support gradients and stroke+fill

core/fxge/skia/fx_skia_device.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.
 
 #include "core/include/fxge/fx_ge.h"
 
 #if defined(_SKIA_SUPPORT_)
 #include "core/include/fxcodec/fx_codec.h"
 
+#include "core/fpdfapi/fpdf_page/cpdf_shadingpattern.h"
+#include "core/fpdfapi/fpdf_page/pageint.h"
+#include "core/fpdfapi/fpdf_parser/include/cpdf_array.h"
+#include "core/fpdfapi/fpdf_parser/include/cpdf_dictionary.h"
 #include "core/fxge/agg/fx_agg_driver.h"
 #include "core/fxge/skia/fx_skia_device.h"
 
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkColorPriv.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/SkStream.h"
 #include "third_party/skia/include/core/SkTypeface.h"
 #include "third_party/skia/include/effects/SkDashPathEffect.h"
+#include "third_party/skia/include/effects/SkGradientShader.h"
+#include "third_party/skia/include/pathops/SkPathOps.h"
 
 namespace {
 
 #define SHOW_SKIA_PATH 0  // set to 1 to print the path contents
 #define DRAW_SKIA_CLIP 0  // set to 1 to draw a green rectangle around the clip
 
 void DebugShowSkiaPath(const SkPath& path) {
 #if SHOW_SKIA_PATH
   char buffer[4096];
   sk_bzero(buffer, sizeof(buffer));
@@ skipping 112 matching lines @@
     case FXDIB_BLEND_COLOR:
       return SkXfermode::kColor_Mode;
     case FXDIB_BLEND_LUMINOSITY:
       return SkXfermode::kLuminosity_Mode;
     case FXDIB_BLEND_NORMAL:
     default:
       return SkXfermode::kSrcOver_Mode;
   }
 }
 
+bool AddColors(const CPDF_Function* pFunc, SkTDArray<SkColor>* skColors) {
+  if (pFunc->CountInputs() != 1)
+    return false;
+  const CPDF_ExpIntFunc* expIntFunc =

[Tom Sepez, 2016/03/24 18:07:08]

nit: want to assert on type before the cast?

[caryclark, 2016/03/25 20:47:56]

Done.

+      static_cast<const CPDF_ExpIntFunc*>(pFunc);
+  if (expIntFunc->m_Exponent != 1)
+    return false;
+  if (expIntFunc->m_nOrigOutputs != 3)
+    return false;
+  skColors->push(SkColorSetARGB(
+      0xFF, SkUnitScalarClampToByte(expIntFunc->m_pBeginValues[0]),
+      SkUnitScalarClampToByte(expIntFunc->m_pBeginValues[1]),
+      SkUnitScalarClampToByte(expIntFunc->m_pBeginValues[2])));
+  skColors->push(
+      SkColorSetARGB(0xFF, SkUnitScalarClampToByte(expIntFunc->m_pEndValues[0]),
+                     SkUnitScalarClampToByte(expIntFunc->m_pEndValues[1]),
+                     SkUnitScalarClampToByte(expIntFunc->m_pEndValues[2])));
+  return true;
+}
+
+bool AddStitching(const CPDF_Function* pFunc,
+                  SkTDArray<SkColor>* skColors,
+                  SkTDArray<SkScalar>* skPos) {
+  int inputs = pFunc->CountInputs();
+  const CPDF_StitchFunc* stitchFunc =

[Tom Sepez, 2016/03/24 18:07:08]

dittp

[caryclark, 2016/03/25 20:47:56]

Done.

+      static_cast<const CPDF_StitchFunc*>(pFunc);
+  FX_FLOAT boundsStart = stitchFunc->GetDomain(0);
+
+  for (int i = 0; i < inputs; ++i) {
+    const CPDF_Function* pSubFunc = stitchFunc->m_pSubFunctions[i];
+    if (pSubFunc->GetType() != 2)
+      return false;
+    if (!AddColors(pSubFunc, skColors))
+      return false;
+    FX_FLOAT boundsEnd =
+        i < inputs - 1 ? stitchFunc->m_pBounds[i] : stitchFunc->GetDomain(1);
+    skPos->push(boundsStart);
+    skPos->push(boundsEnd);
+    boundsStart = boundsEnd;
+  }
+  return true;
+}
+
 }  // namespace
 
 // convert a stroking path to scanlines
 void CFX_SkiaDeviceDriver::PaintStroke(SkPaint* spaint,
                                        const CFX_GraphStateData* pGraphState,
                                        const SkMatrix& matrix) {
   SkPaint::Cap cap;
   switch (pGraphState->m_LineCap) {
     case CFX_GraphStateData::LineCapRound:
       cap = SkPaint::kRound_Cap;
@@ skipping 133 matching lines @@
       return m_pCanvas->imageInfo().width();
     case FXDC_PIXEL_HEIGHT:
       return m_pCanvas->imageInfo().height();
     case FXDC_BITS_PIXEL:
       return 32;
     case FXDC_HORZ_SIZE:
     case FXDC_VERT_SIZE:
       return 0;
     case FXDC_RENDER_CAPS:
       return FXRC_GET_BITS | FXRC_ALPHA_PATH | FXRC_ALPHA_IMAGE |
-             FXRC_BLEND_MODE | FXRC_SOFT_CLIP | FXRC_ALPHA_OUTPUT;
+             FXRC_BLEND_MODE | FXRC_SOFT_CLIP | FXRC_ALPHA_OUTPUT |
+             FXRC_FILLSTROKE_PATH | FXRC_SHADING;
     case FXDC_DITHER_BITS:
       return m_ditherBits;
   }
   return 0;
 }
 
 void CFX_SkiaDeviceDriver::SaveState() {
   m_pCanvas->save();
 }
 
@@ skipping 61 matching lines @@
     const CFX_GraphStateData* pGraphState,  // graphic state, for pen attributes
     FX_DWORD fill_color,                    // fill color
     FX_DWORD stroke_color,                  // stroke color
     int fill_mode,  // fill mode, WINDING or ALTERNATE. 0 for not filled
     int alpha_flag,
     void* pIccTransform,
     int blend_type) {
   SkIRect rect;
   rect.set(0, 0, GetDeviceCaps(FXDC_PIXEL_WIDTH),
            GetDeviceCaps(FXDC_PIXEL_HEIGHT));
+  SkMatrix skMatrix = ToSkMatrix(*pObject2Device);
+  SkPaint skPaint;
+  skPaint.setAntiAlias(true);
+  int stroke_alpha = FXGETFLAG_COLORTYPE(alpha_flag)
+                         ? FXGETFLAG_ALPHA_STROKE(alpha_flag)
+                         : FXARGB_A(stroke_color);
+  if (pGraphState && stroke_alpha) {
+    PaintStroke(&skPaint, pGraphState, skMatrix);
+  }

[dsinclair, 2016/03/24 17:43:38]

nit: No {}s

[caryclark, 2016/03/25 20:47:56]

Done.

   SkPath skPath = BuildPath(pPathData);
-  SkPaint spaint;
-  spaint.setAntiAlias(true);
-  spaint.setXfermodeMode(GetSkiaBlendMode(blend_type));
   m_pCanvas->save();
-  SkMatrix skMatrix = ToSkMatrix(*pObject2Device);
   m_pCanvas->concat(skMatrix);
   if ((fill_mode & 3) && fill_color) {
     skPath.setFillType((fill_mode & 3) == FXFILL_WINDING
                            ? SkPath::kWinding_FillType
                            : SkPath::kEvenOdd_FillType);
-
-    spaint.setStyle(SkPaint::kFill_Style);
-    spaint.setColor(fill_color);
-    m_pCanvas->drawPath(skPath, spaint);
+    SkPath strokePath;
+    const SkPath* fillPath = &skPath;
+    if (pGraphState && stroke_alpha) {
+      SkAlpha fillA = SkColorGetA(fill_color);
+      SkAlpha strokeA = SkColorGetA(stroke_color);
+      if (fillA && fillA < 0xFF && strokeA && strokeA < 0xFF) {
+        skPaint.getFillPath(skPath, &strokePath);
+        if (Op(skPath, strokePath, SkPathOp::kDifference_SkPathOp,
+               &strokePath)) {
+          fillPath = &strokePath;
+        }
+      }
+    }
+    skPaint.setStyle(SkPaint::kFill_Style);
+    skPaint.setColor(fill_color);
+    m_pCanvas->drawPath(*fillPath, skPaint);
   }
-  int stroke_alpha = FXGETFLAG_COLORTYPE(alpha_flag)
-                         ? FXGETFLAG_ALPHA_STROKE(alpha_flag)
-                         : FXARGB_A(stroke_color);
-
   if (pGraphState && stroke_alpha) {
-    spaint.setColor(stroke_color);
-    PaintStroke(&spaint, pGraphState, skMatrix);
     DebugShowSkiaPath(skPath);
     DebugShowCanvasMatrix(m_pCanvas);
-    m_pCanvas->drawPath(skPath, spaint);
+    skPaint.setStyle(SkPaint::kStroke_Style);
+    skPaint.setColor(stroke_color);
+    m_pCanvas->drawPath(skPath, skPaint);
   }
   m_pCanvas->restore();
   return TRUE;
 }
 
 FX_BOOL CFX_SkiaDeviceDriver::FillRect(const FX_RECT* pRect,
                                        FX_DWORD fill_color,
                                        int alpha_flag,
                                        void* pIccTransform,
                                        int blend_type) {
   SkPaint spaint;
   spaint.setAntiAlias(true);
   spaint.setColor(fill_color);
   spaint.setXfermodeMode(GetSkiaBlendMode(blend_type));
 
   m_pCanvas->drawRect(
       SkRect::MakeLTRB(pRect->left, pRect->top, pRect->right, pRect->bottom),
       spaint);
   return TRUE;
 }
 
+FX_BOOL CFX_SkiaDeviceDriver::DrawShading(CPDF_ShadingPattern* pPattern,
+                                          CFX_Matrix* pMatrix,
+                                          int alpha,
+                                          FX_BOOL bAlphaMode) {
+  CPDF_Function** pFuncs = pPattern->m_pFunctions;
+  int nFuncs = pPattern->m_nFuncs;
+  CPDF_Dictionary* pDict = pPattern->m_pShadingObj->GetDict();
+  CPDF_Array* pCoords = pDict->GetArrayBy("Coords");
+  if (!pCoords)
+    return true;
+  FX_FLOAT start_x = pCoords->GetNumberAt(0);
+  FX_FLOAT start_y = pCoords->GetNumberAt(1);
+  FX_FLOAT end_x = pCoords->GetNumberAt(2);
+  FX_FLOAT end_y = pCoords->GetNumberAt(3);
+  FX_FLOAT t_min = 0, t_max = 1.0f;

[dsinclair, 2016/03/24 17:43:38]

nit: one per line.

[caryclark, 2016/03/25 20:47:56]

Done.

+  CPDF_Array* pArray = pDict->GetArrayBy("Domain");
+  if (pArray) {
+    t_min = pArray->GetNumberAt(0);
+    t_max = pArray->GetNumberAt(1);
+  }
+  FX_BOOL bStartExtend = FALSE, bEndExtend = FALSE;
+  pArray = pDict->GetArrayBy("Extend");
+  if (pArray) {
+    bStartExtend = pArray->GetIntegerAt(0);
+    bEndExtend = pArray->GetIntegerAt(1);
+  }
+  SkTDArray<SkColor> skColors;
+  SkTDArray<SkScalar> skPos;
+  if (nFuncs != 1)

[dsinclair, 2016/03/24 17:43:38]

Can we do this earlier before all the other work?

[caryclark, 2016/03/25 20:47:56]

Done.

+    return false;
+  for (int j = 0; j < nFuncs; j++) {
+    const CPDF_Function* pFunc = pFuncs[j];
+    if (!pFunc)
+      continue;
+    switch (pFunc->GetType()) {
+      case 2:  // exp interp function

[dsinclair, 2016/03/24 17:43:38]

Can you expand 'exp interp' as I don't know what those mean. Exponential
Interpolation?

Or, better, can we add a enum FunctionTypes {} and name the numbers?

[caryclark, 2016/03/25 20:47:56]

Done.

+        if (!AddColors(pFunc, &skColors))
+          return false;
+        skPos.push(0);
+        skPos.push(1);
+        break;
+      case 3:  // stitching functions
+        if (!AddStitching(pFunc, &skColors, &skPos))
+          return false;
+        break;
+      default:
+        return false;
+    }
+  }
+  SkMatrix skMatrix = ToSkMatrix(*pMatrix);
+  SkPoint pts[] = {{start_x, start_y}, {end_x, end_y}};
+  SkPaint paint;
+  paint.setAntiAlias(true);
+  paint.setShader(SkGradientShader::MakeLinear(pts, skColors.begin(),
+                                               skPos.begin(), skColors.count(),
+                                               SkShader::kClamp_TileMode));
+  paint.setAlpha(alpha);
+  m_pCanvas->save();
+  m_pCanvas->concat(skMatrix);
+  m_pCanvas->drawRect(SkRect::MakeWH(1, 1), paint);
+  m_pCanvas->restore();
+  return true;
+}
+
 FX_BOOL CFX_SkiaDeviceDriver::GetClipBox(FX_RECT* pRect) {
   // TODO(caryclark) call m_canvas->getClipDeviceBounds() instead
   pRect->left = 0;
   pRect->top = 0;
   const SkImageInfo& canvasSize = m_pCanvas->imageInfo();
   pRect->right = canvasSize.width();
   pRect->bottom = canvasSize.height();
   return TRUE;
 }
 
@@ skipping 176 matching lines @@
   SetDeviceDriver(pDriver);
   return TRUE;
 }
 
 CFX_SkiaDevice::~CFX_SkiaDevice() {
   if (m_bOwnedBitmap && GetBitmap())
     delete GetBitmap();
 }
 
 #endif