add native draw bitmap with alpha mask

PDFs draw bitmaps with alpha by supplying an
image alpha mask along side the image color data.

The alpha mask may not be the same scale as the
image data. Skia doesn't have a direct mapping
for this draw call, but can come close by using
the internal SkCompositeShader class.

This scales the alpha mask to match the size of
the image data, then puts both in the composite
shader to draw.

There are more things to do:

- Allow Alpha8 or Gray8 to draw scaled to
  a matching device (blit doesn't work today)

Temporary code marked with
a TODO implements this functionality.

- Refactor PDFium to allow SkComposeShader's
  components to take a matrix.

The latter goal will defer drawing so that PDFium
doesn't resize the mask, discarding resolution,
before Skia has a chance to record it.

Additionally fix drawing text with a negative
font size.

R=reed@google.com,dsinclair@chromium.org,herb@chromium.org

Review-Url: https://codereview.chromium.org/2182763002

2 files changed, 233 insertions, 78 deletions

diff --git a/core/fxge/skia/fx_skia_device.cpp b/core/fxge/skia/fx_skia_device.cpp
index 49c4639866..3effa0a6a6 100644
--- a/core/fxge/skia/fx_skia_device.cpp
+++ b/core/fxge/skia/fx_skia_device.cpp
@@ -24,9 +24,11 @@
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkColorFilter.h"
 #include "third_party/skia/include/core/SkColorPriv.h"
+#include "third_party/skia/include/core/SkMaskFilter.h"
 #include "third_party/skia/include/core/SkPaint.h"
 #include "third_party/skia/include/core/SkPath.h"
 #include "third_party/skia/include/core/SkPictureRecorder.h"
+#include "third_party/skia/include/core/SkShader.h"
 #include "third_party/skia/include/core/SkStream.h"
 #include "third_party/skia/include/core/SkTypeface.h"
 #include "third_party/skia/include/effects/SkDashPathEffect.h"
@@ -140,9 +142,10 @@ SkMatrix ToSkMatrix(const CFX_Matrix& m) {
 }
 
 // use when pdf's y-axis points up insead of down
-SkMatrix ToFlippedSkMatrix(const CFX_Matrix& m) {
+SkMatrix ToFlippedSkMatrix(const CFX_Matrix& m, SkScalar flip) {
   SkMatrix skMatrix;
-  skMatrix.setAll(m.a, -m.c, m.e, m.b, -m.d, m.f, 0, 0, 1);
+  skMatrix.setAll(m.a * flip, -m.c * flip, m.e, m.b * flip, -m.d * flip, m.f, 0,
+                  0, 1);
   return skMatrix;
 }
 
@@ -367,6 +370,107 @@ void ClipAngledGradient(const SkPoint pts[2],
   clip->lineTo(IntersectSides(rectPts[maxBounds], slope, startEdgePt));
 }
 
+void SetBitmapMatrix(const CFX_Matrix* pMatrix,
+                     int width,
+                     int height,
+                     SkMatrix* skMatrix) {
+  const CFX_Matrix& m = *pMatrix;
+  skMatrix->setAll(m.a / width, -m.c / height, m.c + m.e, m.b / width,
+                   -m.d / height, m.d + m.f, 0, 0, 1);
+}
+
+void SetBitmapPaint(bool isAlphaMask,
+                    uint32_t argb,
+                    int bitmap_alpha,
+                    int blend_type,
+                    SkPaint* paint) {
+  paint->setAntiAlias(true);
+  if (isAlphaMask) {
+    paint->setColorFilter(
+        SkColorFilter::MakeModeFilter(argb, SkXfermode::kSrc_Mode));
+  }
+  // paint->setFilterQuality(kHigh_SkFilterQuality);
+  paint->setXfermodeMode(GetSkiaBlendMode(blend_type));
+  paint->setAlpha(bitmap_alpha);
+}
+
+bool Upsample(const CFX_DIBSource* pSource,
+              std::unique_ptr<uint8_t, FxFreeDeleter>& dst8Storage,
+              std::unique_ptr<uint32_t, FxFreeDeleter>& dst32Storage,
+              SkColorTable** ctPtr,
+              SkBitmap* skBitmap,
+              int* widthPtr,
+              int* heightPtr,
+              bool forceAlpha) {
+  void* buffer = pSource->GetBuffer();
+  if (!buffer)
+    return false;
+  SkColorType colorType = forceAlpha || pSource->IsAlphaMask()
+                              ? SkColorType::kAlpha_8_SkColorType
+                              : SkColorType::kGray_8_SkColorType;
+  SkAlphaType alphaType =
+      pSource->IsAlphaMask() ? kPremul_SkAlphaType : kOpaque_SkAlphaType;
+  int width = pSource->GetWidth();
+  int height = pSource->GetHeight();
+  int rowBytes = pSource->GetPitch();
+  switch (pSource->GetBPP()) {
+    case 1: {
+      dst8Storage.reset(FX_Alloc2D(uint8_t, width, height));
+      uint8_t* dst8Pixels = dst8Storage.get();
+      for (int y = 0; y < height; ++y) {
+        const uint8_t* srcRow =
+            static_cast<const uint8_t*>(buffer) + y * rowBytes;
+        uint8_t* dstRow = dst8Pixels + y * width;
+        for (int x = 0; x < width; ++x)
+          dstRow[x] = srcRow[x >> 3] & (1 << (~x & 0x07)) ? 0xFF : 0x00;
+      }
+      buffer = dst8Storage.get();
+      rowBytes = width;
+      break;
+    }
+    case 8:
+      if (pSource->GetPalette()) {
+        *ctPtr =
+            new SkColorTable(pSource->GetPalette(), pSource->GetPaletteSize());
+        colorType = SkColorType::kIndex_8_SkColorType;
+      }
+      break;
+    case 24: {
+      dst32Storage.reset(FX_Alloc2D(uint32_t, width, height));
+      uint32_t* dst32Pixels = dst32Storage.get();
+      for (int y = 0; y < height; ++y) {
+        const uint8_t* srcRow =
+            static_cast<const uint8_t*>(buffer) + y * rowBytes;
+        uint32_t* dstRow = dst32Pixels + y * width;
+        for (int x = 0; x < width; ++x) {
+          dstRow[x] = SkPackARGB32(0xFF, srcRow[x * 3 + 2], srcRow[x * 3 + 1],
+                                   srcRow[x * 3 + 0]);
+        }
+      }
+      buffer = dst32Storage.get();
+      rowBytes = width * sizeof(uint32_t);
+      colorType = SkColorType::kN32_SkColorType;
+      alphaType = kOpaque_SkAlphaType;
+      break;
+    }
+    case 32:
+      colorType = SkColorType::kN32_SkColorType;
+      alphaType = kPremul_SkAlphaType;
+      pSource->DebugVerifyBitmapIsPreMultiplied(buffer);
+      break;
+    default:
+      SkASSERT(0);  // TODO(caryclark) ensure that all cases are covered
+      colorType = SkColorType::kUnknown_SkColorType;
+  }
+  SkImageInfo imageInfo =
+      SkImageInfo::Make(width, height, colorType, alphaType);
+  skBitmap->installPixels(imageInfo, buffer, rowBytes, *ctPtr, nullptr,
+                          nullptr);
+  *widthPtr = width;
+  *heightPtr = height;
+  return true;
+}
+
 }  // namespace
 
 // Encapsulate the state used for successive text and path draws so that
@@ -500,22 +604,24 @@ class SkiaState {
     int count = m_positions.count();
     m_positions.setCount(nChars + count);
     m_glyphs.setCount(nChars + count);
+    SkScalar flip = m_fontSize < 0 ? -1 : 1;
     for (int index = 0; index < nChars; ++index) {
       const FXTEXT_CHARPOS& cp = pCharPos[index];
-      m_positions[index + count] = {cp.m_OriginX, cp.m_OriginY};
+      m_positions[index + count] = {cp.m_OriginX * flip, cp.m_OriginY * flip};
       m_glyphs[index + count] = (uint16_t)cp.m_GlyphIndex;
     }
     SkPoint delta;
     if (MatrixOffset(pMatrix, &delta)) {
       for (int index = 0; index < nChars; ++index)
-        m_positions[index + count].offset(delta.fX, -delta.fY);
+        m_positions[index + count].offset(delta.fX * flip, -delta.fY * flip);
     }
     m_drawText = true;
     return true;
   }
 
   void FlushText(CFX_SkiaDeviceDriver* pDriver) {
-    SkMatrix skMatrix = ToFlippedSkMatrix(m_drawMatrix);
+    SkScalar flip = m_fontSize < 0 ? -1 : 1;
+    SkMatrix skMatrix = ToFlippedSkMatrix(m_drawMatrix, flip);
     SkPaint skPaint;
     skPaint.setAntiAlias(true);
     skPaint.setColor(m_fillColor);
@@ -919,7 +1025,8 @@ FX_BOOL CFX_SkiaDeviceDriver::DrawDeviceText(int nChars,
   paint.setTextSize(font_size);
   paint.setSubpixelText(true);
   m_pCanvas->save();
-  SkMatrix skMatrix = ToFlippedSkMatrix(*pObject2Device);
+  SkScalar flip = font_size < 0 ? -1 : 1;
+  SkMatrix skMatrix = ToFlippedSkMatrix(*pObject2Device, flip);
   m_pCanvas->concat(skMatrix);
   SkTDArray<SkPoint> positions;
   positions.setCount(nChars);
@@ -927,7 +1034,7 @@ FX_BOOL CFX_SkiaDeviceDriver::DrawDeviceText(int nChars,
   glyphs.setCount(nChars);
   for (int index = 0; index < nChars; ++index) {
     const FXTEXT_CHARPOS& cp = pCharPos[index];
-    positions[index] = {cp.m_OriginX, cp.m_OriginY};
+    positions[index] = {cp.m_OriginX * flip, cp.m_OriginY * flip};
     glyphs[index] = (uint16_t)cp.m_GlyphIndex;
   }
   m_pCanvas->drawPosText(glyphs.begin(), nChars * 2, positions.begin(), paint);
@@ -1339,86 +1446,39 @@ FX_BOOL CFX_SkiaDeviceDriver::StartDIBits(const CFX_DIBSource* pSource,
                                           void*& handle,
                                           int blend_type) {
   DebugValidate(m_pBitmap, m_pOriDevice);
-  SkColorType colorType = pSource->IsAlphaMask()
-                              ? SkColorType::kAlpha_8_SkColorType
-                              : SkColorType::kGray_8_SkColorType;
-  SkAlphaType alphaType =
-      pSource->IsAlphaMask() ? kPremul_SkAlphaType : kOpaque_SkAlphaType;
   SkColorTable* ct = nullptr;
-  void* buffer = pSource->GetBuffer();
-  if (!buffer)
-    return FALSE;
   std::unique_ptr<uint8_t, FxFreeDeleter> dst8Storage;
   std::unique_ptr<uint32_t, FxFreeDeleter> dst32Storage;
-  int width = pSource->GetWidth();
-  int height = pSource->GetHeight();
-  int rowBytes = pSource->GetPitch();
-  switch (pSource->GetBPP()) {
-    case 1: {
-      dst8Storage.reset(FX_Alloc2D(uint8_t, width, height));
-      uint8_t* dst8Pixels = dst8Storage.get();
-      for (int y = 0; y < height; ++y) {
-        const uint8_t* srcRow =
-            static_cast<const uint8_t*>(buffer) + y * rowBytes;
-        uint8_t* dstRow = dst8Pixels + y * width;
-        for (int x = 0; x < width; ++x)
-          dstRow[x] = srcRow[x >> 3] & (1 << (~x & 0x07)) ? 0xFF : 0x00;
-      }
-      buffer = dst8Storage.get();
-      rowBytes = width;
-    } break;
-    case 8:
-      if (pSource->GetPalette()) {
-        ct = new SkColorTable(pSource->GetPalette(), pSource->GetPaletteSize());
-        colorType = SkColorType::kIndex_8_SkColorType;
-      }
-      break;
-    case 24: {
-      dst32Storage.reset(FX_Alloc2D(uint32_t, width, height));
-      uint32_t* dst32Pixels = dst32Storage.get();
-      for (int y = 0; y < height; ++y) {
-        const uint8_t* srcRow =
-            static_cast<const uint8_t*>(buffer) + y * rowBytes;
-        uint32_t* dstRow = dst32Pixels + y * width;
-        for (int x = 0; x < width; ++x) {
-          dstRow[x] = SkPackARGB32(0xFF, srcRow[x * 3 + 2], srcRow[x * 3 + 1],
-                                   srcRow[x * 3 + 0]);
-        }
-      }
-      buffer = dst32Storage.get();
-      rowBytes = width * sizeof(uint32_t);
-      colorType = SkColorType::kN32_SkColorType;
-      alphaType = kOpaque_SkAlphaType;
-    } break;
-    case 32:
-      colorType = SkColorType::kN32_SkColorType;
-      alphaType = kPremul_SkAlphaType;
-      pSource->DebugVerifyBitmapIsPreMultiplied(buffer);
-      break;
-    default:
-      SkASSERT(0);  // TODO(caryclark) ensure that all cases are covered
-      colorType = SkColorType::kUnknown_SkColorType;
-  }
-  SkImageInfo imageInfo =
-      SkImageInfo::Make(width, height, colorType, alphaType);
   SkBitmap skBitmap;
-  skBitmap.installPixels(imageInfo, buffer, rowBytes, ct, nullptr, nullptr);
+  int width, height;
+  if (!Upsample(pSource, dst8Storage, dst32Storage, &ct, &skBitmap, &width,
+                &height, false)) {
+    return FALSE;
+  }
   m_pCanvas->save();
   SkMatrix skMatrix;
-  const CFX_Matrix& m = *pMatrix;
-  skMatrix.setAll(m.a / width, -m.c / height, m.c + m.e, m.b / width,
-                  -m.d / height, m.d + m.f, 0, 0, 1);
+  SetBitmapMatrix(pMatrix, width, height, &skMatrix);
   m_pCanvas->concat(skMatrix);
   SkPaint paint;
-  paint.setAntiAlias(true);
-  if (pSource->IsAlphaMask()) {
-    paint.setColorFilter(
-        SkColorFilter::MakeModeFilter(argb, SkXfermode::kSrc_Mode));
+  SetBitmapPaint(pSource->IsAlphaMask(), argb, bitmap_alpha, blend_type,
+                 &paint);
+  // TODO(caryclark) Once Skia supports 8 bit src to 8 bit dst remove this
+  if (m_pBitmap->GetBPP() == 8 && pSource->GetBPP() == 8) {
+    SkMatrix inv;
+    SkAssertResult(skMatrix.invert(&inv));
+    for (int y = 0; y < m_pBitmap->GetHeight(); ++y) {
+      for (int x = 0; x < m_pBitmap->GetWidth(); ++x) {
+        SkPoint src = {x + 0.5f, y + 0.5f};
+        inv.mapPoints(&src, 1);
+        // TODO(caryclark) Why does the matrix map require clamping?
+        src.fX = SkTMax(0.5f, SkTMin(src.fX, width - 0.5f));
+        src.fY = SkTMax(0.5f, SkTMin(src.fY, height - 0.5f));
+        m_pBitmap->SetPixel(x, y, skBitmap.getColor(src.fX, src.fY));
+      }
+    }
+  } else {
+    m_pCanvas->drawBitmap(skBitmap, 0, 0, &paint);
   }
-  // paint.setFilterQuality(kHigh_SkFilterQuality);
-  paint.setXfermodeMode(GetSkiaBlendMode(blend_type));
-  paint.setAlpha(bitmap_alpha);
-  m_pCanvas->drawBitmap(skBitmap, 0, 0, &paint);
   m_pCanvas->restore();
   if (ct)
     ct->unref();
@@ -1450,6 +1510,68 @@ void CFX_SkiaDeviceDriver::PreMultiply(CFX_DIBitmap* pDIBitmap) {
   pDIBitmap->DebugVerifyBitmapIsPreMultiplied();
 }
 
+bool CFX_SkiaDeviceDriver::DrawBitsWithMask(const CFX_DIBSource* pSource,
+                                            const CFX_DIBSource* pMask,
+                                            int bitmap_alpha,
+                                            const CFX_Matrix* pMatrix,
+                                            int blend_type) {
+  DebugValidate(m_pBitmap, m_pOriDevice);
+  SkColorTable* srcCt = nullptr;
+  SkColorTable* maskCt = nullptr;
+  std::unique_ptr<uint8_t, FxFreeDeleter> src8Storage, mask8Storage;
+  std::unique_ptr<uint32_t, FxFreeDeleter> src32Storage, mask32Storage;
+  SkBitmap skBitmap, skMask;
+  int srcWidth, srcHeight, maskWidth, maskHeight;
+  if (!Upsample(pSource, src8Storage, src32Storage, &srcCt, &skBitmap,
+                &srcWidth, &srcHeight, false)) {
+    return false;
+  }
+  if (!Upsample(pMask, mask8Storage, mask32Storage, &maskCt, &skMask,
+                &maskWidth, &maskHeight, true)) {
+    return false;
+  }
+  m_pCanvas->save();
+  SkMatrix skMatrix;
+  SetBitmapMatrix(pMatrix, srcWidth, srcHeight, &skMatrix);
+  m_pCanvas->concat(skMatrix);
+  SkPaint paint;
+  SetBitmapPaint(pSource->IsAlphaMask(), 0xFFFFFFFF, bitmap_alpha, blend_type,
+                 &paint);
+  sk_sp<SkImage> skSrc = SkImage::MakeFromBitmap(skBitmap);
+  sk_sp<SkShader> skSrcShader =
+      skSrc->makeShader(SkShader::kClamp_TileMode, SkShader::kClamp_TileMode);
+  sk_sp<SkImage> skMaskImage = SkImage::MakeFromBitmap(skMask);
+  sk_sp<SkShader> skMaskShader = skMaskImage->makeShader(
+      SkShader::kClamp_TileMode, SkShader::kClamp_TileMode);
+  sk_sp<SkXfermode> dstInMode = SkXfermode::Make(SkXfermode::kSrcIn_Mode);
+  paint.setShader(
+      SkShader::MakeComposeShader(skMaskShader, skSrcShader, dstInMode));
+  SkRect r = {0, 0, SkIntToScalar(srcWidth), SkIntToScalar(srcHeight)};
+  m_pCanvas->drawRect(r, paint);
+  m_pCanvas->restore();
+  if (srcCt)
+    srcCt->unref();
+  DebugValidate(m_pBitmap, m_pOriDevice);
+  return true;
+}
+
+bool CFX_SkiaDeviceDriver::SetBitsWithMask(const CFX_DIBSource* pBitmap,
+                                           const CFX_DIBSource* pMask,
+                                           int dest_left,
+                                           int dest_top,
+                                           int bitmap_alpha,
+                                           int blend_type) {
+  if (!m_pBitmap || !m_pBitmap->GetBuffer())
+    return true;
+  CFX_Matrix m(pBitmap->GetWidth(), 0, 0, -pBitmap->GetHeight(), dest_left,
+               dest_top + pBitmap->GetHeight());
+  return DrawBitsWithMask(pBitmap, pMask, bitmap_alpha, &m, blend_type);
+}
+
+void CFX_SkiaDeviceDriver::Clear(uint32_t color) {
+  m_pCanvas->clear(color);
+}
+
 void CFX_SkiaDeviceDriver::Dump() const {
 #ifdef SK_DEBUG
   if (m_pCache)
@@ -1466,6 +1588,12 @@ CFX_FxgeDevice::CFX_FxgeDevice() {
   m_bOwnedBitmap = FALSE;
 }
 
+void CFX_FxgeDevice::Clear(uint32_t color) {
+  CFX_SkiaDeviceDriver* skDriver =
+      static_cast<CFX_SkiaDeviceDriver*>(GetDeviceDriver());
+  skDriver->Clear(color);
+}
+
 SkPictureRecorder* CFX_FxgeDevice::CreateRecorder(int size_x, int size_y) {
   CFX_SkiaDeviceDriver* skDriver = new CFX_SkiaDeviceDriver(size_x, size_y);
   SetDeviceDriver(WrapUnique(skDriver));
@@ -1523,6 +1651,20 @@ void CFX_FxgeDevice::DebugVerifyBitmapIsPreMultiplied() const {
 #endif
 }
 
+bool CFX_FxgeDevice::SetBitsWithMask(const CFX_DIBSource* pBitmap,
+                                     const CFX_DIBSource* pMask,
+                                     int left,
+                                     int top,
+                                     int bitmap_alpha,
+                                     int blend_type) {
+  CFX_SkiaDeviceDriver* skDriver =
+      static_cast<CFX_SkiaDeviceDriver*>(GetDeviceDriver());
+  if (skDriver)
+    return skDriver->SetBitsWithMask(pBitmap, pMask, left, top, bitmap_alpha,
+                                     blend_type);
+  return false;
+}
+
 void CFX_DIBSource::DebugVerifyBitmapIsPreMultiplied(void* opt) const {
 #ifdef SK_DEBUG
   SkASSERT(32 == GetBPP());
diff --git a/core/fxge/skia/fx_skia_device.h b/core/fxge/skia/fx_skia_device.h
index 661cf2e3b9..6e112f5f62 100644
--- a/core/fxge/skia/fx_skia_device.h
+++ b/core/fxge/skia/fx_skia_device.h
@@ -84,6 +84,12 @@ class CFX_SkiaDeviceDriver : public IFX_RenderDeviceDriver {
                     int dest_left,
                     int dest_top,
                     int blend_type) override;
+  bool SetBitsWithMask(const CFX_DIBSource* pBitmap,
+                       const CFX_DIBSource* pMask,
+                       int dest_left,
+                       int dest_top,
+                       int bitmap_alpha,
+                       int blend_type) override;
   FX_BOOL StretchDIBits(const CFX_DIBSource* pBitmap,
                         uint32_t color,
                         int dest_left,
@@ -106,6 +112,12 @@ class CFX_SkiaDeviceDriver : public IFX_RenderDeviceDriver {
 
   void CancelDIBits(void* handle) override {}
 
+  bool DrawBitsWithMask(const CFX_DIBSource* pBitmap,
+                        const CFX_DIBSource* pMask,
+                        int bitmap_alpha,
+                        const CFX_Matrix* pMatrix,
+                        int blend_type);
+
   FX_BOOL DrawDeviceText(int nChars,
                          const FXTEXT_CHARPOS* pCharPos,
                          CFX_Font* pFont,
@@ -125,6 +137,7 @@ class CFX_SkiaDeviceDriver : public IFX_RenderDeviceDriver {
   void PaintStroke(SkPaint* spaint,
                    const CFX_GraphStateData* pGraphState,
                    const SkMatrix& matrix);
+  void Clear(uint32_t color);
   void Flush();
   SkPictureRecorder* GetRecorder() const { return m_pRecorder; }
   static void PreMultiply(CFX_DIBitmap* pDIBitmap);