func()

in draw/impl.go [3834:4008]
160 lines of code
32 McCabe index (conditional complexity)

func (ablInterpolator) transform_RGBA_YCbCr440_Src(dst *image.RGBA, dr, adr image.Rectangle, d2s *f64.Aff3, src *image.YCbCr, sr image.Rectangle, bias image.Point, opts *Options) {
	for dy := int32(adr.Min.Y); dy < int32(adr.Max.Y); dy++ {
		dyf := float64(dr.Min.Y+int(dy)) + 0.5
		d := (dr.Min.Y+int(dy)-dst.Rect.Min.Y)*dst.Stride + (dr.Min.X+adr.Min.X-dst.Rect.Min.X)*4
		for dx := int32(adr.Min.X); dx < int32(adr.Max.X); dx, d = dx+1, d+4 {
			dxf := float64(dr.Min.X+int(dx)) + 0.5
			sx := d2s[0]*dxf + d2s[1]*dyf + d2s[2]
			sy := d2s[3]*dxf + d2s[4]*dyf + d2s[5]
			if !(image.Point{int(sx) + bias.X, int(sy) + bias.Y}).In(sr) {
				continue
			}

			sx -= 0.5
			sx0 := int(sx)
			xFrac0 := sx - float64(sx0)
			xFrac1 := 1 - xFrac0
			sx0 += bias.X
			sx1 := sx0 + 1
			if sx0 < sr.Min.X {
				sx0, sx1 = sr.Min.X, sr.Min.X
				xFrac0, xFrac1 = 0, 1
			} else if sx1 >= sr.Max.X {
				sx0, sx1 = sr.Max.X-1, sr.Max.X-1
				xFrac0, xFrac1 = 1, 0
			}

			sy -= 0.5
			sy0 := int(sy)
			yFrac0 := sy - float64(sy0)
			yFrac1 := 1 - yFrac0
			sy0 += bias.Y
			sy1 := sy0 + 1
			if sy0 < sr.Min.Y {
				sy0, sy1 = sr.Min.Y, sr.Min.Y
				yFrac0, yFrac1 = 0, 1
			} else if sy1 >= sr.Max.Y {
				sy0, sy1 = sr.Max.Y-1, sr.Max.Y-1
				yFrac0, yFrac1 = 1, 0
			}

			s00i := (sy0-src.Rect.Min.Y)*src.YStride + (sx0 - src.Rect.Min.X)
			s00j := ((sy0)/2-src.Rect.Min.Y/2)*src.CStride + (sx0 - src.Rect.Min.X)

			// This is an inline version of image/color/ycbcr.go's YCbCr.RGBA method.
			s00yy1 := int(src.Y[s00i]) * 0x10101
			s00cb1 := int(src.Cb[s00j]) - 128
			s00cr1 := int(src.Cr[s00j]) - 128
			s00ru := (s00yy1 + 91881*s00cr1) >> 8
			s00gu := (s00yy1 - 22554*s00cb1 - 46802*s00cr1) >> 8
			s00bu := (s00yy1 + 116130*s00cb1) >> 8
			if s00ru < 0 {
				s00ru = 0
			} else if s00ru > 0xffff {
				s00ru = 0xffff
			}
			if s00gu < 0 {
				s00gu = 0
			} else if s00gu > 0xffff {
				s00gu = 0xffff
			}
			if s00bu < 0 {
				s00bu = 0
			} else if s00bu > 0xffff {
				s00bu = 0xffff
			}

			s00r := float64(s00ru)
			s00g := float64(s00gu)
			s00b := float64(s00bu)
			s10i := (sy0-src.Rect.Min.Y)*src.YStride + (sx1 - src.Rect.Min.X)
			s10j := ((sy0)/2-src.Rect.Min.Y/2)*src.CStride + (sx1 - src.Rect.Min.X)

			// This is an inline version of image/color/ycbcr.go's YCbCr.RGBA method.
			s10yy1 := int(src.Y[s10i]) * 0x10101
			s10cb1 := int(src.Cb[s10j]) - 128
			s10cr1 := int(src.Cr[s10j]) - 128
			s10ru := (s10yy1 + 91881*s10cr1) >> 8
			s10gu := (s10yy1 - 22554*s10cb1 - 46802*s10cr1) >> 8
			s10bu := (s10yy1 + 116130*s10cb1) >> 8
			if s10ru < 0 {
				s10ru = 0
			} else if s10ru > 0xffff {
				s10ru = 0xffff
			}
			if s10gu < 0 {
				s10gu = 0
			} else if s10gu > 0xffff {
				s10gu = 0xffff
			}
			if s10bu < 0 {
				s10bu = 0
			} else if s10bu > 0xffff {
				s10bu = 0xffff
			}

			s10r := float64(s10ru)
			s10g := float64(s10gu)
			s10b := float64(s10bu)
			s10r = xFrac1*s00r + xFrac0*s10r
			s10g = xFrac1*s00g + xFrac0*s10g
			s10b = xFrac1*s00b + xFrac0*s10b
			s01i := (sy1-src.Rect.Min.Y)*src.YStride + (sx0 - src.Rect.Min.X)
			s01j := ((sy1)/2-src.Rect.Min.Y/2)*src.CStride + (sx0 - src.Rect.Min.X)

			// This is an inline version of image/color/ycbcr.go's YCbCr.RGBA method.
			s01yy1 := int(src.Y[s01i]) * 0x10101
			s01cb1 := int(src.Cb[s01j]) - 128
			s01cr1 := int(src.Cr[s01j]) - 128
			s01ru := (s01yy1 + 91881*s01cr1) >> 8
			s01gu := (s01yy1 - 22554*s01cb1 - 46802*s01cr1) >> 8
			s01bu := (s01yy1 + 116130*s01cb1) >> 8
			if s01ru < 0 {
				s01ru = 0
			} else if s01ru > 0xffff {
				s01ru = 0xffff
			}
			if s01gu < 0 {
				s01gu = 0
			} else if s01gu > 0xffff {
				s01gu = 0xffff
			}
			if s01bu < 0 {
				s01bu = 0
			} else if s01bu > 0xffff {
				s01bu = 0xffff
			}

			s01r := float64(s01ru)
			s01g := float64(s01gu)
			s01b := float64(s01bu)
			s11i := (sy1-src.Rect.Min.Y)*src.YStride + (sx1 - src.Rect.Min.X)
			s11j := ((sy1)/2-src.Rect.Min.Y/2)*src.CStride + (sx1 - src.Rect.Min.X)

			// This is an inline version of image/color/ycbcr.go's YCbCr.RGBA method.
			s11yy1 := int(src.Y[s11i]) * 0x10101
			s11cb1 := int(src.Cb[s11j]) - 128
			s11cr1 := int(src.Cr[s11j]) - 128
			s11ru := (s11yy1 + 91881*s11cr1) >> 8
			s11gu := (s11yy1 - 22554*s11cb1 - 46802*s11cr1) >> 8
			s11bu := (s11yy1 + 116130*s11cb1) >> 8
			if s11ru < 0 {
				s11ru = 0
			} else if s11ru > 0xffff {
				s11ru = 0xffff
			}
			if s11gu < 0 {
				s11gu = 0
			} else if s11gu > 0xffff {
				s11gu = 0xffff
			}
			if s11bu < 0 {
				s11bu = 0
			} else if s11bu > 0xffff {
				s11bu = 0xffff
			}

			s11r := float64(s11ru)
			s11g := float64(s11gu)
			s11b := float64(s11bu)
			s11r = xFrac1*s01r + xFrac0*s11r
			s11g = xFrac1*s01g + xFrac0*s11g
			s11b = xFrac1*s01b + xFrac0*s11b
			s11r = yFrac1*s10r + yFrac0*s11r
			s11g = yFrac1*s10g + yFrac0*s11g
			s11b = yFrac1*s10b + yFrac0*s11b
			pr := uint32(s11r)
			pg := uint32(s11g)
			pb := uint32(s11b)
			dst.Pix[d+0] = uint8(pr >> 8)
			dst.Pix[d+1] = uint8(pg >> 8)
			dst.Pix[d+2] = uint8(pb >> 8)
			dst.Pix[d+3] = 0xff
		}
	}
}