Refactor the PlatformContext layer to have only one class.

skia/ext/vector_platform_device_win.cc

+// Copyright (c) 2009 The Chromium 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 <windows.h>
+
+#include "skia/ext/vector_platform_device_win.h"
+
+#include "base/gfx/gdi_util.h"
+#include "skia/ext/skia_utils_win.h"
+#include "third_party/skia/include/core/SkUtils.h"
+
+namespace skia {
+
+VectorPlatformDevice* VectorPlatformDevice::create(HDC dc,
+                                                   int width, int height) {
+  InitializeDC(dc);
+
+  // Link the SkBitmap to the current selected bitmap in the device context.
+  SkBitmap bitmap;
+  HGDIOBJ selected_bitmap = GetCurrentObject(dc, OBJ_BITMAP);
+  bool succeeded = false;
+  if (selected_bitmap != NULL) {
+    BITMAP bitmap_data;
+    if (GetObject(selected_bitmap, sizeof(BITMAP), &bitmap_data) ==
+        sizeof(BITMAP)) {
+      // The context has a bitmap attached. Attach our SkBitmap to it.
+      // Warning: If the bitmap gets unselected from the HDC,
+      // VectorPlatformDevice has no way to detect this, so the HBITMAP could be
+      // released while SkBitmap still has a reference to it. Be cautious.
+      if (width == bitmap_data.bmWidth &&
+          height == bitmap_data.bmHeight) {
+        bitmap.setConfig(SkBitmap::kARGB_8888_Config,
+                         bitmap_data.bmWidth,
+                         bitmap_data.bmHeight,
+                         bitmap_data.bmWidthBytes);
+        bitmap.setPixels(bitmap_data.bmBits);
+        succeeded = true;
+      }
+    }
+  }
+
+  if (!succeeded)
+    bitmap.setConfig(SkBitmap::kARGB_8888_Config, width, height);
+
+  return new VectorPlatformDevice(dc, bitmap);
+}
+
+VectorPlatformDevice::VectorPlatformDevice(HDC dc, const SkBitmap& bitmap)
+    : PlatformDevice(bitmap),
+      hdc_(dc),
+      previous_brush_(NULL),
+      previous_pen_(NULL) {
+  transform_.reset();
+}
+
+VectorPlatformDevice::~VectorPlatformDevice() {
+  SkASSERT(previous_brush_ == NULL);
+  SkASSERT(previous_pen_ == NULL);
+}
+
+
+void VectorPlatformDevice::drawPaint(const SkDraw& draw, const SkPaint& paint) {
+  // TODO(maruel):  Bypass the current transformation matrix.
+  SkRect rect;
+  rect.fLeft = 0;
+  rect.fTop = 0;
+  rect.fRight = SkIntToScalar(width() + 1);
+  rect.fBottom = SkIntToScalar(height() + 1);
+  drawRect(draw, rect, paint);
+}
+
+void VectorPlatformDevice::drawPoints(const SkDraw& draw,
+                                      SkCanvas::PointMode mode,
+                                      size_t count,
+                                      const SkPoint pts[],
+                                      const SkPaint& paint) {
+  if (!count)
+    return;
+
+  if (mode == SkCanvas::kPoints_PointMode) {
+    SkASSERT(false);
+    return;
+  }
+
+  SkPaint tmp_paint(paint);
+  tmp_paint.setStyle(SkPaint::kStroke_Style);
+
+  // Draw a path instead.
+  SkPath path;
+  switch (mode) {
+    case SkCanvas::kLines_PointMode:
+      if (count % 2) {
+        SkASSERT(false);
+        return;
+      }
+      for (size_t i = 0; i < count / 2; ++i) {
+        path.moveTo(pts[2 * i]);
+        path.lineTo(pts[2 * i + 1]);
+      }
+      break;
+    case SkCanvas::kPolygon_PointMode:
+      path.moveTo(pts[0]);
+      for (size_t i = 1; i < count; ++i) {
+        path.lineTo(pts[i]);
+      }
+      break;
+    default:
+      SkASSERT(false);
+      return;
+  }
+  // Draw the calculated path.
+  drawPath(draw, path, tmp_paint);
+}
+
+void VectorPlatformDevice::drawRect(const SkDraw& draw,
+                                    const SkRect& rect,
+                                    const SkPaint& paint) {
+  if (paint.getPathEffect()) {
+    // Draw a path instead.
+    SkPath path_orginal;
+    path_orginal.addRect(rect);
+
+    // Apply the path effect to the rect.
+    SkPath path_modified;
+    paint.getFillPath(path_orginal, &path_modified);
+
+    // Removes the path effect from the temporary SkPaint object.
+    SkPaint paint_no_effet(paint);
+    paint_no_effet.setPathEffect(NULL)->safeUnref();
+
+    // Draw the calculated path.
+    drawPath(draw, path_modified, paint_no_effet);
+    return;
+  }
+
+  if (!ApplyPaint(paint)) {
+    return;
+  }
+  HDC dc = getBitmapDC();
+  if (!Rectangle(dc, SkScalarRound(rect.fLeft),
+                 SkScalarRound(rect.fTop),
+                 SkScalarRound(rect.fRight),
+                 SkScalarRound(rect.fBottom))) {
+    SkASSERT(false);
+  }
+  Cleanup();
+}
+
+void VectorPlatformDevice::drawPath(const SkDraw& draw,
+                                    const SkPath& path,
+                                    const SkPaint& paint) {
+  if (paint.getPathEffect()) {
+    // Apply the path effect forehand.
+    SkPath path_modified;
+    paint.getFillPath(path, &path_modified);
+
+    // Removes the path effect from the temporary SkPaint object.
+    SkPaint paint_no_effet(paint);
+    paint_no_effet.setPathEffect(NULL)->safeUnref();
+
+    // Draw the calculated path.
+    drawPath(draw, path_modified, paint_no_effet);
+    return;
+  }
+
+  if (!ApplyPaint(paint)) {
+    return;
+  }
+  HDC dc = getBitmapDC();
+  PlatformDevice::LoadPathToDC(dc, path);
+  switch (paint.getStyle()) {
+    case SkPaint::kFill_Style: {
+      BOOL res = StrokeAndFillPath(dc);
+      SkASSERT(res != 0);
+      break;
+    }
+    case SkPaint::kStroke_Style: {
+      BOOL res = StrokePath(dc);
+      SkASSERT(res != 0);
+      break;
+    }
+    case SkPaint::kStrokeAndFill_Style: {
+      BOOL res = StrokeAndFillPath(dc);
+      SkASSERT(res != 0);
+      break;
+    }
+    default:
+      SkASSERT(false);
+      break;
+  }
+  Cleanup();
+}
+
+void VectorPlatformDevice::drawBitmap(const SkDraw& draw,
+                                      const SkBitmap& bitmap,
+                                      const SkMatrix& matrix,
+                                      const SkPaint& paint) {
+  // Load the temporary matrix. This is what will translate, rotate and resize
+  // the bitmap.
+  SkMatrix actual_transform(transform_);
+  actual_transform.preConcat(matrix);
+  LoadTransformToDC(hdc_, actual_transform);
+
+  InternalDrawBitmap(bitmap, 0, 0, paint);
+
+  // Restore the original matrix.
+  LoadTransformToDC(hdc_, transform_);
+}
+
+void VectorPlatformDevice::drawSprite(const SkDraw& draw,
+                                      const SkBitmap& bitmap,
+                                      int x, int y,
+                                      const SkPaint& paint) {
+  SkMatrix identity;
+  identity.reset();
+  LoadTransformToDC(hdc_, identity);
+
+  InternalDrawBitmap(bitmap, x, y, paint);
+
+  // Restore the original matrix.
+  LoadTransformToDC(hdc_, transform_);
+}
+
+void VectorPlatformDevice::drawText(const SkDraw& draw,
+                                    const void* text,
+                                    size_t byteLength,
+                                    SkScalar x,
+                                    SkScalar y,
+                                    const SkPaint& paint) {
+  // This function isn't used in the code. Verify this assumption.
+  SkASSERT(false);
+}
+
+void VectorPlatformDevice::drawPosText(const SkDraw& draw,
+                                       const void* text,
+                                       size_t len,
+                                       const SkScalar pos[],
+                                       SkScalar constY,
+                                       int scalarsPerPos,
+                                       const SkPaint& paint) {
+  // This function isn't used in the code. Verify this assumption.
+  SkASSERT(false);
+}
+
+void VectorPlatformDevice::drawTextOnPath(const SkDraw& draw,
+                                          const void* text,
+                                          size_t len,
+                                          const SkPath& path,
+                                          const SkMatrix* matrix,
+                                          const SkPaint& paint) {
+  // This function isn't used in the code. Verify this assumption.
+  SkASSERT(false);
+}
+
+void VectorPlatformDevice::drawVertices(const SkDraw& draw,
+                                        SkCanvas::VertexMode vmode,
+                                        int vertexCount,
+                                        const SkPoint vertices[],
+                                        const SkPoint texs[],
+                                        const SkColor colors[],
+                                        SkXfermode* xmode,
+                                        const uint16_t indices[],
+                                        int indexCount,
+                                        const SkPaint& paint) {
+  // This function isn't used in the code. Verify this assumption.
+  SkASSERT(false);
+}
+
+void VectorPlatformDevice::drawDevice(const SkDraw& draw,
+                                      SkDevice* device,
+                                      int x,
+                                      int y,
+                                      const SkPaint& paint) {
+  // TODO(maruel):  http://b/1183870 Playback the EMF buffer at printer's dpi if
+  // it is a vectorial device.
+  drawSprite(draw, device->accessBitmap(false), x, y, paint);
+}
+
+bool VectorPlatformDevice::ApplyPaint(const SkPaint& paint) {
+  // Note: The goal here is to transfert the SkPaint's state to the HDC's state.
+  // This function does not execute the SkPaint drawing commands. These should
+  // be executed in drawPaint().
+
+  SkPaint::Style style = paint.getStyle();
+  if (!paint.getAlpha())
+    style = SkPaint::kStyleCount;
+
+  switch (style) {
+    case SkPaint::kFill_Style:
+      if (!CreateBrush(true, paint) ||
+          !CreatePen(false, paint))
+        return false;
+      break;
+    case SkPaint::kStroke_Style:
+      if (!CreateBrush(false, paint) ||
+          !CreatePen(true, paint))
+        return false;
+      break;
+    case SkPaint::kStrokeAndFill_Style:
+      if (!CreateBrush(true, paint) ||
+          !CreatePen(true, paint))
+        return false;
+      break;
+    default:
+      if (!CreateBrush(false, paint) ||
+          !CreatePen(false, paint))
+        return false;
+      break;
+  }
+
+  /*
+  getFlags();
+    isAntiAlias();
+    isDither()
+    isLinearText()
+    isSubpixelText()
+    isUnderlineText()
+    isStrikeThruText()
+    isFakeBoldText()
+    isDevKernText()
+    isFilterBitmap()
+
+  // Skia's text is not used. This should be fixed.
+  getTextAlign()
+  getTextScaleX()
+  getTextSkewX()
+  getTextEncoding()
+  getFontMetrics()
+  getFontSpacing()
+  */
+
+  // BUG 1094907: Implement shaders. Shaders currently in use:
+  //  SkShader::CreateBitmapShader
+  //  SkGradientShader::CreateRadial
+  //  SkGradientShader::CreateLinear
+  // SkASSERT(!paint.getShader());
+
+  // http://b/1106647 Implement loopers and mask filter. Looper currently in
+  // use:
+  //   SkBlurDrawLooper is used for shadows.
+  // SkASSERT(!paint.getLooper());
+  // SkASSERT(!paint.getMaskFilter());
+
+  // http://b/1165900 Implement xfermode.
+  // SkASSERT(!paint.getXfermode());
+
+  // The path effect should be processed before arriving here.
+  SkASSERT(!paint.getPathEffect());
+
+  // These aren't used in the code. Verify this assumption.
+  SkASSERT(!paint.getColorFilter());
+  SkASSERT(!paint.getRasterizer());
+  // Reuse code to load Win32 Fonts.
+  SkASSERT(!paint.getTypeface());
+  return true;
+}
+
+void VectorPlatformDevice::setMatrixClip(const SkMatrix& transform,
+                                 const SkRegion& region) {
+  transform_ = transform;
+  LoadTransformToDC(hdc_, transform_);
+  clip_region_ = region;
+  if (!clip_region_.isEmpty())
+    LoadClipRegion();
+}
+
+void VectorPlatformDevice::drawToHDC(HDC dc, int x, int y,
+                                     const RECT* src_rect) {
+  SkASSERT(false);
+}
+
+void VectorPlatformDevice::LoadClipRegion() {
+  SkMatrix t;
+  t.reset();
+  LoadClippingRegionToDC(hdc_, clip_region_, t);
+}
+
+bool VectorPlatformDevice::CreateBrush(bool use_brush, COLORREF color) {
+  SkASSERT(previous_brush_ == NULL);
+  // We can't use SetDCBrushColor() or DC_BRUSH when drawing to a EMF buffer.
+  // SetDCBrushColor() calls are not recorded at all and DC_BRUSH will use
+  // WHITE_BRUSH instead.
+
+  if (!use_brush) {
+    // Set the transparency.
+    if (0 == SetBkMode(hdc_, TRANSPARENT)) {
+      SkASSERT(false);
+      return false;
+    }
+
+    // Select the NULL brush.
+    previous_brush_ = SelectObject(GetStockObject(NULL_BRUSH));
+    return previous_brush_ != NULL;
+  }
+
+  // Set the opacity.
+  if (0 == SetBkMode(hdc_, OPAQUE)) {
+    SkASSERT(false);
+    return false;
+  }
+
+  // Create and select the brush.
+  previous_brush_ = SelectObject(CreateSolidBrush(color));
+  return previous_brush_ != NULL;
+}
+
+bool VectorPlatformDevice::CreatePen(bool use_pen,
+                                     COLORREF color,
+                                     int stroke_width,
+                                     float stroke_miter,
+                                     DWORD pen_style) {
+  SkASSERT(previous_pen_ == NULL);
+  // We can't use SetDCPenColor() or DC_PEN when drawing to a EMF buffer.
+  // SetDCPenColor() calls are not recorded at all and DC_PEN will use BLACK_PEN
+  // instead.
+
+  // No pen case
+  if (!use_pen) {
+    previous_pen_ = SelectObject(GetStockObject(NULL_PEN));
+    return previous_pen_ != NULL;
+  }
+
+  // Use the stock pen if the stroke width is 0.
+  if (stroke_width == 0) {
+    // Create a pen with the right color.
+    previous_pen_ = SelectObject(::CreatePen(PS_SOLID, 0, color));
+    return previous_pen_ != NULL;
+  }
+
+  // Load a custom pen.
+  LOGBRUSH brush;
+  brush.lbStyle = BS_SOLID;
+  brush.lbColor = color;
+  brush.lbHatch = 0;
+  HPEN pen = ExtCreatePen(pen_style, stroke_width, &brush, 0, NULL);
+  SkASSERT(pen != NULL);
+  previous_pen_ = SelectObject(pen);
+  if (previous_pen_ == NULL)
+    return false;
+
+  if (!SetMiterLimit(hdc_, stroke_miter, NULL)) {
+    SkASSERT(false);
+    return false;
+  }
+  return true;
+}
+
+void VectorPlatformDevice::Cleanup() {
+  if (previous_brush_) {
+    HGDIOBJ result = SelectObject(previous_brush_);
+    previous_brush_ = NULL;
+    if (result) {
+      BOOL res = DeleteObject(result);
+      SkASSERT(res != 0);
+    }
+  }
+  if (previous_pen_) {
+    HGDIOBJ result = SelectObject(previous_pen_);
+    previous_pen_ = NULL;
+    if (result) {
+      BOOL res = DeleteObject(result);
+      SkASSERT(res != 0);
+    }
+  }
+  // Remove any loaded path from the context.
+  AbortPath(hdc_);
+}
+
+HGDIOBJ VectorPlatformDevice::SelectObject(HGDIOBJ object) {
+  HGDIOBJ result = ::SelectObject(hdc_, object);
+  SkASSERT(result != HGDI_ERROR);
+  if (result == HGDI_ERROR)
+    return NULL;
+  return result;
+}
+
+bool VectorPlatformDevice::CreateBrush(bool use_brush, const SkPaint& paint) {
+  // Make sure that for transparent color, no brush is used.
+  if (paint.getAlpha() == 0) {
+    // Test if it ever happen.
+    SkASSERT(false);
+    use_brush = false;
+  }
+
+  return CreateBrush(use_brush, SkColorToCOLORREF(paint.getColor()));
+}
+
+bool VectorPlatformDevice::CreatePen(bool use_pen, const SkPaint& paint) {
+  // Make sure that for transparent color, no pen is used.
+  if (paint.getAlpha() == 0) {
+    // Test if it ever happen.
+    SkASSERT(false);
+    use_pen = false;
+  }
+
+  DWORD pen_style = PS_GEOMETRIC | PS_SOLID;
+  switch (paint.getStrokeJoin()) {
+    case SkPaint::kMiter_Join:
+      // Connects path segments with a sharp join.
+      pen_style |= PS_JOIN_MITER;
+      break;
+    case SkPaint::kRound_Join:
+      // Connects path segments with a round join.
+      pen_style |= PS_JOIN_ROUND;
+      break;
+    case SkPaint::kBevel_Join:
+      // Connects path segments with a flat bevel join.
+      pen_style |= PS_JOIN_BEVEL;
+      break;
+    default:
+      SkASSERT(false);
+      break;
+  }
+  switch (paint.getStrokeCap()) {
+    case SkPaint::kButt_Cap:
+      // Begin/end contours with no extension.
+      pen_style |= PS_ENDCAP_FLAT;
+      break;
+    case SkPaint::kRound_Cap:
+      // Begin/end contours with a semi-circle extension.
+      pen_style |= PS_ENDCAP_ROUND;
+      break;
+    case SkPaint::kSquare_Cap:
+      // Begin/end contours with a half square extension.
+      pen_style |= PS_ENDCAP_SQUARE;
+      break;
+    default:
+      SkASSERT(false);
+      break;
+  }
+
+  return CreatePen(use_pen,
+                   SkColorToCOLORREF(paint.getColor()),
+                   SkScalarRound(paint.getStrokeWidth()),
+                   paint.getStrokeMiter(),
+                   pen_style);
+}
+
+void VectorPlatformDevice::InternalDrawBitmap(const SkBitmap& bitmap,
+                                              int x, int y,
+                                              const SkPaint& paint) {
+  unsigned char alpha = paint.getAlpha();
+  if (alpha == 0)
+    return;
+
+  bool is_translucent;
+  if (alpha != 255) {
+    // ApplyPaint expect an opaque color.
+    SkPaint tmp_paint(paint);
+    tmp_paint.setAlpha(255);
+    if (!ApplyPaint(tmp_paint))
+      return;
+    is_translucent = true;
+  } else {
+    if (!ApplyPaint(paint))
+      return;
+    is_translucent = false;
+  }
+  int src_size_x = bitmap.width();
+  int src_size_y = bitmap.height();
+  if (!src_size_x || !src_size_y)
+    return;
+
+  // Create a BMP v4 header that we can serialize.
+  BITMAPV4HEADER bitmap_header;
+  gfx::CreateBitmapV4Header(src_size_x, src_size_y, &bitmap_header);
+  HDC dc = getBitmapDC();
+  SkAutoLockPixels lock(bitmap);
+  SkASSERT(bitmap.getConfig() == SkBitmap::kARGB_8888_Config);
+  const uint32_t* pixels = static_cast<const uint32_t*>(bitmap.getPixels());
+  if (pixels == NULL) {
+    SkASSERT(false);
+    return;
+  }
+
+  if (!is_translucent) {
+    int row_length = bitmap.rowBytesAsPixels();
+    // There is no quick way to determine if an image is opaque.
+    for (int y2 = 0; y2 < src_size_y; ++y2) {
+      for (int x2 = 0; x2 < src_size_x; ++x2) {
+        if (SkColorGetA(pixels[(y2 * row_length) + x2]) != 255) {
+          is_translucent = true;
+          y2 = src_size_y;
+          break;
+        }
+      }
+    }
+  }
+
+  BITMAPINFOHEADER hdr;
+  gfx::CreateBitmapHeader(src_size_x, src_size_y, &hdr);
+  if (is_translucent) {
+    // The image must be loaded as a bitmap inside a device context.
+    HDC bitmap_dc = ::CreateCompatibleDC(dc);
+    void* bits = NULL;
+    HBITMAP hbitmap = ::CreateDIBSection(
+        bitmap_dc, reinterpret_cast<const BITMAPINFO*>(&hdr),
+        DIB_RGB_COLORS, &bits, NULL, 0);
+    memcpy(bits, pixels, bitmap.getSize());
+    SkASSERT(hbitmap);
+    HGDIOBJ old_bitmap = ::SelectObject(bitmap_dc, hbitmap);
+
+    // After some analysis of IE7's behavior, this is the thing to do. I was
+    // sure IE7 was doing so kind of bitmasking due to the way translucent image
+    // where renderered but after some windbg tracing, it is being done by the
+    // printer driver after all (mostly HP printers). IE7 always use AlphaBlend
+    // for bitmasked images. The trick seems to switch the stretching mode in
+    // what the driver expects.
+    DWORD previous_mode = GetStretchBltMode(dc);
+    BOOL result = SetStretchBltMode(dc, COLORONCOLOR);
+    SkASSERT(result);
+    // Note that this function expect premultiplied colors (!)
+    BLENDFUNCTION blend_function = {AC_SRC_OVER, 0, alpha, AC_SRC_ALPHA};
+    result = GdiAlphaBlend(dc,
+                           x, y,  // Destination origin.
+                           src_size_x, src_size_y,  // Destination size.
+                           bitmap_dc,
+                           0, 0,  // Source origin.
+                           src_size_x, src_size_y,  // Source size.
+                           blend_function);
+    SkASSERT(result);
+    result = SetStretchBltMode(dc, previous_mode);
+    SkASSERT(result);
+
+    ::SelectObject(bitmap_dc, static_cast<HBITMAP>(old_bitmap));
+    DeleteObject(hbitmap);
+    DeleteDC(bitmap_dc);
+  } else {
+    BOOL result = StretchDIBits(dc,
+                                x, y,  // Destination origin.
+                                src_size_x, src_size_y,
+                                0, 0,  // Source origin.
+                                src_size_x, src_size_y,  // Source size.
+                                pixels,
+                                reinterpret_cast<const BITMAPINFO*>(&hdr),
+                                DIB_RGB_COLORS,
+                                SRCCOPY);
+    SkASSERT(result);
+  }
+  Cleanup();
+}
+
+}  // namespace skia
+