ski 文本绘制

void SkCanvas::drawText(const void* text, size_t byteLength,
1883                         SkScalar x, SkScalar y, const SkPaint& paint) {
1884     CHECK_SHADER_NOSETCONTEXT(paint);
1885
1886     LOOPER_BEGIN(paint, SkDrawFilter::kText_Type)
1887
1888     while (iter.next()) {
1889         SkDeviceFilteredPaint dfp(iter.fDevice, looper.paint());
1890         iter.fDevice->drawText(iter, text, byteLength, x, y, dfp.paint());
1891         DrawTextDecorations(iter, dfp.paint(),                                                                                                                               
1892                             static_cast<const char*>(text), byteLength, x, y);
1893     }
1894
1895     LOOPER_END