Implement CGdiPrinterDriver::DrawDeviceText().

core/fxge/win32/fx_win32_print.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "core/fxge/include/fx_ge.h"
 
 #if _FX_OS_ == _FX_WIN32_DESKTOP_ || _FX_OS_ == _FX_WIN64_DESKTOP_
 
 #include <windows.h>
 
+#include <algorithm>
+
 #include "core/fxge/dib/dib_int.h"
 #include "core/fxge/ge/fx_text_int.h"
 #include "core/fxge/include/fx_freetype.h"
 #include "core/fxge/include/fx_ge_win32.h"
 #include "core/fxge/win32/win32_int.h"
 
+// Set to true to enable printing text with GDI.
+bool g_pdfium_print_text_with_gdi = false;

[Lei Zhang, 2016/06/30 07:54:08]

dsinclair: Given the somewhat experimental status, I don't want to add a public/
API for these. Instead, I'm using the awful technique of declaring "extern bool
g_pdfium_print_text_with_gdi" elsewhere. WDYT?

[dsinclair, 2016/06/30 13:31:57]

Why not make it a compile option that's off by default. As far as I know, we
aren't guaranteed to keep API consistency with things that aren't compiled by
default, yea?

[Lei Zhang, 2016/06/30 22:20:09]

It's more complicated, but done in patch set 2. The ensure typeface function
pointer know takes a const LOGFONT pointer, because the public API is C, so no
const refs.

+
+// Pointer to a helper function to make |font| with |text| of |text_length|
+// accessible when printing text with GDI. This is useful in sandboxed
+// environments where PDFium's access to GDI may be restricted.
+typedef void (*PDFiumEnsureTypefaceCharactersAccessible)(const LOGFONT& font,
+                                                         const wchar_t* text,
+                                                         size_t text_length);
+PDFiumEnsureTypefaceCharactersAccessible g_pdfium_typeface_accessible_func =
+    nullptr;
+
 CGdiPrinterDriver::CGdiPrinterDriver(HDC hDC)
     : CGdiDeviceDriver(hDC, FXDC_PRINTER),
       m_HorzSize(::GetDeviceCaps(m_hDC, HORZSIZE)),
       m_VertSize(::GetDeviceCaps(m_hDC, VERTSIZE)) {}
 
 CGdiPrinterDriver::~CGdiPrinterDriver() {}
 
 int CGdiPrinterDriver::GetDeviceCaps(int caps_id) const {
   if (caps_id == FXDC_HORZ_SIZE)
     return m_HorzSize;
@@ skipping 110 matching lines @@
       FXSYS_fabs(pMatrix->c) < 0.5f && pMatrix->d != 0) {
     FX_BOOL bFlipX = pMatrix->a < 0;
     FX_BOOL bFlipY = pMatrix->d > 0;
     return StretchDIBits(pSource, color,
                          bFlipX ? full_rect.right : full_rect.left,
                          bFlipY ? full_rect.bottom : full_rect.top,
                          bFlipX ? -full_rect.Width() : full_rect.Width(),
                          bFlipY ? -full_rect.Height() : full_rect.Height(),
                          nullptr, 0, blend_type);
   }
-  if (FXSYS_fabs(pMatrix->a) < 0.5f && FXSYS_fabs(pMatrix->d) < 0.5f) {
-    std::unique_ptr<CFX_DIBitmap> pTransformed(
-        pSource->SwapXY(pMatrix->c > 0, pMatrix->b < 0));
-    if (!pTransformed)
-      return FALSE;
+  if (FXSYS_fabs(pMatrix->a) >= 0.5f || FXSYS_fabs(pMatrix->d) >= 0.5f)
+    return FALSE;
 
-    return StretchDIBits(pTransformed.get(), color, full_rect.left,
-                         full_rect.top, full_rect.Width(), full_rect.Height(),
-                         nullptr, 0, blend_type);
-  }
-  return FALSE;
+  std::unique_ptr<CFX_DIBitmap> pTransformed(
+      pSource->SwapXY(pMatrix->c > 0, pMatrix->b < 0));
+  if (!pTransformed)
+    return FALSE;
+
+  return StretchDIBits(pTransformed.get(), color, full_rect.left, full_rect.top,
+                       full_rect.Width(), full_rect.Height(), nullptr, 0,
+                       blend_type);
 }
 
-#endif
+FX_BOOL CGdiPrinterDriver::DrawDeviceText(int nChars,
+                                          const FXTEXT_CHARPOS* pCharPos,
+                                          CFX_Font* pFont,
+                                          CFX_FontCache* pCache,
+                                          const CFX_Matrix* pObject2Device,
+                                          FX_FLOAT font_size,
+                                          uint32_t color) {
+  if (!g_pdfium_print_text_with_gdi)
+    return FALSE;
+
+  if (nChars < 1 || !pFont || !pFont->IsEmbedded() || !pFont->IsTTFont())
+    return FALSE;
+
+  // Font
+  //
+  // Note that |pFont| has the actual font to render with embedded within, but

[dsinclair, 2016/06/30 13:31:56]

This sounds like more of a TODO?

[Lei Zhang, 2016/06/30 22:20:09]

Done.

+  // but unfortunately AddFontMemResourceEx() does not seem to cooperate.
+  // Loading font data to memory seems to work, but then enumerating the fonts
+  // fails to find it. This requires more investigation. In the meanwhile,
+  // assume the printing is happening on the machine that generated the PDF, so
+  // the embedded font is available through GDI anyway.
+  LOGFONT lf = {};
+  lf.lfHeight = -font_size;
+  lf.lfWeight = pFont->IsBold() ? FW_BOLD : FW_NORMAL;
+  lf.lfItalic = pFont->IsItalic();
+  lf.lfCharSet = DEFAULT_CHARSET;
+
+  const CFX_WideString wsName = pFont->GetFaceName().UTF8Decode();
+  int len = std::min(wsName.GetLength(), LF_FACESIZE - 1);
+  memcpy(lf.lfFaceName, wsName.c_str(), sizeof(lf.lfFaceName[0]) * len);
+  lf.lfFaceName[len] = 0;
+
+  HFONT font = CreateFontIndirect(&lf);
+  if (!font)
+    return FALSE;
+
+  int dc = SaveDC(m_hDC);
+  HGDIOBJ old_font = SelectObject(m_hDC, font);
+
+  // Transforms
+  //
+  // This is known to work with PDFs generated via Skia's PDF generator. It
+  // obviously do not work for arbitrary PDFs.

[dsinclair, 2016/06/30 13:31:57]

nit: s/do/does/

[Lei Zhang, 2016/06/30 22:20:09]

Done.

+  ASSERT(pObject2Device->GetB() == 0);
+  ASSERT(pObject2Device->GetC() == 0);
+  ASSERT(pObject2Device->GetA() == -pObject2Device->GetD());
+  SetGraphicsMode(m_hDC, GM_ADVANCED);
+  XFORM xform = {};
+  xform.eM11 = pObject2Device->GetA();
+  xform.eM22 = pObject2Device->GetA();
+  xform.eDx = pObject2Device->GetE();
+  xform.eDy = pObject2Device->GetF();
+  ModifyWorldTransform(m_hDC, &xform, MWT_LEFTMULTIPLY);
+
+  // Color
+  int unused_alpha;
+  FX_COLORREF rgb;
+  ArgbDecode(color, unused_alpha, rgb);
+  SetTextColor(m_hDC, rgb);
+  SetBkMode(m_hDC, TRANSPARENT);
+
+  // Text
+  CFX_WideString wstr;
+  for (int i = 0; i < nChars; ++i) {
+    // Same as above. Only works with PDFs from Skia's PDF generator.
+    const FXTEXT_CHARPOS& charpos = pCharPos[i];
+    ASSERT(charpos.m_OriginX == 0);
+    ASSERT(charpos.m_OriginY == 0);
+    ASSERT(charpos.m_AdjustMatrix[0] == 0);
+    ASSERT(charpos.m_AdjustMatrix[1] == 0);
+    ASSERT(charpos.m_AdjustMatrix[2] == 0);
+    ASSERT(charpos.m_AdjustMatrix[3] == 0);
+    wstr += charpos.m_GlyphIndex;
+  }
+
+  // Draw
+  SetTextAlign(m_hDC, TA_LEFT | TA_BASELINE);
+  BOOL ret = ExtTextOutW(m_hDC, 0, 0, ETO_GLYPH_INDEX, nullptr, wstr.c_str(),
+                         nChars, nullptr);
+  if (!ret) {
+    if (g_pdfium_typeface_accessible_func) {
+      g_pdfium_typeface_accessible_func(lf, wstr.c_str(), nChars);
+      ret = ExtTextOutW(m_hDC, 0, 0, ETO_GLYPH_INDEX, nullptr, wstr.c_str(),
+                        nChars, nullptr);
+    }
+  }
+
+  SelectObject(m_hDC, old_font);
+  DeleteObject(font);
+  RestoreDC(m_hDC, dc);
+  return ret;
+}
+
+#endif  // _FX_OS_ == _FX_WIN32_DESKTOP_ || _FX_OS_ == _FX_WIN64_DESKTOP_