Split fx_dib part 5

Move more classes into their own files.

Change-Id: Ic505be9e406eafb378235216ea19221ce172f32e
Reviewed-on: https://pdfium-review.googlesource.com/3593
Commit-Queue: Nicolás Peña <npm@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>

18 files changed, 436 insertions, 343 deletions

diff --git a/BUILD.gn b/BUILD.gn
index 5c12468a98..fa879d3e03 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -862,6 +862,10 @@ static_library("fxge") {
     "core/fxge/cfx_substfont.h",
     "core/fxge/cfx_unicodeencoding.h",
     "core/fxge/cfx_windowsdevice.h",
+    "core/fxge/dib/cfx_bitmapcomposer.cpp",
+    "core/fxge/dib/cfx_bitmapcomposer.h",
+    "core/fxge/dib/cfx_bitmapstorer.cpp",
+    "core/fxge/dib/cfx_bitmapstorer.h",
     "core/fxge/dib/cfx_dibextractor.cpp",
     "core/fxge/dib/cfx_dibextractor.h",
     "core/fxge/dib/cfx_dibitmap.cpp",
@@ -872,12 +876,13 @@ static_library("fxge") {
     "core/fxge/dib/cfx_filtereddib.h",
     "core/fxge/dib/cfx_imagerenderer.cpp",
     "core/fxge/dib/cfx_imagerenderer.h",
+    "core/fxge/dib/cfx_imagestretcher.cpp",
+    "core/fxge/dib/cfx_imagestretcher.h",
     "core/fxge/dib/cfx_imagetransformer.cpp",
     "core/fxge/dib/cfx_imagetransformer.h",
     "core/fxge/dib/cfx_scanlinecompositor.cpp",
     "core/fxge/dib/cfx_scanlinecompositor.h",
     "core/fxge/dib/dib_int.h",
-    "core/fxge/dib/fx_dib_composite.cpp",
     "core/fxge/dib/fx_dib_convert.cpp",
     "core/fxge/dib/fx_dib_engine.cpp",
     "core/fxge/dib/fx_dib_main.cpp",
diff --git a/core/fpdfapi/render/cpdf_imagerenderer.cpp b/core/fpdfapi/render/cpdf_imagerenderer.cpp
index 46c35d9316..858b3c83c6 100644
--- a/core/fpdfapi/render/cpdf_imagerenderer.cpp
+++ b/core/fpdfapi/render/cpdf_imagerenderer.cpp
@@ -29,6 +29,7 @@
 #include "core/fxcrt/fx_safe_types.h"
 #include "core/fxge/cfx_fxgedevice.h"
 #include "core/fxge/cfx_pathdata.h"
+#include "core/fxge/dib/cfx_imagestretcher.h"
 #include "core/fxge/dib/cfx_imagetransformer.h"
 #include "third_party/base/ptr_util.h"
 #include "third_party/base/stl_util.h"
diff --git a/core/fxge/agg/fx_agg_driver.cpp b/core/fxge/agg/fx_agg_driver.cpp
index a82d3cf51c..8cada7cf64 100644
--- a/core/fxge/agg/fx_agg_driver.cpp
+++ b/core/fxge/agg/fx_agg_driver.cpp
@@ -15,6 +15,7 @@
 #include "core/fxge/cfx_graphstatedata.h"
 #include "core/fxge/cfx_pathdata.h"
 #include "core/fxge/dib/cfx_imagerenderer.h"
+#include "core/fxge/dib/cfx_imagestretcher.h"
 #include "core/fxge/ge/cfx_cliprgn.h"
 #include "third_party/agg23/agg_conv_dash.h"
 #include "third_party/agg23/agg_conv_stroke.h"
diff --git a/core/fxge/dib/fx_dib_composite.cpp b/core/fxge/dib/cfx_bitmapcomposer.cpp
index e7912e5a1b..7124ba9d46 100644
--- a/core/fxge/dib/fx_dib_composite.cpp
+++ b/core/fxge/dib/cfx_bitmapcomposer.cpp
@@ -1,13 +1,14 @@
-// Copyright 2014 PDFium Authors. All rights reserved.
+// Copyright 2017 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 <algorithm>
+#include "core/fxge/dib/cfx_bitmapcomposer.h"
 
 #include "core/fxcodec/fx_codec.h"
 #include "core/fxge/cfx_gemodule.h"
+#include "core/fxge/dib/cfx_dibitmap.h"
 #include "core/fxge/ge/cfx_cliprgn.h"
 
 CFX_BitmapComposer::CFX_BitmapComposer() {
diff --git a/core/fxge/dib/cfx_bitmapcomposer.h b/core/fxge/dib/cfx_bitmapcomposer.h
new file mode 100644
index 0000000000..eeca80ed55
--- /dev/null
+++ b/core/fxge/dib/cfx_bitmapcomposer.h
@@ -0,0 +1,81 @@
+// Copyright 2017 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
+
+#ifndef CORE_FXGE_DIB_CFX_BITMAPCOMPOSER_H_
+#define CORE_FXGE_DIB_CFX_BITMAPCOMPOSER_H_
+
+#include "core/fxcrt/cfx_retain_ptr.h"
+#include "core/fxcrt/fx_coordinates.h"
+#include "core/fxge/dib/cfx_scanlinecompositor.h"
+#include "core/fxge/fx_dib.h"
+
+class CFX_ClipRgn;
+class CFX_DIBitmap;
+
+class CFX_BitmapComposer : public IFX_ScanlineComposer {
+ public:
+  CFX_BitmapComposer();
+  ~CFX_BitmapComposer() override;
+
+  void Compose(const CFX_RetainPtr<CFX_DIBitmap>& pDest,
+               const CFX_ClipRgn* pClipRgn,
+               int bitmap_alpha,
+               uint32_t mask_color,
+               FX_RECT& dest_rect,
+               bool bVertical,
+               bool bFlipX,
+               bool bFlipY,
+               bool bRgbByteOrder = false,
+               int alpha_flag = 0,
+               void* pIccTransform = nullptr,
+               int blend_type = FXDIB_BLEND_NORMAL);
+
+  // IFX_ScanlineComposer
+  bool SetInfo(int width,
+               int height,
+               FXDIB_Format src_format,
+               uint32_t* pSrcPalette) override;
+
+  void ComposeScanline(int line,
+                       const uint8_t* scanline,
+                       const uint8_t* scan_extra_alpha) override;
+
+ private:
+  void DoCompose(uint8_t* dest_scan,
+                 const uint8_t* src_scan,
+                 int dest_width,
+                 const uint8_t* clip_scan,
+                 const uint8_t* src_extra_alpha = nullptr,
+                 uint8_t* dst_extra_alpha = nullptr);
+  void ComposeScanlineV(int line,
+                        const uint8_t* scanline,
+                        const uint8_t* scan_extra_alpha = nullptr);
+
+  CFX_RetainPtr<CFX_DIBitmap> m_pBitmap;
+  const CFX_ClipRgn* m_pClipRgn;
+  FXDIB_Format m_SrcFormat;
+  int m_DestLeft;
+  int m_DestTop;
+  int m_DestWidth;
+  int m_DestHeight;
+  int m_BitmapAlpha;
+  uint32_t m_MaskColor;
+  CFX_RetainPtr<CFX_DIBitmap> m_pClipMask;
+  CFX_ScanlineCompositor m_Compositor;
+  bool m_bVertical;
+  bool m_bFlipX;
+  bool m_bFlipY;
+  int m_AlphaFlag;
+  void* m_pIccTransform;
+  bool m_bRgbByteOrder;
+  int m_BlendType;
+  uint8_t* m_pScanlineV;
+  uint8_t* m_pClipScanV;
+  uint8_t* m_pAddClipScan;
+  uint8_t* m_pScanlineAlphaV;
+};
+
+#endif  // CORE_FXGE_DIB_CFX_BITMAPCOMPOSER_H_
diff --git a/core/fxge/dib/cfx_bitmapstorer.cpp b/core/fxge/dib/cfx_bitmapstorer.cpp
new file mode 100644
index 0000000000..ac876b16b7
--- /dev/null
+++ b/core/fxge/dib/cfx_bitmapstorer.cpp
@@ -0,0 +1,56 @@
+// Copyright 2017 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/dib/cfx_bitmapstorer.h"
+
+#include <utility>
+
+#include "core/fxge/dib/dib_int.h"
+#include "third_party/base/ptr_util.h"
+
+CFX_BitmapStorer::CFX_BitmapStorer() {}
+
+CFX_BitmapStorer::~CFX_BitmapStorer() {}
+
+CFX_RetainPtr<CFX_DIBitmap> CFX_BitmapStorer::Detach() {
+  return std::move(m_pBitmap);
+}
+
+void CFX_BitmapStorer::Replace(CFX_RetainPtr<CFX_DIBitmap>&& pBitmap) {
+  m_pBitmap = std::move(pBitmap);
+}
+
+void CFX_BitmapStorer::ComposeScanline(int line,
+                                       const uint8_t* scanline,
+                                       const uint8_t* scan_extra_alpha) {
+  uint8_t* dest_buf = const_cast<uint8_t*>(m_pBitmap->GetScanline(line));
+  uint8_t* dest_alpha_buf =
+      m_pBitmap->m_pAlphaMask
+          ? const_cast<uint8_t*>(m_pBitmap->m_pAlphaMask->GetScanline(line))
+          : nullptr;
+  if (dest_buf)
+    FXSYS_memcpy(dest_buf, scanline, m_pBitmap->GetPitch());
+
+  if (dest_alpha_buf) {
+    FXSYS_memcpy(dest_alpha_buf, scan_extra_alpha,
+                 m_pBitmap->m_pAlphaMask->GetPitch());
+  }
+}
+
+bool CFX_BitmapStorer::SetInfo(int width,
+                               int height,
+                               FXDIB_Format src_format,
+                               uint32_t* pSrcPalette) {
+  auto pBitmap = pdfium::MakeRetain<CFX_DIBitmap>();
+  if (!pBitmap->Create(width, height, src_format))
+    return false;
+
+  if (pSrcPalette)
+    pBitmap->SetPalette(pSrcPalette);
+
+  m_pBitmap = std::move(pBitmap);
+  return true;
+}
diff --git a/core/fxge/dib/cfx_bitmapstorer.h b/core/fxge/dib/cfx_bitmapstorer.h
new file mode 100644
index 0000000000..478d9f7f64
--- /dev/null
+++ b/core/fxge/dib/cfx_bitmapstorer.h
@@ -0,0 +1,41 @@
+// Copyright 2017 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
+
+#ifndef CORE_FXGE_DIB_CFX_BITMAPSTORER_H_
+#define CORE_FXGE_DIB_CFX_BITMAPSTORER_H_
+
+#include <memory>
+#include <vector>
+
+#include "core/fxcrt/cfx_retain_ptr.h"
+#include "core/fxcrt/fx_coordinates.h"
+#include "core/fxge/dib/cfx_dibitmap.h"
+#include "core/fxge/fx_dib.h"
+#include "third_party/base/stl_util.h"
+
+class CFX_BitmapStorer : public IFX_ScanlineComposer {
+ public:
+  CFX_BitmapStorer();
+  ~CFX_BitmapStorer() override;
+
+  // IFX_ScanlineComposer
+  void ComposeScanline(int line,
+                       const uint8_t* scanline,
+                       const uint8_t* scan_extra_alpha) override;
+  bool SetInfo(int width,
+               int height,
+               FXDIB_Format src_format,
+               uint32_t* pSrcPalette) override;
+
+  CFX_RetainPtr<CFX_DIBitmap> GetBitmap() { return m_pBitmap; }
+  CFX_RetainPtr<CFX_DIBitmap> Detach();
+  void Replace(CFX_RetainPtr<CFX_DIBitmap>&& pBitmap);
+
+ private:
+  CFX_RetainPtr<CFX_DIBitmap> m_pBitmap;
+};
+
+#endif  // CORE_FXGE_DIB_CFX_BITMAPSTORER_H_
diff --git a/core/fxge/dib/cfx_dibsource.cpp b/core/fxge/dib/cfx_dibsource.cpp
index f1ea4adfa9..4cdedd1051 100644
--- a/core/fxge/dib/cfx_dibsource.cpp
+++ b/core/fxge/dib/cfx_dibsource.cpp
@@ -10,7 +10,9 @@
 #include <memory>
 #include <utility>
 
+#include "core/fxge/dib/cfx_bitmapstorer.h"
 #include "core/fxge/dib/cfx_dibitmap.h"
+#include "core/fxge/dib/cfx_imagestretcher.h"
 #include "core/fxge/dib/cfx_imagetransformer.h"
 #include "core/fxge/ge/cfx_cliprgn.h"
 #include "third_party/base/ptr_util.h"
diff --git a/core/fxge/dib/cfx_imagerenderer.cpp b/core/fxge/dib/cfx_imagerenderer.cpp
index 9eea474352..776ba92775 100644
--- a/core/fxge/dib/cfx_imagerenderer.cpp
+++ b/core/fxge/dib/cfx_imagerenderer.cpp
@@ -8,6 +8,7 @@
 
 #include <memory>
 
+#include "core/fxge/dib/cfx_imagestretcher.h"
 #include "core/fxge/dib/cfx_imagetransformer.h"
 #include "core/fxge/dib/dib_int.h"
 #include "core/fxge/ge/cfx_cliprgn.h"
diff --git a/core/fxge/dib/cfx_imagerenderer.h b/core/fxge/dib/cfx_imagerenderer.h
index 7e78bfe752..db8bd08638 100644
--- a/core/fxge/dib/cfx_imagerenderer.h
+++ b/core/fxge/dib/cfx_imagerenderer.h
@@ -11,6 +11,7 @@
 
 #include "core/fxcrt/cfx_retain_ptr.h"
 #include "core/fxcrt/fx_coordinates.h"
+#include "core/fxge/dib/cfx_bitmapcomposer.h"
 #include "core/fxge/dib/cfx_dibitmap.h"
 #include "core/fxge/dib/cfx_dibsource.h"
 #include "core/fxge/fx_dib.h"
diff --git a/core/fxge/dib/cfx_imagestretcher.cpp b/core/fxge/dib/cfx_imagestretcher.cpp
new file mode 100644
index 0000000000..799b44432f
--- /dev/null
+++ b/core/fxge/dib/cfx_imagestretcher.cpp
@@ -0,0 +1,184 @@
+// Copyright 2017 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/dib/cfx_imagestretcher.h"
+
+#include <climits>
+
+#include "core/fxge/dib/dib_int.h"
+#include "core/fxge/fx_dib.h"
+#include "third_party/base/ptr_util.h"
+
+namespace {
+
+bool SourceSizeWithinLimit(int width, int height) {
+  const int kMaxProgressiveStretchPixels = 1000000;
+  return !height || width < kMaxProgressiveStretchPixels / height;
+}
+
+FXDIB_Format GetStretchedFormat(const CFX_DIBSource& src) {
+  FXDIB_Format format = src.GetFormat();
+  if (format == FXDIB_1bppMask)
+    return FXDIB_8bppMask;
+  if (format == FXDIB_1bppRgb)
+    return FXDIB_8bppRgb;
+  if (format == FXDIB_8bppRgb && src.GetPalette())
+    return FXDIB_Rgb;
+  return format;
+}
+
+}  // namespace
+
+CFX_ImageStretcher::CFX_ImageStretcher(
+    IFX_ScanlineComposer* pDest,
+    const CFX_RetainPtr<CFX_DIBSource>& pSource,
+    int dest_width,
+    int dest_height,
+    const FX_RECT& bitmap_rect,
+    uint32_t flags)
+    : m_pDest(pDest),
+      m_pSource(pSource),
+      m_Flags(flags),
+      m_bFlipX(false),
+      m_bFlipY(false),
+      m_DestWidth(dest_width),
+      m_DestHeight(dest_height),
+      m_ClipRect(bitmap_rect),
+      m_DestFormat(GetStretchedFormat(*pSource)),
+      m_DestBPP(m_DestFormat & 0xff),
+      m_LineIndex(0) {}
+
+CFX_ImageStretcher::~CFX_ImageStretcher() {}
+
+bool CFX_ImageStretcher::Start() {
+  if (m_DestWidth == 0 || m_DestHeight == 0)
+    return false;
+
+  if (m_pSource->GetFormat() == FXDIB_1bppRgb && m_pSource->GetPalette()) {
+    FX_ARGB pal[256];
+    int a0, r0, g0, b0, a1, r1, g1, b1;
+    ArgbDecode(m_pSource->GetPaletteEntry(0), a0, r0, g0, b0);
+    ArgbDecode(m_pSource->GetPaletteEntry(1), a1, r1, g1, b1);
+    for (int i = 0; i < 256; i++) {
+      int a = a0 + (a1 - a0) * i / 255;
+      int r = r0 + (r1 - r0) * i / 255;
+      int g = g0 + (g1 - g0) * i / 255;
+      int b = b0 + (b1 - b0) * i / 255;
+      pal[i] = ArgbEncode(a, r, g, b);
+    }
+    if (!m_pDest->SetInfo(m_ClipRect.Width(), m_ClipRect.Height(), m_DestFormat,
+                          pal)) {
+      return false;
+    }
+  } else if (m_pSource->GetFormat() == FXDIB_1bppCmyk &&
+             m_pSource->GetPalette()) {
+    FX_CMYK pal[256];
+    int c0, m0, y0, k0, c1, m1, y1, k1;
+    CmykDecode(m_pSource->GetPaletteEntry(0), c0, m0, y0, k0);
+    CmykDecode(m_pSource->GetPaletteEntry(1), c1, m1, y1, k1);
+    for (int i = 0; i < 256; i++) {
+      int c = c0 + (c1 - c0) * i / 255;
+      int m = m0 + (m1 - m0) * i / 255;
+      int y = y0 + (y1 - y0) * i / 255;
+      int k = k0 + (k1 - k0) * i / 255;
+      pal[i] = CmykEncode(c, m, y, k);
+    }
+    if (!m_pDest->SetInfo(m_ClipRect.Width(), m_ClipRect.Height(), m_DestFormat,
+                          pal)) {
+      return false;
+    }
+  } else if (!m_pDest->SetInfo(m_ClipRect.Width(), m_ClipRect.Height(),
+                               m_DestFormat, nullptr)) {
+    return false;
+  }
+
+  if (m_Flags & FXDIB_DOWNSAMPLE)
+    return StartQuickStretch();
+  return StartStretch();
+}
+
+bool CFX_ImageStretcher::Continue(IFX_Pause* pPause) {
+  if (m_Flags & FXDIB_DOWNSAMPLE)
+    return ContinueQuickStretch(pPause);
+  return ContinueStretch(pPause);
+}
+
+bool CFX_ImageStretcher::StartStretch() {
+  m_pStretchEngine = pdfium::MakeUnique<CStretchEngine>(
+      m_pDest, m_DestFormat, m_DestWidth, m_DestHeight, m_ClipRect, m_pSource,
+      m_Flags);
+  m_pStretchEngine->StartStretchHorz();
+  if (SourceSizeWithinLimit(m_pSource->GetWidth(), m_pSource->GetHeight())) {
+    m_pStretchEngine->Continue(nullptr);
+    return false;
+  }
+  return true;
+}
+
+bool CFX_ImageStretcher::ContinueStretch(IFX_Pause* pPause) {
+  return m_pStretchEngine && m_pStretchEngine->Continue(pPause);
+}
+
+bool CFX_ImageStretcher::StartQuickStretch() {
+  if (m_DestWidth < 0) {
+    m_bFlipX = true;
+    m_DestWidth = -m_DestWidth;
+  }
+  if (m_DestHeight < 0) {
+    m_bFlipY = true;
+    m_DestHeight = -m_DestHeight;
+  }
+  uint32_t size = m_ClipRect.Width();
+  if (size && m_DestBPP > static_cast<int>(INT_MAX / size))
+    return false;
+
+  size *= m_DestBPP;
+  m_pScanline.reset(FX_Alloc(uint8_t, (size / 8 + 3) / 4 * 4));
+  if (m_pSource->m_pAlphaMask)
+    m_pMaskScanline.reset(FX_Alloc(uint8_t, (m_ClipRect.Width() + 3) / 4 * 4));
+
+  if (SourceSizeWithinLimit(m_pSource->GetWidth(), m_pSource->GetHeight())) {
+    ContinueQuickStretch(nullptr);
+    return false;
+  }
+  return true;
+}
+
+bool CFX_ImageStretcher::ContinueQuickStretch(IFX_Pause* pPause) {
+  if (!m_pScanline)
+    return false;
+
+  int result_width = m_ClipRect.Width();
+  int result_height = m_ClipRect.Height();
+  int src_height = m_pSource->GetHeight();
+  for (; m_LineIndex < result_height; m_LineIndex++) {
+    int dest_y;
+    int src_y;
+    if (m_bFlipY) {
+      dest_y = result_height - m_LineIndex - 1;
+      src_y = (m_DestHeight - (dest_y + m_ClipRect.top) - 1) * src_height /
+              m_DestHeight;
+    } else {
+      dest_y = m_LineIndex;
+      src_y = (dest_y + m_ClipRect.top) * src_height / m_DestHeight;
+    }
+    src_y = pdfium::clamp(src_y, 0, src_height - 1);
+
+    if (m_pSource->SkipToScanline(src_y, pPause))
+      return true;
+
+    m_pSource->DownSampleScanline(src_y, m_pScanline.get(), m_DestBPP,
+                                  m_DestWidth, m_bFlipX, m_ClipRect.left,
+                                  result_width);
+    if (m_pMaskScanline) {
+      m_pSource->m_pAlphaMask->DownSampleScanline(
+          src_y, m_pMaskScanline.get(), 1, m_DestWidth, m_bFlipX,
+          m_ClipRect.left, result_width);
+    }
+    m_pDest->ComposeScanline(dest_y, m_pScanline.get(), m_pMaskScanline.get());
+  }
+  return false;
+}
diff --git a/core/fxge/dib/cfx_imagestretcher.h b/core/fxge/dib/cfx_imagestretcher.h
new file mode 100644
index 0000000000..785ef9b6cc
--- /dev/null
+++ b/core/fxge/dib/cfx_imagestretcher.h
@@ -0,0 +1,55 @@
+// Copyright 2017 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
+
+#ifndef CORE_FXGE_DIB_CFX_IMAGESTRETCHER_H_
+#define CORE_FXGE_DIB_CFX_IMAGESTRETCHER_H_
+
+#include <memory>
+
+#include "core/fxcrt/cfx_retain_ptr.h"
+#include "core/fxcrt/fx_coordinates.h"
+#include "core/fxge/fx_dib.h"
+
+class CFX_DIBSource;
+
+class CFX_ImageStretcher {
+ public:
+  CFX_ImageStretcher(IFX_ScanlineComposer* pDest,
+                     const CFX_RetainPtr<CFX_DIBSource>& pSource,
+                     int dest_width,
+                     int dest_height,
+                     const FX_RECT& bitmap_rect,
+                     uint32_t flags);
+  ~CFX_ImageStretcher();
+
+  bool Start();
+  bool Continue(IFX_Pause* pPause);
+
+  CFX_RetainPtr<CFX_DIBSource> source() { return m_pSource; }
+
+ private:
+  bool StartQuickStretch();
+  bool StartStretch();
+  bool ContinueQuickStretch(IFX_Pause* pPause);
+  bool ContinueStretch(IFX_Pause* pPause);
+
+  IFX_ScanlineComposer* const m_pDest;
+  CFX_RetainPtr<CFX_DIBSource> m_pSource;
+  std::unique_ptr<CStretchEngine> m_pStretchEngine;
+  std::unique_ptr<uint8_t, FxFreeDeleter> m_pScanline;
+  std::unique_ptr<uint8_t, FxFreeDeleter> m_pMaskScanline;
+  const uint32_t m_Flags;
+  bool m_bFlipX;
+  bool m_bFlipY;
+  int m_DestWidth;
+  int m_DestHeight;
+  FX_RECT m_ClipRect;
+  const FXDIB_Format m_DestFormat;
+  const int m_DestBPP;
+  int m_LineIndex;
+};
+
+#endif  // CORE_FXGE_DIB_CFX_IMAGESTRETCHER_H_
diff --git a/core/fxge/dib/cfx_imagetransformer.cpp b/core/fxge/dib/cfx_imagetransformer.cpp
index 7a519adebf..d8159aabb5 100644
--- a/core/fxge/dib/cfx_imagetransformer.cpp
+++ b/core/fxge/dib/cfx_imagetransformer.cpp
@@ -9,6 +9,7 @@
 #include <memory>
 #include <utility>
 
+#include "core/fxge/dib/cfx_imagestretcher.h"
 #include "core/fxge/fx_dib.h"
 #include "third_party/base/ptr_util.h"
 
diff --git a/core/fxge/dib/cfx_imagetransformer.h b/core/fxge/dib/cfx_imagetransformer.h
index 0183a2fab1..1354c9099a 100644
--- a/core/fxge/dib/cfx_imagetransformer.h
+++ b/core/fxge/dib/cfx_imagetransformer.h
@@ -11,6 +11,7 @@
 
 #include "core/fxcrt/cfx_retain_ptr.h"
 #include "core/fxcrt/fx_coordinates.h"
+#include "core/fxge/dib/cfx_bitmapstorer.h"
 #include "core/fxge/dib/cfx_dibitmap.h"
 #include "core/fxge/dib/cfx_dibsource.h"
 #include "core/fxge/dib/dib_int.h"
diff --git a/core/fxge/dib/fx_dib_engine.cpp b/core/fxge/dib/fx_dib_engine.cpp
index 7aa710b795..d304a56600 100644
--- a/core/fxge/dib/fx_dib_engine.cpp
+++ b/core/fxge/dib/fx_dib_engine.cpp
@@ -13,26 +13,6 @@
 #include "third_party/base/ptr_util.h"
 #include "third_party/base/stl_util.h"
 
-namespace {
-
-bool SourceSizeWithinLimit(int width, int height) {
-  const int kMaxProgressiveStretchPixels = 1000000;
-  return !height || width < kMaxProgressiveStretchPixels / height;
-}
-
-FXDIB_Format GetStretchedFormat(const CFX_DIBSource& src) {
-  FXDIB_Format format = src.GetFormat();
-  if (format == FXDIB_1bppMask)
-    return FXDIB_8bppMask;
-  if (format == FXDIB_1bppRgb)
-    return FXDIB_8bppRgb;
-  if (format == FXDIB_8bppRgb && src.GetPalette())
-    return FXDIB_Rgb;
-  return format;
-}
-
-}  // namespace
-
 CWeightTable::CWeightTable()
     : m_DestMin(0),
       m_ItemSize(0),
@@ -851,155 +831,3 @@ void CStretchEngine::StretchVert() {
                                    m_pDestMaskScanline);
   }
 }
-
-CFX_ImageStretcher::CFX_ImageStretcher(
-    IFX_ScanlineComposer* pDest,
-    const CFX_RetainPtr<CFX_DIBSource>& pSource,
-    int dest_width,
-    int dest_height,
-    const FX_RECT& bitmap_rect,
-    uint32_t flags)
-    : m_pDest(pDest),
-      m_pSource(pSource),
-      m_Flags(flags),
-      m_bFlipX(false),
-      m_bFlipY(false),
-      m_DestWidth(dest_width),
-      m_DestHeight(dest_height),
-      m_ClipRect(bitmap_rect),
-      m_DestFormat(GetStretchedFormat(*pSource)),
-      m_DestBPP(m_DestFormat & 0xff),
-      m_LineIndex(0) {}
-
-CFX_ImageStretcher::~CFX_ImageStretcher() {
-}
-
-bool CFX_ImageStretcher::Start() {
-  if (m_DestWidth == 0 || m_DestHeight == 0)
-    return false;
-
-  if (m_pSource->GetFormat() == FXDIB_1bppRgb && m_pSource->GetPalette()) {
-    FX_ARGB pal[256];
-    int a0, r0, g0, b0, a1, r1, g1, b1;
-    ArgbDecode(m_pSource->GetPaletteEntry(0), a0, r0, g0, b0);
-    ArgbDecode(m_pSource->GetPaletteEntry(1), a1, r1, g1, b1);
-    for (int i = 0; i < 256; i++) {
-      int a = a0 + (a1 - a0) * i / 255;
-      int r = r0 + (r1 - r0) * i / 255;
-      int g = g0 + (g1 - g0) * i / 255;
-      int b = b0 + (b1 - b0) * i / 255;
-      pal[i] = ArgbEncode(a, r, g, b);
-    }
-    if (!m_pDest->SetInfo(m_ClipRect.Width(), m_ClipRect.Height(), m_DestFormat,
-                          pal)) {
-      return false;
-    }
-  } else if (m_pSource->GetFormat() == FXDIB_1bppCmyk &&
-             m_pSource->GetPalette()) {
-    FX_CMYK pal[256];
-    int c0, m0, y0, k0, c1, m1, y1, k1;
-    CmykDecode(m_pSource->GetPaletteEntry(0), c0, m0, y0, k0);
-    CmykDecode(m_pSource->GetPaletteEntry(1), c1, m1, y1, k1);
-    for (int i = 0; i < 256; i++) {
-      int c = c0 + (c1 - c0) * i / 255;
-      int m = m0 + (m1 - m0) * i / 255;
-      int y = y0 + (y1 - y0) * i / 255;
-      int k = k0 + (k1 - k0) * i / 255;
-      pal[i] = CmykEncode(c, m, y, k);
-    }
-    if (!m_pDest->SetInfo(m_ClipRect.Width(), m_ClipRect.Height(), m_DestFormat,
-                          pal)) {
-      return false;
-    }
-  } else if (!m_pDest->SetInfo(m_ClipRect.Width(), m_ClipRect.Height(),
-                               m_DestFormat, nullptr)) {
-    return false;
-  }
-
-  if (m_Flags & FXDIB_DOWNSAMPLE)
-    return StartQuickStretch();
-  return StartStretch();
-}
-
-bool CFX_ImageStretcher::Continue(IFX_Pause* pPause) {
-  if (m_Flags & FXDIB_DOWNSAMPLE)
-    return ContinueQuickStretch(pPause);
-  return ContinueStretch(pPause);
-}
-
-bool CFX_ImageStretcher::StartStretch() {
-  m_pStretchEngine = pdfium::MakeUnique<CStretchEngine>(
-      m_pDest, m_DestFormat, m_DestWidth, m_DestHeight, m_ClipRect, m_pSource,
-      m_Flags);
-  m_pStretchEngine->StartStretchHorz();
-  if (SourceSizeWithinLimit(m_pSource->GetWidth(), m_pSource->GetHeight())) {
-    m_pStretchEngine->Continue(nullptr);
-    return false;
-  }
-  return true;
-}
-
-bool CFX_ImageStretcher::ContinueStretch(IFX_Pause* pPause) {
-  return m_pStretchEngine && m_pStretchEngine->Continue(pPause);
-}
-
-bool CFX_ImageStretcher::StartQuickStretch() {
-  if (m_DestWidth < 0) {
-    m_bFlipX = true;
-    m_DestWidth = -m_DestWidth;
-  }
-  if (m_DestHeight < 0) {
-    m_bFlipY = true;
-    m_DestHeight = -m_DestHeight;
-  }
-  uint32_t size = m_ClipRect.Width();
-  if (size && m_DestBPP > (int)(INT_MAX / size)) {
-    return false;
-  }
-  size *= m_DestBPP;
-  m_pScanline.reset(FX_Alloc(uint8_t, (size / 8 + 3) / 4 * 4));
-  if (m_pSource->m_pAlphaMask)
-    m_pMaskScanline.reset(FX_Alloc(uint8_t, (m_ClipRect.Width() + 3) / 4 * 4));
-
-  if (SourceSizeWithinLimit(m_pSource->GetWidth(), m_pSource->GetHeight())) {
-    ContinueQuickStretch(nullptr);
-    return false;
-  }
-  return true;
-}
-
-bool CFX_ImageStretcher::ContinueQuickStretch(IFX_Pause* pPause) {
-  if (!m_pScanline)
-    return false;
-
-  int result_width = m_ClipRect.Width();
-  int result_height = m_ClipRect.Height();
-  int src_height = m_pSource->GetHeight();
-  for (; m_LineIndex < result_height; m_LineIndex++) {
-    int dest_y;
-    int src_y;
-    if (m_bFlipY) {
-      dest_y = result_height - m_LineIndex - 1;
-      src_y = (m_DestHeight - (dest_y + m_ClipRect.top) - 1) * src_height /
-              m_DestHeight;
-    } else {
-      dest_y = m_LineIndex;
-      src_y = (dest_y + m_ClipRect.top) * src_height / m_DestHeight;
-    }
-    src_y = pdfium::clamp(src_y, 0, src_height - 1);
-
-    if (m_pSource->SkipToScanline(src_y, pPause))
-      return true;
-
-    m_pSource->DownSampleScanline(src_y, m_pScanline.get(), m_DestBPP,
-                                  m_DestWidth, m_bFlipX, m_ClipRect.left,
-                                  result_width);
-    if (m_pMaskScanline) {
-      m_pSource->m_pAlphaMask->DownSampleScanline(
-          src_y, m_pMaskScanline.get(), 1, m_DestWidth, m_bFlipX,
-          m_ClipRect.left, result_width);
-    }
-    m_pDest->ComposeScanline(dest_y, m_pScanline.get(), m_pMaskScanline.get());
-  }
-  return false;
-}
diff --git a/core/fxge/dib/fx_dib_main.cpp b/core/fxge/dib/fx_dib_main.cpp
index f3716c36b1..1214cc1f16 100644
--- a/core/fxge/dib/fx_dib_main.cpp
+++ b/core/fxge/dib/fx_dib_main.cpp
@@ -96,49 +96,3 @@ uint32_t ArgbEncode(int a, FX_COLORREF rgb) {
   return FXARGB_MAKE(a, FXSYS_GetRValue(rgb), FXSYS_GetGValue(rgb),
                      FXSYS_GetBValue(rgb));
 }
-
-CFX_BitmapStorer::CFX_BitmapStorer() {
-}
-
-CFX_BitmapStorer::~CFX_BitmapStorer() {
-}
-
-CFX_RetainPtr<CFX_DIBitmap> CFX_BitmapStorer::Detach() {
-  return std::move(m_pBitmap);
-}
-
-void CFX_BitmapStorer::Replace(CFX_RetainPtr<CFX_DIBitmap>&& pBitmap) {
-  m_pBitmap = std::move(pBitmap);
-}
-
-void CFX_BitmapStorer::ComposeScanline(int line,
-                                       const uint8_t* scanline,
-                                       const uint8_t* scan_extra_alpha) {
-  uint8_t* dest_buf = const_cast<uint8_t*>(m_pBitmap->GetScanline(line));
-  uint8_t* dest_alpha_buf =
-      m_pBitmap->m_pAlphaMask
-          ? const_cast<uint8_t*>(m_pBitmap->m_pAlphaMask->GetScanline(line))
-          : nullptr;
-  if (dest_buf)
-    FXSYS_memcpy(dest_buf, scanline, m_pBitmap->GetPitch());
-
-  if (dest_alpha_buf) {
-    FXSYS_memcpy(dest_alpha_buf, scan_extra_alpha,
-                 m_pBitmap->m_pAlphaMask->GetPitch());
-  }
-}
-
-bool CFX_BitmapStorer::SetInfo(int width,
-                               int height,
-                               FXDIB_Format src_format,
-                               uint32_t* pSrcPalette) {
-  auto pBitmap = pdfium::MakeRetain<CFX_DIBitmap>();
-  if (!pBitmap->Create(width, height, src_format))
-    return false;
-
-  if (pSrcPalette)
-    pBitmap->SetPalette(pSrcPalette);
-
-  m_pBitmap = std::move(pBitmap);
-  return true;
-}
diff --git a/core/fxge/fx_dib.h b/core/fxge/fx_dib.h
index 3be4fc6e3b..e0018f32f5 100644
--- a/core/fxge/fx_dib.h
+++ b/core/fxge/fx_dib.h
@@ -132,126 +132,4 @@ class IFX_ScanlineComposer {
                        uint32_t* pSrcPalette) = 0;
 };
 
-class CFX_BitmapComposer : public IFX_ScanlineComposer {
- public:
-  CFX_BitmapComposer();
-  ~CFX_BitmapComposer() override;
-
-  void Compose(const CFX_RetainPtr<CFX_DIBitmap>& pDest,
-               const CFX_ClipRgn* pClipRgn,
-               int bitmap_alpha,
-               uint32_t mask_color,
-               FX_RECT& dest_rect,
-               bool bVertical,
-               bool bFlipX,
-               bool bFlipY,
-               bool bRgbByteOrder = false,
-               int alpha_flag = 0,
-               void* pIccTransform = nullptr,
-               int blend_type = FXDIB_BLEND_NORMAL);
-
-  // IFX_ScanlineComposer
-  bool SetInfo(int width,
-               int height,
-               FXDIB_Format src_format,
-               uint32_t* pSrcPalette) override;
-
-  void ComposeScanline(int line,
-                       const uint8_t* scanline,
-                       const uint8_t* scan_extra_alpha) override;
-
- protected:
-  void DoCompose(uint8_t* dest_scan,
-                 const uint8_t* src_scan,
-                 int dest_width,
-                 const uint8_t* clip_scan,
-                 const uint8_t* src_extra_alpha = nullptr,
-                 uint8_t* dst_extra_alpha = nullptr);
-  void ComposeScanlineV(int line,
-                        const uint8_t* scanline,
-                        const uint8_t* scan_extra_alpha = nullptr);
-
-  CFX_RetainPtr<CFX_DIBitmap> m_pBitmap;
-  const CFX_ClipRgn* m_pClipRgn;
-  FXDIB_Format m_SrcFormat;
-  int m_DestLeft;
-  int m_DestTop;
-  int m_DestWidth;
-  int m_DestHeight;
-  int m_BitmapAlpha;
-  uint32_t m_MaskColor;
-  CFX_RetainPtr<CFX_DIBitmap> m_pClipMask;
-  CFX_ScanlineCompositor m_Compositor;
-  bool m_bVertical;
-  bool m_bFlipX;
-  bool m_bFlipY;
-  int m_AlphaFlag;
-  void* m_pIccTransform;
-  bool m_bRgbByteOrder;
-  int m_BlendType;
-  uint8_t* m_pScanlineV;
-  uint8_t* m_pClipScanV;
-  uint8_t* m_pAddClipScan;
-  uint8_t* m_pScanlineAlphaV;
-};
-
-class CFX_BitmapStorer : public IFX_ScanlineComposer {
- public:
-  CFX_BitmapStorer();
-  ~CFX_BitmapStorer() override;
-
-  // IFX_ScanlineComposer
-  void ComposeScanline(int line,
-                       const uint8_t* scanline,
-                       const uint8_t* scan_extra_alpha) override;
-  bool SetInfo(int width,
-               int height,
-               FXDIB_Format src_format,
-               uint32_t* pSrcPalette) override;
-
-  CFX_RetainPtr<CFX_DIBitmap> GetBitmap() { return m_pBitmap; }
-  CFX_RetainPtr<CFX_DIBitmap> Detach();
-  void Replace(CFX_RetainPtr<CFX_DIBitmap>&& pBitmap);
-
- private:
-  CFX_RetainPtr<CFX_DIBitmap> m_pBitmap;
-};
-
-class CFX_ImageStretcher {
- public:
-  CFX_ImageStretcher(IFX_ScanlineComposer* pDest,
-                     const CFX_RetainPtr<CFX_DIBSource>& pSource,
-                     int dest_width,
-                     int dest_height,
-                     const FX_RECT& bitmap_rect,
-                     uint32_t flags);
-  ~CFX_ImageStretcher();
-
-  bool Start();
-  bool Continue(IFX_Pause* pPause);
-
-  CFX_RetainPtr<CFX_DIBSource> source() { return m_pSource; }
-
- private:
-  bool StartQuickStretch();
-  bool StartStretch();
-  bool ContinueQuickStretch(IFX_Pause* pPause);
-  bool ContinueStretch(IFX_Pause* pPause);
-
-  IFX_ScanlineComposer* const m_pDest;
-  CFX_RetainPtr<CFX_DIBSource> m_pSource;
-  std::unique_ptr<CStretchEngine> m_pStretchEngine;
-  std::unique_ptr<uint8_t, FxFreeDeleter> m_pScanline;
-  std::unique_ptr<uint8_t, FxFreeDeleter> m_pMaskScanline;
-  const uint32_t m_Flags;
-  bool m_bFlipX;
-  bool m_bFlipY;
-  int m_DestWidth;
-  int m_DestHeight;
-  FX_RECT m_ClipRect;
-  const FXDIB_Format m_DestFormat;
-  const int m_DestBPP;
-  int m_LineIndex;
-};
-
 #endif  // CORE_FXGE_FX_DIB_H_
diff --git a/core/fxge/skia/fx_skia_device.cpp b/core/fxge/skia/fx_skia_device.cpp
index e9dc982ce1..1dc8ab2c7b 100644
--- a/core/fxge/skia/fx_skia_device.cpp
+++ b/core/fxge/skia/fx_skia_device.cpp
@@ -19,7 +19,9 @@
 #include "core/fxge/cfx_graphstatedata.h"
 #include "core/fxge/cfx_pathdata.h"
 #include "core/fxge/cfx_renderdevice.h"
+#include "core/fxge/dib/cfx_bitmapcomposer.h"
 #include "core/fxge/dib/cfx_imagerenderer.h"
+#include "core/fxge/dib/cfx_imagestretcher.h"
 #include "core/fxge/skia/fx_skia_device.h"
 
 #ifdef _SKIA_SUPPORT_PATHS_