enum Part {

  kScrollbarDownArrow,

  kScrollbarLeftArrow,

  kScrollbarRightArrow,

  kScrollbarUpArrow,

};

​

// Parameters

SkColor backgroundColor = SK_ColorWHITE;

SkColor borderColor = SK_ColorLTGRAY;

SkColor foregroundColor = SK_ColorBLACK;

int scrollbarSize = 15;

​

// Implementation (set only one)

#define IMPL_CURRENT 0

#define IMPL_1911973002_PS5 1

​

#if IMPL_CURRENT

​

void DrawArrow(SkCanvas* canvas, Part direction, SkIRect rect) {

  int width_middle, length_middle;

  if (direction == kScrollbarUpArrow || direction == kScrollbarDownArrow) {

    width_middle = rect.width() / 2 + 1;

    length_middle = rect.height() / 2 + 1;

  } else {

    length_middle = rect.width() / 2 + 1;

    width_middle = rect.height() / 2 + 1;

  }

​

  SkPaint paint;

  paint.setColor(foregroundColor);

  paint.setAntiAlias(false);

  paint.setStyle(SkPaint::kFill_Style);

​

  SkPath path;

  // The constants in this block of code are hand-tailored to produce good

  // looking arrows without anti-aliasing.

  switch (direction) {

    case kScrollbarUpArrow:

      path.moveTo(rect.x() + width_middle - 4, rect.y() + length_middle + 2);

      path.rLineTo(7, 0);

      path.rLineTo(-4, -4);

      break;

    case kScrollbarDownArrow:

      path.moveTo(rect.x() + width_middle - 4, rect.y() + length_middle - 3);

      path.rLineTo(7, 0);

      path.rLineTo(-4, 4);

      break;

    case kScrollbarRightArrow:

      path.moveTo(rect.x() + length_middle - 3, rect.y() + width_middle - 4);

      path.rLineTo(0, 7);

      path.rLineTo(4, -4);

      break;

    case kScrollbarLeftArrow:

      path.moveTo(rect.x() + length_middle + 1, rect.y() + width_middle - 5);

      path.rLineTo(0, 9);

      path.rLineTo(-4, -4);

      break;

    default:

      break;

  }

  path.close();

  canvas->drawPath(path, paint);

}

​

#elif IMPL_1911973002_PS5

​

void DrawArrow(SkCanvas* canvas, Part direction, SkIRect rect) {

  SkPaint paint;

  paint.setColor(foregroundColor);

  paint.setAntiAlias(false);

​

  SkIRect bounding_rect(rect);

  const int padding_width = ceil(rect.width() / 4.f);

  const int padding_height = ceil(rect.height() / 4.f);

  bounding_rect.inset(padding_width, padding_height);

  const SkIPoint center = SkIPoint::Make(bounding_rect.centerX(), bounding_rect.centerY());

​

  SkPath path;

  SkMatrix transform;

  transform.setIdentity();

  if (direction == kScrollbarUpArrow || direction == kScrollbarDownArrow) {

    int arrow_altitude = bounding_rect.height() / 2 + 1;

    path.moveTo(bounding_rect.x(), bounding_rect.y() + bounding_rect.height());

    path.rLineTo(bounding_rect.width(), 0);

    path.rLineTo(-bounding_rect.width() / 2.0f, -arrow_altitude);

    path.close();

    path.offset(0, -arrow_altitude / 2 + 1);

    if (direction == kScrollbarDownArrow) {

      path.offset(0, -1);

      transform.setScale(1, -1, center.x(), center.y());

    }

  } else {

    int arrow_altitude = bounding_rect.width() / 2 + 1;

    path.moveTo(bounding_rect.x(), bounding_rect.y());

    path.rLineTo(0, bounding_rect.height());

    path.rLineTo(arrow_altitude, -bounding_rect.height() / 2.0f);

    path.close();

    path.offset(arrow_altitude / 2, 0);

    if (direction == kScrollbarLeftArrow) {

      path.offset(-1, 0);

      transform.setScale(-1, 1, center.x(), center.y());

    }

  }

  path.transform(transform);

​

  canvas->drawPath(path, paint);

}

​

#endif

​

void DrawArrowButton(SkCanvas* canvas, Part direction, SkIRect rect) {

  SkPaint borderPaint;

  borderPaint.setStyle(SkPaint::kStroke_Style);

  borderPaint.setColor(borderColor);

  canvas->drawRect(SkRect::Make(rect), borderPaint);

  DrawArrow(canvas, direction, rect);

}

​

void draw(SkCanvas* canvas) {

  canvas->clear(backgroundColor);

  DrawArrowButton(canvas, kScrollbarUpArrow, SkIRect::MakeXYWH(0, 0, scrollbarSize, scrollbarSize));

  DrawArrowButton(canvas, kScrollbarDownArrow, SkIRect::MakeXYWH(0, scrollbarSize, scrollbarSize, scrollbarSize));

  DrawArrowButton(canvas, kScrollbarLeftArrow, SkIRect::MakeXYWH(scrollbarSize, 0, scrollbarSize, scrollbarSize));

  DrawArrowButton(canvas, kScrollbarRightArrow, SkIRect::MakeXYWH(2 * scrollbarSize, 0, scrollbarSize, scrollbarSize));

}