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| author | Nicolas Pena <npm@chromium.org> | 2017-06-19 17:07:40 -0400 |
|---|---|---|
| committer | Chromium commit bot <commit-bot@chromium.org> | 2017-06-19 21:35:03 +0000 |
| commit | 4db9046e56c884a350fa2c5087f8d5b8110463c4 (patch) | |
| tree | a423eb6dfe89dd9e7aa5ffc8c728c9bfec938f1b /core/fpdfapi/font | |
| parent | b73ce7bcd72a97c780176d9f63681a5415c06422 (diff) | |
| download | pdfium-4db9046e56c884a350fa2c5087f8d5b8110463c4.tar.xz | |
Add heuristic for improving text rendering in CPDF_CharPosList::Load
This CL uses the following algorithm for improving substitute font spacing (we
are assuming the text layout is horizontal):
* Calculate PDFWidth, the width that the PDF says the glyph should have.
* Calculate FTWidth, the width calculated by freetype for the glyph, using the
substitute font that we'll use to render it. Note that some embedded fonts have
PDFWidth == FTWidth + 1, so we consider that to be matching widths.
* If PDFWidth > FTWidth + 1 , move the x coordinate by the difference / 2 so
that the glyph is rendered in a more centered spot and the text looks better.
* If PDFWidth < FTWidth, transform the glyph horizontally by PDFWidth / FTWidth
so that the glyph gets compressed and does not overlap with surrounding glyphs.
Bug: chromium:431507
Change-Id: Ia378344253fabe44d93af4daab98bb3b7bca22de
Reviewed-on: https://pdfium-review.googlesource.com/6630
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Nicolás Peña <npm@chromium.org>
Diffstat (limited to 'core/fpdfapi/font')
| -rw-r--r-- | core/fpdfapi/font/cpdf_font.cpp | 4 | ||||
| -rw-r--r-- | core/fpdfapi/font/cpdf_font.h | 1 | ||||
| -rw-r--r-- | core/fpdfapi/font/cpdf_simplefont.cpp | 4 | ||||
| -rw-r--r-- | core/fpdfapi/font/cpdf_simplefont.h | 2 |
4 files changed, 11 insertions, 0 deletions
diff --git a/core/fpdfapi/font/cpdf_font.cpp b/core/fpdfapi/font/cpdf_font.cpp index 1faa4ec4be..bdd3464ed2 100644 --- a/core/fpdfapi/font/cpdf_font.cpp +++ b/core/fpdfapi/font/cpdf_font.cpp @@ -159,6 +159,10 @@ uint32_t CPDF_Font::CharCodeFromUnicode(wchar_t unicode) const { return m_pToUnicodeMap ? m_pToUnicodeMap->ReverseLookup(unicode) : 0; } +bool CPDF_Font::HasFontWidths() const { + return true; +} + void CPDF_Font::LoadFontDescriptor(CPDF_Dictionary* pFontDesc) { m_Flags = pFontDesc->GetIntegerFor("Flags", FXFONT_NONSYMBOLIC); int ItalicAngle = 0; diff --git a/core/fpdfapi/font/cpdf_font.h b/core/fpdfapi/font/cpdf_font.h index 1fef77b322..f70542223c 100644 --- a/core/fpdfapi/font/cpdf_font.h +++ b/core/fpdfapi/font/cpdf_font.h @@ -61,6 +61,7 @@ class CPDF_Font { virtual int GlyphFromCharCodeExt(uint32_t charcode); virtual CFX_WideString UnicodeFromCharCode(uint32_t charcode) const; virtual uint32_t CharCodeFromUnicode(wchar_t Unicode) const; + virtual bool HasFontWidths() const; const CFX_ByteString& GetBaseFont() const { return m_BaseFont; } CFX_SubstFont* GetSubstFont() const { return m_Font.GetSubstFont(); } diff --git a/core/fpdfapi/font/cpdf_simplefont.cpp b/core/fpdfapi/font/cpdf_simplefont.cpp index ebf2cb65c7..a6c3ba0547 100644 --- a/core/fpdfapi/font/cpdf_simplefont.cpp +++ b/core/fpdfapi/font/cpdf_simplefont.cpp @@ -212,3 +212,7 @@ uint32_t CPDF_SimpleFont::CharCodeFromUnicode(wchar_t unicode) const { return ret; return m_Encoding.CharCodeFromUnicode(unicode); } + +bool CPDF_SimpleFont::HasFontWidths() const { + return !m_bUseFontWidth; +} diff --git a/core/fpdfapi/font/cpdf_simplefont.h b/core/fpdfapi/font/cpdf_simplefont.h index 3e414fa788..6a22f46966 100644 --- a/core/fpdfapi/font/cpdf_simplefont.h +++ b/core/fpdfapi/font/cpdf_simplefont.h @@ -29,6 +29,8 @@ class CPDF_SimpleFont : public CPDF_Font { CPDF_FontEncoding* GetEncoding() { return &m_Encoding; } + bool HasFontWidths() const override; + protected: virtual void LoadGlyphMap() = 0; |