin(), fontTypes.cend(), FontType::Invalid);
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if (fontType == FontType::Invalid)
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{
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throw PDFParserException(PDFTranslationContext::tr("Invalid font type."));
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}
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QByteArray name = fontLoader.readNameFromDictionary(fontDictionary, "Name");
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QByteArray baseFont = fontLoader.readNameFromDictionary(fontDictionary, "BaseFont");
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const PDFInteger firstChar = fontLoader.readIntegerFromDictionary(fontDictionary, "FirstChar", 0);
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const PDFInteger lastChar = fontLoader.readIntegerFromDictionary(fontDictionary, "LastChar", 255);
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std::vector<PDFInteger> widths = fontLoader.readIntegerArrayFromDictionary(fontDictionary, "Widths");
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// Read standard font
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constexpr const std::array<std::pair<const char*, StandardFontType>, 14> standardFonts = {
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std::pair<const char*, StandardFontType>{ "Times-Roman", StandardFontType::TimesRoman },
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std::pair<const char*, StandardFontType>{ "Times-Bold", StandardFontType::TimesRomanBold },
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std::pair<const char*, StandardFontType>{ "Times-Italic", StandardFontType::TimesRomanItalics },
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std::pair<const char*, StandardFontType>{ "Times-BoldItalic", StandardFontType::TimesRomanBoldItalics },
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std::pair<const char*, StandardFontType>{ "Helvetica", StandardFontType::Helvetica },
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std::pair<const char*, StandardFontType>{ "Helvetica-Bold", StandardFontType::HelveticaBold },
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std::pair<const char*, StandardFontType>{ "Helvetica-Oblique", StandardFontType::HelveticaOblique },
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std::pair<const char*, StandardFontType>{ "Helvetica-BoldOblique", StandardFontType::HelveticaBoldOblique },
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std::pair<const char*, StandardFontType>{ "Courier", StandardFontType::Courier },
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std::pair<const char*, StandardFontType>{ "Courier-Bold", StandardFontType::CourierBold },
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std::pair<const char*, StandardFontType>{ "Courier-Oblique", StandardFontType::CourierOblique },
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std::pair<const char*, StandardFontType>{ "Courier-BoldOblique", StandardFontType::CourierBoldOblique },
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std::pair<const char*, StandardFontType>{ "Symbol", StandardFontType::Symbol },
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std::pair<const char*, StandardFontType>{ "ZapfDingbats", StandardFontType::ZapfDingbats }
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};
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const StandardFontType standardFont = fontLoader.readEnumByName(fontDictionary->get("BaseFont"), standardFonts.cbegin(), standardFonts.cend(), StandardFontType::Invalid);
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// Read Font Descriptor
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// TODO: Read font descriptor
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// Read Font Encoding
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// The font encoding for the simple font is determined by this algorithm:
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// 1) Try to use Encoding dictionary to determine base encoding
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// (it can be MacRomanEncoding, MacExpertEncoding, WinAnsiEncoding or StandardEncoding)
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// 2) If it is not present, then try to obtain built-in encoding from the font file (usually, this is not possible)
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// 3) Use default encoding for the font depending on the font type
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// - one of the 14 base fonts - use builtin encoding for the font type
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// - TrueType - use WinAnsiEncoding
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// - all others - use StandardEncoding
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// 4) Merge with Differences, if present
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// 5) Fill missing characters from StandardEncoding
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// TODO: Read font encoding from the font file
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PDFEncoding::Encoding encoding = PDFEncoding::Encoding::Invalid;
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encoding::EncodingTable simpleFontEncodingTable = { };
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switch (fontType)
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{
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case FontType::Type1:
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case FontType::TrueType:
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{
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bool hasDifferences = false;
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encoding::EncodingTable differences = { };
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if (fontDictionary->hasKey("Encoding"))
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{
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constexpr const std::array<std::pair<const char*, PDFEncoding::Encoding>, 3> encodings = {
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std::pair<const char*, PDFEncoding::Encoding>{ "MacRomanEncoding", PDFEncoding::Encoding::MacRoman },
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std::pair<const char*, PDFEncoding::Encoding>{ "MacExpertEncoding", PDFEncoding::Encoding::MacExpert },
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std::pair<const char*, PDFEncoding::Encoding>{ "WinAnsiEncoding", PDFEncoding::Encoding::WinAnsi }
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};
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const PDFObject& encodingObject = document->getObject(fontDictionary->get("Encoding"));
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if (encodingObject.isName())
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{
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// Decode name of the encoding
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encoding = fontLoader.readEnumByName(encodingObject, encodings.cbegin(), encodings.cend(), PDFEncoding::Encoding::Invalid);
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}
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else if (encodingObject.isDictionary())
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{
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// Dictionary with base encoding and differences (all optional)
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const PDFDictionary* encodingDictionary = encodingObject.getDictionary();
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if (encodingDictionary->hasKey("BaseEncoding"))
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{
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encoding = fontLoader.readEnumByName(encodingDictionary->get("BaseEncoding"), encodings.cbegin(), encodings.cend(), PDFEncoding::Encoding::Invalid);
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}
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else
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{
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// We get encoding for the standard font. If we have invalid standard font,
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// then we get standard encoding. So we shouldn't test it.
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encoding = getEncodingForStandardFont(standardFont);
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}
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if (encodingDictionary->hasKey("Differences"))
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{
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const PDFObject& differencesArray = document->getObject(encodingDictionary->get("Differences"));
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if (differencesArray.isArray())
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{
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hasDifferences = true;
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const PDFArray* array = differencesArray.getArray();
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size_t currentOffset = 0;
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for (size_t i = 0, count = array->getCount(); i < count; ++i)
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{
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const PDFObject& item = document->getObject(array->getItem(i));
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if (item.isInt())
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{
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currentOffset = static_cast<size_t>(item.getInteger());
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}
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else if (item.isName())
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{
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if (currentOffset >= differences.size())
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{
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throw PDFParserException(PDFTranslationContext::tr("Invalid differences in encoding entry of the font."));
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}
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QChar character = PDFNameToUnicode::getUnicodeForName(item.getString());
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// Try ZapfDingbats, if this fails
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if (character.isNull())
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{
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character = PDFNameToUnicode::getUnicodeForNameZapfDingbats(item.getString());
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}
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differences[currentOffset] = character;
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++currentOffset;
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}
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else
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{
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throw PDFParserException(PDFTranslationContext::tr("Invalid differences in encoding entry of the font."));
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}
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}
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}
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else
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{
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throw PDFParserException(PDFTranslationContext::tr("Invalid differences in encoding entry of the font."));
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}
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}
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}
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else
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{
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throw PDFParserException(PDFTranslationContext::tr("Invalid encoding entry of the font."));
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}
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}
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else
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{
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// We get encoding for the standard font. If we have invalid standard font,
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// then we get standard encoding. So we shouldn't test it.
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encoding = getEncodingForStandardFont(standardFont);
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}
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if (encoding == PDFEncoding::Encoding::Invalid)
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{
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throw PDFParserException(PDFTranslationContext::tr("Invalid encoding entry of the font."));
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}
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simpleFontEncodingTable = *PDFEncoding::getTableForEncoding(encoding);
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// Fill in differences
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if (hasDifferences)
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{
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for (size_t i = 0; i < differences.size(); ++i)
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{
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if (!differences[i].isNull())
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{
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simpleFontEncodingTable[i] = differences[i];
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}
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}
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// Set the encoding to custom
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encoding = PDFEncoding::Encoding::Custom;
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}
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// Fill in missing characters from standard encoding
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const encoding::EncodingTable& standardEncoding = *PDFEncoding::getTableForEncoding(PDFEncoding::Encoding::Standard);
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for (size_t i = 0; i < standardEncoding.size(); ++i)
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{
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if ((simpleFontEncodingTable[i].isNull() || simpleFontEncodingTable[i] == QChar(QChar::SpecialCharacter::ReplacementCharacter)) &&
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(!standardEncoding[i].isNull() && standardEncoding[i] != QChar(QChar::SpecialCharacter::ReplacementCharacter)))
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{
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simpleFontEncodingTable[i] = standardEncoding[i];
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}
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}
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break;
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}
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default:
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{
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Q_ASSERT(false);
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break;
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}
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}
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switch (fontType)
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{
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case FontType::Type1:
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return PDFFontPointer(new PDFType1Font(qMove(name), qMove(baseFont), firstChar, lastChar, qMove(widths), encoding, simpleFontEncodingTable, standardFont));
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case FontType::TrueType:
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return PDFFontPointer(new PDFTrueTypeFont(qMove(name), qMove(baseFont), firstChar, lastChar, qMove(widths), encoding, simpleFontEncodingTable));
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default:
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{
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Q_ASSERT(false);
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break;
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}
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}
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// Read To Unicode
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// TODO: Read To Unicode
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// Read Embedded fonts
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// TODO: Read embedded fonts
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return PDFFontPointer();
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}
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PDFSimpleFont::PDFSimpleFont(QByteArray name,
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QByteArray baseFont,
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PDFInteger firstChar,
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PDFInteger lastChar,
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std::vector<PDFInteger> widths,
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PDFEncoding::Encoding encodingType,
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encoding::EncodingTable encoding) :
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m_name(qMove(name)),
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m_baseFont(qMove(baseFont)),
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m_firstChar(firstChar),
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m_lastChar(lastChar),
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m_widths(qMove(widths)),
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m_encodingType(encodingType),
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m_encoding(encoding)
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{
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}
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QRawFont PDFSimpleFont::getRealizedFont(PDFReal fontSize) const
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{
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// TODO: Fix font creation to use also embedded fonts, font descriptor, etc.
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QFont font(m_baseFont);
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font.setHintingPreference(QFont::PreferNoHinting);
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font.setPixelSize(fontSize);
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return QRawFont::fromFont(font, QFontDatabase::Any);
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}
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QString PDFSimpleFont::getTextUsingEncoding(const QByteArray& byteArray) const
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{
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QString string;
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string.resize(byteArray.size(), QChar());
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for (int i = 0, count = byteArray.size(); i < count; ++i)
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{
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string[i] = m_encoding[static_cast<uint8_t>(byteArray[i])];
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}
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return string;
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}
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PDFType1Font::PDFType1Font(QByteArray name,
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QByteArray baseFont,
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PDFInteger firstChar,
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PDFInteger lastChar,
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std::vector<PDFInteger> widths,
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PDFEncoding::Encoding encodingType,
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encoding::EncodingTable encoding,
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StandardFontType standardFontType) :
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PDFSimpleFont(qMove(name), qMove(baseFont), firstChar, lastChar, qMove(widths), encodingType, encoding),
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m_standardFontType(standardFontType)
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{
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}
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FontType PDFType1Font::getFontType() const
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{
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return FontType::Type1;
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}
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FontType PDFTrueTypeFont::getFontType() const
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{
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return FontType::TrueType;
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}
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} // namespace pdf
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